1. First Resolution of Microlensed Images of a Binary-Lens Event
- Author
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Wu, Zexuan, Dong, Subo, Mérand, A., Kochanek, Christopher S., Mróz, Przemek, Shangguan, Jinyi, Christie, Grant, Tan, Thiam-Guan, Bensby, Thomas, Bland-Hawthorn, Joss, Buder, Sven, Eisenhauer, Frank, Gould, Andrew P., Kos, Janez, Natusch, Tim, Sharma, Sanjib, Udalski, Andrzej, Woillez, J., Buckley, David A. H., Thompson, I. B., Dayem, Karim Abd El, Berdeu, Anthony, Berger, Jean-Philippe, Bourdarot, Guillaume, Brandner, Wolfgang, Davies, Richard I., Defrère, Denis, Dougados, Catherine, Drescher, Antonia, Eckart, Andreas, Fabricius, Maximilian, Feuchtgruber, Helmut, Schreiber, Natascha M. Förster, Garcia, Paulo, Genzel, Reinhard, Gillessen, Stefan, Heißel, Gernot, Hönig, Sebastian, Houlle, Mathis, Kervella, Pierre, Kreidberg, Laura, Lacour, Sylvestre, Lai, Olivier, Laugier, Romain, Bouquin, Jean-Baptiste Le, Leftley, James, Lopez, Bruno, Lutz, Dieter, Mang, Felix, Millour, Florentin, Montargès, Miguel, Nowacki, Hugo, Nowak, Mathias, Ott, Thomas, Paumard, Thibaut, Perraut, Karine, Perrin, Guy, Petrov, Romain, Petrucci, Pierre-Olivier, Pourre, Nicolas, Rabien, Sebastian, Ribeiro, Diogo C., Robbe-Dubois, Sylvie, Bordoni, Matteo Sadun, Santos, Daryl, Sauter, Jonas, Scigliuto, Jules, Shimizu, Taro T., Straubmeier, Christian, Sturm, Eckhard, Subroweit, Matthias, Sykes, Calvin, Tacconi, Linda, Vincent, Frédéric, and Widmann, Felix
- Subjects
Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
We resolve the multiple images of the binary-lens microlensing event ASASSN-22av using the GRAVITY instrument of the Very Large Telescope Interferometer (VLTI). The light curves show weak binary-lens perturbations, complicating the analysis, but the joint modeling with the VLTI data breaks several degeneracies, arriving at a strongly favored solution. Thanks to precise measurements of angular Einstein radius \theta_E = 0.724 +/- 0.002 mas and microlens parallax, we determine that the lens system consists of two M dwarfs with masses of M_1 = 0.258 +/- 0.008 M_sun and M_2 = 0.130 +/- 0.007 M_sun, a projected separation of r_\perp = 6.83 +/- 0.31 au and a distance of D_L = 2.29 +/- 0.08 kpc. The successful VLTI observations of ASASSN-22av open up a new path for studying intermediate-separation (i.e., a few astronomical units) stellar-mass binaries, including those containing dark compact objects such as neutron stars and stellar-mass black holes., Comment: Published in ApJ. See the ancillary file for animation associated with Fig. 8
- Published
- 2024