Mid-Infrared Spectroscopy of High-Redshift Submillimeter Galaxies: First Results

February 2007 • 2007ApJ...655L..65M

Authors • Menéndez-Delmestre, Karín • Blain, Andrew W. • Alexander, Dave M. • Smail, Ian • Armus, Lee • Chapman, Scott C. • Frayer, D. T. • Ivison, Rob J. • Teplitz, H. I.

Abstract • We present mid-infrared spectra of five submillimeter galaxies at z=0.65-2.38 taken with the Spitzer Space Telescope. Four of these sources, at z<~1.5, have strong PAH features and their composite spectrum is well fitted by an M82-like spectrum with an additional power-law component consistent with that expected from AGN activity. Based on comparison with local templates of the 7.7 μm PAH equivalent width and the PAH-to-infrared luminosity ratio, we conclude that these galaxies host both star formation and AGN activity, with star formation dominating the bolometric luminosity. The source at z=2.38 displays a Mrk 231-type broad emission feature at rest frame ~8 μm that does not conform to the typical 7.7 μm/8.6 μm PAH complex in starburst galaxies, suggesting a more substantial AGN contribution.

Links

• PREPRINT http://arxiv.org/abs/astro-ph/0610915
• NED https://ned.ipac.caltech.edu/uri/NED::InRefcode/2007ApJ...655L..65M
• ELECTR https://doi.org/10.1086%2F512038
• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2007ApJ...655L..65M
• PDF https://iopscience.iop.org/article/10.1086/512038/pdf
• DATA https://irsa.ipac.caltech.edu/bibdata/2007/M/2007ApJ...655L..65M.html
• SPIRES http://inspirehep.net/search?p=find+eprint+astro-ph/0610915