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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 475/742<br />

Spitzer Space Telescope − General Observer Proposal #2306<br />

Buried AGNs in ultraluminous infrared galaxies − A search for a strong dust<br />

temperature gradient −<br />

Principal Investigator: Masatoshi Imanishi<br />

Institution: National Astronomical Observatory <strong>of</strong> Japan<br />

Technical Contact: Masatoshi Imanishi, NAOJ<br />

Co−Investigators:<br />

Philip R. Maloney, University <strong>of</strong> Colorado<br />

Charles C. Dudley, Naval Research Labolatory<br />

Roberto Maiolino, INAF−Osservatorio di Arcetri<br />

Guido Risaliti, INAF−Osservatorio di Arcetri<br />

Takao Nakagawa, ISAS, JAXA<br />

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

Observing Modes: IrsStare<br />

Hours Approved: 15.5<br />

Abstract:<br />

Ultraluminous infrared galaxies (ULIRGs) have been used extensively to trace the<br />

history <strong>of</strong> star formation in the early universe. However, the major issue <strong>of</strong><br />

whether ULIRGs are powered primarily by starbursts or buried AGNs is poorly<br />

understood. We propose Spitzer IRS low−resolution spectroscopy <strong>of</strong> a complete<br />

sample <strong>of</strong> nearby non−Seyfert ULIRGs. By combining these data with ancillary<br />

ground−based 2.8−4.1 micron spectra, we will search for the signature <strong>of</strong> a<br />

strong dust temperature gradient, an excellent method to distinguish a buried<br />

AGN from a starburst, and quantitatively estimate the energetic importance <strong>of</strong><br />

buried AGNs in ULIRGs. The wide wavelength coverage <strong>of</strong> Spitzer IRS is crucial<br />

for the success <strong>of</strong> this experiment.<br />

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

Printed_by_SSC<br />

Mar 25, 10 16:24 Page 476/742<br />

Spitzer Space Telescope − General Observer Proposal #3377<br />

To what extent does star formation precede the onset <strong>of</strong> AGN activity?<br />

Principal Investigator: Katherine Inskip<br />

Institution: Cavendish Astrophysics Group<br />

Technical Contact: Katherine Inskip, University <strong>of</strong> Sheffield<br />

Co−Investigators:<br />

Paul Alexander, Cavendish Astrophysics<br />

Garret Cotter, Oxford Astrophysics, University <strong>of</strong> Oxford<br />

Malcolm Longair, Cavendish Astrophysics<br />

Bojan Nikolic, Cavendish Astrophysics<br />

Timothy Pearson, Caltech Astronomy<br />

Anthony Readhead, Caltech Astronomy<br />

Richard Savage, Sussex Astronomy Centre, University <strong>of</strong> Sussex<br />

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

Observing Modes: IrsStare<br />

Hours Approved: 5.9<br />

Abstract:<br />

There is increasing evidence that the onset <strong>of</strong> radio−loud AGN activity now<br />

appears to be closely related to starbursts, possibly triggered by mergers. A<br />

commonly proposed evolutionary scenario has emerged in which an<br />

interaction/merger leads to infall <strong>of</strong> gas to the nuclear region, triggering a<br />

starburst. This is followed by a large increase in the amount <strong>of</strong> material being<br />

fed to the central black hole, thereby triggering the production <strong>of</strong> strong radio<br />

emission (e.g. Heckman et al. 1986). Here we propose observations <strong>of</strong> a small<br />

sample <strong>of</strong> radio loud AGN which are known to be young, i.e. their active phase<br />

has been triggered well within the last million years. Our aim is to search,<br />

using mid−IR spectroscopy, for signatures <strong>of</strong> ongoing star formation. Since we<br />

can date, with some confidence, the onset <strong>of</strong> significant AGN activity in these<br />

systems (i.e. the radio jet) such a detection would <strong>of</strong>fer strong support to an<br />

evolutionary scenario in which significant star formation precedes the onset <strong>of</strong><br />

AGN activity.<br />

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

238/371

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