ROSAT observations of the gravitationally lensed system 0957+561

Details ROSAT observations of the gravitationally lensed system 0957+561 ROSAT observations of the gravitationally lensed system 0957+561

May 1995

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995apj...445..140c&link_type=abstract

The Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 445, no. 1, p. 140-147

Astronomy and Astrophysics

Astronomy

13

Galactic Mass, Galaxies, Gravitational Lenses, Quasars, Time Lag, Variations, X Ray Density Measurement, Brightness, Radiant Flux Density, Red Shift, Rosat Mission, X Ray Astronomy, X Ray Imagery

Scientific paper

Observations of 0957+561 with the Einstein High Resolution Imager (HRI) in 1979 May and 1979 November and with the ROSAT HRI in 1991 May and 1992 October reveal large variations in the X-ray fluxes for images A and B which significantly differ from simultaneously observed changes of the corresponding optical continuum emission. Most striking was the apparent increase by over fivefold in the flux of image B from the late 1970's to the early 1900's. Further, in the 1990's the X-ray flux for image A increased by a factor of 1.7 +/- 0.3 and that of B by a factor of 1.9 +/- 0.2 between the two ROSAT observations (separated by 540 days), whereas optical measurements showed nearly no changes for A and B between these epochs. No significant changes in X-ray emission were observed on timescales of hours to days. Of we adopt 1.5 yr as the difference between the propagation time from the quasar to us via the two images ('time delay'), then the ratio of the X-ray flux of image B for the 1992 October epoch to that of A for the 1991 May epoch is 2.7 +/- 0.4. This ratio is significantly greater than the ratio of 1.05 +/- 0.03 observed in the optical R band, 0.75 in the broad line region (BLR), and 0.76 +/- 0.03 in the radio (VLBI lambda 13 cm core) for approximately the same epoch. The wavelength dependence in the ratio of the fluxes of the two images suggests that either microlensing may be significant for the X-ray band or the time delay is substanially different from 1.5 yr (and the intrinsic variation of the quasar emission were significant within an interval comparable to the uncertainty of the time delay), or both.

Affiliated with

Also associated with

No associations

Rating

ROSAT observations of the gravitationally lensed system 0957+561 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 ROSAT observations of the gravitationally lensed system 0957+561, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and ROSAT observations of the gravitationally lensed system 0957+561 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1058981