Extragalactic abstracts - IRSA - California Institute of Technology

Spitzer_Approved_Extragalactic
Mar 25, 10 16:24 Page 515/742
Spitzer Space Telescope − Guaranteed Time Observer Proposal #59
Starburst Activity in Nearby Galaxies
Principal Investigator: George Rieke
Institution: The University of Arizona
Technical Contact: Chad Engelbracht, The University of Arizona
Science Category: AGN/quasars/radio galaxies
Observing Modes: IracMap IrsMap IrsStare MipsPhot MipsScan
Hours Approved: 45.3
Abstract:
This program combines MIPS and IRAC imaging and MIPS and IRS spectroscopy (where
available) of a sample of nearby starburst galaxies, over a range of metallicity
and luminosity that includes the lowest metallicity galaxies known. These
galaxies are near enough that groundbased support data already exist for many of
them and they are bright enough that observing them does not take much time
(except for the lowest metallicity galaxies). These data will be combined with
new groundbased data and data from the literature to constrain a suite of
starburst models. The models will provide the age and intensity of the burst
that is consistent with the observations over a broad range of wavelengths and
could be used to predict the subsequent evolution of the galaxy properties.
Furthermore, this extremely detailed study of a small sample of starburst
galaxies would provide the insight required to interpret observations of more
distant galaxies (such as in the cosmological surveys) where we may only have a
few photometric data points.
Spitzer_Approved_Extragalactic
Printed_by_SSC
Mar 25, 10 16:24 Page 516/742
Spitzer Space Telescope − Guaranteed Time Observer Proposal #61
Intrinsic Spectra of Hyperluminous Infrared Galaxies
Principal Investigator: George Rieke
Institution: The University of Arizona
Technical Contact: Dean Hines, Space Science Institute
Science Category: AGN/quasars/radio galaxies
Observing Modes: IrsStare
Hours Approved: 8.2
Abstract:
We will use the low and high spectral resolution capabilities of the IRS aboard
SIRTF to obtain high signal−to−noise mid−infrared spectra of a small sample of
the most luminous Active Galactic Nuclei, which are characterized by their
"warm" far−infrared spectral energy distributions as obtained by IRAS (the so
called Hyperluminous Infrared Galaxies or HIGs). The sample consists of both
Type 2 and Type 1 AGNs. The Type 1 objects present a relatively unobscured view
of the central engine, and also have a polarized (scattered) component that is
completely unobscured. The Type 2 objects have Type 1 polarized spectra, but
this scattered light is highly extinguished indicating some obscuration even
along the line of sight to the scattering region. The sample will allow us to
compare the properties of the Type 1s and Type 2s, thus providing a check on the
orientation and providing strong constraints on the geometry and internal
structure of all four objects.
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