J/ApJ/442/523Multiparam. Analysis, Einstein Sample. II. (Eskridge+ 1995)

A Multiparametric Analysis of the Einstein Sample of Early-Type Galaxies. II. Galaxy Formation History and Properties of the Interstellar Medium Eskridge P.B., Fabbiano G., Kim D.-W. <Astrophys. J. 442, 523 (1995)> =1995ApJ...442..523EADC_Keywords: Galaxies, optical; Interstellar mediumKeywords: galaxies: elliptical and lenticular, cD -- galaxies: ISM -- galaxies: structure -- X-rays: galaxiesAbstract: 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. =1992ApJS...80..531F). 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. (1989A&A...217...35B) 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 um and 100 um 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.File Summary:

FileName Lrecl Records Explanations

ReadMe 80 . This file tablea1a.dat 63 113 Partial Spearman Rank Analysis: Trends with Log(a/b), E+S0 Sample tablea1b.dat 50 18 Partial Spearman Rank Analysis: Trends with Log(a/b), Separate E and S0 Samples tablea2.dat 63 143 Partial Spearman Rank Analysis: Trends with Mg_2 tablea3.dat 63 155 Partial Spearman Rank Analysis: Trends with sigma_v tablea4.dat 63 233 Partial Spearman Rank Analysis: Trends with a_4

Comments for file: tablea1a.dat -------------------------------------------------------------------------------- Table A1a shows the partial Spearman rank statistical analysis of L_B--a/b, L_X--a/b, L_{X/L}B--a/b, and L_6--a/b.Byte-by-byte Description of file: tablea1a.dat

Bytes Format Units Label Explanations

1- 14 A14 --- Pair Test pair, if blank, record is a continuation 15- 44 A30 --- Held Quantities to be held constant in the test 45- 47 I3 --- Size Number of objects in the sample 48- 55 F8.3 --- Spearman Partial Spearman rank statistic 57 A1 --- l_Prob Probability limiting character 58- 63 F6.3 --- Prob Probability that the test pair shows a correlation for this set of parameters

Comments for file: tablea1b.dat -------------------------------------------------------------------------------- Table A1b shows the partial Spearman rank statistical analysis of separate E and S0 samples for L_B--a/b, L_X--a/b, and L_{X/L}B--a/bByte-by-byte Description of file: tablea1b.dat

Bytes Format Units Label Explanations

1- 14 A14 --- Pair Test pair, if blank, record is a continuation 15- 26 A12 --- Held Quantities to be held constant in the test 28- 31 A4 --- Sample Sample designation, Es or S0s 32- 34 I3 --- Size Number of objects in the sample 35- 42 F8.3 --- Spearman Partial Spearman rank statistic 44 A1 --- l_Prob Probability limiting character 45- 50 F6.3 --- Prob Probability that the test pair shows a correlation for this set of parameters

Comments for file: tablea2.dat -------------------------------------------------------------------------------- Table A2 shows the partial Spearman rank statistical analysis of L_{B--Mg}2, L_{X--Mg}2, L_{X/L}B--Mg_2, a/b--Mg_2 and Mg_{2--C}21.Byte-by-byte Description of file: tablea2.dat

Bytes Format Units Label Explanations

1- 14 A14 --- Pair Test pair, if blank, record is a continuation 15- 44 A30 --- Held Quantities to be held constant in the test 45- 47 I3 --- Size Number of objects in the sample 48- 55 F8.3 --- Spearman Partial Spearman rank statistic 57 A1 --- l_Prob Probability limiting character 58- 63 F6.3 --- Prob Probability that the test pair shows a correlation for this set of parameters

Comments for file: tablea3.dat -------------------------------------------------------------------------------- Table A3 shows the partial Spearman rank statistical analysis of L_{B--sigma}v, L_{X--sigma}v, L_{X/L}B--sigma_v, a/b--sigma_v, and Mg_{2--sigma}v.Byte-by-byte Description of file: tablea3.dat

Bytes Format Units Label Explanations

1- 18 A18 --- Pair Test pair, if blank, record is a continuation 19- 44 A26 --- Held Quantities to be held constant in the test 45- 47 I3 --- Size Number of objects in the sample 48- 55 F8.3 --- Spearman Partial Spearman rank statistic 57 A1 --- l_Prob Probability limiting character 58- 63 F6.3 --- Prob Probability that the test pair shows a correlation for this set of parameters

Comments for file: tablea4.dat -------------------------------------------------------------------------------- Table A4 shows the partial Spearman rank statistical analysis of L_{B--a}4, L_{X--a}4, L_{X/L}B--a_4, L_{6--a}4, a/b--a_4, Mg_{2--a}4, and sigma_{v--a}4Byte-by-byte Description of file: tablea4.dat

Bytes Format Units Label Explanations

1- 14 A14 --- Pair Test pair, if blank, record is a continuation 15- 44 A30 --- Held Quantities to be held constant in the test 45- 47 I3 --- Size Number of objects in the sample 48- 55 F8.3 --- Spearman Partial Spearman rank statistic 57 A1 --- l_Prob Probability limiting character 58- 63 F6.3 --- Prob Probability that the test pair shows a correlation for this set of parameters

Origin: AAS CD-ROM series, Volume 4, 1995 Lee Brotzman [ADS] 06-May-1995(End)[CDS] 11-Jul-1995

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