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J/ApJ/511/595       An X-Ray Survey of Galaxies in Pairs    (Henriksen+, 1999)

An X-Ray Survey of Galaxies in Pairs Henriksen M., Cousineau S. <Astrophys. J. 511, 595 (1999)> =1999ApJ...511..595H
ADC_Keywords: Clusters, galaxy; Surveys; X-ray sources Mission_Name: ROSAT Keywords: clusters: general - galaxies: interactions - surveys - X-rays: galaxies Abstract: Results are reported from the first survey of X-ray emission from galaxies in pairs. The sample consists of 52 pairs of galaxies from the Catalog of Paired Galaxies (Cat. VII/77) whose coordinates overlap the ROSAT Position Sensitive Proportional Counter pointed observations. The mean observed log(Lx) for early-type pairs is 41.35±0.21, while the mean log(Lx) predicted using the (LX-Lb) relationship for isolated early-type galaxies is 42.10±0.19. With 95% confidence, the galaxies in pairs are underluminous in the X-ray, compared with isolated galaxies, for the same Lb. A significant fraction of the mixed pair sample also appears similarly underluminous. A spatial analysis shows that the X-ray emission from pairs of both types typically has an extent of 10 - 50 kpc, much smaller than the group intergalactic medium, and thus likely originates from the galaxies. CPG 564, the most X-ray luminous early-type pair, 4.7x1042ergs/s, is an exception. The extent of its X-ray emission, greater than 169 kpc, and HWHM, ∼80 kpc, is comparable to that expected from an intergalactic medium. The sample shows only a weak correlation, ∼81% confidence, between LX and Lb, presumably due to variations in gas content within the galaxies. No correlation between LX and the pair velocity difference (δv), separation (δr), or far-infrared luminosity (Lfir) is found, although the detection rate is low, 22%. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 101 52 Data for spiral galaxy pairs table2.dat 101 16 Data for early-type galaxy pairs table3.dat 101 36 Data for mixed galaxy pairs
See also: VII/77 : Catalogue of isolated pairs of galaxies in northern hemisphere J/other/ApL/30.1 : Southern catalogue of isolated pairs extension (Reduzzi+ 1995) VII/113 : Catalogued Galaxies + QSOs observed in IRAS Survey, Vers.2 (IPAC 1989) II/156A : IRAS Faint Source Catalog, |b| > 10, Version 2.0 (Moshir+ 1989) Byte-by-byte Description of file: table*.dat
Bytes Format Units Label Explanations
1- 3 I3 --- CPG Catalog of Paired Galaxies number (1) 8- 19 A12 --- Morph Galaxy morphological type from NED 21- 22 I2 h RAh Right Ascension (J2000) 24- 25 I2 min RAm Right Ascension (J2000) 27- 28 I2 s RAs Right Ascension (J2000) 30 A1 --- DE- Sign of the Declination (J2000) 31- 32 I2 deg DEd Declination (J2000) 34- 35 I2 arcmin DEm Declination (J2000) 37- 38 I2 arcsec DEs Declination (J2000) 43- 48 F6.2 arcmin Sep ? Separation of Galaxy pairs 50- 54 I5 km/s Vel Recessional velocity 56- 60 F5.2 10+36W LumB Blue luminosity (1043ergs/s) 68- 74 F7.3 10-2ct/s Cnts ? Background subtracted Xray counts (10-2/s) 79- 83 F5.3 10-2ct/s e_Cnts ? 1 sigma error in Cnts (10-2/s) 85 A1 --- l_LumX limit on LumX 87- 92 F6.2 10+34W LumX ? Xray luminosity from 0.25-2 KeV (1041ergs/s) 96-101 F6.2 [10-7W] LumIR ? Log of the Far IR luminosity (erg/s) (2)
Note (1): Data in columns CPG and between RAh and LumB are based on information from Karachentsev (1972). A Hubble constant of 50 km.s-1.Mpc-1 is used to calculate the luminosities. Note (2): Calculated from fluxes obtained from the Catalogue of Galaxies and Quasars Observed in the IRAS Survey, version 2.1, as well as the Point Source Catalog and the Faint Source Catalog. The FIR sources occur within a 25 kpc search radius centered on each of the galaxy positions.
History: From ApJ electronic edition References: Karachentsev, I. 1972, Comm. Spec. Ap. Obs., USSR, 7, 1 (CPG)
(End) Greg Schwarz (AAS) 10-Feb-2000
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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