A comparison of different cluster mass estimates: Consistency or discrepancy?

被引:67
作者
Wu, XP [1 ]
Chiueh, T
Fang, LZ
Xue, YJ
机构
[1] Natl Cent Univ, Inst Astron, Chungli 32054, Taiwan
[2] Chinese Acad Sci, Beijing Astron Observ, Beijing 100012, Peoples R China
[3] Univ Arizona, Dept Phys, Tucson, AZ 85721 USA
关键词
galaxies : clusters : general; dark matter; gravitational lensing; X-rays : galaxies;
D O I
10.1046/j.1365-8711.1998.02055.x
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Rich and massive clusters of galaxies at intermediate redshift are capable of magnifying and distorting the images of background galaxies. A comparison of different mass estimators among these clusters can provide useful information about the distribution and composition of cluster matter and its dynamical evolution. Using the hitherto largest sample of lensing clusters drawn from the literature, we compare the gravitating masses of clusters derived from the strong/weak gravitational lensing phenomena, from the X-ray measurements based on the assumption of hydrostatic equilibrium, and from the conventional isothermal sphere model for the dark matter profile characterized by the velocity dispersion and core radius of galaxy distributions in clusters. While there is excellent agreement between the weak lensing, X-ray and isothermal sphere model-determined cluster masses, these methods are likely to underestimate the gravitating masses enclosed within the central cores of clusters by a factor of 2-4 as compared with the strong lensing results. Such a mass discrepancy has probably arisen from the inappropriate applications of the weak lensing technique and the hydrostatic equilibrium hypothesis to the central regions of clusters, as well as from assuming an unreasonably large core radius for both luminous and dark matter profiles. Nevertheless, it is pointed out that these cluster mass estimators may be safely applied on scales greater than the core sizes. Namely, the overall clusters of galaxies at intermediate redshift can still be regarded as the dynamically relaxed systems, in which the velocity dispersion of galaxies and the temperature of X-ray emitting gas are good indicators of the underlying gravitational potentials of clusters.
引用
收藏
页码:861 / 871
页数:11
相关论文
共 59 条
[1]   A combined X-ray and gravitational lensing study of the massive cooling-flow cluster PKS 0745-191 [J].
Allen, SW ;
Fabian, AC ;
Kneib, JP .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1996, 279 (02) :615-635
[2]   Resolving the discrepancy between X-ray and gravitational lensing mass measurements for clusters of galaxies [J].
Allen, SW .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1998, 296 (02) :392-406
[3]  
BAHCALL NA, 1995, ASTROPHYS J, V447, pL81, DOI 10.1086/309577
[4]   Constraining Omega with cluster evolution [J].
Bahcall, NA ;
Fan, XH ;
Cen, RY .
ASTROPHYSICAL JOURNAL, 1997, 485 (02) :L53-L56
[5]   A comparison of X-ray and strong lensing properties of simulated X-ray clusters [J].
Bartelmann, M ;
Steinmetz, M .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1996, 283 (02) :431-446
[6]  
BONNET H, 1994, APJ, V427, P83
[7]   A weak lensing survey in the fields of z similar to 1 luminous radio sources [J].
Bower, RG ;
Smail, I .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1997, 290 (02) :292-302
[8]   Gravitational lensing in low-redshift clusters of galaxies: The arclike object in Abell 3408 and its lensing interpretation [J].
Campusano, LE ;
Kneib, JP ;
Hardy, E .
ASTROPHYSICAL JOURNAL, 1998, 496 (02) :L79-+
[9]   Average mass and light profiles of galaxy clusters [J].
Carlberg, RG ;
Yee, HKC ;
Ellingson, E .
ASTROPHYSICAL JOURNAL, 1997, 478 (02) :462-475
[10]   Galaxy cluster virial masses and Omega [J].
Carlberg, RG ;
Yee, HKC ;
Ellingson, E ;
Abraham, R ;
Gravel, P ;
Morris, S ;
Pritchet, CJ .
ASTROPHYSICAL JOURNAL, 1996, 462 (01) :32-49