Extragalactic abstracts - IRSA - California Institute of Technology

Spitzer_Approved_Extragalactic
Mar 25, 10 16:24 Page 469/742
Spitzer Space Telescope − Guaranteed Time Observer Proposal #15
Seeking Redshifts for Optically Unidentifiable Infrared Sources
Principal Investigator: James R. Houck
Institution: Cornell University
Technical Contact: Daniel Weedman, National Science Foundation
Science Category: AGN/quasars/radio galaxies
Observing Modes: IrsStare
Hours Approved: 129.4
Abstract:
Optically faint or unidentifiable sources from ISOCAM 15 micron, ISO FIRBACK,
and SCUBA surveys are selected for MIPS and IRS lo res observations with the
objective of determining spectroscopic redshifts. IRS observations will be
obtained only for sources found to have MIPS 24 micron fluxes above about 0.7
mJy. Eventual IRS targets will also be chosen from the First Look Survey.
Spitzer_Approved_Extragalactic
Printed_by_SSC
Mar 25, 10 16:24 Page 470/742
Spitzer Space Telescope − Guaranteed Time Observer Proposal #30272
IRS mapping of the 500 pc nuclear dust shell in Centaurus A
Principal Investigator: James R. Houck
Institution: Cornell University
Technical Contact: Alice Quillen, University of Rochester
Co−Investigators:
Alice Quillen, University of Rochester
Joss Bland Hawthorne, Anglo Australian Observatory
Mairi Brookes, JPL
Charles Lawrence, JPL
J.D. Smith, University of Arizona
Kieran Cleary, JPL
Science Category: AGN/quasars/radio galaxies
Observing Modes: IrsMap
Hours Approved: 7.1
Abstract:
We propose to map the central 1.5’ of Centaurus A with IRS. This region covers a
recently discovered 500pc bipolar shell. This shell, if confirmed, could be the
only extragalactic nuclear shell with a mid−infrared counter part. Hence
Centaurus A represents a unique laboratory to test scenarios and models of
feedback from an AGN or/and circumnuclear star formation on the ISM near the
nucleus. By comparing the IRS spectra of the shell component with the star
forming parallelogram shaped region corresponding to the warped disk, we will
seek confirmation that the shell is a separate and coherent structure, and
better estimate its dust temperature and so mass. Derived constraints on its
energetics will form the basis of subsequent models accounting for its
formation. We will search for evidence of shocks in the shell due to its
expansion and where the jets pass through it. As the shell covers all solid
angles from the nuclear black hole, the IRS spectra will also be used to search
for angular variations in the ambient UV radiation field.
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