Tuesday 07/10/2012

AKARI Near-Infrared Spectroscopy of Luminous Infrared Galaxies Jong Chul Lee (KASI), Ho Seong Hwang (CfA), Myung Gyoon Lee (SNU), Minjin Kim (KASI), Joon Hyeop Lee (KASI) (Submitted on 7 Jul 2012)

We present the AKARI near-infrared (NIR; 2.5-5 micron) spectroscopic study of 36 (ultra)luminous infrared galaxies [(U)LIRGs] at z=0.01-0.4. We measure the NIR spectral features including the strengths of 3.3 micron polycyclic aromatic hydrocarbon (PAH) emission and hydrogen recombination lines (Br\alpha. and Br\beta), optical depths at 3.1 and 3.4 micron, and NIR continuum slope. These spectral features are used to identify optically elusive, buried AGN. We find that half of the (U)LIRGs optically classified as non-Seyferts show AGN signatures in their NIR spectra. Using a combined sample of (U)LIRGs with NIR spectra in the literature, we measure the contribution of buried AGN to the infrared luminosity from the SED-fitting to the IRAS photometry. The contribution of these buried AGN to the infrared luminosity is 5-10%, smaller than the typical AGN contribution of (U)LIRGs including Seyfert galaxies (10-40%). We show that NIR continuum slopes correlate well with WISE [3.4]-[4.6] colors, which would be useful for identifying a large number of buried AGN using the WISE data.

Comments: ApJ, accepted. 37 pages, 11 figures
Subjects: Cosmology and Extragalactic Astrophysics (astro-ph.CO)
Cite as: arXiv:1207.1816v1 [astro-ph.CO]

Updating quasar bolometric luminosity corrections. II. Infrared bolometric corrections Jessie C. Runnoe, Michael S. Brotherton, Zhaohui Shang (Submitted on 9 Jul 2012)

We present infrared bolometric luminosity corrections derived from the detailed spectral energy distributions of 62 bright quasars of low- to moderate-redshift (z=0.03-1.4). At 1.5, 2, 3, 7, 12, 15, and 24 microns we provide bolometric corrections of the mathematical forms L_iso=\zeta \lambda L_\lambda and log(L_iso)=A+B log(\lambda L_\lambda). Bolometric corrections for radio-loud and radio-quiet objects are consistent within 95% confidence intervals, so we do not separate them. Bolometric luminosities estimated using these corrections are typically smaller than those derived from some commonly used in the literature. We investigate the possibility of a luminosity dependent bolometric correction and find that, while the data are consistent with such a correction, the dispersion is too large and the luminosity range too small to warrant such a detailed interpretation. Bolometric corrections at 1.5 $\mu$m are appropriate for objects with properties that fall in the range log(L_bol)=45.4-47.3 and bolometric corrections at all other wavelengths are appropriate for objects with properties that fall in the range log(L_bol)=45.1-47.0.

Comments: 13 pages, 4 tables, 8 figures, accepted to MNRAS
Subjects: Cosmology and Extragalactic Astrophysics (astro-ph.CO)
Cite as: arXiv:1207.2124v1 [astro-ph.CO]
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