Automated Detection and Modeling of Binary Microlensing Events in OGLE-IV data. I. Events with Well-Separated Bumps

• Autorzy: Oliveira R. A. P. , Poleski R. , Mróz P. , Udalski A. , Skowron J. , Mróz M. J. , Szymański M. K. , Soszyński I. , Ulaczyk K. , Pietrukowicz P. , Rybicki K. A. , Iwanek P. , Wrona M. , Gromadzki M.

Identyfikatory

ISBN

10.32023/0001-5237/75.1.2

• Języki publikacji: EN

Abstrakty

EN

Gravitational microlensing depends primarily on the lens mass and presents a larger occurrence rate in crowded regions, which makes it the best tool to uncover the initial mass function (IMF) of low-mass stars in the Galactic bulge. The bulge IMF can be obtained from the luminosity function measured with the Hubble Space Telescope if one knows the statistics of binary stellar systems in the bulge. We aim to analyze a statistically significant number of binary-lens/single-source and single-lens/binary-source events, in order to explore the lower-mass end of the bulge IMF even in unresolved binary systems. This paper deals with events with clearly separated bumps and no caustic crossing or approach, whereas other types will be analyzed in following works. A fully-automated approach in the search and modeling of binary events was implemented. Event detection was carried out with a modified version of the algorithm used in previous studies. Model fitting was carried out with Markov chain Monte Carlo and nested sampling methods, in order to find the most probable solution among binary lens or binary source models. We retrieved 107 binary events in the Optical Gravitational Lensing Experiment (OGLE) light curves spanning ten years in 9 high-cadence and 112 low-cadence fields toward the bulge. Several criteria were applied to reduce false positives, resulting in 59 most likely binary lenses and 48 binary sources. The tools were effective in detecting a bona-fide sample of binary events, with a distribution of Einstein timescales around 35-40 d and flat distributions for mass ratio and source flux ratio. After proper consideration of detection efficiency, the statistics for binary fraction and mass ratio will provide valuable constraints for the bulge IMF.

Słowa kluczowe

EN

gravitational lensing: micro; galaxy: bulge; stars: luminosity function; mass function; binaries: general

• Wydawca: Copernicus Foundation for Polish Astronomy
• Czasopismo: Acta Astronomica
• Rocznik: 2025
• Tom: Vol. 75, No. 1
• Strony: 27--52
• Opis fizyczny: Bibliogr. 62 poz., rys., tab., wykr.

Twórcy

autor

Oliveira R. A. P.

• Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

autor

Poleski R.

• Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

autor

Mróz P.

• Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

autor

Udalski A.

• Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

autor

Skowron J.

• Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

autor

Mróz M. J.

• Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

autor

Szymański M. K.

• Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

autor

Soszyński I.

• Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

autor

Ulaczyk K.

• Department of Physics, University of Warwick, Coventry CV4 7AL, UK
• Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

autor

Pietrukowicz P.

• Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

autor

Rybicki K. A.

• Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100, Israel
• Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

autor

Iwanek P.

• Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

autor

Wrona M.

• Department of Astrophysics and Planetary Sciences, Villanova University, 800 Lancaster Avenue, Villanova, PA 19085, USA
• Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

autor

Gromadzki M.

• Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

Bibliografia

• Abrams, N.S., Lu, J.R., Lam, C.Y., et al. 2025, ApJ, 980, 103.
• Alard, C., and Lupton, R.H. 1998, ApJ, 503, 325.
• Alcock, C., Allsman, R.A., Alves, D.R., et al. 2000, ApJ, 541, 734.
• Barbuy, B., Chiappini, C., and Gerhard, O. 2018, Ann. Rev. Astron. and Astrophys., 56, 223.
• Bastian, N., Covey, K.R., and Meyer, M.R. 2010, Ann. Rev. Astron. and Astrophys., 48, 339.
• Bond, I.A., Abe, F., Dodd, R.J., et al. 2001, MNRAS, 327, 868.
• Bozza, V., Bachelet, E., Bartoli´c, F., et al. 2018, MNRAS, 479, 5157.
• Buchner, J. 2016, Statistics and Computing, 26, 383.
• Buchner, J. 2019, PASP, 131, 108005.
• Buchner, J. 2021, The Journal of Open Source Software, 6, 3001.
• Calamida, A., Sahu, K.C., Casertano, S., et al. 2015, ApJ, 810, 8.
• Calchi Novati, S., de Luca, F., Jetzer, P., Mancini, L., and Scarpetta, G. 2008, A&A, 480, 723.
• Calchi Novati, S., Gould, A., Udalski, A., et al. 2015, ApJ, 804, 20.
• Cappellari, M., McDermid, R.M., Alatalo, K., et al. 2012, Nature, 484, 485.
• Clarkson, W., Sahu, K., Anderson, J., et al. 2008, ApJ, 684, 1110.
• Da Rio, N., Gouliermis, D.A., and Henning, T. 2009, ApJ, 696, 528.
• Di Stefano, R., and Perna, R. 1997, ApJ, 488, 55.
• Dominik, M. 1998, A&A, 333, 893.
• Duchêne, G., and Kraus, A. 2013, Ann. Rev. Astron. and Astrophys, 51, 269.
• Foreman-Mackey, D., Hogg, D.W., Lang, D., and Goodman, J. 2013, PASP, 125, 306.
• Geha, M., Brown, T.M., Tumlinson, J., et al. 2013, ApJ, 771, 29.
• Golovich, N., Dawson, W., Bartoli´c, F., et al. 2022, ApJS, 260, 2.
• Griest, K., and Hu, W. 1992, ApJ, 397, 362.
• Han, C., and Gould, A. 1996, ApJ, 467, 540.
• Han, C., and Jeong, Y. 1998, MNRAS, 301, 231.
• Henderson, C.B., Poleski, R., Penny, M., et al. 2016, PASP, 128, 124401.
• Holtzman, J.A., Watson, A.M., Baum, W.A., et al. 1998, AJ, 115, 1946.
• Jaroszyński, M., Skowron, J., Udalski, A., et al. 2010, Acta Astron., 60, 197.
• Jung, Y.K., Udalski, A., Sumi, T., et al. 2015, ApJ, 798, 123.
• Kalirai, J.S., Anderson, J., Dotter, A., et al. 2013, ApJ, 763, 110.
• Kim, S.-L., Lee, C.-U., Park, B.-G., et al. 2016, Journal of Korean Astronomical Society, 49, 37.
• Kiraga, M., and Paczyński, B. 1994, ApJ, 430, L101.
• Li, S.S., Zang, W., Udalski, A., et al. 2019, MNRAS, 488, 3308.
• Liebig, C., D’Ago, G., Bozza, V., and Dominik, M. 2015, MNRAS, 450, 1565.
• Mao, S., and Paczyński, B. 1991, ApJ, 374, L37.
• Mróz, P., Udalski, A., Poleski, R., et al. 2015, Acta Astron., 65, 313.
• Mróz, P., Udalski, A., Skowron, J., et al. 2017, Nature, 548, 183.
• Mróz, P., Udalski, A., Skowron, J., et al. 2019, ApJS, 244, 29.
• Mróz, P., Poleski, R., Gould, A., et al. 2020, ApJ, 903, L11.
• Navarro, M.G., Minniti, D., and Contreras Ramos, R. 2017, ApJ, 851, L13.
• Paczy´nski, B. 1986, ApJ, 304, 1.
• Penny, M.T., Gaudi, B.S., Kerins, E., et al. 2019, ApJS, 241, 3.
• Poleski, R., Skowron, J., Udalski, A., et al. 2014, ApJ, 795, 42.
• Poleski, R., and Yee, J.C. 2019, Astronomy and Computing, 26, 35.
• Skowron, J., Wyrzykowski, Ł., Mao, S., and Jaroszyński, M. 2009, MNRAS, 393, 999.
• Skowron, J., Udalski, A., Gould, A., et al. 2011, ApJ, 738, 87.
• Skowron, J., and Gould, A. 2012, arXiv e-prints, , arXiv:2310.12069.
• Steinhardt, C.L., Kokorev, V., Rusakov, V., Garcia, E., and Sneppen, A. 2023, ApJ, 951, L40.
• Sumi, T., Kamiya, K., Bennett, D.P., et al. 2011, Nature, 473, 349.
• Tomaney, A.B., and Crotts, A.P.S. 1996, AJ, 112, 2872.
• Udalski, A., Szymański, M., Kaluzny, J., Kubiak, M., and Mateo, M. 1992, Acta Astron., 42, 253.
• Udalski, A. 2003, Acta Astron., 53, 291.
• Udalski, A., Szymański, M.K., and Szymański, G. 2015, Acta Astron., 65, 1.
• van Dokkum, P., and Conroy, C. 2024, ApJ, 973, L32.
• Wegg, C., Gerhard, O., and Portail, M. 2017, ApJ, 843, L5.
• Woodrum, C., Rieke, M., Ji, Z., et al. 2024, Proceedings of the National Academy of Science, 121, e2317375121.
• Woźniak, P.R. 2000, Acta Astron., 50, 421.
• Wyrzykowski, Ł., Udalski, A., Mao, S., et al. 2006, Acta Astron., 56, 145.
• Wyrzykowski, Ł., Kozłowski, S., Skowron, J., et al. 2009, MNRAS, 397, 1228.
• Wyrzykowski, Ł., Rynkiewicz, A.E., Skowron, J., et al. 2015, ApJS, 216, 12.
• Yee, J.C., Udalski, A., Calchi Novati, S, et al. 2015, ApJ, 802, 76.
• Zoccali, M., Cassisi, S., Frogel, J.A., et al. 2000, ApJ, 530, 418.