201502---Issue-127---February-2015

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201502---Issue-127---February-2015

OBSERVERTHE AUSTRALIAN ASTRONOMICAL OBSERVATORY NEWSLETTER NUMBER 126 FEBRUARY 2015Celebrating40 Years ofAAT ScienceHuntsman Eye Sees Deep | SAMI unveils galaxy relation | AAO Shaw Visitor Scheme


DIRECTOR’S MESSAGEDirector’s messageWarrick CouchAs we move into 2015 and put 2014behind us, it is a time when we arevery mindful of the AAO’s past and itsrich and distinguished track record ofscientific discovery and technologicalinnovation, but also one when we needto keep a keen eye on its future.The year that was, 2014, marked two highlysignificant anniversaries for the AAO: 40years since ‘first light’ was achieved on theAAT on 27 April 1974, and 40 years sincethe official inauguration (by HRH PrinceCharles) of the AAT on 16 October 1974.These two events and, more generally,2014 being the AAT’s 40th birthday year,were celebrated in a number of differentways both in Sydney and at Siding SpringObservatory. Here, the highlights wereundoubtedly the extraordinarily successful“Starfest” Open Day held at Siding Springon the long Labor Day weekend in earlyOctober – at which the AAT dome wasadorned in a stunning red ribbon, anda massive birthday cake featuring theAAT dome was cut and distributed tothe huge crowd in attendance – as wellas a public lecture on the AAO’s historyand future directions held in Sydney onthe 16 October. But as often the case,it is also the unexpected things thatwe remember about significant events,and for me there were two things inthis category. Firstly, to have so manycolleagues from our neighbouringNational Measurement Institute at NorthRyde attend the celebratory morningtea we had on the 16 October, and thegreat interest they showed in the AAT’shistory and the significance of thatparticular day. Secondly, the specialplaque commemorating the AAO’s 40years of scientific achievement that,unbeknownst to me, was made for thevisitors’ gallery in the AAT dome, andwhich I had the privilege of unveilingat our staff planning day held in earlyNovember (see photo below).As promised in the last issue of theAAO Observer, the 40th birthday themecontinues in this one with articles fromtwo very distinguished former AAO staffmembers – Russell Cannon and DavidContentsSCIENCE HIGHLIGHTSReflecting on 40 Years of AAT Operations 4Distant ‘cannibal twin’ shows how galaxies grow 9SAMI unveils a unified relation for all galaxies 10Testing HERMES radial velocity precision 12News from OzDES 14Huntsman Eye Sees Deep 19The FunnelWeb Survey: Building the HD Catalog of the 21st Century 21Adaptive Optics Experiments on the AAT 23OBSERVATORY NEWSThe AAO Shaw Visitor Scheme 25Hidden GeMS: observing with the Gemini multi-conjugate adaptive optics system 26LOCAL NEWSStarFest 2014 28Planning Day 2014 – Old and New 30ITSO Corner 32News from North Ryde 34Letter from Coonabarabran 35Front cover photo Credit: J. GaBany (Blackbird Observatory)Caption: The Umbrella Galaxy takes its name from a mysterious feature seen on the left here, that is now found to be debris from a tinygalaxy, only a 50th its size, that has been shredded apart by gravity. The image is a combination of data from the 0.5-metre BlackBirdRemote Observatory Telescope and Suprime-Cam on the 8-metre Subaru Telescope. (See Article on Page 9 of this Issue).


SCIENCE HIGHLIGHTSReflecting on 40 Years of AAT OperationsDavid Malin and Russell Cannon2014 was a year filled with celebratingthe 40th Anniversary of Australia’sbiggest optical telescope, the 4-metreAnglo-Australian Telescope, and all thespectacular observations and technologydevelopments astronomers and engineershave achieved using it. The following aretwo personal accounts of the evolutionof both the AAT and the AAO over theyears, from two AAO associates.First, we hear from David Malin (AAO,1976 - 2001) whose work with AAOrevolutionized the way humans viewthe cosmos. Next we hear from RussellCannon (AAO, 1986 - 2002), who wasbased at the Royal Observatory, Edinburghwith responsibility for the UKST and itsSky Surveys (1973-1986), then becameAAO Director (1986-1996), and continuesworking on the cutting-edge GALAHSurvey with the new HERMES instrument.The beginnings of the AATby David MalinFifty years ago research facilities forsouthern hemisphere optical astronomywere far behind those under northernskies. Despite its richness and its accessto unique objects such the Galacticcentre, the Magellanic Clouds and thefinest globular clusters, the southern skywas relatively unexplored by modernastronomers. This disparity became evenmore obvious when radio astronomybegan to flourish in Australia, resultingin the Parkes radio telescope, whichwas commissioned in the early 1960s.After much discussion, controversyand many alternative proposals fromthe astronomical communities in bothBritain and Australia, it was decidedto build a 4-metre-class telescope atSiding Spring, the facilities to be sharedequally between astronomers from bothcountries. As readers might imagine,the sentence above is a bland outline ofa long and complex process and not alittle controversy, much of which is setout in Gascoigne, Proust and RobinsFig. 1. Leighton's crane dominates the picture as the concrete structure of the AAT domereaches first floor level in mid-1971.Photo: Russell Cannon(1990). The Anglo-Australian TelescopeAgreement that made a bi-nationaltelescope possible was signed in 1969, butits final form was hammered out in 1972during a visit to Canberra by the then UKMinister of Science, Margaret Thatcher andher Australian counterpart at the time,Malcolm Fraser, both formidable figures.The final agreement was a unique Actof Parliament that made the AAT Boardessentially autonomous and largely freefrom political interference. This agreementformed an excellent basis for a joint Anglo-Australian facility that endured until 2010.4Australian Astronomical Observatory Newsletter - FEBRUARY 2015


SCIENCE HIGHLIGHTSFig. 2. By mid-1971, the AAT's distinctive horse-shoe bearing is assembled and awaiting the fitting of the centre section.Photo: George Searle.Construction of the AAT building began inlate 1970 and was ready for its telescopein early 1973. The design chosen for theAAT was based on the Kitt Peak 4-mMayall Telescope, extensively modified tostiffen the horseshoe, and importantly, touse a somewhat slower focal ratio for theprimary mirror, F/3.3 compared to F/2.7for the KPNO instrument. With a tripletcorrector, this provided a one-degree fieldwith a 16 arc second per mm plate-scaleat the prime focus for photography. Yearslater the slower focal ratio allowed this tobe expanded to a two-degree field for thetwo-degree field (2dF) instrument. Thedesign of both the building and telescopealso allowed for the construction oftwo coudé foci. Both of these decisionswere to have a profound influence onthe subsequent evolution of the AAT.After four years of building construction,telescope assembly and testing, thelengthy commissioning process beganin late April 1974, led by Ben Gascoigne,who was also responsible for much of theoptical design. Using the newly-installed(but unsilvered) 3.9 m mirror and thetelescope's only 'instrument' and detector,the prime focus camera and photographicplates, the first 'good' image (of theglobular cluster Omega Cen) was takenin June 1974, by Ben's co-commissioner,Roderick Willstrop. However, accordingto Ben, the first usable astronomical platewith a coated mirror was made on the4-5th of December, and it was of the SMCglobular cluster Kron 3, one of his favouriteobjects. Also recorded in the plate log asin attendance on that memorable nightwere John Rock, Peter Gillingham andPatrick Wallace. Such was the excitementin these early days that some of theseearly plates appear to have been fixedin a solution of household cleaner!Three weeks later the famous 'Ann plate'was taken, and the computer-drivenLissajou figures and raster scans tracedby the stars immediately convinceddoubters that the AAT's then-noveland largely untried computer controlsystem—and its mechanical tolerances—were the best in the world.Six months after the primary mirrorhad been installed, and before it wasaluminised, the telescope was officiallyinaugurated by Prince Charles in October1974. However, apart from prime focusphotography the telescope was woefullyunder-instrumented. This was thesituation faced the AAO's first Director,Joe Wampler, who arrived from theLick Observatory in September 1974.Fig. 3. The AAT was officially inauguratedby HRH Prince Charles in October 1974.AAT Board Chairman Sir Fred Hoyle (right)presents HRH with a disc of materialcored from the AAT's primary mirror, tocommemorate the event.Australian Astronomical Observatory Newsletter - FEBRUARY 2015 5


SCIENCE HIGHLIGHTSInstrumentation was not his only problem.Joe had to decide (with the AAT Board)where the new observatory's offices andlaboratories were going to be, SidingSpring, Canberra or Sydney, a decisionfraught with logistical and politicaldifficulties. Indeed the underlying decision— would the AAO be an observatory atall, or just a telescope with support staff— had only just been settled. Eventually,Epping was decided on for the laboratoriesand administration offices, and Joe couldconsider appointing the first scientificand other staff. The advertisement formy job, along with six other support staff,appeared in Nature in November 1974, andI turned up in Epping in mid-August 1975.Naturally, there was plenty for me todo, but that's all covered in Cannon andMalin (2011). My main impression washow helpful and friendly everyone was,though there was a definite feeling ofmaking it up as we went along. But whata remarkably interesting group of people!Among the scientific staff were JohnDanziger, Paul Murdin, Mike Penston,Bruce Peterson, Louise Turtle (neeWebster) and John Whelan. Doug Cunliffewas the AAO's legendary ExecutiveOfficer and he shared an office with Joeand his secretary in a small temporarybuilding in Epping that was also thedrawing office and electronics lab.Joe Wampler returned to Lick in early1976 and was replaced as Director byDon Morton, who had a quite differentbut very effective style of management.Apart from finessing the transition fromcommissioning to operating a major newtelescope and establishing an efficientlyrunning observatory, Joe's main legacy wasthe Robinson-Wampler Image DissectorScanner (IDS, also known affectionately asthe Wamplertron), which had immediatelyput the AAO on the astronomical map.At around this time a lot of attentionwas being devoted to the developmentof an instrument that would soondisplace the IDS. It was the Image PhotonCounting System (IPCS) developedby Alec Boksenberg's group at UCL.This consisted of an image intensifiercombined with a special TV camera, whichused event-centering logic to outputthe X, Y coordinates of each recordedphoton, with essentially no read noise.The main initial manifestation of this inAustralia was the large number of people(Boksenberg's Flying Circus) involved ingetting it to work on the telescope, anda new, large console and several new,very large computer racks in the AATcontrol-room. The Circus re-appeared,season after season as upgrades weremade. One member of the troupe wasKeith Shortridge, who enjoyed the AAO somuch that he is still on the staff. Althoughthe IPCS was mainly used attached toa spectrograph, with sufficient effort itcould be used for imaging, which led tothe first detection and imaging of theflashes of the Vela Pulsar, whose meanmagnitude is about B~24. It was thesecond pulsar whose optical flashes hadbeen recorded. The first of course was theCrab Pulsar, captured by Joe Wampler andJoe Miller, using a strobe disk! After manyimprovements and modifications and avery impressive record of discoveries,the IPCS was retired in November 1995,after almost 20 years of service.The Wamplertron and the IPCS had setan exciting tone for the AAO, which wasmaintained by the continuity and endlessinnovation of the technical and supportstaff at the telescope and in Epping. Alsoendless was the injection of new ideas andnew projects from the regular renewal ofthe short-term scientific staff, many ofwhom went on to positions of influence inastronomical positions around the world.In my mind, it is these features, combinedFig. 4. Star trails demonstrating the AAT's drive control capabilities. 'Ann' was to impress Ann Savage, who happened to be in the controlroom at the time!6Australian Astronomical Observatory Newsletter - FEBRUARY 2015


SCIENCE HIGHLIGHTSapparent that some other new sites hadspectacularly better transparency and'seeing'. Nevertheless, the AAT was ableto stay fully competitive by evolvingits suite of instruments and selectingscientific objectives that exploited itsstrengths and minimised its weaknesses.One curious corollary of having a relativelypoor climate for optical astronomycompared with the 'best' sites on earth,was that Siding Spring Mountain provideda much more comfortable workingenvironment for technical staff, manyof whom lived close to the observatory.Thus the AAO was able to develop andmaintain complicated or equipment,and to provide a high level of technicalsupport around the clock. This factor atleast partially compensated for the lowerpercentage of good observing conditions.Fig. 5. Doug Cunliffe (left) and Joe Wampler at an AAT Board meeting, March 1976.Photo: David Malinwith the fairly stable and predictablefunding environment provided by theAAT Agreement, that have made theAAO such an enduring success. And sucha wonderful place to spend 26 years.In the next contribution, Russell Cannontakes a broader view of the evolutionof the AAO and provides a briefaccount of the scientific highlights.Reference.Gascoigne, S.C.B., Proust, K.M. & Robins, M.O. TheCreation Of The Anglo-Australian Observatory,Cambridge University Press, 1990.Cannon, R.D., Malin, D.F. (eds), Celebrating AAO Past,Present Future, Commonwealth Of Australia, 2011.The Evolution of the AAOBy Russell CannonHow does one summarise the evolution ofa major international facility over 40 years?Describing a few astronomical discoveriesand technical innovations would beone way, but how do you rank the mostsignificant topics? And how do you balanceone-off spectacular events against theimpact of long-term survey projects?Sometimes a totally unexpected eventhas led to major discoveries and therapid development of new ideas andeven instruments: Supernova 1987A isan obvious example of what McCrea(1972) described as "Astronomers' Luck."At the other extreme, the mapping ofthe large scale structure of the Universedone by the 2dF Galaxy Redshift Survey(2dFGRS: e.g. Colless 2002, AAONewsletter 100) was carefully plannedfor nearly a decade while the new 2dFinstrument was designed and built,and it took almost as long to completethe survey and analyse all the data.What external factors are most significantin determining success? The quality of thetelescope is clearly fundamental: the AATwas one of the biggest and best telescopesin the world 40 years ago. However, bysome measures the power of the AAT hasincreased by three orders of magnitudesince 1975 without any major change to thebasic telescope: instrumentation, detectorsand data processing have given muchlarger gains than could have been achievedby simply building a bigger telescope.Since the 1990s, a new wave of 8-10m classtelescopes has relegated the AAT to thesecond rank and now the next generationof ~30m telescopes is taking shape.How important is site quality? Beingable to observe at Siding Spring for upto two-thirds of the time was heavenlyfor British astronomers accustomedto something closer to ten percentfrom the foggy Sussex marshes orcloudy Edinburgh, but it soon becameWhat about the management, fundingand staffing of an observatory? Formost of its life, the AAO was a bilateralinternational facility, with the Australianand British Governments each providinghalf the funds, appointing half thescientific staff and with two independenttime assignment panels each allocatinghalf of the nights. A Board of threeindividuals from each side, includingone representative from each nationalfunding agency, who collectively ownedthe AAT. This proved to be a remarkablysimple, stable and robust arrangementfor more than 30 years, leaving the stafflargely free to concentrate on keeping thetelescope working and doing cutting-edgeastronomy. The bilateral AAT Agreementnot only provided funding for the AAO,it resulted in a mutually beneficial crossfertilisationof astronomical ideas andinstrumentation expertise. In a similar way,the co-location of the AAO base in Sydneywith the CSIRO Division of Radiophysicsresulted in many successful collaborationsbetween optical and radio astronomers.In addition to those mentioned above,various other factors have interactedin complex ways to determine theoverall success of the AAO: the rise ofobservational cosmology, the launchof the Hubble Space Telescope in1990, and searches for extra-solarplanets have drastically alteredthe overall balance of our field.Australian Astronomical Observatory Newsletter - FEBRUARY 2015 7


SCIENCE HIGHLIGHTSDistant ‘cannibal twin’ shows how galaxies growHelen SimA distant ‘twin’ of the Milky Waythat is swallowing another galaxyhas opened the way to a betterunderstanding of how galaxies grow.A team led by Dr Caroline Foster of theAustralian Astronomical Observatory(AAO) has been studying the Umbrellagalaxy, so called because of its‘parasol’ of stars — the remains ofa smaller galaxy it’s consuming.The Umbrella (NGC 4651) lies 62million light-years away, in the northernconstellation of Coma Berenices.Twenty years ago, astronomers usingthe AAT identified a new ‘dwarf’ galaxy,the Sagittarius dwarf, being engulfedby our own Milky Way Galaxy.This was the first sign that the Milky Wayhad fattened up — acquired stars — bysnacking on other, smaller, galaxies.Since then, astronomers have spottedstellar streams in other galaxies.The present work is a follow-up to a 2010study, led by David Martínez-Delgado(University of Heidelberg), which usedsmall robotic telescopes to image eightisolated spiral galaxies, and found thesigns of mergers — shells, clouds andarcs of tidal debris — in six of them.That study posited that the Umbrellagalaxy’s distinctive arc was the resultof a single merger, rather than ofseveral events over time — a resultconfirmed by the present work.“Through new techniques we have beenable to measure the movements of thestars in the very distant, very faint, stellarstream in the Umbrella,” Dr Foster said.“This allows us to reconstruct the historyof the system, which we couldn’t before.”Being able to study streams this farout means that many more galaxiescan be put under the microscope, saidco-author Dr Aaron Romanowsky (SanJosé State University and Universityof California Observatories).“In turn that means we can get a handleon how often these ‘minor mergers’— an important way that galaxiesgrow — actually occur,” he said.For this work the astronomersused data from the Subaru andKeck telescopes in Hawai’i.They determined the movement of thestars in the stream by using three sets of‘tracers’: clusters of old stars (globularclusters); old, brightly glowing stars(planetary nebulae); and patches ofglowing hydrogen gas (HII regions).PublicationC. Foster, H. Lux, A.J. Romanowsky, D. Martínez-Delgado, S. Zibetti, J.A. Arnold, J.P. Brodie, R. Ciardullo,R.J. GaBany, M.R. Merrifield, N. Singh and J. Strader.“Kinematics and simulations of the stellar stream inthe halo of the Umbrella Galaxy”. MNRAS 442, 3544(2014). Download refereed preprint from http://arxiv.org/abs/1406.5511The Umbrella Galaxy with data from the0.5-metre BlackBird Remote ObservatoryTelescope and Suprime-Camon the 8-metre Subaru Telescope.Credit: R. J. GaBany (Blackbird Observatory)Australian Astronomical Observatory Newsletter – FEBRUARY 20159


SCIENCE HIGHLIGHTSSAMI unveils a unified relation for all galaxiesLuca Cortese (Centre for Astrophysics and Supercomputing, SwinburneUniversity) and the SAMI Galaxy Survey Team.Galaxies in the Universe show animpressive variety of shapes and sizes:from massive, quiescent elliptical galaxiesin the centre of clusters, to tiny starburstingdwarf irregular systems inisolation. In order to develop a properunderstanding of such heterogeneouspopulation, astronomers have beenlooking for scaling relations able to link allgalaxies despite their visual differences.Particularly powerful are the correlationsbetween dynamics and luminosity/stellarmass, such as the Tully-Fisher (Tully &Fisher 1977) and the Faber-Jackson (Faber& Jackson 1976) relations, as they link thevisible mass of a galaxy to its rotational ordispersion velocity, respectively, providingunique insights into the interplay betweenbaryonic and dark matter content.Thanks to the SAMI Galaxy Survey (Bryant et al. 2015, Allen et al. 2015, Sharp et al. 2015),currently carried out at the Anglo Australian Telescope, we finally have the first chanceto properly tackle this issue. Thus, we took advantage of the first 235 galaxies observedby SAMI in the footprint of the GAMA survey to investigate if a unified dynamical scalingrelation for galaxies of all types does indeed exist (Cortese et al. 2014). In particular,we compared the traditional stellar mass Tully-Fisher and Faber-Jackson relationswith a new dynamical scaling relation between stellar mass and total internal velocity,quantified by the S0.5 parameter (S0.5=√0.5V 2 +σ 2 ), which combines the contribution ofboth dispersion (σ) and rotational velocity (V) to the dynamical support of a galaxy.Our main findings are summarised in Fig. 1, where the stellar mass vs rotational(left), dispersion velocity (centre) and S0.5 (right) relations are presented. In thetop row, circles and triangles indicate galaxies with kinematical parameters fromstellar and gas components, respectively, while in the bottom row galaxies arecolour-coded according to their morphological type. Both rotation and dispersionvelocities have been measured within the optical effective radius of the galaxy.Unfortunately, both relations hold only foraccurately pre-selected classes of objects(i.e., inclined disks and bulge-dominatedsystems, respectively), and their scattersand slopes vary when wider ranges ofmorphologies are considered. This ismainly because, as the typical galaxy hasboth a bulge and a disk component, theuse of just the rotational or the dispersionvelocity does not provide a properestimate of the total gravitational potential.Thus, recent studies have investigatedthe possibility of bringing galaxiesof all morphologies onto the samedynamical scaling relation, by combiningthe contribution of both ordered anddisordered motions to the dynamicalsupport, with promising results (Kassinet al. 2007, Zaritsky et al. 2008, Catinellaet al. 2012). However, no work has yetbeen able to perform such analysisfor both quiescent and star-forminggalaxies at the same time, as this requiresresolved kinematics maps of both starsand gas for large samples of galaxies:something unthinkable before the dawnof integral field spectroscopic surveys.Fig. 1. The stellar mass vs. rotational (left), dispersion velocity (centre) and S0.5 (right)relations for our sample. Circles and triangles indicate stellar and gas kinematics,respectively. In the bottom row, symbols are colour-coded according to morphologicaltype: E-S0/Sa (magenta), Sa-Sb/Sc (dark green), Sc or later types (black).10Australian Astronomical Observatory Newsletter - FEBRUARY 2015


SCIENCE HIGHLIGHTSIt appears that, while the Tully-Fisher and Faber-Jackson relations show a significant scatter(mainly driven by those galaxy types that are generally excluded a priori), the S0.5 relationholds for galaxies of all types. Intriguingly, the scatter in this relation (0.1 dex in velocity)is comparable to the scatter of the pruned Tully-Fisher and Faber-Jackson relations.Moreover, from Fig.1 it emerges that the stellar mass vs. V and σ relations for gas(triangles) and stars (circles) are offset, with the gas showing larger rotationalvelocities and lower dispersions. This is even more evident in Fig. 2, where therotation and dispersion velocities of gas and stars are compared for the 62 galaxiesfor which both measurements are available. Remarkably, the S0.5 parameter of gasand stars agree very well, not only confirming that the S0.5 is a better proxy forthe total dynamical mass of a galaxy, but also justifying the simultaneous use ofboth stellar and gas measurements on the same dynamical scaling relation.Fig. 2. Comparison between rotation (left), dispersion velocities (centre) and S0.5 (right) of gas and stars, for the 62 galaxiesin our sample with both measurements available. Empty circles highlight galaxies where gas and stars have a misalignedrotation axis. In each panel, the dotted line shows the 1-to-1 relation.Our results illustrate how the combination of dispersion and rotation velocities canproduce a dynamical scaling relation which appears to be more general than, andat least as tight as any other dynamical scaling relation, representing a unique toolfor investigating the link between galaxy kinematics and baryonic content.As always, this new finding has also triggered several new questions, such as:which physical process regulates the scatter and slope of this relation? Is theS0.5 parameter the best, physically-motivated way to combine rotation andvelocity dispersion? Can we use this relation as a distance indicator?Luckily, with the completion of the SAMI survey, we will soon be able to gain furtherinsights into the origin of this new dynamical scaling relation. In the meantime, itis clear that the absence of any pre-selection in the sample not only makes theS0.5 parameter extremely promising for characterising the dynamical properties ofgalaxies, but also allows a more rigorous comparison with theoretical models.Allen, J. T. et al., 2015, MNRAS, 446, 1567Bryant, J. J. et al., 2015, MNRAS, in press (arXiv:1407.7335)Catinella, B. et al., 2012, MNRAS, 420, 1959Cortese, L. et al., 2014, ApJ, 795, L37Faber, S. M. & Jackson, R. E., 1976, ApJ, 204, 668Kassin, S. A. et al., 2007, ApJ, 660, L35Sharp, R. et al., 2015, MNRAS, 446, 1551Tully, R. B. & Fisher, J. R. 1977, A&A, 54, 661Zaritsky, D., Zabludoff, A. I., & Gonzalez, A. H. 2008, ApJ, 682, 68Australian Astronomical Observatory Newsletter - FEBRUARY 2015 11


SCIENCE HIGHLIGHTSTesting HERMES radial velocity precisionCarlos Bacigalupo (MQ), Gayandhi De Silva (AAO), Michael Ireland (ANU), Daniel Zucker (MQ)The High Efficiency and Resolution Multi-Element Spectrograph (HERMES) wasformally launched by the Minister for Industry in April 2014 (see AAO Observer,August 2014, 126, 20). The primary science driver for HERMES is the GALAHsurvey aiming to measure individual elemental abundances for ~1 million stars.However, HERMES is not limited to elemental abundance studies. In this articlewe explore the radial velocity (RV) precision possible with HERMES.Between 20-25th of August 2014, 5 part-nights of Director’s Discretionary timewere awarded to carry out observations to test the RV precision of HERMES.Three targets with well established RV variations (ρ-Tuc, HD285507, HD1581)were observed with fibres close to the centre of the CCD, which is where theinstrument performs best in terms of resolving power. The observing time availabledid not permit us to test the impact of fibre-to-fibre variations on RV precision.Summaries of the targets and observations are given in Table 1 and in Figure 1.Table 1: Summary of ObservationsTarget Type 2dF Configuration Exposure timeρ-Tucanae Spectroscopic binary Plate 0, Fibre #175 600secHD285507 Exoplanet host Plate 1, Fibre #223 1200secHD1581 RV standard Plate 0, Fibre #175 120secFigure 1: Observation schedule. Each strike represents a single exposure.ρ-Tuc is a F6V-type dwarf star and is a single-lined spectroscopic binary on a4.82d period with a semi-amplitude of 26.1 km/s (Pourbaix et al., 2004). Singlelinedbinaries show large radial velocity variations due to the presence of a stellarcompanion. Nonetheless, the associated star shows no detectable spectral lines andits presence is only inferred by the wobble it produces on the observable star.The star HD285507 is a K5 giant in the Hyades open cluster and a confirmed exoplanethost. The study by Quinn et al. (2014) shows it has a 6-day period with RV semi-amplitudeof 125.8 m/s. Exoplanet host stars wobble due to the effect of their planetary companion,and the RV signature of a planetary presence is subtle compared to a binary system.HD1581 is a F9.5 spectral type dwarf with a measured RV scatter of only1.26 m/s over 7 years of monitoring (Pepe et al., 2011), making it an ideal RVstandard star. Since we do not expect to be able to measure such minute RVvariations, we use this star as the standard of essentially zero RV variation.The basic data reduction was performedusing the 2dfdr v6.0 pipeline, whichoutputs extracted and wavelengthcorrectedspectra. A python-basedscript was used to measure therelative RV by cross-correlating eachspectrum per exposure with respectto the first observed spectrum of eachstar. This method yields relative RVvalues corresponding to the numberof observations, with the initial valuebeing 0 m/s as it is the product of crosscorrelating the first spectrum with itself.The relative barycentric velocity correctionwas applied to derive the final RVs.The relative RVs were measured forall HERMES channels except for the IRchannel, which is heavily contaminatedby telluric absorption features. Themost consistent results were seen in theBlue channel data. We plot the derivedrelative RV from the Blue channel spectraagainst Modified Julian Date for HD1581in Figure 2. The error bars represent thestandard deviation about the mean RVfor each time step. Compared to the Bluechannel data we found an average velocitydispersion of ±1 km/s in the Green andRed channels over all the measured datapoints. The source of this larger scatter inthe Green and Red data is uncertain at thisstage. A possibility is subtle instrumentaldrifting, as the cryostats in the Green andRed are known to lose vacuum withinseveral days, where as the Blue cryostatmaintains its vacuum over months.From Figure 2, we see that the relative RVsvary between ±300 m/s. Recall this targetis our RV standard with essentially zero RVvariations expected with time. Note thatthe calculated relative RVs are influencedby not only the stellar signature but alsoby instrumental and reduction effects.The wavelength calibration routine within2dfdr and the accuracy of the wavelengthcalibration source (ThXe lamp emissionlines) are only known to ~500 m/s.12Australian Astronomical Observatory Newsletter - FEBRUARY 2015


SCIENCE HIGHLIGHTSFigure 2: Relative RV vs Modified Julian Date. Values are the average of each epoch. Errorbars are the standard deviation of the set of values corresponding to each epoch.Figure 3: Relative RV vs Modified Julian Date. Data points are the average of each epochand the error bars are the standard deviation for the corresponding data.In Figures 3, and 4 we present the derivedrelative RV from the Blue channel spectraagainst MJD for HD285507 and ρ-Tucrespectively, where the error bars are thestandard deviation about the mean RVfor each time epoch. The solid line showsthe expected RV variation based on thetarget parameters from the literature.Even though the data for HD285507appear to follow the solid line, the actualRV precision is unlikely to be better than300m/s (as discussed regarding Figure1), making it impossible to measureoscillations less than this value. Howeverfor large RV oscillations as seen in ρ-Tucin Figure 4, the measured RVs match theamplitude of the expected oscillations.In conclusion, the observed 300 m/svariation for the standard star pointsto the limit of the RV precision possiblewith HERMES using the abovementionedreduction and analysis methodology.Hence the present state of affairs limits theuse of HERMES for exoplanet detectionstudies. Nonetheless, HERMES will becapable of studying stellar oscillationsof larger amplitude, for example, binarystars or seismology of giant stars. Withan improved wavelength scale modeland well-secured cryostats, it maybepossible to push HERMES RV accuracyto less than 100 m/s. HERMES RVprecision may also be improved by analternative reduction process using theensemble of stars as a simultaneousreference, which is being developed.Figure 4: Relative RV vs Modified Julian Date. Each point is the average of the measuredradial velocities in the combined blue and green channels for a given epoch and thecorresponding standard deviation from the mean defines the error bars.Australian Astronomical Observatory Newsletter - FEBRUARY 2015 13


SCIENCE HIGHLIGHTSNews from OzDESChris Lidman 1 , Filipe B. Abdalla 2 , Chris D’Andrea 3 , Chris Blake 4 , Rahul Biswas 5 , Aurelio, Carnero 6 ,Daniela Carollo 7 , Michael Childress 8,9 , Tamara M. Davis 9,10 , Karl Glazebrook 4 , Julia Gschwend 6 , AntheaKing 10 , Alex Kim 11 , Kyler Kuehn 1 , Geraint Lewis 12 , Paul Martini 13 , Dale Mudd 13 , Bob Nicho l3 , Conor R.O’Neill 9,10 , David Parkinson 10 , Andreas Papadopoulos 3 , Richard Scalzo 8 , Nick Seymour 14 , Flavia Sobreira 6 ,Rob Sharp 8 , William Wester III 2 , Chris Wolf 8 , Syed Uddin 4,9 , Fang Yuan 8,9 , Bonnie Zhang 8,9OzDES is a five year survey on the AATtargeting the 10 deep fields of the DarkEnergy Survey (DES) with the 2dF fibrepositioner and AAOmega spectrograph.In its first two years, OzDES has obtainedthe host galaxy redshifts of thousandsof transients, identified dozens ofsupernovae, and monitored hundreds ofActive Galactic Nuclei (AGN). OzDES isjust about to complete the second yearof observations. In this article, we providean update on how OzDES is progressing.DES and OzDESDuring the five years it will run, the DarkEnergy Survey will image almost a quarterof the Southern Hemisphere with DECam,a 3 square degree imager mounted on theCTIO 4m Blanco Telescope. DES, whichstarted taking data in 2013, consists of twosurveys: a wide survey, coveringapproximately 5,000 square degrees, and1AAO2University of Chicago3University of Portsmouth4Swinburne University5Argonne National Laboratory6Observatorio Nacional de Riode Janeiro / Laboratorio interinstitucionalde e-Astronomia7Macquarie University8Australian National University9ARC Centre of Excellence in AllSky Astrophysics (CAASTRO)10University of Queensland11Lawrence Berkeley National Laboratory12University of Sydney13The Ohio State University14ICRARa deep survey, which repeatedly images 10fields with a 6-day cadence over a 5 to 6month period. The deep survey fields arethemselves split into 2 deep fields and 8shallow fields. All 10 fields are visible fromthe AAT from late July to early January.The principle aim of DES is to understandthe physics behind the acceleratinguniverse. To do this, it uses fourastronomical probes: galaxy clustercounts, baryon acoustic oscillations,weak lensing and Type Ia Supernovae(SNe Ia). While DES is purely an imagingsurvey, the scientific grasp of DES isbroadened and strengthened withspectroscopic follow-up. This is OzDES.OzDES has two main scientific goals.The first goal is to constrain the darkenergy equation-of-state parameter andits evolution with time by combininghost galaxy redshifts of 3000 TypeIa supernovae measured with theAAT with distance estimates of thesesupernovae from light-curves obtainedwith DECam. The second goal is tomap out the growth in supermassiveblack holes, from 12 billion years ago topresent today, using AGN reverberationmapping (King et al. in preparation).At the same time, OzDES is observingtransients that happen to be brightenough to observe at the time OzDEStakes data (to date, OzDES has published10 ATELs announcing the discoveryof 32 supernovae). OzDES is alsoobtaining redshifts for thousands ofother sources, including radio galaxiesfrom the ATLAS radio survey [1-3], andluminous red galaxies from DES.At the time of writing this article, OzDEShas used about a quarter of its 100 nightallocation. Starting with 12 nights in 2013,the number of nights per year increasesby 4 nights each year. OzDES ends with28 nights in 2017. The yearly increase is tocover the expected rise with time of thenumber of SN hosts that lack redshifts.Observing StrategyThe observing strategy of OzDES is tospend at least two hours (broken up intothree 40 minute exposures) on each ofthe DES deep fields about once a month.Over the course of the five years of thesurvey, each of the DES fields will betargeted about 25 times. With this strategy,we'll obtain masses for about 40% of thesupermassive black holes that we observe.OzDES targets span a very broadrange of magnitudes, from r=17 to r=24.Redshifts for objects that are as brightas r=17 can be obtained in about 15minutes of integration. On the other hand,objects with r=24 require many hoursof integration. To maximize efficiency,we deselect targets 1 as soon as theirredshifts are measured. This enables usto free fibres to observe other targets.Over the course of the survey, we havedeveloped procedures and pipelines toprocess the data quickly. The data arenow reduced within about 20 minutesof the last frame being taken. During thefollowing day, the files are redshifted andthe results digested into the database,which is then used to help choose targetsfor the following night. These proceduresand pipelines also allow us to reducethe number of people that are neededat the telescope, from four that wehad during the first run to two now. Inprinciple, the whole operation could berun by a single experienced observer.1 This does not apply to AGN that are beingmonitored or to live transients. AGN are alwaysobserved and we observe transients until theybecome too faint to observe with the AAT.14Australian Astronomical Observatory Newsletter - FEBRUARY 2015


SCIENCE HIGHLIGHTSWe've also implemented a number ofchanges that are designed to improvethe quality of the data that comesfrom the survey. Since the end of thefirst season (Y1), we started to observearound 10 F-stars per field. With anr-band magnitude between 17 and 18,these stars are bright enough to result inspectra with high signal-to-noise ratios,yet are not too bright to contaminatethe spectra of neighbouring objects,which may be up to 1,000 times fainter.We use F stars to measure the throughput.Since the g and i-bands nicely fit intothe area covered by the blue and redarms of AAOmega, respectively, we geta measure of the throughput for boththe red and blue arms separately. Thethroughput measurements, which areautomatically determined by the pipeline,give us a quantitative indication of whenwe should switch to our backup program.The configuration time of AAOmega is nowless than 40 minutes, so these decisionscan be made almost in real time. Thebackup program consists of obtainingspectra of the brightest galaxies in eachof the DES fields. AGN and transients arestill targeted in the backup program.Co-adding data frommultiple runsMost of the galaxies in OzDES areconsiderably fainter than galaxies thatare normally observed with AAOmegaat the AAT. For example, the medianmagnitude of the SN hosts is r=22.5.For objects this faint, the signal-tonoiseratio in a two hour exposure 2 isusually too low for one to measure aredshift. Instead, these objects needto be observed over several observingruns before a redshift can be obtained.The signal-to-noise ratio is very sensitiveto the observing conditions, such as seeingand transparency. It is not unusual for theend-to-end throughput of the system tovary by a factor of five or more. Coaddingdata, without taking this variability intoaccount, may degrade the data, i.e. onemay end up with fewer redshifts not more.Currently, we simply do not include datathat were taken in poor conditions. Wethen equally weight the rest. In future2 Two hours is about the maximum length-of-time onecan observe without needing to reconfigure. Exposuresthat last longer than this become increasingly lessefficient, because atmospheric refraction causes objectsto become displaced with respect to the fibres.runs, we'll apply a more optimal weightingscheme that will be based on thethroughputs that are derived from F starsthat are observed contemporaneously.Many targets have already accumulatedmore that a day of integration. The currentrecord holder in OzDES is an AGN, whichhas 115,000 seconds. This is probably thelongest exposure on a single object withAAOmega. With such deep observations,it is interesting to explore how the noisechanges with exposure time. Ideally, thenoise should decrease with the square rootof time, if one is averaging the individualexposures. This is what we and others find[4]. At the same time, the signal-to-noiseratio should increase with square rootof time. For small spectral windows, thisappears to hold, even in the regions wherethere are bright night sky lines. However,over broader regions, one sees features inthe data, such as large scale modulations inthe continuum and spectral discontinuities,that are artifacts from the data processing.Over the past 12 months, considerablework has gone into upgrading 2dfdr,the software that processes datafrom AAOmega, and this had led tosignificant improvement in the qualityof the reduced data. This work isongoing and we expect that there willbe further substantial improvementsover the next twelve months.It is also essential to understand how thethe redshift success evolves with exposuretime. We use this information to predicthow many sources we will observe bysurvey end, as shown in Figs. 1 and 2,and to ensure that we reach our goals.The best way to understand Fig. 1 is tostart at the top and to work down. The keypoint is that objects that have good qualityredshifts 3 in the upper plots (qop>2) areremoved from further consideration inthe lower plots. For example, there are2,182 galaxies that hosted a transientof some kind that have been observedwith at least 1 exposure. Of these 2,182galaxies, 958 of them have redshifts fromfour exposures or less. These 958 galaxiesare removed from the lower plots. Of theremaining 1,224 galaxies, 706 have beenobserved with at least 5 exposures. Of3 In OzDES, we use a flag, labled ‘qop’ to indicate thelikelihood that a redshift is correct. The redshift ofan object with qop=3, will be correct 95% of thetime. Likewise, an object with qop=4 will have thecorrect redshift more than 99% of the time.these, 145 have redshifts from 7 exposuresor less. From this plot, one can evaluatehow the completeness changes withthe number of exposures. Summing thecompleteness over all runs results in Fig. 2.We then use this information to determinethe survey yield under different observingstrategies. For example, we'd like toknow if there is a point where continuingto integrate longer on the target is lessproductive than switching to a newtarget. The answer is quite complex anddepends on the target. For the hostgalaxies of transients, we find, as shownin Fig. 3, that we asymptote to the casewhere we obtain as many redshifts asthere are new SN hosts to observe, andthat we never reach the limiting quotathat is assigned to these targets.Current Status and SummaryAt the time of writing, we have observed18,165 unique targets and obtainedredshifts for 11,424. Of these, 2,182 aregalaxies that hosted a transient and1,170 have a redshift. The location ofsome of the host galaxies is shownin Fig 4. Examples of the spectra weare taking are shown in Fig. 5.To increase both the efficiency andpurity of the SNe Ia sample, we aretargeting not only galaxies that hostlikely SN Ia, but galaxies that hostother kinds of transients. About everysecond transient will be a non SN Ia.The redshift distribution of galaxies thathosted photometrically identified SNeIa from the first year of the survey (Y1)is shown as the blue histogram in Fig 6.For comparison the predicted redshiftdistribution from [5] is shown in green.Also shown is the split between SNeIa that are discovered in the two deepfields and the eight shallow fields. Theplot shows that we are detecting SNhosts with approximately the expectedredshift distribution. There is a slightdeficit at higher redshifts, but this is notunexpected. The hosts of these SNe Iawill be fainter, on average, and it willtake longer to get their redshifts.In Fig. 7, we show the redshift distributionof the AGN that are being monitoredby OzDES and the number of AGN thatalready have five or more observationsfrom the 8 OzDES runs that have occurredsince the start of Y1 in 2013. By the end ofour next season, we may already be ableAustralian Astronomical Observatory Newsletter - FEBRUARY 2015 15


SCIENCE HIGHLIGHTSFig. 3. A figure showing the how thecumulative number of host galaxy redshiftsincreases with each observing run. Thisis for a single DES field and assumes thatthere are 20 new transients per run. At thisrate, we never run out of fibres, so thereis no point deselecting targets once theyhave been observed a finite number ofruns. By the end of the survey, we expectthat 80% of all transients will have a hostgalaxy redshift.Fig. 4. The angular distribution of OzDESand GAMA galaxies in a 3 degree wideslice centred on the XMM-LSS 2hr field. Inthe left hand plot, we show the distributionout to redshift one. Not shown are theAGN which go out to redshift 4. In the righthand plot, we zoom into the region aroundz=0.78. Plotted here are galaxies shown inthe left hand plot together with galaxiesthat hosted a transient some time duringthe first two years of the DES surveyplotted in black.Fig 5. Sample spectra from OzDES. Fromtop to bottom, the hosts of a SN, an AGN,an Emission Line Galaxy (ELG) and aLuminous Red Galaxy (LRG). The spectraare shown in black. The error spectra areshown in light grey.Australian Astronomical Observatory Newsletter - FEBRUARY 2015 17


SCIENCE HIGHLIGHTSFig 6. Redshift distribution of galaxies thathosted photometrically identified SNe Iafrom Y1. In blue, the measured distribution.In green, the predicted distribution forthe DES survey from [2]. The solid greenline is made up from SNe Ia in the 2 deepfields (dotted line) and the 8 shallow fields(dashed line). The deficit in the number ofobserved SNe Ia at higher redshifts will befilled as we observe longer on the faintertargets that do not yet have a redshift.Fig 7. Redshift distribution of AGN that arebeing monitored compared to the numberthat have been observed already 5 timesor more. Since the start of the first season,there have been 8 OzDES runs.18Australian Astronomical Observatory Newsletter - FEBRUARY 2015


SCIENCE HIGHLIGHTSHuntsman Eye Sees DeepBron Reichardt (Macquarie) and Jack Vidler (Macquarie), Anthony Horton (AAO), Lee Spitler (AAO/Macquarie)Over the past few months, an excitingproject involving both the AAO andMacquarie University has been inthe works. A grant from Macquarie’sundergraduate industrial placementProfessional And Community Involvement(PACE) program provided the necessaryinitial funding to buy equipment for theHuntsman Eye as well as presenting us(Jack and Bron) with an opportunityto work on some real cutting edgescience. For more info on that, checkout this video http://goo.gl/78JdJ1The Huntsman Eye is designed forextremely low surface brightness imaging,which will allow us to examine previouslyinaccessible faint structures of galaxies.The imaging system is based upon theDragonfly Telephoto Array, which a teamin North America published last year. Ascan be seen in Figure 2, the HuntsmanEye primarily consists of a telephotoCanon lens with a special nano-coatingthat allows the detection of fainterstructures than can be seen from muchlarger telescopes. This “Eye” is intendedto be the first in an array of eight ormore – hence the name “Huntsman”,an Australian version of “Dragonfly”,to do southern hemisphere science.When comparing the images of Barnard’sgalaxy from Macquarie Observatory andSteve Lee’s observatory (Figure 3), it isclear that Coonabarabran gives a hugeadvantage in terms of less light pollutionand better seeing because so muchmore detail can be seen in those imagesusing the same technical equipment.Figure 1 (from front) Jack, Bron and Leeobserving at MQ observatory.Figure 2 The Huntsman Telephoto Eye –Canon EF 400mm f/2.8 L IS II USM lens,coupled to a science-grade commercialSBIG STM-8300m CCD camera using aBirger Canon EF-232 adaptor.At the beginning of the project, we spenttime getting familiar with the lens. A fewnights at Macquarie’s Observatory allowedus to trial both the setup and the systemused to control the camera, lens andmount while observing. We took imagesof Barnard’s Galaxy, which amounted to100 minutes of integration time. Afterreducing the data obtained from thesenights and fixing a few bugs in the system,we took the Huntsman Eye on a roadtripto Coonabarabran, near Siding SpringObservatory. An observing run of tendays at Steve Lee’s Observatory enabledus to take images under a dark sky. Weused this opportunity to take images of afew different objects, including a repeatof Barnard’s Galaxy for comparison.Figure 3 Barnard’s Galaxy, 100x1 minuteexposures in r’-band (top) at MQObservatory and (bottom) inCoonabarabran.Australian Astronomical Observatory Newsletter - FEBRUARY 2015 19


SCIENCE HIGHLIGHTSWe also took 18 hours of integration time on NGC300 in r’-band. NGC300 is amassive spiral galaxy in the Sculptor constellation, one of the closest galaxies toour Local Group. You can see a false colour, 500 min image of NGC300 in Figure 4.Reduction of data is still ongoing, and we are waiting to find how the Huntsman Eyeobservations compare to other science already done on this particular galaxy.Figure 4 NGC300 false colour image, 250 mins in both r’ – and g’-bands.Future science to be done with the entire array could focus on the fainter structureof galaxies, including the extent of the halo and disc. How far do these componentsextend in certain galaxies? Could we see evidence of smaller galaxies interacting withlarger ones? But we’ll leave you with this amazing image taken of the Orion Nebula.For regular updates, keep your eye on the #HuntsmanEye hashtagthrough the AAO’s twitter account @AAOastro.Figure 5 Orion Nebula (M42) – Combined 10s, 60s and 300s exposures in r’-band.20Australian Astronomical Observatory Newsletter - FEBRUARY 2015


SCIENCE HIGHLIGHTSThe FunnelWeb Survey:Building the HD Catalog of the 21st CenturyChris Tinney (UNSW) & Michael Ireland (ANU)To all intents and purposes, thedevelopment of all-sky spectroscopiccatalogues for bright stars stopped inthe middle of the 20th century with thecompletion of the Henry Draper (HD)catalogue by Jump-Cannon and colleaguesat the Harvard College Observatory. With359083 stars observed and spectrallycatalogued one at a time, the availabletechnology had reached its limits. To thisday, if you want to search the brightest,and nearest stars for exoplanets via directimaging or Doppler Wobble, you start witha catalogue that is essentially the list ofHD spectral types from the late 1940s.The TAIPAN facility on the UKST is set tochange all that. Its unique ability toreposition in just minutes, makes it the firstspectrograph capable of taking the nextstep in the spectral mapping of thebrightest stars. In just under 3 years, it canobserve around four million bright starsand extend the HD catalogue from itscurrent 8-9th magnitude limits to 12-14thmagnitude.In the process it can enable breakthroughscience on multiple fronts by providinga superbly robust input catalogue tothe NASA TESS transiting exoplanetsatellite, extending the list of young(


SCIENCE HIGHLIGHTSspectral types for some 360 000 stars inthe northern and southern hemispheres.These surveys enabled the developmentof meaningful systems of stellar spectralclassification, which in turn drovedeeper insights into stellar propertiesand evolution (e.g. Cecilia Payne-Gaposchkin's demonstration that theOBAFGKM sequence is a temperaturesequence). The Harvard spectralclassification system developed in thesesurveys is still used today. Moreover, theclassifications of individual stars fromthese surveys have, in most cases, notreally been updated to this day. Andeven more incredibly, no subsequentsurvey of bright stars has extended theHD Catalogues to fainter magnitudes.The development of multi- objectspectrographs (pioneered by the AAO)has done little to change this situation.The fundamental problem being that,in spite of the fact the exposure timesrequired to get spectral types for brightstars are tiny (just a few minutes of a1m telescope), current multi- objectspectrographs have repositioning timeson the order of an hour. So spending 2minutes on sky, then repositioning for anhour, makes such a survey impossible.This is the reason why, to this day, if youwant to search the brightest and neareststars for exoplanets via direct imagingor Doppler Wobble, you start with acatalogue that is essentially the list ofHD spectral types from the late 1940s!What's Hiding in the Mist?So let's assume that one thinks basingeverything we know about the brighteststars on visually classified data from50-to-100 year old photographicplates is unacceptable. How does onego about re-doing the HD processin the digital age, and doing it for anorder of magnitude more stars?As noted above, the problem is not one ofcollecting area or integration time – with amodern spectrograph even a 1m telescopecan acquire a Signal-to-Noise ratio 100spectrum at R~2500 for a 12th magnitudestar in around a minute. A suitablemulti- object spectrograph (observing,say, 100 objects at a time) could bangoff 4 million stars in just 66 nights.The word "suitable" here hides a lotthough. Current generation multi- objectspectrographs take on-the-order of halfan-hourto reposition 100 objects one at atime, which increases the time to do thissurvey to an inconceivable 2000 nights.Building HD Cataloguefor the 21st CenturyThis is where the TAIPAN facility, thatthe AAO, ANU, AAL, Macquarie, Sydney,Swinburne, UNSW and others arebuilding for the UKST, comes in. Its uniqueStarbug positioning system allows eachfibre aperture to the spectrograph tobe repositioned in parallel for a totalreconfiguration time of minutes.This makes an order-of-magnitude increasein survey numbers over the HD catalogue(i.e. 4 million stars down to 12th magnitude)doable in three years, rather than thirty.Moreover, it will deliver digital data, ratherthan visual spectral types from theinspection of photographic plates, enablingthe creation of an on-line queriable spectralcatalogue that will become the HDCatalogue of the coming century.FunnelWeb in a nutshell• All stars δ10, I


SCIENCE HIGHLIGHTSAdaptive Optics Experiments on the AATBy Michael Goodwin, Jessica Zheng, Sam Richards, Jon LawrenceOver the last year, the Instrument ScienceGroup at the AAO has embarked on asmall research and development projectto investigate the use of AdaptiveOptics technologies on the 4 metreAAT at Siding Spring Observatory.Adaptive Optics (AO) is a technique toimprove the sharpness of astronomicalimages taken from the surface of Earth.Light from distant stars gets bent manytimes as it passes through the Earth'satmosphere because natural pockets ofatmospheric turbulence act like lensesand prisms. This causes stars to "twinkle"to our eyes. The more turbulent theatmosphere, the more bending of thelight and the bigger and "fuzzier" objectsappear in our telescopic images.AO provides a way to determine andcorrect for atmospheric turbulenceby measuring how much the lightreceived by the telescope changes(called the “wavefront distortion”) veryrapidly (200 times per second). Whensuccessful, the efficiency of a telescopeimplementing AO is maximized, suchthat the optical quality is only limitedby the diffraction limit of the telescope.AO greatly improves the performanceof spectrographs and interferometersas well as imaging detectors, whichmakes the technology very beneficialfor large ground based telescopes.A project milestone was achieved onthe nights of 9-10 December 2014, asthe AO demonstrator was tested on theAAT for the first time. Figure 1 shows theAO demonstrator test-bed mounted tothe Cassegrain focus of the AAT, withassociated equipment attached to thecage perimeter. The Cassegrain focusallows the possibility of future experimentsto test multi- object AO system overits 20 arcminutes wide field of view.finally imaged onto the science detectors.A Shack Hartmann wavefront sensor isused, which consists of a 26x26 microlensarray and an Andor SCMOS Zyla camera.If there was no atmospheric turbulence,the wavefront sensor would measure a flatoptical wavefront, but it does not, and thedistorted optical wavefront is measuredwith a sampling frequency of 200Hz tokeep up with the changing turbulence.The conjugated wavefront is reconstructedin real-time with control software andsent to the 97-actuator deformablemirror (Alpao DM97-15). With closedloopoperation, the perturbed opticalwavefront is iteratively flattened bychoosing the proper loop gain toimprove the image quality as seenon the science camera (Xenics for J-,H-band and Thorlabs for V-band).The adaptive optics demonstratoris configured in the simplest mode,where the science target is used as thewavefront source. A calibration sourcein the visible and near-infrared is alsoused to calibrate (interaction matrix) thedeformable mirror and wavefront sensor.It is a laser source with a fibre collimator.The acquisition camera provides feedbackto the telescope operator to preciselypoint the telescope at the target.The key components and layout of the AOsystem are shown in Figure 2. The lightfrom the telescope is first collimated anddirected onto the deformable mirror, thenit passes to the wavefront sensor, andFigure 1: Photo of the adaptive optics test-bed mounted on the Cassegrain focus onthe AAT.Australian Astronomical Observatory Newsletter - FEBRUARY 2015 23


SCIENCE HIGHLIGHTSAs with testing any new technology, theAO demonstrator’s first two nights onthe telescope taught us a lot about thesystem. The control software was notconfigured to close the loop with the lowlight levels encountered at Cassegrainfocus so software modifications wereimplemented and system realignmentwas made for the second night ofobservations. Unfortunately, thesecond night was mostly cloudy.However, a break in the clouds duringthe final part of the night allowed a fewminutes of observing. During this shortwindow, the adaptive optics systemwas sufficiently stable with closedloopoperation and good data werecollected. The results from the visiblecamera are shown in Figure 3, wherean improvement to the image quality isevident, which is very encouraging.With modifications to our set-up, it shouldbe possible to measure the near-infraredcorrection soon. Future work will focus onnovel technology developments includingminiaturised wavefront sensors that can bedistributed over focal planes for multiobjectadaptive optics. The miniaturewavefront sensors are compact enoughand lightweight to be positioned byStarbugs. The project team based inSydney is appreciative of the efforts of thesite technical staff to get the adaptiveoptics demonstrator on-sky.Figure 2: Photo of the adaptive optics test-bed in the laboratory with key componentslabelled.(a) Star image displacement (centroid) per frame withoutcorrection (red circles) and with correction (blue dots).(b) Averaged star image in the visible without correctionapprox. 1.8” (left) and with correction 1.5” (right).Figure 3: Results showing a slight improvement (partial correction) in the visible (camera response 0.4 to 0.8 microns) for data taken10 seconds immediately before and after correction by adaptive optics. Data taken from the bright star Sirius approximately 2:44 amon the 11 December 2014.24Australian Astronomical Observatory Newsletter - FEBRUARY 2015


OBSERVATORY NEWSThe AAO Shaw Visitor SchemeThe AAO is pleased to announce a new source of funding tosupport visits to the AAO by researchers based in the UK,the Shaw Visitor Scheme. The AAO’s Shaw Visitor Scheme isfunded by a generous donation from Professor John Peacock(Royal Observatory Edinburgh) and Professor Shaun Cole(Durham University) who were joint winners with DanielEisenstein of the 2014 Shaw Prize in Astronomy. The 2014Shaw Prize in Astronomy was awarded “for their contributionsto the measurements of features in the large-scale structure ofgalaxies used to constrain the cosmological model includingbaryon acoustic oscillations and redshift-space distortions.”This Scheme expands on the existing and highlysuccessful AAO Distinguished Visitor Scheme, that aims tostrengthen and enhance the AAO's visibility both locallyand internationally, and to provide opportunities for AAOstaff to benefit from longer term collaborative visits bydistinguished international colleagues. The Shaw VisitorScheme supports visits to the AAO by researchers atUK institutions, in order to develop, continue and fostersuccessful collaborations such as the original 2dF GalaxyRedshift Survey. The aims are to maintain and enhance linksbetween AAO and UK astronomers providing both withopportunities to benefit from longer term collaborative visits.The AAO will typically award one Shaw Visitorship annually.Figure 1: The Shaw Prize recipients at the awards ceremony.Full details, including the application processand deadline, can be found at:http://www.aao.gov.au/science/shaw-visitor-schemeAny queries can be directed to the Head of Research andOutreach, Andrew Hopkins (ahopkins@aao.gov.au).Figure 2: Professor John Peacock receiving his award.Figure 3: Professor Shaun Cole receiving his award.Australian Astronomical Observatory Newsletter - FEBRUARY 201525


OBSERVATORY NEWSHidden GeMS: observing with the Geminimulti-conjugate adaptive optics systemSarah Sweet, ANU“El avión va a entrar la zona seguridaden uno minuto": a phrase heard a fewtoo many times during the run for myliking. The aircraft spotters warned thatyet another aeroplane would shortly beflying within the 6-km radius safety zone,meaning that the laser must be terminatedand the current observation would needto be stopped. The aeroplanes seemedto have heard that the laser would bepropagating and had come to see the show(Figure 1). Unfortunately, they and I wereultimately to be disappointed that night…The control room was busy early on; closerto the `many hands make light work’ thanthe `too many cooks’ end of the spectrum.The team included the Gemini observer,visiting observer (me!), SOS (telescopeoperator), two aircraft spotters – one towatch a radar and the other to watchthe sky, two to three laser techs – one tooptimise the adaptive optics (AO) systemand another to continually tune thecalibration and be urgently alerted whenthe laser loops were in danger of breaking.as five minutes. When things are notgoing so well, the loops can be lost bysudden changes in the conditions, andcan take half an hour to reclose. At themost dramatic, we had one catastrophicfailure caused perhaps by an electricalglitch. This triggered an emergency stop,causing all of the telescope systems tocrash. The laser couldn’t be resurrectedthat night, so we resorted to queueobserving for Flamingos-2 instead.For the remainder of the run, we werehappily restricted to the more mundaneweather-watching. Even in the dryAtacama, observations are beholden toclouds rolling in (Figure 2) and to changesin the turbulent layer. As one techniciancommented, “We build an adaptive opticssystem to correct for poor seeing, but werequire good seeing to use it!” Still, typicalcorrections in the infrared give an order ofmagnitude better resolution than natural,optical seeing, and up to three timesbetter resolution than Hubble (Figure 3).It should be pointed out that this systemis world-first, and this makes it bothchallenging and exciting. When workingon the on the cutting edge, it can beexpected that things will break. However,GeMS & GSAOI are already deliveringscience-quality results. The pipelinedoes a good job of basic processing(flat-fielding and the like) althoughnot mosaicking: the optics introduce asignificant off-axis distortion patternwhich is semi-static, changing with epoch(as the instrument is swapped out),possibly position angle, and dither stepdue to the relative position of the guidestar probes. The good news is that I havea working solution to this – but that isanother story. If you’re interested in usingGSAOI for your science, please contactme and I will be happy to give details.GeMS, the Gemini Multi-conjugate AOSystem, uses an asterism of five laserguide stars in conjunction with up to threenatural guide stars to achieve better than100 milli-arcsecond resolution acrossthe whole 80-arcsecond field of view ofthe Gemini South AO imager (GSAOI).The complexity of the instrument meansthat the path of the laser beam throughthe AO bench is formed in several loops,each of which must be carefully closedin order to make the corrections for thethree (currently two) deformable mirrors.That process takes up to half an hour,depending on the seeing, strength ofthe sodium layer, target elevation andbrightness of the guide stars. It must berepeated every time the laser is terminatedor shuttered, so the fewer interruptionsthe better! When observations aregoing smoothly, most interruptionsare by aeroplanes or satellites, andobservations can be resumed in as littleFigure. 1. Laser propagating. Image credit – Gemini26Australian Astronomical Observatory Newsletter - FEBRUARY 2015


OBSERVATORY NEWSFigure. 2. Red sky at night: astronomers’ warning. CTIO can be seen in the distance near image centre.Figure. 3. Left: GSAOI Ks-band image ofa galaxy cluster at z~1; cluster centre isdenoted by blue rectangle. Right: zoom-inof cluster centre – upper: GSAOI; lower:HST F814W image.Australian Astronomical Observatory Newsletter - FEBRUARY 201527


LOCAL NEWSStarFest 2014Amanda BauerStarFest and Open Day at Siding SpringObservatory are events held annuallyduring the long weekend in October.This year we welcomed AustralianAstronaut Andy Thomas to give theBok Lecture. Here are photo highlightsfrom the long weekend of events.28 Australian Astronomical Observatory Newsletter - FEBRUARY 2015


LOCAL NEWS1: Siding Spring Observatory duringOpen DayCredit: Anna Tenne2: Andy Green talks to families aboutJupiter.Credit: Anna Tenne3: Science in the Pub Panelists (L-R)Assoc. Prof Charles Lineweaver, Prof.Fred Watson, Dr Amanda Bauer, ProfJoss Bland-Hawthorn and moderatorRobyn Williams.Credit: Anna Tenne4: Blasting off water rockets!Credit: Anna Tenne5 a: Amanda Bauer cuts the ribbon toopen a new telescope in the iTelescopenetwork. b: The plaque dedicating thenew iTelescope.Credit: Eran Segev6: AAO Director Warrick Couchdescribes the mysteries of Dark Matterin the Bullet Cluster of galaxies.Credit: Anna Tenne7: Visitors at the entrance of the AAT,ready for cake.Credit: Pete Poulos8: Director Warrick Couch cuts the bigbirthday cake!Credit: Amanda Bauer9: Guests enjoyed dressing up likeastronauts on the AAT dome floor.Credit: Amanda BauerAustralian Astronomical Observatory Newsletter - FEBRUARY 201529


LOCAL NEWSPlanning Day 2014 – Old and Newby Cathy Parisi, Executive Officer, AAOThe day began with excitement andanticipation as we headed off on our bustrip to Coonabarabran for the AAO 2014Planning Day. This was soon dashed aswe headed through the Sydney traffic andslowed to snail pace due to an accidenton the road. However we managed topass the time catching up with colleagueson matters that we did not have time todiscuss at the work place. The time passedquickly and we arrived at our destinationto enjoy good old country hospitality.The planning day was a day to reminisceabout the old days – where the AAO hadcome from and where it is headed today.In celebration of 40 years on the mountain,Fred Watson presented a wonderfuldepiction of the “History of the AAT” andwhat it was like in the early days of operatingthe AAT and the UKST, both the challengesand innovation being developed at thetime. There were even sightings of somevery young unrecognisable characters!We enjoyed viewing two short films whichshowed the AAT Operations Team atwork. The first film “Steve and the Stars”featured our very own Head TelescopeOperator, Steve Lee, who has worked atthe AAT for almost its entire 40 years ofoperation. The film provided an insight intoworking at the AAT, how observationaltechniques have changed from the 1970s,and the future plans for the AAT. Thiscan be viewed at http://www.aao.gov.au/public/video/steve-and-the-stars.The second film showed how the mirror ofthe telescope is cleaned and aluminsed.It was quite amazing to see how labourintensive this process is and the number ofstages involved getting the mirror to thestandard required for optimum observing!There was also a guest speaker, ChrisTinney from University of NSW, to tell usabout the Anglo Australian Planet Searchand Doug Gray and Jon Lawrence followedwith plans for the UKST refurbishmentand the use of the UKST as a test bedfor future innovative instruments.Figure 1. AAT Enclosure being built in 1972. Photo: George Searle30 Australian Astronomical Observatory Newsletter - FEBRUARY 2015


LOCAL NEWSFigure 2. (above) Fred Watson now andthen. Photo: Stuart RyderFigure 3. (left) Listening to short projectupdates on the AAT dome floor.Photo: Jurek BrzeskiAll in all it was a great opportunity fornetworking and exchange of ideasbetween Site and Sydney staff. A bigthank you should go to the organisingcommittee who did a wonderfuljob in bringing it all together.Australian Astronomical Observatory Newsletter - FEBRUARY 201531


LOCAL NEWSITSO CORNERStuart Ryder (International Telescopes Support Office, AAO)Proposal StatisticsA total of 27 Gemini proposals werereceived by ATAC for Semester 2015A, upfrom 23 in Semester 2014B. There were 8proposals for Gemini North; 14 for GeminiSouth; 4 for both Gemini North and South;and one Subaru exchange time request.Including exchange time requests theoversubscription for Gemini North was just1.1, while Gemini South was oversubscribedby a factor of 1.8. ATAC was able tocompensate for this imbalance to somedegree by moving some GMOS-S programswith equatorial targets to GMOS-N (withallowance for the lower quantum efficiencyof the GMOS-N E2V CCDs relative tothe new GMOS-S Hamamatsu CCDs).Magellan demand in 2015A was similarto 2014B, with 10 proposals received andan oversubscription of 2.2. MIKE, PFS,and FourStar were the most popularinstruments, while most other instrumentsreceived one proposal each. Here againthere was a substantial imbalance inrequests between the two telescopes, with8 requests for time on the Clay telescope,and just 2 for the Baade telescope. ATACwas forced to switch one MagE proposalon Clay into an IMACS program on Baadeto meet scheduling requirements.AGUSSThe Australian Gemini UndergraduateSummer Studentship (AGUSS) programoffers talented undergraduate studentsthe opportunity to spend 10 weeks oversummer working at the Gemini Southobservatory in La Serena, Chile, on aresearch project with Gemini staff. Theyalso assist with queue observationsat Gemini South itself, and visit theMagellan telescopes at Las CampanasObservatory. There were 29 applicationsfor the 2014/15 AGUSS program, themost ever. Rhiannon Gardiner fromMonash University and Conor O’Neillfrom the University of Queensland werethis year’s lucky recipients, and startedwork at Gemini South on 9 Dec (Figure 1).Rhiannon is working with Blair Connand Djazia Ladjal on a spatially-resolvedspectral analysis of planetary nebulae,while Conor is working with Juan Madridon understanding why neighboringgalaxies contain vastly different numbersof globular clusters. Towards the end oftheir time in Chile, Conor and Rhiannonwill present the results of their projectsto Gemini staff, as well as by video linkto the AAO and their home institutions.Figure 1: The 2014/15 AGUSS recipients,Conor O'Neill and Rhiannon Gardiner.Credit: Stuart Ryder.ATAC would like to encourage all potentialapplicants to consider submittingproposals for Gemini North and/or theBaade telescope in Semester 2015B, asthese are likely to be easier to schedule.Applicants should also bear in mindthat Semester 2015B will also be thefinal semester in which Australian PIscan apply for regular queue time on theGemini telescopes. As foreshadowed inthe previous issue of the AAO Observer,Australian Gemini access in 2016 will bein the form of 7 classical nights spreadacross both semesters and telescopes,though a “mini-queue” system is likely tobe offered which will allow some flexibilityin which instruments and how much timecan be applied for. Further details will bepublished in the August 2015 issue of theAAO Observer, and on the ITSO web page.Figure 2: Rhiannon (left front) and Conor (right front) are introduced to operationsat Gemini South by their supervisors Djazia Ladjal (left rear), Blair Conn (centre rear)and Juan Madrid (right rear).Credit: Gemini Observatory.32 Australian Astronomical Observatory Newsletter - FEBRUARY 2015


LOCAL NEWSWorkshop PresentationsBack in April 2014 ITSO and the AAO rana very successful workshop over 4 dayson observational techniques and datareduction. Some of the talks were capturedvia the AARNet videoconferencing system.Caroline Foster-Guanzon put a lot of effortinto synchronising the presenters talkingwith their slides, and has uploaded theseas video files to the Gemini ObservatoryYouTube channel. Links to thesepresentations, which capture a lot moreexplanatory information plus questionsand comments from the audience thanthe presentation slides alone, are nowavailable via the workshop programpage at http://tinyurl.com/omtg68t.Future & Science of GeminiObservatory MeetingRegistration is now open for the “Future &Science of Gemini Observatory” meeting,to be held in Toronto, Canada from 14–18June 2015 (http://www.gemini.edu/fsg15).As with previous Gemini Science Meetings,this meeting will focus on scientific resultsmade possible from Gemini’s latestcapabilities, including new observingand proposal modes. This gathering ofGemini’s users and stakeholders will alsoconsolidate plans to assure Gemini’sscientific legacy is sustained well into thefuture. Contributions from participants andpartner communities will serve as a focalpoint for next-generation instruments,observing modes and synergies withother facilities as the Observatorylooks ahead to 2020 and beyond.The early registration and abstractdeadline is 4 March 2015. To facilitatea healthy turnout by Australian users,ITSO will be providing a limited numberof travel subsidies (up to A$1,500maximum). Anyone interested in claiminga subsidy as a reimbursement upon theirreturn should contact us (ausgo@aao.gov.au) with a copy of your registrationconfirmation before 15 April 2015.Successful applicants will be informed ofthe amount of their subsidy by 20 April.2015 Australian Gemini, Magellan,and Keck Science SymposiumFollowing the first very successfulAustralian Gemini and Magellan sciencesymposium in 2012, ITSO will host a similarevent on 21 & 22 May 2015 at the AAO inSydney. This meeting will also featureAustralian science being conducted withthe Keck telescopes, in recognition of thefact that our users at Swinburne Universityof Technology as well as at the AustralianNational University already enjoy access tothese telescopes, as will the entireAustralian community from 2016.Participants will also be introduced to thefull “smorgasbord” of instrumentation theywill have access to on Gemini, Magellan,and Keck from next year, and there will bediscussions about how best to exploit the40 nights per year of Australian Keck time.For information about the symposium andto register, please visit the ITSO home page(http://ausgo.aao.gov.au).A Star is BornEveryone at the AAO was delightedby the news that AusGO ResearchFellow Dr Caroline Foster-Guanzongave birth to a healthy baby daughterKiara, on 14 November 2014.Congratulations to Caroline and herhusband Frederick! Caroline is currentlyon maternity leave and plans to return towork later in 2015.Australian Astronomical Observatory Newsletter - FEBRUARY 201533


LOCAL NEWSNews from North RydeBy Amanda BauerLlew Cedric Denning, BEM,01 Oct 1933 – 29 Nov 2014By Peter Gillingham andRussell CannonThe last six months have been busy andproductive for AAO Staff. In addition tocelebrating the 40th anniversary of theAAT, hosting the largest ever StarFestweekend extravaganza at Siding SpringObservatory, and launching our veryown YouTube channel, several staffmembers and users of AAO facilitiesaround the world have won awardsand grants in honour of new scientificdiscoveries and furthering our worldclass technology development.Director Warrick Couch, AAOAstronomer Chris Lidman and formerDirector Brian Boyle shared thehonour of being part of the researchteams winning the 2015 BreakthroughPrize in Fundamental Physics.Astronomer Lee Spitler was recognizedamongst New South Wales’ bestyoung scientists as a recipient of theprestigious Young Tall Poppy Award.Rolf Muller was a finalist as theCOMCARE Work Health and SafetyRepresentative of the year.The AAO was one of just twoastronomy institutions to receivea “Silver” Pleiades Award from theAstronomical Society of Australia,in recognition of its commitment toadvancing women in astronomy.Quentin Parker won the MacquarieUniversity’s 2014 Jim Piper Award forExcellence in Research Leadership.The AAO was a partner in foursuccessful ARC Linkage Infrastructure,Equipment and Facilities (LIEF) grants.These grants were awarded between$430,000 and $760,000 for thefollowing projects: (1) Hector, LeadInvestigator Joss Bland-Hawthorn(University of Sydney), (2) Veloce,Lead Investigator Chris Tinney(UNSW), (3) 4MOST, Lead InvestigatorSimon Driver (UWA), and (4) AST3NIR Camera, Lead InvestigatorJeremy Mould (Swinburne).Two AAO Astronomers, Sarah Broughand Matt Owers, received coveted4-year ARC Future Fellowships.Congratulations to both, and welook forward to working withthem for many more years!Bob Dean won this year's Citizenof the Year in CoonabarabranAward! This honour is awarded bythe Warrumbungle Shire Councileach year by nomination.Head of Instrument Science JonLawrence received one of theDepartment of Industry’s DistinguishedLeadership Awards in 2014.We celebrated the AAT’s 40thanniversary of the official opening byPrince Charles on 16 October, 1974.Celebrations included our mostsuccessful StarFest and Open Day atSiding Spring Observatory. The eventheld each year during the longweekend in October welcomed as avery special guest, Australian AstronautAndy Thomas. We also held a publicevent in Sydney on the anniversarydate, with a joint lecture given byDirector Warrick Couch about theAAT’s past and by Amanda Bauerlooking into the future for AAT scienceand instrumentation. This evening alsomarked the official Launch of ourYouTube Channel and the release of ashort film featuring AAO’s Steve Leecalled “Steve and the Stars.”AAO AstroCheck out our new YouTubechannel for all the latest AAOScience and Technology.https://www.youtube.com/user/AAOastroLlew Denning started his career as anapprentice in the RAAF at age 16, servedin Japan after the Korean War and thendid pioneering work on flight simulators,which led to the award of a British EmpireMedal. He continued in this field with TAA(later part of Qantas) until he came to theAAT as head of the electronics group. Heeventually took on responsibility for alloperational activities for both the AAT andthe UK Schmidt. After Peter Gillinghammoved to the Keck Telescope in 1992, Llewsucceeded him as Officer-in-Charge (laterOperations Manager) until he retired in 1998.Llew could handle almost any technicalproblem that arose, and proved to be anideal team manager and natural leader. Hewas always calm and quietly confident ina crisis. He epitomised the ethos that theAAO's top priority was to ensure that theequipment worked as well as possible, withminimal loss of time for visiting observers.He was all too often at the telescope outof normal work hours, a lifestyle facilitatedby the fact that he lived on the side ofSiding Spring Mountain. His herd of hairyScottish highland cattle became a familiarif incongruous sight, sharing their fieldswith kangaroos and emus. Llew was a manwith many other interests and abilities.Some of us will recall his performances incomedy sketches at the AAO's "GoldenDome" social nights, others may have beenmoved by the dramatic launch ceremony heorganised for the 2dF instrument in 1996.An essential element in the AAT's successhas always been its ability to attract andkeep excellent staff; Llew was amongstthe most outstanding examples. His wifeEdna also deserves our very sincere thanksfor her willingness to share so much ofLlew's time and energies with the AAO.34 Australian Astronomical Observatory Newsletter - FEBRUARY 2015


LOCAL NEWSLetter from Coonabarabranby Zoe HolcombeHi everyone,July 2014SNOW SNOW SNOW! I never thoughtI would actually see snow in Coona.Poor Darren Mathews had to put upwith me going on like a little child onthe way up the mountain “OMG IT’SSNOWING” “STOP THE CAR DARRENIT’S SNOWING”. And yes when we gotto work it was still snowing, so I threwa few snow balls and had some photosand went inside. The wind picked upand it turned to ICE. It was FREEZING!On 29th July the AAO was awarded aspecial commendation for outstandingsupport to the NSW Rural Fire ServiceVolunteers Program. AAO was one oftwelve businesses to be awarded thespecial commendation. The Ceremony washeld with a few speeches, photos and awelcoming BBQ lunch.Zoe Holcombe enjoys a rare snowstorm onSiding Spring ObservatoryStarFest Committee: The committee that organized the 2014 StarFest weekendExtravaganza of events and special guest, Australian Astronaut Andy Thomas. (Clockwisefrom Top Left: Fred Watson, Katrina Sealey, Pete Verwayen, Pete Poulos, Andy Thomas,Marnie Ogg, Amanda Wherrett, Sarah O’Callaghan, Doug Gray, Kristin Fiegert, ZoeHolcombe, Bob Dean, Amanda Bauer, Kiri Robbie)OctoberOctober started off with StarFest, a hugeweekend including Science in the Pub,Siding Spring Open Day, and to finish off,we blasted off into space with AustralianAstronaut Andy Thomas giving the annualBok Lecture. The weekend was a hugesuccess and could not have happenedwithout the help of the dedication of theStarFest Committee. Also, a huge thankyou to all the AAO staff who workedover the long weekend to make StarFestso successful. For the CoonabarabranMen’s Shed, we raised over $5300 overthe weekend, collected from Sciencein the Pub ticket sales, raffles, and theBok Lecture gold coin donation.NovemberPlanning Day this year saw AAO Sydneystaff head to Coona for a couple ofdays. After a day on the bus, myCoonabarabran team hosted a BBQdinner at the Golf Club for everyone.I arranged some golf activities, whichwere enjoyed by most people, althoughmany preferred to sit inside, watchingfrom where the air was cool.The next day we listened to various staffupdates and went on a tour of themountain. That night we went to PilligaPottery, where we all joined in singingHappy Birthday to Fred, much to hissurprise. A big thanks goes out to all thePlanning Day Team members whoorganised everything.Planning Day: (L-R) Jessica Parr, JennyGabache, Zoe Holcombe, and Nalini Joshistand in from of the Warrumbungles atPlanning Day this year.DecemberMid-December saw a week ofthunderstorms – not good for observing,but great for the National Park (and thegolf course!). Lately, the storms seemto drop rain on Coonabarabran and thesurrounding areas, but miss the mountain.See you all next time… Zoe HolcombeAustralian Astronomical Observatory Newsletter - FEBRUARY 201535


HCG 07: (top) Galaxies in this cluster are undergoing a burst of starformation, but no tidal tails. How many dwarf galaxies are hidden here?(This image covers an area about a third the size of the full moon.)HCG 48: (left)This group is dominated by a massive ellipticalgalaxy that has presumably formed by ingesting (astronomersrefer to this as accreting) all of its neighbours.HCG 59: (right)Two interacting giants have released a giant stellar streamin this Compact Group, which also hosts a bursting irregular galaxy.Images provided by Iraklis Konstantopoulos and Dane KleinerEDITOR: Amanda BauerDESIGN AND PRODUCTION: Communications Branch,Corporate Network, Department of Industry and ScienceISSN 0728-5833Published by the Australian Astronomical ObservatoryPO BOX 915, North Ryde NSW 1670, AUSTRALIAAAO SydneyTelephone: (02) 9372 4800Fax: (02) 9372 4880AAO Siding SpringTelephone: (02) 6842 6291Fax: (02) 6842 2266Email: director@aao.gov.auwww.aao.gov.au

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