J/ApJ/795/L21 Limits on gamma-ray emission from galaxy clusters (Griffin+, 2014)
New limits on gamma-ray emission from galaxy clusters.
Griffin R.D., Dai X., Kochanek C.S.
<Astrophys. J., 795, L21 (2014)>
=2014ApJ...795L..21G 2014ApJ...795L..21G (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxies, nearby ; Redshifts ; Gamma rays
Keywords: acceleration of particles - galaxies: clusters: general -
galaxies: clusters: intracluster medium -
gamma rays: galaxies: clusters
Abstract:
Galaxy clusters are predicted to produce γ-rays through cosmic
ray interactions and/or dark matter annihilation, potentially
detectable by the Fermi Large Area Telescope (Fermi-LAT). We present a
new, independent stacking analysis of Fermi-LAT photon count maps
using the 78 richest nearby clusters (z<0.12) from the Two Micron
All Sky Survey cluster catalog. We obtain the lowest limit on the
photon flux to date, 2.3x10-11 photons/cm2/s (95% confidence) per
cluster in the 0.8-100 GeV band, which corresponds to a luminosity
limit of 3.5x1044 photons/s. We also constrain the emission limits
in a range of narrower energy bands. Scaling to recent cosmic ray
acceleration and γ-ray emission models, we find that cosmic rays
represent a negligible contribution to the intra-cluster energy
density and gas pressure.
Description:
Our cluster sample consists of the richest, nearby (z<0.12) clusters
in the Two Micron All Sky Survey (2MASS) catalog of clusters
identified using a matched filter algorithm (Kochanek et al.
2003ApJ...585..161K 2003ApJ...585..161K). Like Fermi, 2MASS is also an all-sky survey, and
we start with the 163 richest clusters outside of the Galactic plane
(|b|>20°) with z<0.12 ({barz=0.08) and typical masses of
M200∼6x1014M☉. The sample is well-characterized in richness and
distance with extensive calibrations using both near-IR and X-ray
stacking analyses (Dai et al. 2007ApJ...658..917D 2007ApJ...658..917D; Dai et al.
2010ApJ...719..119D 2010ApJ...719..119D; Blackburne & Kochanek 2012ApJ...744...76B 2012ApJ...744...76B).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 47 163 Galaxy Cluster Sample
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See also:
VII/145 : Nearby Galaxies Catalogue (NBG) (Tully 1988)
I/110A : Rich Clusters of Galaxies (Abell+ 1989)
VIII/50 : VLA Survey of Rich Clusters of Galaxies (Slee+ 1996)
J/AJ/149/171 : 2MASS galaxy group catalog (Tully, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- --- [2MASSCL_]
9- 18 A10 --- Name Source identifier (JHHMM-DDMM) (1)
20- 26 F7.3 deg RAdeg Right Ascension in decimal degrees (J2000)
28- 34 F7.3 deg DEdeg Declination in decimal degrees (J2000)
36- 40 F5.3 --- z Redshift
42- 47 F6.3 --- Rich Richness (1)
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Note (1): Position, redshift, and richness for the 163 galaxy clusters used in
our study, where the richness is the number of galaxies with
luminosity L>L* (Kochanek et al. 2003ApJ...585..161K 2003ApJ...585..161K). The first 78
are the clusters used in the final stacked image and are ordered by
the variance of the background, starting with the lowest variance
cluster. Note that 5 of the 78 clusters in our final stack (33 of 163)
are HIFLUGCS clusters (Reiprich & Bohringer 2002ApJ...567..716R 2002ApJ...567..716R).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 17-May-2017