Dark lenses through the dust: parallax microlensing events in the VVV

ABSTRACT We use near-infrared photometry and astrometry from the VISTA Variables in Via Lactea (VVV) survey to analyse microlensing events containing annual parallax information. These are located highly extincted low-latitude regions of Galactic bulge typically off-limits optical surveys. fit a catalogue 1959 previously found VVV extract 21 candidates. The fitting is done using nested sampling automatically characterize multimodal degenerate posterior distributions signal. compute probability density lens mass-distance source proper motion model disc deflectors. By comparing expected flux main sequence baseline magnitude blending parameter, we identify four candidates which have >50 per cent that dark. strongest candidate corresponds nearby (≈0.78 kpc), medium-mass ($1.46^{+1.13}_{-0.71} \ M_{\odot }$) dark remnant as lens. In next strongest, at heliocentric distance ≈5.3 kpc. It with mass $1.63^{+1.15}_{-0.70} }$. Both those most likely neutron stars, though possibly high-mass white dwarfs. last two may also be caused by remnants, unable rule out other possibilities because limitations data. demonstrating future studying similar Roman Space Telescopeby modelling mock dataset for an event resembling our candidate.