On Finding Black Holes in Photometric Microlensing Surveys

Kaczmarek, Zofia; McGill, Peter; Perkins, Scott E.; Dawson, William A.; Huston, Macy; Ho, Ming-Feng; Abrams, Natasha S.; Lu, Jessica R.

doi:10.3847/1538-4357/adb1d7

On Finding Black Holes in Photometric Microlensing Surveys

Journal Article · Fri Mar 07 00:00:00 EST 2025 · The Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/adb1d7· OSTI ID:2563331

^[1]; ^[2]; ^[2]; ^[2]; ^[3]; ^[4]; ^[3]; ^[3]

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Zentrum für Astronomie der Universität Heidelberg (Germany)
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
University of California, Berkeley, CA (United States)
University of California, Riverside, CA (United States); University of Michigan, Ann Arbor, MI (United States); Leinweber Center for Theoretical Physics, Ann Arbor, MI (United States)

There are expected to be millions of isolated black holes in the galaxy resulting from the deaths of massive stars. Measuring the abundance and properties of this remnant population would shed light on the end stages of stellar evolution and the evolution paths of black hole systems. Detecting isolated black holes is currently only possible via gravitational microlensing, which has so far yielded one definitive detection. The difficulty in finding microlensing black holes lies in having to choose a small subset of events, based on characteristics of their light curves, to allocate expensive and scarce follow-up resources to confirm the identity of the lens. Current methods either rely on simple cuts in parameter space without using the full distribution information or are only effective on small subsets of events. In this paper, we present a new lens classification method. The classifier takes in posterior constraints on light-curve parameters and combines them with a Galactic simulation to estimate the lens class probability. This method is flexible and can be used with any set of microlensing light-curve parameters, making it applicable to large samples of events. We make this classification framework available via the popclass Python package. We apply the classifier to ~10,000 microlensing events from the Optical Gravitational Lensing Experiment survey and find 23 high-probability black hole candidates. Our classifier also suggests that the only known isolated black hole is an observational outlier, according to current Galactic models, and the allocation of astrometric follow-up on this event was a high-risk strategy.

View Accepted Manuscript (DOE)

Research Organization:: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Organization:: Heising–Simons Foundation; National Aeronautics and Space Administration (NASA); National Science Foundation (NSF); USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE National Nuclear Security Administration (NNSA)

Grant/Contract Number:: AC52-07NA27344

OSTI ID:: 2563331

Report Number(s):: LLNL--JRNL-870480; 1107678

Journal Information:: The Astrophysical Journal, Journal Name: The Astrophysical Journal Journal Issue: 2 Vol. 981; ISSN 0004-637X

Publisher:: IOP PublishingCopyright Statement

Country of Publication:: United States

Language:: English

References (117)

The James Webb Space Telescope Gardner, Jonathan P.; Mather, John C.; Clampin, Mark Space Science Reviews, Vol. 123, Issue 4 https://doi.org/10.1007/s11214-006-8315-7	journal	November 2006
Dynamic nested sampling: an improved algorithm for parameter estimation and evidence calculation Higson, Edward; Handley, Will; Hobson, Michael Statistics and Computing, Vol. 29, Issue 5 https://doi.org/10.1007/s11222-018-9844-0	journal	December 2018
VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way Minniti, D.; Lucas, P. W.; Emerson, J. P. New Astronomy, Vol. 15, Issue 5 https://doi.org/10.1016/j.newast.2009.12.002	journal	July 2010
Cygnus X-1—a Spectroscopic Binary with a Heavy Companion ? Webster, B. Louise; Murdin, Paul Nature, Vol. 235, Issue 5332 https://doi.org/10.1038/235037a0	journal	January 1972
Identification of Cygnus X-1 with HDE 226868 Bolton, C. T. Nature, Vol. 235, Issue 5336 https://doi.org/10.1038/235271b0	journal	February 1972
Array programming with NumPy Harris, Charles R.; Millman, K. Jarrod; van der Walt, Stéfan J. Nature, Vol. 585, Issue 7825 https://doi.org/10.1038/s41586-020-2649-2	journal	September 2020
SciPy 1.0: fundamental algorithms for scientific computing in Python Virtanen, Pauli; Gommers, Ralf; Oliphant, Travis E. Nature Methods https://doi.org/10.1038/s41592-019-0686-2	journal	February 2020
Optical Gravitational Lensing Experiment OGLE 1999 BUL 32: the longest ever microlensing event – evidence for a stellar mass black hole? Mao, Shude; Smith, Martin C.; Woźniak, P. Monthly Notices of the Royal Astronomical Society, Vol. 329, Issue 2 https://doi.org/10.1046/j.1365-8711.2002.04986.x	journal	January 2002
X-rays from isolated black holes in the Milky Way Agol, E.; Kamionkowski, M. Monthly Notices of the Royal Astronomical Society, Vol. 334, Issue 3 https://doi.org/10.1046/j.1365-8711.2002.05523.x	journal	August 2002
Acceleration and parallax effects in gravitational microlensing Smith, Martin C.; Mao, Shude; Paczyński, Bohdan Monthly Notices of the Royal Astronomical Society, Vol. 339, Issue 4 https://doi.org/10.1046/j.1365-8711.2003.06183.x	journal	March 2003
Astropy: A community Python package for astronomy Robitaille, Thomas P.; Tollerud, Erik J.; Greenfield, Perry Astronomy & Astrophysics, Vol. 558 https://doi.org/10.1051/0004-6361/201322068	journal	September 2013
The RAVE survey: the Galactic escape speed and the mass of the Milky Way Piffl, T.; Scannapieco, C.; Binney, J. Astronomy & Astrophysics, Vol. 562 https://doi.org/10.1051/0004-6361/201322531	journal	February 2014
The Gaia mission Prusti, T.; de Bruijne, J. H. J.; Brown, A. G. A. Astronomy & Astrophysics, Vol. 595 https://doi.org/10.1051/0004-6361/201629272	journal	November 2016
Constraining the masses of microlensing black holes and the mass gap with Gaia DR2 Wyrzykowski, Łukasz; Mandel, Ilya Astronomy & Astrophysics, Vol. 636 https://doi.org/10.1051/0004-6361/201935842	journal	April 2020
Expectations on mass determination using astrometric microlensing by Gaia Klüter, J.; Bastian, U.; Wambsganss, J. Astronomy & Astrophysics, Vol. 640 https://doi.org/10.1051/0004-6361/201937061	journal	August 2020
Gaia Early Data Release 3: Parallax bias versus magnitude, colour, and position Lindegren, L.; Bastian, U.; Biermann, M. Astronomy & Astrophysics, Vol. 649 https://doi.org/10.1051/0004-6361/202039653	journal	April 2021
Stellar and substellar companions from Gaia EDR3 Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric Astronomy & Astrophysics, Vol. 657 https://doi.org/10.1051/0004-6361/202142146	journal	December 2021
Gaia Data Release 3 Wyrzykowski, Ł.; Kruszyńska, K.; Rybicki, K. A. Astronomy & Astrophysics, Vol. 674 https://doi.org/10.1051/0004-6361/202243756	journal	June 2023
Gaia Data Release 3 No authors listed Astronomy & Astrophysics, Vol. 674 https://doi.org/10.1051/0004-6361/202243940	journal	June 2023
A possible nearby microlensing stellar remnant hiding in Gaia DR3 astrometry Jabłońska, Maja; Wyrzykowski, Łukasz; Rybicki, Krzysztof A. Astronomy & Astrophysics, Vol. 666 https://doi.org/10.1051/0004-6361/202244656	journal	October 2022
An empirical model of the Gaia DR3 selection function Cantat-Gaudin, Tristan; Fouesneau, Morgan; Rix, Hans-Walter Astronomy & Astrophysics, Vol. 669 https://doi.org/10.1051/0004-6361/202244784	journal	January 2023
Dark lens candidates from Gaia Data Release 3 Kruszyńska, K.; Wyrzykowski, Ł.; Rybicki, K. A. Astronomy & Astrophysics, Vol. 692 https://doi.org/10.1051/0004-6361/202449322	journal	November 2024
Discovery of a dormant 33 solar-mass black hole in pre-release Gaia astrometry No authors listed Astronomy & Astrophysics, Vol. 686 https://doi.org/10.1051/0004-6361/202449763	journal	May 2024
Gaia DR3 detectability of unresolved binary systems Castro-Ginard, Alfred; Penoyre, Zephyr; Casey, Andrew R. Astronomy & Astrophysics, Vol. 688 https://doi.org/10.1051/0004-6361/202450172	journal	July 2024
Uncovering the invisible: A study of Gaia18ajz, a candidate black hole revealed by microlensing Howil, K.; Wyrzykowski, Ł.; Kruszyńska, K. Astronomy & Astrophysics, Vol. 694 https://doi.org/10.1051/0004-6361/202451046	journal	February 2025
A synthetic view on structure and evolution of the Milky Way Robin, A. C.; Reylé, C.; Derrière, S. Astronomy & Astrophysics, Vol. 416, Issue 1 https://doi.org/10.1051/0004-6361:20040968	journal	February 2004
Astrometry for Determining the MACHO Mass and Trajectory Miyamoto, M.; Yoshi, Y. The Astronomical Journal, Vol. 110 https://doi.org/10.1086/117616	journal	September 1995
Microlensed Image Motions Walker, Mark A. The Astrophysical Journal, Vol. 453 https://doi.org/10.1086/176367	journal	November 1995
Proper motions of MACHOs Gould, Andrew The Astrophysical Journal, Vol. 421 https://doi.org/10.1086/187190	journal	February 1994
Astrometric Microlensing of Stars Dominik, Martin; Sahu, Kailash C. The Astrophysical Journal, Vol. 534, Issue 1 https://doi.org/10.1086/308716	journal	May 2000
Gravitational Microlensing Events Due to Stellar‐Mass Black Holes Bennett, D. P.; Becker, A. C.; Quinn, J. L. The Astrophysical Journal, Vol. 579, Issue 2 https://doi.org/10.1086/342225	journal	November 2002
Finding Black Holes with Microlensing Agol, Eric; Kamionkowski, Marc; Koopmans, Léon V. E. The Astrophysical Journal, Vol. 576, Issue 2 https://doi.org/10.1086/343758	journal	September 2002
Resolution of the MACHO‐LMC‐5 Puzzle: The Jerk‐Parallax Microlens Degeneracy Gould, Andrew The Astrophysical Journal, Vol. 606, Issue 1 https://doi.org/10.1086/382782	journal	May 2004
Systematic Analysis of 22 Microlensing Parallax Candidates Poindexter, Shawn; Afonso, Cristina; Bennett, David P. The Astrophysical Journal, Vol. 633, Issue 2 https://doi.org/10.1086/468182	journal	November 2005
The Initial‐Final Mass Relation: Direct Constraints at the Low‐Mass End Kalirai, Jasonjot S.; Hansen, Brad M. S.; Kelson, Daniel D. The Astrophysical Journal, Vol. 676, Issue 1 https://doi.org/10.1086/527028	journal	March 2008
Galaxia: a code to Generate a Synthetic Survey of the Milky way Sharma, Sanjib; Bland-Hawthorn, Joss; Johnston, Kathryn V. The Astrophysical Journal, Vol. 730, Issue 1 https://doi.org/10.1088/0004-637X/730/1/3	journal	February 2011
Measuring Reddening with Sloan Digital sky Survey Stellar Spectra and Recalibrating sfd Schlafly, Edward F.; Finkbeiner, Douglas P. The Astrophysical Journal, Vol. 737, Issue 2 https://doi.org/10.1088/0004-637X/737/2/103	journal	August 2011
The mass Distribution of Stellar-Mass Black Holes Farr, Will M.; Sravan, Niharika; Cantrell, Andrew The Astrophysical Journal, Vol. 741, Issue 2 https://doi.org/10.1088/0004-637X/741/2/103	journal	October 2011
Mass Measurements of Black Holes in X-Ray Transients: is There a mass gap? Kreidberg, Laura; Bailyn, Charles D.; Farr, Will M. The Astrophysical Journal, Vol. 757, Issue 1 https://doi.org/10.1088/0004-637X/757/1/36	journal	September 2012
Missing Black Holes Unveil the Supernova Explosion Mechanism Belczynski, Krzysztof; Wiktorowicz, Grzegorz; Fryer, Chris L. The Astrophysical Journal, Vol. 757, Issue 1 https://doi.org/10.1088/0004-637X/757/1/91	journal	September 2012
REDDENING AND EXTINCTION TOWARD THE GALACTIC BULGE FROM OGLE-III: THE INNER MILKY WAY'S R _V ∼ 2.5 EXTINCTION CURVE Nataf, David M.; Gould, Andrew; Fouqué, Pascal The Astrophysical Journal, Vol. 769, Issue 2 https://doi.org/10.1088/0004-637X/769/2/88	journal	May 2013
The Microlensing Event rate and Optical Depth Toward the Galactic Bulge from Moa-Ii Sumi, T.; Bennett, D. P.; Bond, I. A. The Astrophysical Journal, Vol. 778, Issue 2 https://doi.org/10.1088/0004-637X/778/2/150	journal	November 2013
The Compactness of Presupernova Stellar Cores Sukhbold, Tuguldur; Woosley, S. E. The Astrophysical Journal, Vol. 783, Issue 1 https://doi.org/10.1088/0004-637X/783/1/10	journal	February 2014
Ogle-Iii Microlensing Events and the Structure of the Galactic Bulge Wyrzykowski, Łukasz; Rynkiewicz, Alicja E.; Skowron, Jan The Astrophysical Journal Supplement Series, Vol. 216, Issue 1 https://doi.org/10.1088/0067-0049/216/1/12	journal	January 2015
YSE-PZ: A Transient Survey Management Platform that Empowers the Human-in-the-loop Coulter, D. A.; Jones, D. O.; McGill, P. Publications of the Astronomical Society of the Pacific, Vol. 135, Issue 1048 https://doi.org/10.1088/1538-3873/acd662	journal	June 2023
On the Neutron Star/Black Hole Mass Gap and Black Hole Searches Shao, Yong Research in Astronomy and Astrophysics, Vol. 22, Issue 12 https://doi.org/10.1088/1674-4527/ac995e	journal	November 2022
dynesty: a dynamic nested sampling package for estimating Bayesian posteriors and evidences Speagle, Joshua S. Monthly Notices of the Royal Astronomical Society, Vol. 493, Issue 3 https://doi.org/10.1093/mnras/staa278	journal	February 2020
A microlensing search of 700 million VVV light curves Husseiniova, Andrea; McGill, Peter; Smith, Leigh C. Monthly Notices of the Royal Astronomical Society, Vol. 506, Issue 2 https://doi.org/10.1093/mnras/stab1882	journal	July 2021
Dark lenses through the dust: parallax microlensing events in the VVV Kaczmarek, Zofia; McGill, Peter; Evans, N. Wyn Monthly Notices of the Royal Astronomical Society, Vol. 514, Issue 4 https://doi.org/10.1093/mnras/stac1507	journal	June 2022
A Sun-like star orbiting a black hole El-Badry, Kareem; Rix, Hans-Walter; Quataert, Eliot Monthly Notices of the Royal Astronomical Society, Vol. 518, Issue 1 https://doi.org/10.1093/mnras/stac3140	journal	November 2022
First semi-empirical test of the white dwarf mass–radius relationship using a single white dwarf via astrometric microlensing McGill, Peter; Anderson, Jay; Casertano, Stefano Monthly Notices of the Royal Astronomical Society, Vol. 520, Issue 1 https://doi.org/10.1093/mnras/stac3532	journal	December 2022
Astrometric identification of nearby binary stars – I. Predicted astrometric signals Penoyre, Zephyr; Belokurov, Vasily; Evans, N. Wyn Monthly Notices of the Royal Astronomical Society, Vol. 513, Issue 2 https://doi.org/10.1093/mnras/stac959	journal	April 2022
A red giant orbiting a black hole El-Badry, Kareem; Rix, Hans-Walter; Cendes, Yvette Monthly Notices of the Royal Astronomical Society, Vol. 521, Issue 3 https://doi.org/10.1093/mnras/stad799	journal	March 2023
Spatially resolved microlensing time-scale distributions across the Galactic bulge with the VVV survey Kaczmarek, Zofia; McGill, Peter; Evans, N. Wyn Monthly Notices of the Royal Astronomical Society, Vol. 529, Issue 2 https://doi.org/10.1093/mnras/stae445	journal	February 2024
The mass spectrum of compact remnants from the parsec stellar evolution tracks Spera, Mario; Mapelli, Michela; Bressan, Alessandro Monthly Notices of the Royal Astronomical Society, Vol. 451, Issue 4 https://doi.org/10.1093/mnras/stv1161	journal	June 2015
Extinction law in the range 0.4–4.8 μm and the 8620 Å DIB towards the stellar cluster Westerlund 1 Damineli, A.; Almeida, L. A.; Blum, R. D. Monthly Notices of the Royal Astronomical Society, Vol. 463, Issue 3 https://doi.org/10.1093/mnras/stw2122	journal	August 2016
Black hole, neutron star and white dwarf candidates from microlensing with OGLE-III Wyrzykowski, Ł.; Kostrzewa-Rutkowska, Z.; Skowron, J. Monthly Notices of the Royal Astronomical Society, Vol. 458, Issue 3 https://doi.org/10.1093/mnras/stw426	journal	February 2016
On the accuracy of mass measurement for microlensing black holes as seen by Gaia and OGLE Rybicki, Krzysztof A.; Wyrzykowski, Łukasz; Klencki, Jakub Monthly Notices of the Royal Astronomical Society, Vol. 476, Issue 2 https://doi.org/10.1093/mnras/sty356	journal	February 2018
Predictions of Gaia’s prize microlensing events are flawed McGill, Peter; Everall, Andrew; Boubert, Douglas Monthly Notices of the Royal Astronomical Society: Letters, Vol. 498, Issue 1 https://doi.org/10.1093/mnrasl/slaa118	journal	June 2020
A predicted astrometric microlensing event by a nearby white dwarf McGill, Peter; Smith, Leigh C.; Evans, N. Wyn Monthly Notices of the Royal Astronomical Society: Letters, Vol. 478, Issue 1 https://doi.org/10.1093/mnrasl/sly066	journal	April 2018
Ongoing astrometric microlensing events from VVV and Gaia McGill, P.; Smith, L. C.; Evans, N. W. Monthly Notices of the Royal Astronomical Society: Letters, Vol. 487, Issue 1 https://doi.org/10.1093/mnrasl/slz073	journal	May 2019
GWTC-2.1: Deep extended catalog of compact binary coalescences observed by LIGO and Virgo during the first half of the third observing run Abbott, R.; Abbott, T. D.; Acernese, F. Physical Review D, Vol. 109, Issue 2 https://doi.org/10.1103/PhysRevD.109.022001	journal	January 2024
Investigating the mixing between two black hole populations in LIGO-Virgo-KAGRA GWTC-3 Ho, Ming-Feng; Perkins, Scott E.; Bird, Simeon Physical Review D, Vol. 110, Issue 6 https://doi.org/10.1103/PhysRevD.110.063031	journal	September 2024
GWTC-2: Compact Binary Coalescences Observed by LIGO and Virgo during the First Half of the Third Observing Run Abbott, R.; Abbott, T. D.; Abraham, S. Physical Review X, Vol. 11, Issue 2 https://doi.org/10.1103/PhysRevX.11.021053	journal	June 2021
GWTC-3: Compact Binary Coalescences Observed by LIGO and Virgo during the Second Part of the Third Observing Run Abbott, R.; Abbott, T. D.; Acernese, F. Physical Review X, Vol. 13, Issue 4 https://doi.org/10.1103/PhysRevX.13.041039	journal	December 2023
Binary Black Hole Mergers in the First Advanced LIGO Observing Run Abbott, B. P.; Abbott, R.; Abbott, T. D. Physical Review X, Vol. 6, Issue 4 https://doi.org/10.1103/PhysRevX.6.041015	journal	October 2016
GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO and Virgo during the First and Second Observing Runs Abbott, B. P.; Abbott, R.; Abbott, T. D. Physical Review X, Vol. 9, Issue 3 https://doi.org/10.1103/PhysRevX.9.031040	journal	September 2019
Matplotlib: A 2D Graphics Environment Hunter, John D. Computing in Science & Engineering, Vol. 9, Issue 3 https://doi.org/10.1109/MCSE.2007.55	journal	January 2007
The nature of parallax microlensing events towards the Galactic bulge Smith, Martin C.; Belokurov, Vasily; Evans, N. Wyn Monthly Notices of the Royal Astronomical Society, Vol. 361, Issue 1 https://doi.org/10.1111/j.1365-2966.2005.09147.x	journal	July 2005
General-purpose software for managing astronomical observing programs in the LSST era Street, Rachel; Bowman, Mark K.; Saunders, Eric Software and Cyberinfrastructure for Astronomy V https://doi.org/10.1117/12.2312293	conference	July 2018
Relativistic deflection of background starlight measures the mass of a nearby white dwarf star Sahu, Kailash C.; Anderson, Jay; Casertano, Stefano Science, Vol. 356, Issue 6342 https://doi.org/10.1126/science.aal2879	journal	June 2017
A pulsar in a binary with a compact object in the mass gap between neutron stars and black holes Barr, Ewan D.; Dutta, Arunima; Freire, Paulo C. C. Science, Vol. 383, Issue 6680 https://doi.org/10.1126/science.adg3005	journal	January 2024
X-Ray Properties of Black-Hole Binaries Remillard, Ronald A.; McClintock, Jeffrey E. Annual Review of Astronomy and Astrophysics, Vol. 44, Issue 1 https://doi.org/10.1146/annurev.astro.44.051905.092532	journal	September 2006
Nested sampling for general Bayesian computation Skilling, John Bayesian Analysis, Vol. 1, Issue 4 https://doi.org/10.1214/06-BA127	journal	December 2006
SkyPortal: An Astronomical Data Platform van der Walt, Stéfan; Crellin-Quick, Arien; Bloom, Joshua Journal of Open Source Software, Vol. 4, Issue 37 https://doi.org/10.21105/joss.01247	journal	May 2019
Core-Collapse Supernovae from 9 to 120 Solar Masses Based on Neutrino-Powered Explosions Sukhbold, Tuguldur; Ertl, T.; Woosley, S. E. The Astrophysical Journal, Vol. 821, Issue 1 https://doi.org/10.3847/0004-637X/821/1/38	journal	April 2016
A Search for Stellar-Mass Black Holes via Astrometric Microlensing Lu, J. R.; Sinukoff, E.; Ofek, E. O. The Astrophysical Journal, Vol. 830, Issue 1 https://doi.org/10.3847/0004-637X/830/1/41	journal	October 2016
Ukirt Microlensing Surveys as a Pathfinder for Wfirst: the Detection of five Highly Extinguished Low- Events Shvartzvald, Y.; Bryden, G.; Gould, A. The Astronomical Journal, Vol. 153, Issue 2 https://doi.org/10.3847/1538-3881/153/2/61	journal	January 2017
pyLIMA: An Open-source Package for Microlensing Modeling. I. Presentation of the Software and Analysis of Single-lens Models Bachelet, E.; Norbury, M.; Bozza, V. The Astronomical Journal, Vol. 154, Issue 5 https://doi.org/10.3847/1538-3881/aa911c	journal	November 2017
OGLE-2016-BLG-1190Lb: The First Spitzer Bulge Planet Lies Near the Planet/Brown-dwarf Boundary Ryu, Y. -H.; Yee, J. C.; Udalski, A. The Astronomical Journal, Vol. 155, Issue 1 https://doi.org/10.3847/1538-3881/aa9be4	journal	December 2017
Binary Companions of Evolved Stars in APOGEE DR14: Search Method and Catalog of ∼5000 Companions Price-Whelan, Adrian M.; Hogg, David W.; Rix, Hans-Walter The Astronomical Journal, Vol. 156, Issue 1 https://doi.org/10.3847/1538-3881/aac387	journal	June 2018
SPISEA: A Python-based Simple Stellar Population Synthesis Code for Star Clusters Hosek Jr., Matthew W.; Lu, Jessica R.; Lam, Casey Y. The Astronomical Journal, Vol. 160, Issue 3 https://doi.org/10.3847/1538-3881/aba533	journal	August 2020
Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. II. Free-floating Planet Detection Rates Johnson, Samson A.; Penny, Matthew; Gaudi, B. Scott The Astronomical Journal, Vol. 160, Issue 3 https://doi.org/10.3847/1538-3881/aba75b	journal	August 2020
Real-time Likelihood-free Inference of Roman Binary Microlensing Events with Amortized Neural Posterior Estimation Zhang, Keming; Bloom, Joshua S.; Gaudi, B. Scott The Astronomical Journal, Vol. 161, Issue 6 https://doi.org/10.3847/1538-3881/abf42e	journal	May 2021
Adaptive Optics Imaging Can Break the Central Caustic Cusp Approach Degeneracy in High-magnification Microlensing Events Terry, Sean K.; Bennett, David P.; Bhattacharya, Aparna The Astronomical Journal, Vol. 164, Issue 5 https://doi.org/10.3847/1538-3881/ac9518	journal	October 2022
Systematic KMTNet Planetary Anomaly Search. XI. Complete Sample of 2016 Subprime Field Planets Shin, In-Gu; Yee, Jennifer C.; Zang, Weicheng The Astronomical Journal, Vol. 167, Issue 6 https://doi.org/10.3847/1538-3881/ad3ba3	journal	May 2024
Estimating Microlensing Parameters from Observables and Stellar Isochrones with pyLIMASS Bachelet, E.; Hundertmark, M.; Calchi Novati, S. The Astronomical Journal, Vol. 168, Issue 1 https://doi.org/10.3847/1538-3881/ad4862	journal	June 2024
Pulsational Pair-instability Supernovae Woosley, S. E. The Astrophysical Journal, Vol. 836, Issue 2 https://doi.org/10.3847/1538-4357/836/2/244	journal	February 2017
Confronting Models of Massive Star Evolution and Explosions with Remnant Mass Measurements Raithel, Carolyn A.; Sukhbold, Tuguldur; Özel, Feryal The Astrophysical Journal, Vol. 856, Issue 1 https://doi.org/10.3847/1538-4357/aab09b	journal	March 2018
First Resolution of Microlensed Images Dong, Subo; Mérand, A.; Delplancke-Ströbele, F. The Astrophysical Journal, Vol. 871, Issue 1 https://doi.org/10.3847/1538-4357/aaeffb	journal	January 2019
LSST: From Science Drivers to Reference Design and Anticipated Data Products Ivezić, Željko; Kahn, Steven M.; Tyson, J. Anthony The Astrophysical Journal, Vol. 873, Issue 2 https://doi.org/10.3847/1538-4357/ab042c	journal	March 2019
PopSyCLE: A New Population Synthesis Code for Compact Object Microlensing Events Lam, Casey Y.; Lu, Jessica R.; Hosek, Matthew W. The Astrophysical Journal, Vol. 889, Issue 1 https://doi.org/10.3847/1538-4357/ab5fd3	journal	January 2020
The Birth Function for Black Holes and Neutron Stars in Close Binaries Woosley, S. E.; Sukhbold, Tuguldur; Janka, H. -T. The Astrophysical Journal, Vol. 896, Issue 1 https://doi.org/10.3847/1538-4357/ab8cc1	journal	June 2020
On the Possibility of Stellar Lenses in the Black Hole Candidate Microlensing Events MACHO-96-BLG-5 and MACHO-98-BLG-6 Abdurrahman, Fatima N.; Stephens, Haynes F.; Lu, Jessica R. The Astrophysical Journal, Vol. 912, Issue 2 https://doi.org/10.3847/1538-4357/abee83	journal	May 2021
An Isolated Stellar-mass Black Hole Detected through Astrometric Microlensing* Sahu, Kailash C.; Anderson, Jay; Casertano, Stefano The Astrophysical Journal, Vol. 933, Issue 1 https://doi.org/10.3847/1538-4357/ac739e	journal	July 2022
The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package* No authors listed The Astrophysical Journal, Vol. 935, Issue 2 https://doi.org/10.3847/1538-4357/ac7c74	journal	August 2022
The Impact of Initial–Final Mass Relations on Black Hole Microlensing Rose, Sam; Lam, Casey Y.; Lu, Jessica R. The Astrophysical Journal, Vol. 941, Issue 2 https://doi.org/10.3847/1538-4357/aca09d	journal	December 2022
60 Microlensing Events from the Three Years of Zwicky Transient Facility Phase One Medford, Michael S.; Abrams, Natasha S.; Lu, Jessica R. The Astrophysical Journal, Vol. 947, Issue 1 https://doi.org/10.3847/1538-4357/acba8f	journal	April 2023
A Reanalysis of the Isolated Black Hole Candidate OGLE-2011-BLG-0462/MOA-2011-BLG-191 Lam, Casey Y.; Lu, Jessica R. The Astrophysical Journal, Vol. 955, Issue 2 https://doi.org/10.3847/1538-4357/aced4a	journal	September 2023
Disentangling the Black Hole Mass Spectrum with Photometric Microlensing Surveys Perkins, Scott E.; McGill, Peter; Dawson, William The Astrophysical Journal, Vol. 961, Issue 2 https://doi.org/10.3847/1538-4357/ad09bf	journal	January 2024
Astrometric Microlensing by Primordial Black Holes with the Roman Space Telescope Fardeen, James; McGill, Peter; Perkins, Scott E. The Astrophysical Journal, Vol. 965, Issue 2 https://doi.org/10.3847/1538-4357/ad3243	journal	April 2024
Primordial Black Hole Dark Matter Simulations Using PopSyCLE Pruett, Kerianne; Dawson, William; Medford, Michael S. The Astrophysical Journal, Vol. 970, Issue 2 https://doi.org/10.3847/1538-4357/ad3df0	journal	July 2024
Influence of Black Hole Kick Velocity on Microlensing Distributions Koshimoto, Naoki; Kawanaka, Norita; Tsuna, Daichi The Astrophysical Journal, Vol. 973, Issue 1 https://doi.org/10.3847/1538-4357/ad5feb	journal	September 2024
Analysis of the Full Spitzer Microlensing Sample. I. Dark Remnant Candidates and Gaia Predictions Rybicki, Krzysztof A.; Shvartzvald, Yossi; Yee, Jennifer C. The Astrophysical Journal, Vol. 975, Issue 2 https://doi.org/10.3847/1538-4357/ad7bb1	journal	November 2024
Assessing the Impact of Binary Systems on Microlensing Using `SPISEA` and `PopSyCLE` Population Simulations Abrams, Natasha S.; Lu, Jessica R.; Lam, Casey Y. The Astrophysical Journal, Vol. 980, Issue 1 https://doi.org/10.3847/1538-4357/ada5f9	journal	February 2025
Predictions of the WFIRST Microlensing Survey. I. Bound Planet Detection Rates Penny, Matthew T.; Scott Gaudi, B.; Kerins, Eamonn The Astrophysical Journal Supplement Series, Vol. 241, Issue 1 https://doi.org/10.3847/1538-4365/aafb69	journal	February 2019
Microlensing Optical Depth and Event Rate toward the Galactic Bulge from 8 yr of OGLE-IV Observations Mróz, Przemek; Udalski, Andrzej; Skowron, Jan The Astrophysical Journal Supplement Series, Vol. 244, Issue 2 https://doi.org/10.3847/1538-4365/ab426b	journal	October 2019
Microlensing Optical Depth and Event Rate in the OGLE-IV Galactic Plane Fields Mróz, Przemek; Udalski, Andrzej; Szymański, Michał K. The Astrophysical Journal Supplement Series, Vol. 249, Issue 1 https://doi.org/10.3847/1538-4365/ab9366	journal	July 2020
A Reanalysis of Public Galactic Bulge Gravitational Microlensing Events from OGLE-III and -IV Golovich, Nathan; Dawson, William; Bartolić, Fran The Astrophysical Journal Supplement Series, Vol. 260, Issue 1 https://doi.org/10.3847/1538-4365/ac5969	journal	April 2022
Supplement: “An Isolated Mass-gap Black Hole or Neutron Star Detected with Astrometric Microlensing” (2022, ApJL, 933, L23) Lam, Casey Y.; Lu, Jessica R.; Udalski, Andrzej The Astrophysical Journal Supplement Series, Vol. 260, Issue 2 https://doi.org/10.3847/1538-4365/ac7441	journal	June 2022
Microlensing Discovery and Characterization Efficiency in the Vera C. Rubin Legacy Survey of Space and Time Abrams, Natasha S.; Hundertmark, Markus P. G.; Khakpash, Somayeh The Astrophysical Journal Supplement Series, Vol. 276, Issue 1 https://doi.org/10.3847/1538-4365/ad91b0	journal	December 2024
An Isolated Mass-gap Black Hole or Neutron Star Detected with Astrometric Microlensing Lam, Casey Y.; Lu, Jessica R.; Udalski, Andrzej The Astrophysical Journal Letters, Vol. 933, Issue 1 https://doi.org/10.3847/2041-8213/ac7442	journal	July 2022
OGLE-IV: Fourth Phase of the Optical Gravitational Lensing Experiment Udalski, A.; Szymański, M. K.; Szymański, G. arXiv https://doi.org/10.48550/arXiv.1504.05966	text	January 2015
The Optical Gravitational Lensing Experiment. Real Time Data Analysis Systems in the OGLE-III Survey Udalski, A. arXiv https://doi.org/10.48550/arXiv.astro-ph/0401123	text	January 2004
The MOA 1.8-metre alt-az wide-field survey telescope and the MOA project Hearnshaw, J. B.; Abe, F.; Bond, I. A. arXiv https://doi.org/10.48550/arXiv.astro-ph/0509420	preprint	January 2005
YSE-PZ: An Open-source Target and Observation Management System Coulter, D. A.; Jones, D. O.; McGill, P. https://doi.org/10.5281/zenodo.7278430	software	November 2022
Kmtnet: a Network of 1.6 m Wide-Field Optical Telescopes Installed at Three Southern Observatories Kim, Seung-Lee; Lee, Chung-Uk; Park, Byeong-Gon Journal of The Korean Astronomical Society, Vol. 49, Issue 1 https://doi.org/10.5303/JKAS.2016.49.1.37	journal	February 2016