The Time Delay in the Double Quasar 0957+561 and a Search for Gravitational Lenses

Details The Time Delay in the Double Quasar 0957+561 and a Search for Gravitational Lenses The Time Delay in the Double Quasar 0957+561 and a Search for Gravitational Lenses

Feb 1991

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1991phdt........77l&link_type=abstract

Thesis (PH.D.)--MASSACHUSETTS INSTITUTE OF TECHNOLOGY, 1991.Source: Dissertation Abstracts International, Volume: 53-02, Secti

Mathematics

Logic

10

Quasar

Scientific paper

The flux densities of 0957+561 A and B have been monitored for the past eleven years using the VLA at lambda6 cm. The VLA data are best fit by a time delay of 1.40 +/- 0.1 yr (513 +/- 40 days) with the A image leading. Using recent estimates of the velocity dispersion in the principal lensing galaxy and the model of Falco, Gorenstein & Shapiro, an estimate of Hubble's constant can be obtained which falls between 46 and 90 km s^{-1} Mpc^{-1}. This result is an independent confirmation of the current determinations. The VLA data also show that the image magnification ratio changes substantially over the 50 milliarcsecond radio structure. The variable core flux has a magnification ratio of 0.765 +/- 0.052, in agreement with previous determinations from optical spectral line emission, and consistent with VLBI observations of the core flux variability. The nonvarying jet flux ratio is more difficult to determine from the VLA light curves, but appears to be consistent with the VLBI determinations of the jet flux ratio. The first two sessions of the MIT-Greenbank-VLA gravitational lens search at lambda3.6 cm have been completed. Over 100 candidates for gravitational lensing were identified on a morphological basis, of which 27 are particularly suggestive. This result gives encouragement to the continuing MG-VLA lambda3.6 cm lens search. Two candidates are particularly promising: MG0959+2947, a close pair of quasars at differing redshifts; and MG1549+3047, the fourth "Einstein ring" candidate to have been found. Using a point-mass model for the lensing galaxy, the mass-to-light ratio within the ring must exceed 8M_odot/L_odot, and the predicted central velocity dispersion is 180 km s^{-1}. These figures are typical for elliptical galaxies. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.).

Affiliated with

Also associated with

No associations

Rating

The Time Delay in the Double Quasar 0957+561 and a Search for Gravitational Lenses 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 Time Delay in the Double Quasar 0957+561 and a Search for Gravitational Lenses, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Time Delay in the Double Quasar 0957+561 and a Search for Gravitational Lenses will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1319046