About the proper motion of lensed quasars in Gaia DR2
| Main Authors: | Alex Bombrun, Maggie Lieu, Ivan Valtchanov, Guillaume Belanger |
|---|---|
| Format: | Article eJournal |
| Bahasa: | eng |
| Terbitan: |
, 2019
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/3236773 |
Daftar Isi:
- The distribution of the normalised parallaxes and proper motions of Gaia DR2 quasars follows nicely a Gaussian distribution with standard deviation close to 1. One would naively expect that the subset of lensed QSOs has the same property. We propose 2 different Bayesian statistical models to compare the proper motion distributions of the non-lensed QSOs and lensed QSOs subsets. We conclude that these 2 distributions are different. Finally we discuss different hypotheses to explain this discrepancy. In particular one should always keep in mind that DR2 astrometry is biased for objects that are not isolated within a few arcseconds because of blended astrometric observations. The lensed QSOs potentially illustrate such biases.