Zooming into the broad line region of the gravitationally lensed quasar [...] (D. Sluse et al.)

Vol. 528In Section 4. Extragalactic astronomy

Zooming into the broad line region of the gravitationally lensed quasar QSO 2237+0305 ≡ the Einstein Cross: III. Determination of the size and structure of the CIV and CIII] emitting regions using microlensing

The Einstein Cross (or Q2237+0305) is a z=1.7 quasar, which is split into 4 images by a gravitational lens on the line of sight at z=0.04. The authors have used microlensing due to individual stars in the lens to study the structure of the broad line region (BLR) and measure the size of the CIV and CIII emission regions. Detection of microlensing events has required monitoring between Oct. 2004 and Dec. 2007. The region emitting the CIV line is found to be ~66 light-days or 0.06 pc. This size agrees with the radius-luminosity relationship derived from reverberation mapping, as shown in the figure.