Total Molecular Gas Masses of Planck – Herschel Selected Strongly Lensed Hyper Luminous Infrared Galaxies
Monthly Notices of the Royal Astronomical Society
We report the detection of CO(1–0) line emission from seven Planck and Herschel selected hyper luminous (LIR(8−1000μm) > 1013 L⊙) infrared galaxies with the Green Bank Telescope (GBT). CO(1–0) measurements are a vital tool to trace the bulk molecular gas mass across all redshifts. Our results place tight constraints on the total gas content of these most apparently luminous high-z star-forming galaxies (apparent IR luminosities of LIR > 1013 − 14 L⊙), while we confirm their predetermined redshifts measured using the Large Millimeter Telescope, LMT (zCO = 1.33–3.26). The CO(1–0) lines show similar profiles as compared to Jup = 2–4 transitions previously observed with the LMT. We report enhanced infrared to CO line lu- minosity ratios of ⟨LIR/L′CO(1−0)⟩ = 110 ± 22 L⊙(K km s−1 pc−2)−1 compared to normal star-forming galaxies, yet similar to those of well-studied IR-luminous galaxies at high-z. We find average brightness temperature ratios of ⟨ r21 ⟩ = 0.93 (2 sources), ⟨ r31 ⟩ = 0.34 (5 sources), and ⟨r41⟩ = 0.18 (1 source). The r31 and r41 values are roughly half the average values for SMGs. We estimate the total gas mass content as μMH2 = (0.9−27.2) × 1011(αCO/0.8) M⊙, where μ is the magnification factor and αCO is the CO line luminosity to molecular hydrogen gas mass conversion factor. The rapid gas depletion times, ⟨τdepl⟩ = 80 Myr, reveal vigorous starburst activity, and contrast the Gyr depletion time-scales observed in local, normal star-forming galaxies.
galaxies: high-redshift, galaxies: ISM, galaxies: starburst
© 2017 The Author(s)
Harrington, K. C.; Yun, M. S.; Magnelli, B.; Frayer, D. T.; Karim, A.; Weiß, A.; Riechers, D.; Jiménez-Andrade, E. F.; Berman, D.; Lowenthal, James; and Bertoldi, F., "Total Molecular Gas Masses of Planck – Herschel Selected Strongly Lensed Hyper Luminous Infrared Galaxies" (2017). Astronomy: Faculty Publications, Smith College, Northampton, MA.
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