Annual Report 2011 Max Planck Institute for Astronomy

72 IV. Instrumental Developments and Projects
Credit: Morganson et al., arXiv:1109.6241
Flux [10 –21 W / (m 2 nm)]
0.9
0.6
0.3
0
0.9
0.6
0.3
0
0.9
0.6
0.3
0
MMT spectrum
CAHA spectrum
PS1 total efficiency
700
i z y
800 900 1000
Observed Wavelength [nm]
Fig. IV.1.2: The spectra of the first PS1 high-redshift quasar
obtained by MMT and Calar Alto as well as the PS1 iP1, zP1,
yP1 filter curves.
These data will fill the V 10–15 mag gap between the
Hipparcos photometry of bright stars, the deep photometry
of PS1 and SDSS. This range is crucial for the detailed
study of the closest cool stars and is only available
with large uncertainties from the plate surveys.
Other surveys of interest to us are the Medium Deep
Survey, which monitors daily up to four pointings, and
cover 70 square degrees, and the PanPlanets survey dedicated
to the search over transiting exoplanets, particularly
around M-type dwarfs.
Published results cover the Solar system and near-
Earth asteroids up to the most distant quasars, with a
z 6.0 quasar discovered at MPIA. As the first deep,
wide, high-accuracy optical survey, PS1 is a unique
resource for the community. Prior to its full data release
expected 2015, it has established Memoranda of
Understanding with several large projects with other
wavelength coverage or spectral resolutions, which
greatly benefit from the PS1 catalogue. High-schools in
Heidelberg and world-wide have access to the images to
search for asteroids, and have successfully done so.
Early Results obtained at MPIA
MPIA has concentrated its efforts in four main areas:
very-low mass stars and brown dwarfs of the solar
neighbourhood, exoplanets, the structure of the Milky
Way, and Quasars.
Our search for cool brown dwarfs of the solar neighbourhood
firstly involved cross-matching with 2MASS
and selecting red y-J candidates. As SDSS before, PS1
has the right wavelength sensitivity to detect the early
T-type dwarfs. Over 40 new T-type dwarfs have been
discovered (Deacon et al., 2011, AJ 142, 77). A crossmatch
with WISE is underway. Proper motions based
on 2MASS and PS1 data also revealed new brown
dwarf companions to Hipparcos stars (Deacon et al.,
arXiv:1109.6319), providing new benchmark objects to
calibrate the brown dwarf models.
We take advantage of the wide sky coverage of PS1
to study the nearby 625-Myr-old Hyades cluster. We
can select cluster candidates to large cluster radii (30
pc) to study the cluster evaporation, especially close to
the stellar/brown dwarf boundary (Goldman et al., submitted
to A&A). We confirm previous indications of
mass segregation with a larger significance and the lack
of low-mass members at the cluster centre. The PS1
survey also offers an unprecedented look at the structure
of our Galaxy, with deep, uniform optical data in
five bands covering the whole Galactic plane in addition
to the Northern Galactic Cap. The MPIA leads the
PS1 science collaboration’s study of the Galaxy. Our
research in this area includes: a search for new dwarf
galaxies, the characterisation of the structure of the
Monoceros stream, and mapping the Galaxy’ dust.
Regarding our quasar work, we first use the deep z–
and y–band imaging to select for optical dropout highredshift
candidates. We found the first PS1 high-redshift
quasar (Morganson et al., arXiv:1109.6241: The
First High-redshift Quasar from Pan-StarrS) at redshift
6 (see Figure IV.1.2); the prospect to discover z 7
QSOs is promising.
B. Goldman, E. Bañados, N. Deacon,
T. Henning, N. Martin, E. Morganson,
H.-W. Rix, B. Venemans, F. Walter
In collaboration with partner institutes of the
PS1 Science Consortium,in particular the
Institute for Astronomy of the University of Hawaii;
as well as the ZAH of the University of Heidelberg
through the SFB 881 “The Milky Way”