The Astronomical Journal (Jan 2024)
A Close Binary Lens Revealed by the Microlensing Event Gaia20bof
- E. Bachelet,
- P. Rota,
- V. Bozza,
- P. Zieliński,
- Y. Tsapras,
- M. Hundertmark,
- J. Wambsganss,
- Ł. Wyrzykowski,
- P. J. Mikołajczyk,
- R. A. Street,
- R. Figuera Jaimes,
- A. Cassan,
- M. Dominik,
- D. A. H. Buckley,
- S. Awiphan,
- N. Nakhaharutai,
- S. Zola,
- K. A. Rybicki,
- M. Gromadzki,
- K. Howil,
- N. Ihanec,
- M. Jabłońska,
- K. Kruszyńska,
- K. Kruszyńska,
- U. Pylypenko,
- M. Ratajczak,
- M. Sitek,
- M. Rabus
Affiliations
- E. Bachelet
- ORCiD
- IPAC , Mail Code 100-22, Caltech, 1200 E. California Blvd., Pasadena, CA 91125, USA
- P. Rota
- ORCiD
- Dipartimento di Fisica “E.R. Caianiello,” Università di Salerno , Via Giovanni Paolo II 132, 84084 Fisciano, Italy; Istituto Nazionale di Fisica Nucleare , Sezione di Napoli, Via Cintia, 80126 Napoli, Italy
- V. Bozza
- ORCiD
- Dipartimento di Fisica “E.R. Caianiello,” Università di Salerno , Via Giovanni Paolo II 132, 84084 Fisciano, Italy; Istituto Nazionale di Fisica Nucleare , Sezione di Napoli, Via Cintia, 80126 Napoli, Italy
- P. Zieliński
- ORCiD
- Institute of Astronomy, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń , Grudziądzka 5, 87-100 Toruń, Poland
- Y. Tsapras
- ORCiD
- Zentrum für Astronomie der Universität Heidelberg , Astronomisches Rechen-Institut, Mönchhofstr. 12-14, 69120 Heidelberg, Germany
- M. Hundertmark
- ORCiD
- Zentrum für Astronomie der Universität Heidelberg , Astronomisches Rechen-Institut, Mönchhofstr. 12-14, 69120 Heidelberg, Germany
- J. Wambsganss
- ORCiD
- Zentrum für Astronomie der Universität Heidelberg , Astronomisches Rechen-Institut, Mönchhofstr. 12-14, 69120 Heidelberg, Germany
- Ł. Wyrzykowski
- ORCiD
- Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, Poland
- P. J. Mikołajczyk
- Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, Poland; Astronomical Institute, University of Wrocław , Kopernika 11, 51-622 Wrocław, Poland
- R. A. Street
- Las Cumbres Observatory Global Telescope Network , Inc., 6740 Cortona Dr., Suite 102, Goleta, CA 93117, USA
- R. Figuera Jaimes
- Millennium Institute of Astrophysics MAS , Nuncio Monsenor Sotero Sanz 100, Of. 104, Providencia, Santiago, Chile; Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile , Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago, Chile
- A. Cassan
- Institut d’Astrophysique de Paris, Sorbonne Université , CNRS, UMR 7095, 98 bis bd Arago, F-75014 Paris, France
- M. Dominik
- University of St Andrews , Centre for Exoplanet Science, School of Physics & Astronomy, North Haugh, St Andrews KY16 9SS, UK
- D. A. H. Buckley
- ORCiD
- South African Astronomical Observatory , PO Box 9, Observatory Rd., Observatory 7935, South Africa; Department of Astronomy, University of Cape Town , Private Bag X3, Rondebosch 7701, South Africa; Department of Physics, University of the Free State , PO Box 339, Bloemfontein 9300, South Africa
- S. Awiphan
- ORCiD
- National Astronomical Research Institute of Thailand (Public Organization) , 260 Moo 4, Donkaew, Mae Rim, Chiang Mai 50180, Thailand
- N. Nakhaharutai
- Department of Statistics, Faculty of Science, Chiang Mai University , Chiang Mai 50200, Thailand
- S. Zola
- ORCiD
- Astronomical Observatory, Jagiellonian University , Orla 171, 30-244 Kraków, Poland
- K. A. Rybicki
- ORCiD
- Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, Poland; Department of Particle Physics and Astrophysics, Weizmann Institute of Science , Rehovot 76100, Israel
- M. Gromadzki
- ORCiD
- Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, Poland
- K. Howil
- Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, Poland
- N. Ihanec
- Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, Poland
- M. Jabłońska
- Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, Poland; Research School of Astronomy & Astrophysics, Australian National University , Cotter Rd., Weston, ACT 2611, Australia
- K. Kruszyńska
- Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, Poland; Las Cumbres Observatory Global Telescope Network , Inc., 6740 Cortona Dr., Suite 102, Goleta, CA 93117, USA
- K. Kruszyńska
- Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, Poland; Las Cumbres Observatory Global Telescope Network , Inc., 6740 Cortona Dr., Suite 102, Goleta, CA 93117, USA
- U. Pylypenko
- Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, Poland
- M. Ratajczak
- Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, Poland
- M. Sitek
- Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, Poland
- M. Rabus
- ORCiD
- Departamento de Matemática y Física Aplicadas, Facultad de Ingeniería, Universidad Católica de la Santísima Concepción , Alonso de Rivera 2850, Concepción, Chile
- DOI
- https://doi.org/10.3847/1538-3881/ad46fc
- Journal volume & issue
-
Vol. 168,
no. 1
p. 9
Abstract
During the last 25 yr, hundreds of binary stars and planets have been discovered toward the Galactic bulge by microlensing surveys. Thanks to a new generation of large-sky surveys, it is now possible to regularly detect microlensing events across the entire sky. The OMEGA Key Projet at the Las Cumbres Observatory carries out automated follow-up observations of microlensing events alerted by these surveys with the aim of identifying and characterizing exoplanets as well as stellar remnants. In this study, we present the analysis of the binary lens event Gaia20bof. By automatically requesting additional observations, the OMEGA Key Project obtained dense time coverage of an anomaly near the peak of the event, allowing characterization of the lensing system. The observed anomaly in the lightcurve is due to a binary lens. However, several models can explain the observations. Spectroscopic observations indicate that the source is located at ≤2.0 kpc, in agreement with the parallax measurements from Gaia. While the models are currently degenerate, future observations, especially the Gaia astrometric time series as well as high-resolution imaging, will provide extra constraints to distinguish between them.
Keywords
