NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-03-26 T07:28:28 PDT
Help | Comment | NED Home

For refcode 1995ApJ...442..523E:
Retrieve 84 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
1995ApJ...442..523E A MULTIPARAMETRIC ANALYSIS OF THE EINSTEIN SAMPLE OF EARLY-TYPE GALAXIES. II. GALAXY FORMATION HISTORY AND PROPERTIES OF THE INTERSTELLAR MEDIUM PAUL B. ESKRIDGE AND GIUSEPPINA FABBIANO Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 AND DONG-WOO KIM Harvard-Smithsonian Center for Astrophysics; and Department of Astronomy and Space Science, Chungnam National University, Taejon. 305-764, South Korea Received 1994 July 22; accepted 1994 October 12 ABSTRACT We have conducted bivariate and multivariate statistical analysis of data measuring the integrated luminosity, shape, and potential depth of the Einstein sample of early-type galaxies (presented by Fabbiano et al. 1992). We find significant correlations between the X-ray properties and the axial ratios (a/b) of our sample, such that the roundest systems tend to have the highest L_X_ and L_X_/L_B_. The most radio-loud objects are also the roundest. We confirm the assertion of Bender et al. (1989) that galaxies with high L_X_ are boxy (have negative a_4_). Both a/b and a_4_ are correlated with L_B_, but not with IRAS 12 micron and 100 micron luminosities. There are strong correlations between L_X_, Mg_2_ and {sigma}_v_ in the sense that those systems with the deepest potential wells have the highest L_X_ and Mg_2_. Thus the depth of the potential well appears to govern both the ability to retain an ISM at the present epoch and to retain the enriched ejecta of early star formation bursts. Both L_X_/L_B_ and L_6_ (the 6 cm radio luminosity) show threshold effects with {sigma}_v_ exhibiting sharp increases at log ({sigma}_v_)~ 2.2. Finally, there is clearly an interrelationship between the various stellar and structural parameters: The scatter in the bivariate relationships between the shape parameters (a/b and a_4_) and the depth parameter ({sigma}_v_) is a function of abundance in the sense that, for a given a_4_ or a/b, the systems with the highest {sigma}_v_ also have the highest Mg_2_. Furthermore, for a constant {sigma}_v_ disky galaxies tend to have higher Mg_2_ than boxy ones. Alternatively, for a given abundance, boxy ellipticals tend to be more massive than disky ellipticals. One possibility is that early-type galaxies of a given mass, originating from mergers (boxy ellipticals), have lower abundances than "primordial" (disky) early-type galaxies. Another is that disky inner isophotes are due not to primordial dissipational collapse, but to either the self-gravitating inner disks of captured spirals or the dissipational collapse of new disk structures from the premerger ISM. The high measured nuclear Mg_2_ values would thus be due to enrichment from secondary bursts of star formation triggered by the merging event. Subject headings: galaxies: elliptical and lenticular, cD - galaxies: ISM - galaxies: structure - X-rays: galaxies
Retrieve 84 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home