Analysis of the Full Spitzer Microlensing Sample. I. Dark Remnant Candidates and Gaia Predictions
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Date
2024-11-10
Open Access Location
Journal Title
Journal ISSN
Volume Title
Publisher
American Astronomical Society
Rights
(c) 2024 The Author/s
CC BY 4.0
CC BY 4.0
Abstract
In the pursuit of understanding the population of stellar remnants within the Milky Way, we analyze the sample of ∼950 microlensing events observed by the Spitzer Space Telescope between 2014 and 2019. In this study we focus on a subsample of nine microlensing events, selected based on their long timescales, small microlensing parallaxes, and joint observations by the Gaia mission, to increase the probability that the chosen lenses are massive and the mass is measurable. Among the selected events we identify lensing black holes and neutron star candidates, with potential confirmation through forthcoming release of the Gaia time-series astrometry in 2026. Utilizing Bayesian analysis and Galactic models, along with the Gaia Data Release 3 proper-motion data, four good candidates for dark remnants were identified: OGLE-2016-BLG-0293, OGLE-2018-BLG-0483, OGLE-2018-BLG-0662, and OGLE-2015-BLG-0149, with lens masses of 3.0-1.3+1.8M☉, 4.7-2.1+3.2 M☉, 3.15-0.64+0..66 M☉ and 1.40-0.55+0.75 M☉, respectively. Notably, the first two candidates are expected to exhibit astrometric microlensing signals detectable by Gaia, offering the prospect of validating the lens masses. The methodologies developed in this work will be applied to the full Spitzer microlensing sample, populating and analyzing the timescale (tE) versus parallax (πE) diagram to derive constraints on the population of lenses in general and massive remnants in particular.
Description
Keywords
Astrometric microlensing effect, Gravitational microlensing, Satellite microlensing parallax, Microlensing parallax, Black holes, Neutron stars, Stellar remnants, Gaia, Stellar masses
Citation
Rybicki KA, Shvartzvald Y, Yee JC, Novati SC, Ofek EO, Bond IA, Beichman C, Bryden G, Carey S, Henderson C, Zhu W, Fausnaugh MM, Wibking B, Udalski A, Poleski R, Mróz P, Szymański MK, Soszyński I, Pietrukowicz P, Kozłowski S, Skowron J, Ulaczyk K, Iwanek P, Wrona M, Ryu YH, Albrow MD, Chung SJ, Gould A, Han C, Hwang KH, Jung YK, Shin IG, Yang H, Zang W, Cha SM, Kim DJ, Kim HW, Kim SL, Lee CU, Lee DJ, Lee Y, Park BG, Pogge RW, Abe F, Barry R, Bennett DP, Bhattacharya A, Fukui A, Hamada R, Hamada S, Hamasaki N, Hirao Y, Silva SI, Itow Y, Kirikawa R, Koshimoto N, Matsubara Y, Miyazaki S, Muraki Y, Nagai T, Nunota K, Greg O, Ranc C, Rattenbury NJ, Satoh YK, Sumi T, Suzuki D, Tristram PJ, Vandorou A, Yama H, Wyrzykowski Ł, Howil K, Kruszyńska K. (2024). Analysis of the Full Spitzer Microlensing Sample. I. Dark Remnant Candidates and Gaia Predictions. Astrophysical Journal. 975. 2.