Gaia GraL: Gaia DR2 gravitational lens systems II. The known multiply imaged quasars
Context . Thanks to its spatial resolution, the ESA/ Gaia space mission offers a unique opportunity to discover new multiply imaged quasars and to study the already known lensed systems at sub-milliarcsecond astrometric precisions. Aims . In this paper, we address the detection of the known multiply...
Saved in:
Published in | Astronomy and astrophysics (Berlin) Vol. 618; p. A56 |
---|---|
Main Authors | , , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
EDP Sciences
01.10.2018
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Context
. Thanks to its spatial resolution, the ESA/
Gaia
space mission offers a unique opportunity to discover new multiply imaged quasars and to study the already known lensed systems at sub-milliarcsecond astrometric precisions.
Aims
. In this paper, we address the detection of the known multiply imaged quasars from the
Gaia
Data Release 2 (DR2) and determine the astrometric and photometric properties of the individually detected images found in the
Gaia
DR2 catalogue.
Methods
. We have compiled an exhaustive list of quasar gravitational lenses from the literature to search for counterparts in the
Gaia
DR2. We then analysed the astrometric and photometric properties of these
Gaia
’s detections. To highlight the tremendous potential of
Gaia
at the sub-milliarcsecond level we finally performed a simple Bayesian modelling of the well-known gravitational lens system HE0435-1223, using
Gaia
DR2 and HST astrometry.
Results
. From 481 known multiply imaged quasars, 206 have at least one image found in the
Gaia
DR2. Among the 44 known quadruply imaged quasars of the list, 29 have at least one image in the
Gaia
DR2, 12 of which are fully detected (2MASX J01471020+4630433, HE 0435-1223, SDSS1004+4112, PG1115+080, RXJ1131-1231, 2MASS J11344050-2103230, 2MASS J13102005-1714579, B1422+231, J1606-2333, J1721+8842, WFI2033-4723, WGD2038-4008), eight have three counterparts, eight have two and one has only one. As expected, the modelling of HE0435-1223 shows that the model parameters are significantly better constrained when using
Gaia
astrometry compared to HST astrometry, in particular the relative positions of the background quasar source and the centroid of the deflector. The
Gaia
sub-milliarcsecond astrometry also significantly reduces the parameter correlations.
Conclusions
. Besides providing an up-to-date list of multiply imaged quasars and their detection in the
Gaia
DR2, this paper shows that more complex modelling scenarios will certainly benefit from
Gaia
sub-milliarcsecond astrometry. |
---|---|
ISSN: | 0004-6361 1432-0746 1432-0756 |
DOI: | 10.1051/0004-6361/201833480 |