Related papers: PopSyCLE: A New Population Synthesis Code for Comp…
The Pan-STARRS 1 (PS1) survey of M31 (PAndromeda) is designed to identify gravitational microlensing events, caused by bulge and disk stars (self-lensing) and by compact matter in the halos of M31 and the Milky Way (halo lensing, or lensing…
We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole (BH). We used the Hubble Space Telescope (HST) to carry out precise astrometry of the source star of the long-duration (t_E~270 days),…
It has been suggested that a monitoring program employing the pixel lensing method to search for microlensing events towards galactic globular clusters may increase the statistics and discriminate among different halo models. Stimulated by…
The measurements of the possible gravitational microlensing events are analysed with a simple yet accurate disc--halo model of the Milky Way Galaxy. This comprises a luminous exponential disc embedded in a flattened dark matter halo with…
The first directly observed gravitational wave event, GW150914, featuring the merger of two massive black holes, highlighted the need to determine how these systems of compact remnant binaries are formed. We use the binary population…
Observations of caustic-crossing galaxies at redshift $0.7<z<1$ show a wealth of transient events. Most of them are believed to be microlensing events of highly magnified stars. Earlier work predicted such events should be common near the…
The $Roman$ microlensing program can detect and fully characterize black holes (BHs) that are in orbit with about 30 million solar-type and evolved stars with periods up to the mission lifetime $P<T=5$ yr, and semi-major axes $a>0.2$au,…
Gravitational lensing of short astrophysical transients provides a uniquely direct avenue for searching for primordial black holes (PBHs) across a vast range of masses. While past search efforts have focused on particular source…
Recently Sahu et al., using the Hubble Space Telescope to monitor stars in the direction of the old globular cluster M22, detected six events in which otherwise constant stars brightened by ~50% during a time of <1 day. They tentatively…
Microlensing searches aim to detect compact halo dark matter via its gravitational lensing effect on stars within the Large Magellanic Cloud. The most recent results have led to the claim that roughly one fifth of the galactic halo dark…
Starting from the assumption that there is a large population (> 10^8) of isolated, stellar-mass black holes (IBH) distributed throughout our galaxy, we consider the detectable signatures of accretion from the interstellar medium (ISM) that…
We report the discovery of a large timescale candidate microlensing event of a bulge stellar source based on near-infrared observations with the VISTA Variables in the Via Lactea Survey (VVV). The new microlensing event is projected only…
We consider the imprint of superradiant instabilities of nonevaporating primordial black holes (PBHs) on the spectrum of the cosmic microwave background (CMB). In the radiation dominated era, PBHs are surrounded by a roughly homogeneous…
We report the results of a study aiming to detect signs of astrometric microlensing caused by an intermediate-mass black hole (IMBH) in the center of globular cluster M 22 (NGC 6656). We used archival data from the Hubble Space Telescope…
We present the results from the OGLE-II survey (1996-2000) towards the Large Magellanic Cloud (LMC), which has the aim of detecting the microlensing phenomena caused by dark matter compact objects in the Galactic Halo (Machos). We use high…
Supercooled first-order phase transition (FOPT) can lead to the formation of primordial black holes (PBHs). This scenario imposes stringent requirements on the profile of the effective potential. In this work, we use the singlet extended…
The resolution of photon rings of Sgr~A$^*$ and M87 is the next milestone of upcoming EHT-like interferometries. We extend the formalism developed in our previous work~\cite{Verma:2023hes} to constrain primordial black hole (PBH) dark…
We investigate microlensing amplification of faint stars in the dense stellar cluster in the Galactic Center (GC) by the super-massive black hole (BH). Such events would appear very close to the position of the radio source SgrA*, which is…
In a recent search (Kim et al. 2022), we looked for microlensing signature in gravitational waves from spectrograms of the binary black hole events in the first and second gravitational-wave transient catalogs. For the search, we have…
The long-duration Galactic-bulge microlensing event OGLE-2011-BLG-0462 produced relativistic astrometric deflections of the source star, which we measured using HST observations taken at 8 epochs over ~6 years. Analysis of the microlensing…