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J/ApJ/470/724       Abell 576 galaxies magnitude and velocities (Mohr+ 1996)

An optical and X-ray study of Abell 576, a galaxy cluster with a cold core. Mohr J.J., Geller M.J., Fabricant D.G., Wegner G., Thorstensen J., Richstone D.O. <Astrophys. J. 470, 724 (1996)> =1996ApJ...470..724M (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Magnitudes ; Spectroscopy Keywords: galaxies: clusters: individual (A576) - galaxies: distances and redshifts - galaxies: luminosity function, mass function - galaxies: photometry - X-rays: galaxies Abstract: We analyse the galaxy population and dynamics of the galaxy cluster A576; the observational constraints include 281 redshifts (230 new), R-band CCD galaxy photometry over a 2h-1Mpcx2h-1Mpc region centered on the cluster, an Einstein IPC X-ray image, and an Einstein MPC X-ray spectrum. We focus on an 86% complete magnitude-limited sample (R23.5<17) of 169 cluster galaxies. The cluster galaxies with emission lines in their spectra have a larger velocity dispersion and are significantly less clustered on this 2h-1Mpc scale than galaxies without emission lines. We show that excluding the emission-line galaxies from the cluster sample decreases the velocity dispersion by 18% and the virial mass estimate by a factor of 2. The central cluster region contains a non-emission galaxy population and an intracluster medium which is significantly cooler (σcore=387+250-105km/s and TX=1.6-0.3/+0.4keV at 90% confidence) than the global populations (σ=977+124-96km/s for the non-emission population and TX>4keV at 90% confidence). Because (1) the low-dispersion galaxy population is no more luminous than the global population and (2) the evidence for a cooling flow is weak, we suggest that the core of A576 may contain the remnants of a lower mass subcluster. We examine the cluster mass, baryon fraction, and luminosity function. The cluster virial mass varies significantly depending on the galaxy sample used. Consistency between the hydrostatic and virial estimators can be achieved if (1) the gas temperature at r∼1h-1Mpc is TX∼8keV (the best-fit value) and (2) several velocity outliers are excluded from the virial calculation. Although the best-fit Schechter function parameters and the ratio of galaxy to gas mass in A576 are typical of other clusters, the baryon fraction is relatively low. Using the consistent cluster binding mass, we show that the gas mass fraction is ∼3h-3/2% and the baryon fraction is ∼4%. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 53 281 Galaxy velocities and photometry
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1 I1 h RAh [7] Right ascension (1950) 3- 4 I2 min RAm Right ascension (1950) 6- 10 F5.2 s RAs Right ascension (1950) 12 A1 --- DE- Declination sign 13- 14 I2 deg DEd [55/56] Declination (1950) 16- 17 I2 arcmin DEm Declination (1950) 19- 22 F4.1 arcsec DEs Declination (1950) 24- 28 F5.2 mag R23.5 Isophotal R=23.5mag/arcsec2 magnitude 29 A1 --- n_R23.5 Note on R23.5 (1) 31- 35 F5.3 mag e_R23.5 rms uncertainty on R23.5 37- 41 I5 km/s Vel Line-of-sight velocity 42 A1 --- n_Vel Note on velocity (1) 44- 46 I3 km/s e_Vel rms uncertainty on Vel 48 A1 --- Type [NE] E: emission; N: non-emission
Note (1): #: POSS digitized scan photometry +: Hintzen et al., 1982AJ.....87.1656H *: Marzke & Huchra 1996, in prep. x: Hill et al., 1980ApJ...242L..69H
History: Prepared via OCR at CDS. * 30-Sep-1998: 4 OCR errors detected by H. Andernach and corrected ()
(End) James Marcout, Patricia Bauer [CDS] 30-Sep-1997
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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