F. Boone
Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches
Boone, F.; Schaerer, D.; Pelló, R.; Lutz, D.; Weiss, A.; Egami, E.; Smail, I.; Rex, M.; Rawle, T.; Ivison, R.; Laporte, N.; Beelen, A.; Combes, F.; Blain, A.W.; Richard, J.; Kneib, J.-P.; Zamojski, M.; Dessauges-Zavadsky, M.; Altieri, B.; van der Werf, P.; Swinbank, M.; Pérez-Gonzá&lez, P.G.; Clement, B.; Nordon, R.; Magnelli, B.; Menten, K.M.
Authors
D. Schaerer
R. Pelló
D. Lutz
A. Weiss
E. Egami
Ian Smail ian.smail@durham.ac.uk
Emeritus Professor
M. Rex
T. Rawle
R. Ivison
N. Laporte
A. Beelen
F. Combes
A.W. Blain
J. Richard
J.-P. Kneib
M. Zamojski
M. Dessauges-Zavadsky
B. Altieri
P. van der Werf
M. Swinbank
P.G. Pérez-Gonzá&lez
B. Clement
R. Nordon
B. Magnelli
K.M. Menten
Abstract
The spectral energy distributions (SED) of dusty galaxies at intermediate redshift may look similar to very high-redshift galaxies in the optical/near infrared (NIR) domain. This can lead to the contamination of high-redshift galaxy searches based on broad-band optical/NIR photometry by lower redshift dusty galaxies because both kind of galaxies cannot be distinguished. The contamination rate could be as high as 50%. This work shows how the far-infrared (FIR) domain can help to recognize likely low-z interlopers in an optical/NIR search for high-z galaxies. We analyze the FIR SEDs of two galaxies that are proposed to be very high-redshift (z > 7) dropout candidates based on deep Hawk-I/VLT observations. The FIR SEDs are sampled with PACS/Herschel at 100 and 160 μm, with SPIRE/Herschel at 250, 350 and 500 μm and with LABOCA/APEX at 870 μm. We find that redshifts > 7 would imply extreme FIR SEDs (with dust temperatures >100 K and FIR luminosities >1013 L⊙). At z ~ 2, instead, the SEDs of both sources would be compatible with those of typical ultra luminous infrared galaxies or submillimeter galaxies. Considering all available data for these sources from visible to FIR we re-estimate the redshifts and find z ~ 1.6–2.5. Owing to the strong spectral breaks observed in these galaxies, standard templates from the literature fail to reproduce the visible-to-near-IR part of the SEDs even when additional extinction is included. These sources strongly resemble dust-obscured galaxies selected in Spitzer observations with extreme visible-to-FIR colors, and the galaxy GN10 at z = 4. Galaxies with similar SEDs could contaminate other high-redshift surveys.
Citation
Boone, F., Schaerer, D., Pelló, R., Lutz, D., Weiss, A., Egami, E., …Menten, K. (2011). Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches. Astronomy & Astrophysics, 534, Article A124. https://doi.org/10.1051/0004-6361/201117338
Journal Article Type | Article |
---|---|
Publication Date | Oct 1, 2011 |
Deposit Date | Jan 25, 2012 |
Publicly Available Date | Jun 14, 2013 |
Journal | Astronomy and astrophysics. |
Print ISSN | 0004-6361 |
Electronic ISSN | 1432-0746 |
Publisher | EDP Sciences |
Peer Reviewed | Peer Reviewed |
Volume | 534 |
Article Number | A124 |
DOI | https://doi.org/10.1051/0004-6361/201117338 |
Keywords | Galaxies, distances and redshifts, Dust, Extinction, Gravitational lensing, Weak, High-redshift. |
Public URL | https://durham-repository.worktribe.com/output/1529435 |
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Copyright Statement
The original publication is available at http://www.afs-journal.org
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