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 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 />
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