J/AJ/130/1002 Stroemgren photometry in Abell 2125 and 2218 (Rakos+, 2005)
Cluster populations in Abell 2125 and 2218.
Rakos K., Schombert J.
<Astron. J., 130, 1002-1021 (2005)>
=2005AJ....130.1002R 2005AJ....130.1002R
ADC_Keywords: Clusters, galaxy ; Photometry, uvby
Keywords: galaxies: elliptical and lenticular, cD - galaxies: evolution -
galaxies: stellar content
Abstract:
We combine new narrowband photometry with archival Wide Field
Planetary Camera 2 (WFPC2) data for A2218 (z=0.18) and A2125 (z=0.25),
two clusters with intermediate redshifts but very different cluster
properties, in order to examine the evolution of galaxy populations.
A2218 is a dense, elliptical-rich cluster (Bautz-Morgan type II)
similar to the Coma Cluster in its evolutionary appearance, whereas
A2125 is a less dense, more open cluster (Bautz-Morgan type II-III),
although similar in richness to A2218.
Description:
The photometry for this project was obtained on the Kitt Peak National
Observatory (KPNO) 4m telescope over two nights (2001 June 26 and 27).
The instrument used was the T2KB at prime focus, which resulted in a
plate scale of 0.48"/pix. The uz, vz, bz, yz system is specific to the
rest frame of clusters.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
a2125.dat 91 153 Stroemgren photometry in Abell 2125
a2218.dat 91 277 Stroemgren photometry in Abell 2218
--------------------------------------------------------------------------------
Byte-by-byte Description of file: a2125.dat a2218.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq Galaxy sequential number
5- 12 F8.4 deg RAdeg Right Ascension (J2000)
14- 22 F9.5 deg DEdeg Declination (J2000)
24- 28 F5.2 mag u-v u-v color index
30- 34 F5.2 mag b-y b-y color index
36- 40 F5.2 mag v-y v-y color index
42- 46 F5.2 --- mz mz index, mz=(vz-bz)-(bz-yz)
48- 51 F4.1 mag ymag Stroemgren's y magnitude
53- 57 F5.1 mag yMAG Absolute Stroemgren's y magnitude
59- 63 F5.2 [Sun] [Fe/H] Mean metallicity [Fe/H]
65- 70 F6.3 --- delta delta (definition not given in the paper)
72- 76 F5.2 --- PC1 PC1 color, PC1=0.80(u-v)+0.53(v-b)+0.28(b-y) (1)
78- 82 F5.2 --- PC2 PC2 color, PC2=-0.56(u-v)+0.49(v-b)+0.67(b-y) (1)
84- 88 F5.2 --- PC3 PC3 color, PC3=0.22(u-v)-0.69(v-b)+0.69(b-y) (1)
90- 91 A2 --- class Spectrophotometric classification (2)
--------------------------------------------------------------------------------
Note (1): Principal component analysis from Steindling et al.
(2001ApJS..132...19S 2001ApJS..132...19S).
Note (2): Spectrophotometric classification, defined as follows:
E = passive, red objects
S = star formation rates equivalent to a normal disk galaxy
S+ = starburst objects
S- = transition between E and S
A = AGN
A+ = AGN core (based on PC2 colors)
A- = AGN subclassification (based on PC2 colors)
--------------------------------------------------------------------------------
History:
Copied at: http://abyss.uoregon.edu/~js
(End) Marianne Brouty [CDS] 24-Feb-2006