We have initiated a program to study the baryon content and dynamic state of galaxy clusters. Here we present results primarily from XMM-Newton observations of two optically selected galaxy clusters, A1095 (z similar or equal to 0.210) and A1926 (z similar or equal to 0.136). We find that both of them are actually cluster pairs at similar redshifts. We characterize the temperatures of these individual clusters through X-ray spectral fits and then estimate their gravitational masses. We show a rich set of substructures, including large position offsets between the diffuse X-ray centroids and the brightest galaxies of the clusters, which suggests that they are dynamically young. For both A1095 and A1926, we find that the mass required for the cluster pairs to be bound is smaller than the total gravitational mass. Thus both cluster pairs appear to be ongoing major mergers. Incorporating Sloan Digital Sky Survey and NRAO VLA Sky Survey/Faint Images of the Radio Sky at Twenty-cm data, we further examine the large-scale structure environment and radio emission of the clusters to probe their origins, which also leads to the discovery of two additional X-ray-emitting clusters (z similar or equal to 0.097 and similar or equal to 0.147) in the field of A1926. We estimate the hot gas and stellar masses of each cluster, which compared with the expected cosmological baryonic mass fraction, leave ample room for warm gas.
WOS标题词:
Science & Technology
; Physical Sciences
类目[WOS]:
Astronomy & Astrophysics
研究领域[WOS]:
Astronomy & Astrophysics
关键词[WOS]:
DIGITAL SKY SURVEY
; NEAR-INFRARED PROPERTIES
; X-RAY-CLUSTERS
; DARK-MATTER
; COSMOLOGICAL SIMULATIONS
; CHANDRA SAMPLE
; ABELL CLUSTERS
; OUTER REGIONS
; BINDING MASS
; LOW-REDSHIFT
National Natural Science Foundation of China(11273015
; National Basic Research Program(2013CB834905)
; China Scholarships Council(201206190041)
; Recruitment Program of Global Youth Experts
; 11133001
; U1531248)
1.Nanjing Univ, Sch Astron & Space Sci, Nanjing 210093, Jiangsu, Peoples R China 2.Nanjing Univ, Minist Educ, Key Lab Modern Astron & Astrophys, Nanjing 210093, Jiangsu, Peoples R China 3.Collaborat Innovat Ctr Modern Astron & Space Expl, Nanjing 210093, Jiangsu, Peoples R China 4.Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA 5.Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Jiangsu, Peoples R China 6.Chinese Acad Sci, Key Lab Dark Matter & Space Astron, PMO, Nanjing 210008, Jiangsu, Peoples R China
