Related papers: One Small Step for $Roman$; One Giant Leap for Bla…
Isolated Stellar-Mass BlackHoles (ISMBHs) are potentially discernible through microlensing observations. In this work, we study detecting and characterizing ISMBHs with the Roman observations. We simulate a big ensemble of these events as…
Roman telescope provides the best opportunity to detect a large number of Isolated Stellar-Mass Black Holes (ISMBHs) through microlensing. Roman will not only detect long-duration microlensing events caused by ISMBHs, but will also measure…
With its capacity to observe $\sim 10^{5-6}$ faint active galactic nuclei (AGN) out to redshift $z\approx 6$, Roman is poised to reveal a population of $10^{4-6}\, {\rm M_\odot}$ black holes during an epoch of vigorous galaxy assembly. By…
Primordial Black Holes (PBHs) could explain some fraction of dark matter and shed light on many areas of early-universe physics. Despite over half a century of research interest, a PBH population has so far eluded detection. The most…
Though stellar-mass black holes (BHs) are likely abundant in the Milky Way (N=10^8-10^9), only ~20 have been detected to date, all in accreting binary systems (Casares 2006). Gravitational microlensing is a proposed technique to search for…
The LIGO-Virgo gravitational-wave (GW) observation unveiled the new population of black holes (BHs) that appears to have an extended mass spectrum up to around $70M_\odot$, much heavier than the previously-believed mass range ($\sim…
Accreting massive black hole binaries (MBHBs) often display periodic variations in their emitted radiation, providing a distinctive signature for their identification. In this work, we explore the MBHBs identification via optical…
Although there are estimated to be 100 million isolated black holes (BHs) in the Milky Way, only one has been found so far, resulting in significant uncertainty about their properties. The Galactic Bulge Time Domain Survey provides the only…
Compact object binaries (a black hole or a neutron star orbiting a non-degenerate stellar companion) are key to our understanding of late massive star evolution, in addition to being some of the best probes of extreme gravity and accretion…
Nearly 150 massive black hole binary (MBHB) candidates at sub-pc orbital separations have been reported in recent literature. Nevertheless, the definitive detection of even a single such object remains elusive. If at least one of the black…
Stellar-mass black holes (BHs) above $30 M_\odot$ are predicted to form from low-metallicity progenitors, but direct detections of such systems in the Milky Way remain scarce. Motivated by the recent discovery of Gaia BH3, a $33 M_\odot$ BH…
Primordial black holes (PBHs), theorized to have originated in the early universe, are speculated to be a viable form of dark matter. If they exist, they should be detectable through photometric and astrometric signals resulting from…
Detection of black holes (BHs) with detached luminous companions (LCs) can be instrumental in connecting the BH properties with their progenitors' since the latter can be inferred from the observable properties of the LC. Past studies…
Isolated black holes (BHs) and neutron stars (NSs) are largely undetectable across the electromagnetic spectrum. For this reason, our only real prospect of observing these isolated compact remnants is via microlensing; a feat recently…
Black hole-like objects with mass greater than $10 M_{\odot}$, as discovered by gravitational antennas, can produce long time-scale (several years) gravitational microlensing effects. Considered separately, previous microlensing surveys…
Although supermassive black holes (SMBHs) are found at the centers of most galaxies today, over 300 have now been discovered at $z >$ 6, including UHZ1 at $z = 10.1$ and GHZ9 at $z =$ 10.4. They are thought to form when 10$^4$ - 10$^5$…
If the Dark Matter consists of primordial black holes (PBHs), we show that gravitational lensing of stars being monitored by NASA's Kepler search for extra-solar planets can cause significant numbers of detectable microlensing events. A…
Primordial Black Holes (PBHs) remain a Dark Matter (DM) candidate of the Standard Model of Particle Physics. Previously, we proposed a new method of constraining the remaining PBH DM mass range using microlensing of stars monitored by…
Microlensing is one of the most promising tools for discovering stellar-mass black holes (BHs) in the Milky Way because it allows us to probe dark or faint celestial compact objects. While the existence of stellar-mass BHs has been…
The Roman Space Telescope's Galactic Bulge Time Domain Survey will constitute the most sensitive microlensing survey of the Galactic Bulge to date, opening up new opportunities to search for dark matter (DM). Many extensions of the Standard…