H I in early-type galaxies. I - Observations

Journal Article · Sat Nov 01 04:00:00 EST 1975 · Astrophysical Journal

DOI:https://doi.org/10.1086/153948· OSTI ID:4112047

Gallagher, J. S.; Faber, S. M.; Balick, B.

New 21-cm observations of 25 E and S0 galaxies provide a basis for an observational study of relationships between H i content and other properties of early-type systems. Only two galaxies in the sample, NGC 2685 (S0p) and the normal S0 NGC 5102, are detected. Previously reported detections of NGC 1332, NGC 3115, NGC 4274, and NGC 4526 are not confirmed. A very low limit of M_i/ L_pg<0.007 is also measured for the Sombrero Galaxy, NGC 4594. By assuming that the undetected E's and S0's are representative of homogeneous populations, limits for mean E and S0 galaxies of M_i/ L_pg<0.009 and <0.015, respectively, are found. All available H i observations of early-type galaxies are used to generate a list (containing four normal S0's and 12 peculiar galaxies) of high-probability detections. From these data and our new measurements, it is concluded: Elliptical galaxies contain at most 0.1 percent H i by mass. Some structurally normal S0 galaxies exist with M_i/ L_pg approximately-greater-than 0.05, while other, apparently similar, systems have upper limits M_i/ L_pg<0.03. In terms of H i content, the S0 class to be a true transition between the H i properties of spirals and ellipticals. In some galaxies an extensive interstellar medium is obviously present, but has different properties from those usually found in later type spirals. Among the morphologically peculiar early-type galaxies, those which exhibit violent activity are rich in H i. (AIP)

• Research Organization: University of Nebraska-Lincoln, and University of Minnesota, Minneapolis
• Sponsoring Organization: USDOE
• NSA Number: NSA-33-018198
• OSTI ID: 4112047
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Vol. 202; ISSN 0004-637X
• Publisher: Institute of Physics (IOP)
• Country of Publication: United States
• Language: English

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