The mass distribution of a moderate redshift galaxy group and brightest group galaxy from gravitational lensing and kinematics

Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

18 pages, 14 figures, 5 tables, accepted for publication in MNRAS

Scientific paper

The gravitational lens system CLASS B2108+213 has two radio-loud lensed images separated by 4.56 arcsec. The relatively large image separation implies that the lensing is caused by a group of galaxies. In this paper, new optical imaging and spectroscopic data for the lensing galaxies of B2108+213 and the surrounding field galaxies are presented. These data are used to investigate the mass and composition of the lensing structure. The redshift and stellar velocity dispersion of the main lensing galaxy (G1) are found to be z = 0.3648 +/- 0.0002 and sigma_v = 325 +/- 25 km/s, respectively. The optical spectrum of the lensed quasar shows no obvious emission or absorption features and is consistent with a BL Lac type radio source. However, the tentative detection of the G-band and Mg-b absorption lines, and a break in the spectrum of the host galaxy of the lensed quasar gives a likely source redshift of z = 0.67. Spectroscopy of the field around B2108+213 finds 51 galaxies at a similar redshift to G1, thus confirming that there is a much larger structure at z ~ 0.365 associated with this system. The width of the group velocity distribution is 694 +/- 93 km/s, but is non-Gaussian, implying that the structure is not yet viralized. The main lensing galaxy is also the brightest group member and has a surface brightness profile consistent with a typical cD galaxy. A lensing and dynamics analysis of the mass distribution, which also includes the newly found group members, finds that the logarithmic slope of the mass density profile is on average isothermal inside the Einstein radius, but steeper at the location of the Einstein radius. This apparent change in slope can be accounted for if an external convergence gradient, representing the underlying parent halo of the galaxy group, is included in the mass model.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

The mass distribution of a moderate redshift galaxy group and brightest group galaxy from gravitational lensing and kinematics 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 The mass distribution of a moderate redshift galaxy group and brightest group galaxy from gravitational lensing and kinematics, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The mass distribution of a moderate redshift galaxy group and brightest group galaxy from gravitational lensing and kinematics will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-35456

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.