Abell 1656 (Coma Cluster)

Introduction

Data Format

1. serial number
2. '?' denotes a 'probable' identification only
3. X coördinate in arcsec relative to cluster centre, increasing westwards
4. Y coördinate in arcsec relative to cluster centre, increasing northwards
5. '*' denotes overlap by a neighbouring b-band image
6. b_26·5, integrated blue (b-band) magnitude within the 26·5 b mag.arcsec^-2 isophote; an asterisk denotes an image corrected for overlap
7. r*(26·5) arcsec = (A/pi)^0·5 where A is the area enclosed by the 26·5 b mag.arcsec^-2 isophote
8. '*' denotes overlap by a neighbouring r-band image
9. r_24·75, integrated red (r-band) magnitude within the 24·75 r mag.arcsec^-2 isophote; an asterisk denotes an image corrected for overlap
10. r*(24·75) arcsec = (A/pi)^0·5 where A is the area enclosed by the 24·75 r mag.arcsec^-2 isophote
11. (b - r) colour of the image bounded by an isophote of area A where
12. r*(b - r) arcsec = (A/pi)^0·5
13. epsilon = (1 - b/a), the ellipticity of the image (usually r-band) at the outermost uncontaminated isophote (a and b denote the major and minor semi-axes of the notional ellipse respectively)
14. theta deg, the position angle of the major axis of the image
15. alpha mag.arcsec^-2 for the b-band image, the slope of the logarithmic brightness residuals relative to the stellar profile
16. gamma mag, the amount by which the central surface brightness of the b-band image falls short of that which would have been expected for a stellar image with the same number of points measured
17. the number of points used to form alpha and gamma
18. the GP number (Godwin and Peach 1977)
19. the Rood and Baum number (Rood and Baum 1967, 1968)
20. comments, in particular whether double or triple, and NGC/IC numbers.

The sample is essentially complete to b_26·5 = 20·0, extending to b_26·5 = 21·0, with rms deviations in b_26·5, r_24·75 and (b - r) all about 0·15 mag brightward of b_26·5 = 20. Full details of the catalogue are given in Godwin, Metcalfe and Peach 1983.

References

• Rood HJ, Baum WA. Astr J 1967; 72: 398-.
• Rood HJ, Baum WA. Astr J 1968; 73: 442-.
• Godwin JG, Peach JV. Mon Not R Astr Soc 1977; 181: 323-.
• Godwin JG, Metcalfe N, Peach JV. The Coma cluster. I. A catalogue of magnitudes, colours, ellipticities and position angles for 6724 galaxies in the field of the Coma cluster. Mon Not R Astr Soc 1983; 202: 113-.

Links to Data Files

[Download 207 kb compressed data file A1656.ZIP] 

[Link to 913 kb uncompressed data file for Abell 1656] 

[Return to the Clusters of Galaxies Page] 

[End of document, updated to 5 February 1997]