A measurement of the transverse velocity of Q2237+0305

J. S.B. Wyithe, R. L. Webster, E. L. Turner

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


Determination of microlensing parameters in the gravitationally lensed quasar Q2237+0305 from the statistics of high-magnification events will require monitoring for more than 100 years (Wambsganss, Paczynski & Schneider). However, we show that the effective transverse velocity of the lensing galaxy can be determined on a more realistic time-scale through consideration of the distribution of light-curve derivatives. The 10 years of existing monitoring data for Q2237+0305 are analysed. These data display strong evidence for microlensing that is not associated with a high-magnification event. An upper limit of υt < 500kms-1 is obtained for the galactic transverse velocity, which is smaller than previously assumed values. The analysis suggests that the observed microlensing variation may be predominantly due to stellar proper motions. The statistical significance of the results obtained from our method will be increased by the addition of data points from current and future monitoring campaigns. However, reduced photometric errors will be more valuable than an increased sampling rate.

Original languageEnglish (US)
Pages (from-to)261-272
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Oct 11 1999

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Gravitational lensing
  • Methods: numerical quasars: individual: Q2237+0305


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