Uncovering the invisible: A study of Gaia18ajz, a candidate black hole revealed by microlensing

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00617099" target="_blank" >RIV/67985815:_____/25:00617099 - isvavai.cz</a>

Alternative codes found

RIV/68407700:21230/25:00381937 RIV/47813059:19630/25:A0000480 RIV/00216208:11320/25:10511212

Result on the web

<a href="https://hdl.handle.net/11104/0365922" target="_blank" >https://hdl.handle.net/11104/0365922</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202451046" target="_blank" >10.1051/0004-6361/202451046</a>

Result language

angličtina

Original language name

Uncovering the invisible: A study of Gaia18ajz, a candidate black hole revealed by microlensing

Original language description

Context. Identifying black holes is essential for our understanding of the development of stars and can reveal novel principles of physics. Gravitational microlensing provides an exceptional opportunity to examine an undetectable population of black holes in the Milky Way. In particular, long-lasting events are likely to be associated with massive lenses, including black holes. Aims. We present an analysis of the Gaia18ajz microlensing event reported by the Gaia Science Alerts system. Gaia18ajz is a long-timescale event exhibiting features indicative of the annual microlensing parallax effect. Our objective is to estimate its lens parameters based on the best-fitting model. Methods. We used photometric data obtained from the Gaia satellite and terrestrial observatories to investigate a variety of microlensing models and calculate the most probable mass and distance to the lens, taking into consideration a Galactic model as a prior. Subsequently, we applied a mass-brightness relation to evaluate the likelihood that the lens is a main sequence star. We also describe the DarkLensCode (DLC), an open- source routine that computes the distribution of probable lens mass, distance, and luminosity employing the Galaxy priors on stellar density and velocity for microlensing events with detected microlensing parallax. Results. We modelled the Gaia18ajz event and found its two possible models, the most probable Einstein timescales for which are 316(30 )(+36)days and 299(22)(+25) days. Applying Galaxy priors for stellar density and motion, we calculated a most probable lens mass of 4.9(-2.3)(+5.4) M (R) located at 1.14(+0.75) (-0.57) kpc, and a less probably mass of 11.1(+10.3) (-4.7) M (R) located at 1.31(-0.60)(+0.80) kpc. Our analysis of the blended light suggests that the lens is likely a dark remnant of stellar evolution rather than a main sequence star.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Volume of the periodical

694

Issue of the periodical within the volume

Feb.

Country of publishing house

FR - FRANCE

Number of pages

19

Pages from-to

A94

UT code for WoS article

001414735800002

EID of the result in the Scopus database

2-s2.0-85217995284