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Extragalactic abstracts - IRSA - California Institute of Technology

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Spitzer_Approved_<strong>Extragalactic</strong><br />

Mar 25, 10 16:24 Page 413/742<br />

Spitzer Space Telescope − General Observer Proposal #30119<br />

Infrared Emission from the Smallest Active Galaxies<br />

Principal Investigator: Aaron Barth<br />

Institution: University <strong>of</strong> <strong>California</strong>, Irvine<br />

Technical Contact: Aaron Barth, University <strong>of</strong> <strong>California</strong>, Irvine<br />

Co−Investigators:<br />

Jenny Greene, Harvard−Smithsonian Center for Astrophysics<br />

Luis Ho, Observatories <strong>of</strong> the Carnegie Institution <strong>of</strong> Washi<br />

Science Category: AGN/quasars/radio galaxies<br />

Observing Modes: IrsStare<br />

Hours Approved: 26.1<br />

Abstract:<br />

Virtually all <strong>of</strong> our current knowledge <strong>of</strong> black hole demographics, both in<br />

nearby inactive galaxies and in AGNs, comes from observations <strong>of</strong> black holes<br />

with masses between a few million and a few billion solar masses in host<br />

galaxies with stellar velocity dispersions between about 70 and 400 km/sec.<br />

Searching for smaller black holes in low−mass galaxies can yield important clues<br />

to the origin and early evolution <strong>of</strong> supermassive black holes, and AGN surveys<br />

are the best available way to identify such objects. Using the Sloan Digital Sky<br />

Survey, we have identified 19 Seyfert 1 galaxies with black hole mass below 10^6<br />

solar masses (Greene & Ho 2004), and 20 Seyfert 2 galaxies having stellar<br />

velocity dispersions smaller than 70 km/sec as determined by new Keck<br />

observations. These AGN samples <strong>of</strong>fer a unique opportunity to study the very<br />

early growth stages <strong>of</strong> black holes and their host galaxies. Spitzer observations<br />

<strong>of</strong> mid−infrared emission will be the best available calorimeter <strong>of</strong> the<br />

energetics <strong>of</strong> these tiny AGNs. Our primary goal is to determine the infrared<br />

contribution to the bolometric luminosities, which will be a key to<br />

understanding the black hole accretion rates. From the infrared spectral shapes<br />

we will constrain the dust temperatures and search for silicate features in<br />

emission or absorption that may indicate the presence <strong>of</strong> an obscuring torus, and<br />

which will help to determine whether the Type 1 and Type 2 objects differ<br />

primarily as a result <strong>of</strong> our viewing angle, as in classic AGN unified models.<br />

PAH features and narrow emission lines will be used to diagnose the relative<br />

contributions <strong>of</strong> AGN and star formation to the infrared luminosity. To<br />

accomplish these goals, we request IRS staring−mode spectroscopy in the SL2,<br />

SL1, LL2, and LL1 settings for our Sloan−selected sample <strong>of</strong> 19 Seyfert 1s and 20<br />

Seyfert 2s, as well as NGC 4395 and POX 52, which are the prototypical nearby<br />

examples <strong>of</strong> Seyfert nuclei in dwarf host galaxies.<br />

Spitzer_Approved_<strong>Extragalactic</strong><br />

Printed_by_SSC<br />

Mar 25, 10 16:24 Page 414/742<br />

Spitzer Space Telescope − General Observer Proposal #20719<br />

IRS Spectroscopy <strong>of</strong> 3CR Radio Galaxies<br />

Principal Investigator: Stefi Baum<br />

Institution: Rochester <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong><br />

Technical Contact: Stefi Baum, Rochester <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong><br />

Co−Investigators:<br />

Catherine Buchanan, Rochester <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong><br />

Christopher O’Dea, Rochester <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong><br />

David Axon, Rochester <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong><br />

Jack Gallimore, Bucknell University<br />

Andrew Robinson, Rochester <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong><br />

William Sparks, Space Telescope Science <strong>Institute</strong><br />

Eric Perlman, University <strong>of</strong> Maryland, Baltimore County<br />

Alice Quillen, University <strong>of</strong> Rochester<br />

David Floyd, Space Telescope Science <strong>Institute</strong><br />

Science Category: AGN/quasars/radio galaxies<br />

Observing Modes: IrsMap<br />

Hours Approved: 17.0<br />

Abstract:<br />

Radio galaxies are among the largest and most powerful objects in the universe<br />

and, due to their interaction with their environment, are excellent objects to<br />

study the role <strong>of</strong> nuclear activity in galaxy evolution. However the interaction<br />

between radio−emitting active nuclei and their host galaxies on parsec scales is<br />

poorly understood. This is complicated by our lack <strong>of</strong> understanding <strong>of</strong> the<br />

relation between different classes <strong>of</strong> radio galaxy, defined by radio and optical<br />

properties. We propose to obtain IRS spectra <strong>of</strong> a sample <strong>of</strong> nearby radio<br />

galaxies in order to address fundamental questions about the nature <strong>of</strong> radio<br />

galaxies and their interaction with their environment. Low−resolution spectral<br />

maps <strong>of</strong> the central few kiloparsecs <strong>of</strong> these galaxies will enable us to probe<br />

the dusty central regions surrounding the active nucleus in these objects and to<br />

compare the classes <strong>of</strong> FRI and FRII radio galaxies. The IRS observations<br />

proposed here will be used along with archival IRAC and MIPS photometry to model<br />

the mid− to far−infrared spectral energy distributions (SEDs) <strong>of</strong> nearby radio<br />

galaxies. These SEDs will be compared with the IR SEDs <strong>of</strong> radio−quiet Seyfert<br />

galaxies, being obtained in a current Spitzer program, in order to understand<br />

how the interaction between an active nucleus and its host galaxy scales with<br />

host type, mass, and luminosity, black hole mass, and radio power.<br />

Thursday March 25, 2010 xgal_covers.txt<br />

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