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NIR Spectroscopy and a Search for CO Emission in Three Extremely Luminous IRAS Sources; IR 09105+4108, IR 15307+3252, and PG 1634+706

A. S. Evans·D. B. Sanders·R. M. Cutri·S. J. E. Radford·J. A. Surace·P. M. Solomon·D. Downes·C. Kramer
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Abstract

Rest-frame 0.48-1.1 micron emission line strengths and molecular gas mass (H_2) upper limits for 3 luminous infrared sources - the hyperluminous infrared galaxies IR F09105+4108 (z=0.44), IR F15307+3252 (z=0.93), and the optically-selected QSO PG 1634+706 (z=1.3) - are presented. Diagnostic emission-line ratios indicate a Seyfert 2-like spectrum for both infrared galaxies, consistent with previously published work. The upper limits of molecular gas mass for all 3 sources are M(H_2) < 1-3x10^10 h^-2 M_sun (q=0.5, H=100h km/s/Mpc), less than that of the most gas-rich infrared galaxies in the local Universe. All 3 sources have L_ir/L'_CO = 1300-2000, and thus are the extragalactic sources with the most extreme L_ir/L'_CO values measured to date. Given the relatively warm far-infrared colors for all 3 objects, much of their infrared luminosity may emanate from a relatively modest amount of warm dust (e.g. M_d = 10^5-7 M_sun, T_d = 200-100 K) near the AGN...

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A. S. Evans, D. B. Sanders, R. M. Cutri, S. J. E. Radford, J. A. Surace, P. M. Solomon, D. Downes, C. Kramer. 1998-06-05. NIR Spectroscopy and a Search for CO Emission in Three Extremely Luminous IRAS Sources; IR 09105+4108, IR 15307+3252, and PG 1634+706. https://doi.org/10.1086/306234

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