2008A&A...491..587C


C.D.S. - SIMBAD4 rel 1.7 - 2020.04.01CEST04:15:01

2008A&A...491..587C - Astronomy and Astrophysics, volume 491, 587-595 (2008/11-4)

An alternative parameterisation for binary-lens caustic-crossing events.

CASSAN A.

Abstract (from CDS):

Microlensing events are being discovered and alerted by the two survey teams OGLE and MOA at an increasing rate. Around ten percent of these events involve binary lenses. Such events potentially contain much information on the physical properties of the observed binary systems, which can then be used for e.g. statistical studies on binary objects in the Galactic disk or bulge. However, such events are usually not straightforward to study, because the model equations are strongly non-linear and there are many local minima that can fool the search for the best solution if the parameter space is not inspected with great care. In this work an alternative parameterisation for the binary lens fitting problem is proposed, in which the parameters involved are defined to represent as closely as possible the caustic-crossing features observed in most binary lens light curves. Furthermore, we work out an extension of the method in order to make use of the straight line fold caustic approximation, when the latter applies for both the caustic entry and exit. We introduce an alternative parameterisation in order to confine the exploration of the parameter space to regions where the models only involve caustic crossing at the dates seen in the light curve. We find that the proposed parameterisation provides more robustness to the light curve fitting process, in particular in avoiding a code to get stuck in false minima.

Abstract Copyright:

Journal keyword(s): gravitational lensing - methods: numerical - methods: analytical

Status at CDS:  

Simbad objects: 16

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Number of rows : 16

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 MACHO 98-SMC-1 Lev 00 45 35.3 -72 52 33           ~ 64 0
2 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9283 1
3 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11310 0
4 EWS 2002-BUL-69 Lev 17 48 01.00 -21 16 09.3           G5III 17 0
5 NAME EWS 2005-BUL-071b Pl 17 50 09.77 -34 40 23.5           ~ 38 1
6 NAME EWS 2006-BUL-109c Pl 17 52 34.55 -30 05 15.7           ~ 32 1
7 NAME OGLE 2005-BLG-390Lb Pl 17 54 19.2 -30 22 38           ~ 66 1
8 EWS 2007-BLG-50 Lev 17 58 19.39 -28 38 59.0           ~ 9 0
9 NAME OGLE 2003-BLG-235 * 18 05 16.35 -28 53 42.0           GIV 51 1
10 NAME OGLE 2003-BLG-235Lb Pl 18 05 16.35 -28 53 42.0           ~ 21 1
11 NAME EWS 2005-BUL-169b Pl 18 06 05.32 -30 43 57.5           ~ 33 1
12 MOA 2007-BLG-197 Lev 18 07 04.729 -31 56 46.77           ~ 8 0
13 MOA 2007-BLG-192b Pl 18 08 03.798 -27 09 00.27           ~ 24 1
14 QSO J2240+0321 QSO 22 40 30.234 +03 21 30.63           ~ 633 0
15 Z 378-15 G 22 40 30.23447 +03 21 30.6290           ~ 629 0
16 NAME Galactic Bulge reg ~ ~           ~ 3325 0

    Equat.    Gal    SGal    Ecl

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2020.04.01-04:15:01

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