Mass-to-Light Ratios of Groups and Clusters of Galaxies

Details Mass-to-Light Ratios of Groups and Clusters of Galaxies Mass-to-Light Ratios of Groups and Clusters of Galaxies

Dec 1999

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999aas...195.1009h&link_type=abstract

American Astronomical Society, 195th AAS Meeting, #10.09; Bulletin of the American Astronomical Society, Vol. 31, p.1389

Other

Scientific paper

We use galaxy catalogs resulting from the digitization and automated processing of the second generation Palomar Sky Survey plates calibrated with CCD images in Gunn-Thuan g, r, and i bands, ASCA spatially resolved spectroscopic X-ray observations and ROSAT PSPC images to constrain total and gas mass-to-light ratios, gas mass fraction, baryon mass fraction and the ratio of total to luminous mass for a sample of 8 nearby relaxed galaxy groups and clusters. They are A262, A426, A478, A1795, A2052, A2063, A2199 and MKW4s. Under the assumption of hydrostatic equilibrium and spherical symmetry, we can measure the total masses of clusters from their intracluster gas temperature and density profiles. Previous cluster mass estimates assumed the gas is isothermal, however ASCA spatially resolved spectra show the gas temperature decreases with increasing distance from the center. By comparison, the isothermal assumption results in an underestimate of the total mass at small radii, and an overestimate at large cluster radii. The discrepancy between mass-to-light ratios obtained using virial mass estimates and X-ray mass estimates is thus increased. We argue that the virial mass estimate is a less reliable one, subject to systematic errors due to limited cluster volumes sampled and possible galaxy velocity anisotropies. We obtained luminosity functions for the clusters in our sample using the digitized Palomar Sky Survey data calibrated with CCD images. To correct for contamination by background and foreground galaxies, we use color information to reject obvious non-members and subtract background galaxies statistically. We then estimate the total cluster luminosity using Schechter function fits to the galaxy catalogs. The measured mass-to-light ratios are 100 Msun}/L{sun, assuming H0 =50 km s-1 Mpc-1. This, along with a high baryonic fraction, are indicative of a low density universe with Ω 0.2. V.H. was partially supported by the Caltech SURF fellowship.

Affiliated with

Also associated with

No associations

Rating

Mass-to-Light Ratios of Groups and Clusters of Galaxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Mass-to-Light Ratios of Groups and Clusters of Galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mass-to-Light Ratios of Groups and Clusters of Galaxies will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1736335