Molecular Gas Content of HI Monsters and Implications to Cold Gas Content Evolution in Galaxies

Abstract

We present 12CO (J=1-0) observations of a sample of local galaxies (0.04<z<0.08) with a large neutral hydrogen reservoir, or "HI monsters". The data were obtained using the Redshift Search Receiver on the FCRAO 14 m telescope. The sample consists of 20 HI-massive galaxies with M(HI)>3e10Msun from the ALFALFA survey and 8 LSBs with a comparable M(HI) (>1.5e10Msun). Our sample selection is purely based on the amount of neutral hydrogen, thereby providing a chance to study how atomic and molecular gas relate to each other in these HI-massive systems. We have detected CO in 15 out of 20 ALFALFA selected galaxies and 4 out of 8 LSBs with molecular gas mass M(H2) of (1-11)e9Msun. Their total cold gas masses of (2-7e10Msun make them some of the most gas-massive galaxies identified to date in the Local Universe. Observed trends associated with HI, H2, and stellar properties of the HI massive galaxies and the field comparison sample are analyzed in the context of theoretical models of galaxy cold gas content and evolution, and the importance of total gas content and improved recipes for handling spatially differentiated behaviors of disk and halo gas are identified as potential areas of improvement for the modeling.

18 pages, 11 figures, 2 tables; Accepted for publication in MNRAS

References in corpus (9)

• Cold streams in early massive hot haloes as the main mode of galaxy formation
• The Role of Pressure in GMC Formation II: The H_2 - Pressure Relation
• COLD GASS, an IRAM Legacy Survey of Molecular Gas in Massive Galaxies: II. The non-universality of the Molecular Gas Depletion Timescale
• Vigorous star formation with low efficiency in massive disk galaxies at z=1.5
• The Atomic to Molecular Transition and its Relation to the Scaling Properties of Galaxy Disks in the Local Universe
• The Cosmic Decline in the H2/HI-Ratio in Galaxies
• WSRT Ultra-Deep Neutral Hydrogen Imaging of Galaxy Clusters at z=0.2, a Pilot Survey of Abell 963 and Abell 2192
• A Pilot Survey of HI in Field Galaxies at Redshift z~0.2
• Potential Condensed Fuel for the Milky Way

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• HIghMass - High HI Mass, HI-Rich Galaxies at $z\sim 0$: Combined HI and H${}_2$ Observations
• Non-circular flows in HIghMass galaxies in a test of the late accretion hypothesis
• Galaxies with Abnormally High Gas Content in the Disk
• MUSE Study of Two Giant Low-surface-brightness Galaxies with Compact Satellites