Extragalactic abstracts - IRSA - California Institute of Technology

Spitzer_Approved_Extragalactic
Mar 25, 10 16:24 Page 355/742
Spitzer Space Telescope − General Observer Proposal #30431
Mid−IR Ultra−Deep Spectroscopy of the Cosmic Infrared Background
Principal Investigator: Lin Yan
Institution: Caltech
Technical Contact: Lin Yan, Caltech
Co−Investigators:
Guilaine Lagache, Institut d’Astrophysique Spatiale, France
Anna Sajina, Spitzer Science Center, Caltech
Karina Caputi, Institut d’Astrophysique Spatiale, Orsay, France
Emeric Le Floc’h, University of Arizona
Dieter Lutz, MPE, Garching, Germany
Herve Dole, Institut d’Astrophysique Spatiale, Orsay, France
Andrew Blain, Caltech
Dario Fadda, Spitzer Science Center, Caltech
Reinhard Genzel, MPE, Garching, Germany
Bruce Draine, Princeton University
Jean−Loup Puget, Institut d’Astrophysique Spatiale, France
Henrik Spoon, Cornell University
Catherine Cesarsky, European Southern Observatory
Sylvain Veilleux, University of Maryland
Dave Sanders, University of Hawaii
George Helou, Spitzer Science Center, Caltech
Frank Bertoldi, University of Bonn
Hector Flores, Observatoire de Paris−Meudon, France
Dave Frayer, Spitzer Science Center, Caltech
Science Category: high−z galaxies (z>0.5)
Observing Modes: IrsMap
Hours Approved: 307.0
Abstract:
We propose to obtain low resolution, mid−IR spectra of a sample of 48 galaxies
at z~1 and 2 with 24um flux densities between 0.15−0.5mJy in the CDFS. These
sub−mJy 24um sources are shown to dominate the Cosmic Infrared Background (CIB)
emission at 70 & 160um (Dole et al. 2006). Their redshift distribution peaks
around 1, with a secondary peak at z~2. This implies these sources are LIRGs and
ULIRGs at z=1 and 2, respectively. Measurements of IR luminosity functions
support these findings and directly show these populations are responsible for
more than 70% of the total (UV+IR) luminosity density at z=0.8−2.5. The proposed
program is the natural extension of our previous studies of brighter, mJy 24um
galaxies. Our primary goal is to characterize the mid−IR spectral properties of
the galaxies producing the bulk of CIB. Specifically, we will disentangle the
AGN/SB contribution to mid−IR emission, thus constrain the estimate of
bolometric luminosities. The proposed spectra, in combination with brighter
samples from previous IRS surveys, will allow us to trace the evolution of
AGN/SB ratio, strength of PAH emission and mid−IR opacities as a function of
L(ir) and z. The deep mid−IR spectra, together with the existing
multi−wavelength dataset, will provide the lasting legacy for the astronomical
communities for many years to come.
Spitzer_Approved_Extragalactic
Printed_by_SSC
Mar 25, 10 16:24 Page 356/742
Spitzer Space Telescope − General Observer Proposal #3407
Filling the IRAC Gap in a Deep MIPS 24−micron Field
Principal Investigator: Haojing Yan
Institution: JPL
Technical Contact: Haojing Yan, JPL
Co−Investigators:
Stefano Casertano, STScI
Ranga−Ram Chary, Spitzer Science Center
Mark Dickinson, STScI
Peter Eisenhardt, JPL
David Elbaz, CEA Saclay, France
Harry Ferguson, STScI
Norman Grogin, STScI
Leonidas Moustakas, STScI
Daniel Stern, JPL
Lin Yan, Spitzer Science Center
Science Category: high−z galaxies (z>0.5)
Observing Modes: IracMap
Hours Approved: 4.4
Abstract:
As a validation test of the GOODS MIPS program, the Spitzer Space Telescope has
obtained a very deep 24−micron exposure covering four MIPS pointings in the
ELAIS−N1 field (80 minutes per pointing). These data are public and will be
released to the community in the context of the First Look Survey. These
observations constitute the deepest ever image of the 24−micron sky to date, and
will remain as one of the deepest other than the GOODS observations themselves.
This 24−micron field is uniquely important, especially in addressing the mass
assembly history of typical luminosity galaxies 1 < z < 2. The MIPS observations
are already complemented by deep IRAC data (2 hours per pointing −−− also the
deepest non−GOODS public data set), but with only 2−band coverage at each
position. We propose to complete the full, 4−channel IRAC coverage over the
entire MIPS 24−micron field. With the full spectral coverage provided by the
IRAC, we will be able to provide redshift estimates for the vast majority of the
24−micron sources. A significant fraction of the 24−micron sources have no
R−band counterparts to AB=24.7 mag, which means optical spectroscopic redshifts
for these objects are presently impossible. With this IRAC data set, we will
greatly boost the diagnostic power of the unique 24−micron data. The proposed
observation can be finished in 4.4 hours, including overhead. We request no
proprietary period and the data will be released to the public as part of the
First Look Survey.
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