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J/ApJ/440/28        Brightest Cluster Galaxies velocities (Postman+ 1995)

Brightest cluster galaxies as standard candles. Postman M., Lauer T.R <Astrophys. J. 440, 28 (1995)> =1995ApJ...440...28P (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Magnitudes ; Radial velocities Keywords: galaxies: clusters: general - galaxies: photometry Abstract: We investigate the use of Brightest Cluster Galaxies (BCGs) as standard candles for measuring galaxy peculiar velocities on large scales. We have obtained precise large-format CCD surface photometry and redshifts for an all-sky, volume-limited (z≤0.05) sample of 119 BCG. We reinvestigate the Hoessel (1980ApJ...241..493H) relationship between the metric luminosity, Lm, within the central 10h-1kpc of the BCGs and the logarithmic slope of the surface brightness profile, α. The Lm-α relationship reduces the cosmic scatter in Lm from 0.327mag to 0.244mag, yielding a typical distance accuracy of 17% per BCG. Residuals about the Lm-α relationship are independent of BCG luminosity, BCG B-Rc color, BCG location within the host cluster, and richness of the host cluster. The metric luminosity is independent of cluster richness even before correcting for its dependence on α, which provides further evidence for the unique nature of the BCG luminosity function. Indeed, the BCG luminosity function, both before and after application of the α-correction, is consistent with a single Gaussian distribution. Half the BCGs in the sample show some evidence of small color gradients as a function of radius within their central 50h-1kpc regions but with almost equal numbers becoming redder as becoming bluer. However, with the central 10h-1kpc the colors are remarkably constant, the mean B-Rc color is 1.51 with a dispersion of only 0.06mag. The narrow photometric and color distributions of the BCGs, the lack of "second-parameter" effects, as well as the unique rich cluster environment of BCGs, argue that BCGs are the most homogeneous distance indicators presently available for large-scale structure research. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 67 119 The BCG sample table3.dat 25 856 Brightest cluster galaxy aperture photometry table4.dat 41 33 *Interrun photometry comparisons table5.dat 31 21 External photometry comparisons table6.dat 64 86 Galaxy redshift observations table7.dat 73 29 Second-ranked galaxy observations
Note on table4.dat: Comparisons are shown for the Rc-band Photometry at the adopted metric aperture in the Local Group frame. Details of the runs are given in Table 2. A portion of the comparisons Were based on the second-ranked galaxies in some clusters.
See also: J/AJ/101/1561 : Isophotometry of ellipticals in Abell clusters (Porter+ 1991) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Abell Abell galaxy number 6- 7 I2 h RAh Right ascension (J2000) 9- 10 I2 min RAm Right ascension (J2000) 12- 16 F5.2 s RAs Right ascension (J2000) 18 A1 --- DE- Declination sign 19- 20 I2 deg DEd Declination (J2000) 22- 23 I2 arcmin DEm Declination (J2000) 25- 28 F4.1 arcsec DEs Declination (J2000) 31- 35 I5 km/s czBCG Heliocentric BCG velocity 38- 42 I5 km/s czCl Heliocentric cluster velocity 45- 51 A7 --- Run Runs 53- 67 A15 --- Note Notes (1)
Note (1): 1: The present BCG choice differs from the galaxy selected by Hoessel et al., 1980ApJ...241..493H 2: A0419 appears to consist of two overlapping clusters at z=0.041 and z=0.068. We have selected the lower redshift component. 3: The redshift for the BCG in A1139 (obtained from the CfA Redshift Survey) had a relatively large measurement error of 170km/s (see Table 6). However a remeasurement of its redshift by us in 1992 gives a heliocentric velocity of 11495(±29)km/s, within 35km/s of the less precise value. 4: A1631 appears to consist of two overlapping clusters at z=0.014 and z=0.046. We have selected the higher redshift component. 5: This cluster was included to test for inhomogeneous velocity bias at the sample edge (see Paper I, Lauer et al., 1994ApJ...425..418L).
Table 2: BCG imaging runs -------------------------------------------------------------------------- Run Date Telescope CCD Pixel Scale FOV -------------------------------------------------------------------------- 1 1989 Oct CTIO 1.5m TI 800x800 (TI2) 0.273" 3.6' 2 1989 Nov KPNO 4m TI 800x800 (TI2) 0.299" 4.0' 3 1990 Nov CTIO 1.4m TI 800x800 (TI2) 0.273 3.6' 4 1991 Mar KPNO 2.1m Tek 1024x1024 (TE1K) 0.304" 5.2' 5 1991 Apr CTIO 1.5m Tek 1024x1024 (TEK1K-1) 0.434" 7.4' Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Abell Abell cluster number 6- 11 F6.2 arcsec Rad Radius 13- 18 F6.3 mag Rc Rc magnitude 20- 24 F5.3 mag B-Rc ? B-Rc colour index
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Abell Abell cluster number 5- 6 A2 --- m_Abell Designation in Abell cluster 8- 13 F6.3 mag Rc1 ? Run 1 Rc magnitude 15- 20 F6.3 mag Rc2 ? Run 2 Rc magnitude 22- 27 F6.3 mag Rc3 ? Run 3 Rc magnitude 29- 34 F6.3 mag Rc4 ? Run 4 Rc magnitude 36- 41 F6.3 mag Rc5 ? Run 5 Rc magnitude
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Abell Abell number 6- 10 F5.2 arcsec Rad Radius 12- 17 F6.3 mag Rc Rc magnitude from Colless et al. (1993MNRAS.262..475C) 19- 24 F6.3 mag Rw Rc magnitude from this work 26- 31 F6.3 mag Rc-Rw Rc-Rw value (1)
Note (1): Comparisons are shown for the Rc-band photoelectric photometry of Colless et al. (1993MNRAS.262..475C) (Rc) and the present work (Rw), for the selected Colless et al. aperture
Byte-by-byte Description of file: table6.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Abell Abell cluster number 5- 7 A3 --- m_Abell Designation in Abell cluster 9- 10 I2 h RAh Right ascension (J2000.0) 12- 13 I2 min RAm Right ascension (J2000.0) 15- 19 F5.2 s RAs Right ascension (J2000.0) 21 A1 --- DE- Declination sign 22- 23 I2 deg DEd Declination (J2000.0) 25- 26 I2 arcmin DEm Declination (J2000.0) 28- 31 F4.1 arcsec DEs Declination (J2000.0) 33- 37 I5 km/s cz Heliocentric velocity 39- 41 I3 km/s e_cz rms uncertainty on cz (1) 43 I1 --- Sources [1/3] Sources (2) 45- 64 A20 --- Note Notes (3)
Note (1): For 1837-G1, the value printed, 3, was modified in 30. Note (2): 1: MMT, J. Huchra & A. Zabludoff, private communication. 2: CTIO 1.5m, 1991 Spring 3: CTIO 1.5m, 1990 Fall. Note (3): 1: This galaxy is a background object. 2: This galaxy is in a cluster beyond the 15000km/s heliocentric velocity limit. The redshift measurement, however, was obtained by us to better determine the membership of the z<0.05 cluster sample.
Byte-by-byte Description of file: table7.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Abell Abell cluster number 5- 6 A2 --- m_Abell Designation in Abell cluster 8- 9 I2 h RAh Right ascension (J2000.0) 11- 12 I2 min RAm Right ascension (J2000.0) 14- 18 F5.2 s RAs Right ascension (J2000.0) 20 A1 --- DE- Declination sign 21- 22 I2 deg DEd Declination (J2000.0) 24- 25 I2 arcmin DEm Declination (J2000.0) 27- 30 F4.1 arcsec DEs Declination (J2000.0) 32- 36 F5.3 mag M2-M1 Second ranked minus first ranked galaxies absolute magnitudes 38- 42 F5.3 --- alpha alpha parameter (1) 44- 48 I5 km/s cz ? Heliocentric velocity 50- 52 I3 km/s e_cz ? rms uncertainty on cz 54- 73 A20 --- Note Notes
Note (1): α is proportional to dlog(Lm/d)log(r|rmr) where Lm is the total BCG luminosity within the circular aperture of physical radius rm centered on the BCG nucleus.
History: Prepared via OCR at CDS. + A227 from H. Andernach
(End) James Marcout, Patricia Bauer [CDS] 18-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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