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Gaia21blx: complete resolution of a binary microlensing event in the Galactic disk

Context. Gravitational microlensing is a method that is used to discover planet-hosting systems at distances of several kiloparsec in the Galactic disk and bulge. We present the analysis of a microlensing event reported by the Gaia photometric alert team that might have a bright lens. Aims. In order...

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Main Authors: Rota, Paolo (Author) , Bozza, V. (Author) , Hundertmark, Markus (Author) , Bachelet, E. (Author) , Street, R. (Author) , Tsapras, Yiannis (Author) , Cassan, A. (Author) , Dominik, M. (Author) , Jaimes, R. Figuera (Author) , Rybicki, K. A. (Author) , Wambsganß, Joachim (Author) , Wyrzykowski, Ł (Author) , Zieliński, P. (Author) , Bonavita, M. (Author) , Hinse, T. C. (Author) , Jørgensen, U. G. (Author) , Khalouei, E. (Author) , Korhonen, H. (Author) , Longa-Peña, P. (Author) , Peixinho, N. (Author) , Rahvar, S. (Author) , Sajadian, S. (Author) , Skottfelt, J. (Author) , Snodgrass, C. (Author) , Tregolan-Reed, J. (Author)
Format: Article (Journal)
Language:English
Published: 13 June 2024
In: Astronomy and astrophysics
Year: 2024, Volume: 686, Pages: 1-11
ISSN:1432-0746
DOI:10.1051/0004-6361/202347807
Online Access:Verlag, kostenfrei, Volltext: https://doi.org/10.1051/0004-6361/202347807
Verlag, kostenfrei, Volltext: https://www.aanda.org/articles/aa/abs/2024/06/aa47807-23/aa47807-23.html
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Author Notes:P. Rota, V. Bozza, M. Hundertmark, E. Bachelet, R. Street, Y. Tsapras, A. Cassan, M. Dominik, R. Figuera Jaimes, K.A. Rybicki, J. Wambsganss, Ł. Wyrzykowski, P. Zieliński, (The OMEGA Key Project), M. Bonavita, T.C. Hinse, U.G. Jørgensen, E. Khalouei, H. Korhonen, P. Longa-Peña, N. Peixinho, S. Rahvar, S. Sajadian, J. Skottfelt, C. Snodgrass, and J. Tregolan-Reed (The MiNDSTEp consortium)
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Summary:Context. Gravitational microlensing is a method that is used to discover planet-hosting systems at distances of several kiloparsec in the Galactic disk and bulge. We present the analysis of a microlensing event reported by the Gaia photometric alert team that might have a bright lens. Aims. In order to infer the mass and distance to the lensing system, the parallax measurement at the position of Gaia21blx was used. In this particular case, the source and the lens have comparable magnitudes and we cannot attribute the parallax measured by Gaia to the lens or source alone. Methods. Since the blending flux is important, we assumed that the Gaia parallax is the flux-weighted average of the parallaxes of the lens and source. Combining this assumption with the information from the microlensing models and the finite source effects we were able to resolve all degeneracies and thus obtained the mass, distance, luminosities and projected kinematics of the binary lens and the source. Results. According to the best model, the lens is a binary system at 2.18 ± 0.07 kpc from Earth. It is composed of a G star with 0.95 ± 0.17 M⊙ and a K star with 0.53 ± 0.07 M⊙. The source is likely to be an F subgiant star at 2.38 ± 1.71 kpc with a mass of 1.10 ± 0.18 M⊙. Both lenses and the source follow the kinematics of the thin-disk population. We also discuss alternative models, that are disfavored by the data or by prior expectations, however.
Item Description:Gesehen am 03.03.2025
Physical Description:Online Resource
ISSN:1432-0746
DOI:10.1051/0004-6361/202347807

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