Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2010-05-17
MNRAS, 407 (2010) 1597-1608
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
12 pages, 12 figures, 1 table, published in MNRAS
Scientific paper
10.1111/j.1365-2966.2010.17049.x
The aim of this paper is to study the astrometric trajectory of microlensing events with an extended lens and/or source. We consider not only a dark lens but also a luminous lens as well. We find that the discontinuous finite-lens trajectories given by Takahashi (2003) will become continuous in the finite-source regime. The point lens (source) approximation alone gives an under (over)estimation of the astrometric signal when the size of the lens and source are not negligible. While the finiteness of the source is revealed when the lens transits the surface of the source, the finite-lens signal is most prominent when the lens is very close to the source. Astrometric microlensing towards the Galactic bulge, Small Magellanic Cloud and M31 are discussed, which indicate that the finite-lens effect is beyond the detection limit of current instruments. Nevertheless, it is possible to distinguish between self-lensing and halo lensing through a (non-)detection of the astrometric ellipse. We also consider the case where the lens is luminous itself, as has been observed where a lensing event was followed up with the Hubble Space Telescope. We show that the astrometric signal will be reduced in a luminous-lens scenario. The physical properties of the event, such as the lens-source flux ratio, the size of the lens and source nevertheless can be derived by fitting the astrometric trajectory.
Bender Ralf
Lee Chang Hoon
Riffeser Arno
Seitz Stella
No associations
LandOfFree
Finite-source and finite-lens effects in astrometric microlensing 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 Finite-source and finite-lens effects in astrometric microlensing, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Finite-source and finite-lens effects in astrometric microlensing will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-56486