Astrometry-only detection of microlensing events with Gaia

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378271%3A_____%2F25%3A00637375" target="_blank" >RIV/68378271:_____/25:00637375 - isvavai.cz</a>

Result on the web

<a href="https://hdl.handle.net/11104/0370939" target="_blank" >https://hdl.handle.net/11104/0370939</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202453525" target="_blank" >10.1051/0004-6361/202453525</a>

Result language

angličtina

Original language name

Astrometry-only detection of microlensing events with Gaia

Original language description

Context. Astrometric microlensing events occur when a massive object passes between a distant source and the observer, causing a shift of the light centroid. The precise astrometric measurements of the Gaia mission provide an unprecedented opportunity to detect and analyse these events, revealing properties of lensing objects such as their mass and distance. Aims. We developed and tested the Gaia Astrometric Microlensing Events (GAME) Filter, a software tool for identifying astrometric microlensing events and deriving lensing object properties. Methods. We generated mock Gaia observations for different magnitudes, different numbers of Gaia visits, and events extending beyond Gaia’s observational run. We applied GAME Filter to these datasets and validated its performance. We also assessed the rate of false positives involving binary astrometric systems misidentified as microlensing events. Results. GAME Filter successfully recovers microlensing parameters for strong events. Parameters are more difficult to recover for short events and those extending beyond Gaia’s run, where only a fraction of the events are observed. The astrometric effect breaks the degeneracy in the microlensing parallax present in photometric microlensing. For fainter sources, the observed signal weakens, reducing recovered events and increasing parameter errors. However, even for Gaia G-band magnitude 19, the parameters can be recovered for Einstein radii ≳2 mas. Observing regions with varying numbers of Gaia visits has a minimal impact on filter accuracy when the number of visits is ≳90. Additionally, even if the peak of a microlensing event lies outside Gaia’s run, microlensing parameters can still be recovered. GAME filter characterises lenses with astrometry-only data for lens masses ranging from approximately 1–20 M⊙ and distances of up to ≈6 kpc. Conclusions. GAME Filter reveals the astrometric potential in microlensing events. Our results indicate that astrometric data can enhance photometric detections and refine constraints on microlensing parameters.

Czech name

—

Czech description

—

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

699

Issue of the periodical within the volume

July

Country of publishing house

FR - FRANCE

Number of pages

14

Pages from-to

A156

UT code for WoS article

001522910200023

EID of the result in the Scopus database

2-s2.0-105009992748