Far-infrared properties of early-type galaxies

Abstract

view Abstract Citations (26) References (38) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Far-Infrared Properties of Early-Type Galaxies Mazzei, P. ; de Zotti, G. Abstract We have investigated the IRAS colors and the far-IR to optical luminosity ratios of a complete sample of elliptical and S0 galaxies brighter than B_T_ = 12. On the average, elliptical galaxies emit in the far-IR less than 1% of their bolometric luminosity; S0 galaxies are about a factor of 3 brighter in the far-IR. There is a considerable spread in the far-IR properties of individual galaxies. On the average, the photospheric emission of red giant stars can account for 50%-60% of the 12 micron flux from early-type galaxies; the contribution from diffuse dust at this wavelength is <10% in the case of elliptical galaxies and may amount to 20%-40% for S0 galaxies. An additional, ~30%-40%, contribution from circumstellar emission from evolved giants with mass loss (particularly OH/IR stars) seems to be required in the case of elliptical galaxies. This suggests a small but significant star-formation activity in these galaxies at a look-back time of 1-2 Gyr, corresponding to about 10% of that typical of a disk galaxy having the same V-band luminosity. As for S0 galaxies, the larger diffuse dust emission may swamp to some extent that of circumstellar dust, which is indicated to comprise, on the average, <~20% of the far-IR emission. The weak emission from diffuse interstellar dust, detected mostly at 60 microns and 100 microns, has color temperatures similar to those of disk galaxies; as in the case of the latter, a warm dust component is suggested, associated to star-forming regions, in addition to a cooler component, heated by the general interstellar radiation field. The implied star formation would be a few percent of that of disk galaxies of similar V-band luminosity and could account for a fraction of the observed UV branch of early-type galaxies. Publication: The Astrophysical Journal Pub Date: May 1994 DOI: 10.1086/174042 arXiv: arXiv:astro-ph/9402005 Bibcode: 1994ApJ...426...97M Keywords: Elliptical Galaxies; Far Infrared Radiation; Infrared Astronomy; Infrared Spectra; Interstellar Matter; Lenticular Bodies; Luminosity; Red Giant Stars; Spiral Galaxies; Astronomical Catalogs; Infrared Astronomy Satellite; Satellite-Borne Instruments; Star Formation Rate; Stellar Envelopes; Astrophysics; GALAXIES: ELLIPTICAL AND LENTICULAR; CD; GALAXIES: ISM; GALAXIES: SPIRAL; GALAXIES: STELLAR CONTENT; INFRARED: GALAXIES; Astrophysics E-Print: tex, 9 pages, 6 figures upon request full text sources arXiv | ADS | data products SIMBAD (1)