Kavli Affiliate: Michael M. Fausnaugh
| First 5 Authors: Krzysztof A. Rybicki, Yossi Shvartzvald, Jennifer C. Yee, Sebastiano Calchi Novati, Eran O. Ofek
| Summary:
In the pursuit of understanding the population of stellar remnants within the
Milky Way, we analyze the sample of $sim 950$ microlensing events observed by
the Spitzer Space Telescope between 2014 and 2019. In this study we focus on a
sub-sample 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 $2.98^{+1.75}_{-1.28}~M_{odot}$, $4.65^{+3.12}_{-2.08}~M_{odot}$,
$3.15^{+0.66}_{-0.64}~M_{odot}$ and $1.4^{+0.75}_{-0.55}~M_{odot}$,
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
time-scale ($t_{rm E}$) vs. parallax ($pi_{rm E}$) diagram to derive
constraints on the population of lenses in general and massive remnants in
particular.
| Search Query: ArXiv Query: search_query=au:”Michael M. Fausnaugh”&id_list=&start=0&max_results=3