Confirming candidate self-lensing binary detections with radial velocity measurements
Abstract
Compact objects in approximately edge-on binary orbits with stars are able to produce a self-lensing effect, amplifying light from their companion once per orbit. To date, five white dwarf self-lensing systems are known, while none are known containing black holes or neutron stars. Discovery of such systems is a potential method of finding quiescent black holes and neutron stars, most of which will be pristine and unchanged from their formation. Photometric detections can suffer from degeneracies in the lens mass and orbital parameters when the amplification and crossing time are not well constrained, while photometric searches produce too many false positives to allow radial velocity investigation of every candidate. Therefore we investigate the minimal radial velocity (RV) observational requirements to characterise such systems by simulating detectable self-lensing light curves, using those light curves to generate targeted RV observations, and fitting RV jointly with photometry. We evaluate the median relative error in the recovered lens mass and orbital period, alongside compact-object class recovery. We find that adding RV measurements substantially reduces parameter error, with compact-object class generally easier to determine than the exact lens mass. Parameter accuracy is driven mainly by number of RV observations, with RV precision playing a weaker role except for the shortest-period systems, with even a small number of RV measurements resulting in substantial improvement in accuracy. These results suggest that multi-stage RV follow-up, starting with a small number of observations of many candidates, can efficiently classify self-lensing candidates and identify high-priority systems for further investigation.
Related
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BibTeX
@misc{mcmaster2026confirming,
title = {{Confirming candidate self-lensing binary detections with radial velocity measurements}},
author = {Adam McMaster and Madeline-Mai Ward and Hugh J. Dickinson and Matthew J. Middleton and D. J. Dixon and Adam Ingram and N. Castro Segura and Simon Vaughan and Grzegorz Wiktorowicz},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.30203},
eprint = {2610.30203},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.30203},
note = {CC BY-SA 4.0},
}
RIS
TY - UNPB
TI - Confirming candidate self-lensing binary detections with radial velocity measurements
AU - Adam McMaster
AU - Madeline-Mai Ward
AU - Hugh J. Dickinson
AU - Matthew J. Middleton
AU - D. J. Dixon
AU - Adam Ingram
AU - N. Castro Segura
AU - Simon Vaughan
AU - Grzegorz Wiktorowicz
PY - 2026
DA - 2026/10/27
PB - arXiv
DO - 10.48550/arxiv.2610.30203
UR - https://arxiv.org/abs/2610.30203
AB - Compact objects in approximately edge-on binary orbits with stars are able to produce a self-lensing effect, amplifying light from their companion once per orbit. To date, five white dwarf self-lensing systems are known, while none are known containing black holes or neutron stars. Discovery of such systems is a potential method of finding quiescent black holes and neutron stars, most of which will be pristine and unchanged from their formation. Photometric detections can suffer from degeneracies in the lens mass and orbital parameters when the amplification and crossing time are not well constrained, while photometric searches produce too many false positives to allow radial velocity investigation of every candidate. Therefore we investigate the minimal radial velocity (RV) observational requirements to characterise such systems by simulating detectable self-lensing light curves, using those light curves to generate targeted RV observations, and fitting RV jointly with photometry. We evaluate the median relative error in the recovered lens mass and orbital period, alongside compact-object class recovery. We find that adding RV measurements substantially reduces parameter error, with compact-object class generally easier to determine than the exact lens mass. Parameter accuracy is driven mainly by number of RV observations, with RV precision playing a weaker role except for the shortest-period systems, with even a small number of RV measurements resulting in substantial improvement in accuracy. These results suggest that multi-stage RV follow-up, starting with a small number of observations of many candidates, can efficiently classify self-lensing candidates and identify high-priority systems for further investigation.
ER -