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Baryon content of massive galaxy clusters at 0.57 < z < 1.33.
- Source :
- Monthly Notices of the Royal Astronomical Society; 1/1/2016, Vol. 455 Issue 1, p258-275, 18p
- Publication Year :
- 2016
-
Abstract
- We study the stellar, brightest cluster galaxy (BCG) and intracluster medium (ICM) masses of 14 South Pole Telescope (SPT) selected galaxy clusters with median redshift z = 0.9 and mass M<subscript>500</subscript> = 6 × 10<superscript>14</superscript>M<subscript>☉</subscript>. We estimate stellar masses for each cluster and BCG using six photometric bands, the ICM mass using X-ray observations and the virial masses using the SPT Sunyaev--Zel'dovich effect signature. At z = 0.9, the BCG mass M<superscript>BCG</superscript> <subscript>*</subscript> constitutes 0.12 ± 0.01 per cent of the halo mass for a 6 × 10<superscript>14</superscript>M<subscript>☉</subscript> cluster, and this fraction falls as M <superscript>--0.58±0.07</superscript> <subscript>500</subscript> . The cluster stellar mass function has a characteristic mass M<subscript>0</subscript> = 10<superscript>11.0 ± 0.1</superscript>M<subscript>☉</subscript>, and the number of galaxies per unit mass in clusters is larger than in the field by a factor of 1.65 ± 0.20. We combine our SPT sample with previously published samples at low redshift and correct to a common initial mass function and for systematic virial mass differences. We then explore mass and redshift trends in the stellar fraction f<subscript>*</subscript>, the ICM fraction f<subscript>ICM</subscript>, the collapsed baryon fraction f<subscript>c</subscript> and the baryon fraction f<subscript>b</subscript>. At a pivot mass of 6 × 10<superscript>14</superscript>M<subscript>☉</subscript> and redshift z = 0.9, the characteristic values are f<subscript>*</subscript> = 1.1 ± 0.1 per cent, f<subscript>ICM</subscript> = 9.6 ± 0.5 per cent, f<subscript>c</subscript> = 10.7 ± 1.1 per cent and f<subscript>b</subscript> = 10.7 ± 0.6 per cent. These fractions all vary with cluster mass at high significance, with higher mass clusters having lower f<subscript>*</subscript> and f<subscript>c</subscript> and higher f<subscript>ICM</subscript> and f<subscript>b</subscript>. When accounting for a 15 per cent systematic virial mass uncertainty, there is no statistically significant redshift trend at fixed mass. Our results support the scenario where clusters grow through accretion from subclusters (higher f<subscript>*</subscript>, lower f<subscript>ICM</subscript>) and the field (lower f<subscript>*</subscript>, higher f<subscript>ICM</subscript>), balancing to keep f<subscript>*</subscript> and f<subscript>ICM</subscript> approximately constant since z ~ 0.9. [ABSTRACT FROM AUTHOR]
- Subjects :
- GALAXIES
TELESCOPES
STELLAR initial mass function
X-rays
REDSHIFT
PHOTOMETRY
Subjects
Details
- Language :
- English
- ISSN :
- 00358711
- Volume :
- 455
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Publication Type :
- Academic Journal
- Accession number :
- 111331152
- Full Text :
- https://doi.org/10.1093/mnras/stv2303