Extragalactic abstracts - IRSA - California Institute of Technology
Extragalactic abstracts - IRSA - California Institute of Technology
Extragalactic abstracts - IRSA - California Institute of Technology
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Spitzer_Approved_<strong>Extragalactic</strong><br />
Mar 25, 10 16:24 Page 621/742<br />
Spitzer Space Telescope − General Observer Proposal #20760<br />
IRAC Imaging <strong>of</strong> the Most Distant X−ray Massive Galaxy Cluster at z=1.4<br />
Principal Investigator: Christopher Mullis<br />
Institution: University <strong>of</strong> Michigan<br />
Technical Contact: Christopher Mullis, University <strong>of</strong> Michigan<br />
Co−Investigators:<br />
Piero Rosati, European Southern Observatory<br />
Hans Boehringer, Max−Planck Institut fur extraterrestrische Physik<br />
Axel Schwope, Astrophysikalisches Institut Potsdam<br />
Georg Lamer, Astrophysikalisches Institut Potsdam<br />
Rene Fassbender, Max−Planck Institut fur extraterrestrische Physik<br />
Peter Schuecker, Max−Planck Institut fur extraterrestrische Physik<br />
Veronica Strazzullo, European Southern Observatory<br />
Science Category: galaxy clusters and groups<br />
Observing Modes: IracMap<br />
Hours Approved: 4.0<br />
Abstract:<br />
We propose to obtain deep IRAC imaging <strong>of</strong> the most distant X−ray−luminous<br />
cluster <strong>of</strong> galaxies found to date. XMMU J2235.3−2557 was first detected as an<br />
extended XMM−Newton X−ray source and then spectroscopically confirmed at z=1.393<br />
with the VLT−FORS2. Based on its high X−ray luminosity, ICM gas temperature, and<br />
optical/NIR richness, this galaxy cluster is very likely the most distant and<br />
most massive (z>1) structure yet identified. The proposed IRAC observations will<br />
measure the rest−frame near−IR flux <strong>of</strong> the z=1.4 cluster galaxies. This flux is<br />
known to be strongly correlated with the underlying stellar mass. We will<br />
construct the rest−frame near−IR luminosity function, derive the stellar mass<br />
function, and perform SED fitting to constrain galaxy ages and masses at the<br />
largest look−back times ever probed with clusters. With these diagnostics<br />
extracted from the high−density cluster environment, combined with complementary<br />
measures in the field population, we will directly test the predictions <strong>of</strong><br />
competing models <strong>of</strong> galaxy formation.<br />
Spitzer_Approved_<strong>Extragalactic</strong><br />
Printed_by_SSC<br />
Mar 25, 10 16:24 Page 622/742<br />
Spitzer Space Telescope − General Observer Proposal #30659<br />
A Census <strong>of</strong> Star Formation in Brightest Cluster Galaxies: Is Star Formation the<br />
Ultimate Fate <strong>of</strong> the Cooling Gas?<br />
Principal Investigator: Christopher O’Dea<br />
Institution: Rochester <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong><br />
Technical Contact: Christopher O’Dea, Rochester <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong><br />
Co−Investigators:<br />
Alastair Edge, University <strong>of</strong> Durham<br />
Andy Fabian, University <strong>of</strong> Cambridge<br />
Brian McNamara, Ohio University<br />
Steven Allen, Stanford<br />
Alice Quillen, University <strong>of</strong> Rochester<br />
Mark Voit, Michigan State University<br />
Stefi Baum, Rochester <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong><br />
Richard Wilman, University <strong>of</strong> Durham<br />
William Sparks, STScI<br />
Paul Goudfrooij, STScI<br />
Duccio Macchetto, STScI<br />
Carolin Crawford, University <strong>of</strong> Cambridge<br />
Roderick Johnstone, University <strong>of</strong> Cambridge<br />
David Frayer, IPAC<br />
Craig Sarazin, University <strong>of</strong> Virginia<br />
Joel Bregman, University <strong>of</strong> Michigan<br />
George Rieke, University <strong>of</strong> Arizona<br />
Eiichi Egami, University <strong>of</strong> Arizona<br />
Science Category: galaxy clusters and groups<br />
Observing Modes: IracMap MipsPhot<br />
Hours Approved: 33.2<br />
Abstract:<br />
We propose a comprehensive IRAC and MIPS survey <strong>of</strong> a sample <strong>of</strong> X−ray selected<br />
low redshift brightest cluster galaxies with high H−alpha luminosities to<br />
determine the star formation properties <strong>of</strong> the key class <strong>of</strong> galaxy. The giant<br />
ellipticals in cluster cores have long been regarded as old, quiescent galaxies<br />
free <strong>of</strong> dust and star−formation. However, recent optical, sub−mm, and Spitzer<br />
mir−far IR observations have shown that this is not the case in the cores <strong>of</strong><br />
cooling flows. Instead, substantial masses <strong>of</strong> both molecular gas (1E9−11 solar<br />
masses) and dust (1E7−8 solar masses) are found. Spitzer IRAC and MIPS<br />
observations <strong>of</strong> a few clusters have suggested that the BCGs with high X−ray<br />
luminosity and short cooling times or equivalently high H−alpha luminosities<br />
exhibit IR luminosities consistent with dust heated by star formation at rates<br />
<strong>of</strong> tens <strong>of</strong> solar masses per year (Egami et al 2006). These star formation rates<br />
are now consistent with the revised X−ray derived mass deposition rates <strong>of</strong>fering<br />
the exciting possibility <strong>of</strong> a solution to the conundrum <strong>of</strong> cooling flows. These<br />
observations also revealed that the one source in their sample which hosted a<br />
powerful radio source had a star formation rate much lower than the inferred<br />
mass deposition rate, consistent with feedback from the central AGN lowering the<br />
mass inflow rate. These results are based on observations<strong>of</strong> only a few clusters.<br />
With the observations proposed here we will be able to explore the relationship<br />
between the ICM, cooling flows, star formation, and AGN activity in BCGs and put<br />
these tentative results on firm statistical footing. We will obtain constraints<br />
on the fate <strong>of</strong> cooling gas, heating and cooling processes in the ICM, the nature<br />
<strong>of</strong> star formation in the central galaxies, and the activity <strong>of</strong> the central<br />
massive black hole. We anticipate that for this data set will be <strong>of</strong> great<br />
interest to a large number <strong>of</strong> researchers and will reduce our proprietary<br />
period.<br />
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