[en] Gravitational microlensing[SUP]1[/SUP] is a powerful technique for measuring the mass of isolated and faint or non-luminous objects in the Milky Way[SUP]2,3[/SUP]. In most cases, however, additional observations to the photometric light curve are required to measure accurately the mass of the microlens. Long-baseline optical/infrared interferometry provides a new and efficient way to deliver such independent constraints[SUP]4-7[/SUP], as demonstrated recently by first interferometric observations in microlensing event TCP J05074264+2447555 (`Kojima-1')[SUP]8[/SUP]. Here we report real-time observations of gravitationally lensed arcs in rotation around a microlens, Gaia19bld[SUP]9[/SUP], made with the PIONIER instrument[SUP]10[/SUP] at the Very Large Telescope Interferometer. Our data allowed us to determine the angular separation and length of the arcs, as well as their rotation rate. Combining these measurements with ground-based photometric data enabled the determination of the microlens mass, M = 1.147 ± 0.029 M[SUB]⊙[/SUB], to a very high accuracy. We anticipate interferometric microlensing to play an important future role in the mass and distance determination of isolated stellar-mass black holes[SUP]11-13[/SUP] in the Galaxy, which cannot be addressed by any other technique.
Research Center/Unit :
STAR - Space sciences, Technologies and Astrophysics Research - ULiège
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Cassan, Arnaud; Institut d'Astrophysique de Paris, UMR 7095, Sorbonne Université and CNRS, Paris, France
Ranc, Clément; Institut d'Astrophysique de Paris, UMR 7095, Sorbonne Université and CNRS, Paris, France ; Astrophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, MD, USA
Absil, Olivier ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > PSILab
Wyrzykowski, Łukasz; Astronomical Observatory, University of Warsaw, Warszawa, Poland
Rybicki, Krzysztof A.; Astronomical Observatory, University of Warsaw, Warszawa, Poland
Bachelet, Étienne; Las Cumbres Observatory Global Telescope Network, Goleta, CA, USA
Le Bouquin, Jean-Baptiste; Institut de Planétologie et d'Astrophysique de Grenoble, Université Grenoble Alpes and CNRS, Grenoble, France ; Department of Astronomy, University of Michigan, Ann Arbor, MI, USA
Hundertmark, Markus; Zentrum für Astronomie der Universität Heidelberg, Astronomisches Rechen-Institut, Heidelberg, Germany
Street, Rachel; Las Cumbres Observatory Global Telescope Network, Goleta, CA, USA
Surdej, Jean ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
Tsapras, Yiannis; Zentrum für Astronomie der Universität Heidelberg, Astronomisches Rechen-Institut, Heidelberg, Germany
Wambsganss, Joachim; Zentrum für Astronomie der Universität Heidelberg, Astronomisches Rechen-Institut, Heidelberg, Germany
Wertz, Olivier; Space Sciences, Technologies and Astrophysics Research (STAR) Institute, University of Liège, Liège, Belgium)
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