Related papers: An Isolated Stellar-Mass Black Hole Detected Throu…
Multiple pieces of evidence suggest that neutron stars receive large kicks when formed from the remnant of a collapsing star. However, the evidence for whether black holes (BH) receive natal kicks is less clear, reliant on weak constraints…
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…
Isolated black holes and neutron stars can be revealed through the observation of long duration gravitational microlensing events. A few candidates have been found in surveys of stars in the direction of the Galactic bulge. Recently, thanks…
OGLE and other projects are likely to discover first stellar mass black holes and the first planets through gravitational lensing in the next year or two. It is important to have follow-up projects ready, using diverse observing methods.…
Context: A large number of isolated black holes (IBHs) are expected to populate the Galaxy. However, only one has been confirmed by the analysis of a microlensing event, and no confirmed emission detection from an IBH has been reported so…
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…
Supermassive black holes (SMBHs) are a key catalyst of galaxy formation and evolution, leading to an observed correlation between SMBH mass $M_{\rm BH}$ and host galaxy velocity dispersion $\sigma_{\rm e}$. Outside the local Universe,…
Stellar-mass black holes ($3$ $M_\odot \lesssim M_{\rm BH} \lesssim 150$ $M_\odot$) are the natural product of the evolution of heavy stars ($M_{\rm star} \gtrsim 20$ $M_\odot$). In our Galaxy, we expect $10^8$-$10^9$ stellar-mass black…
The quadruple lensed system WGD2038-4008 was recently discovered with the help of new techniques and observations. Even though black hole mass has been estimated for lensed quasars, it has been calculated mostly for one broad emission line…
The natal kick velocity distribution for black holes (BHs) is unknown regardless of its importance for understanding the BH formation process. Gravitational microlensing is a unique tool for studying the distribution of BHs in our Galaxy,…
Recently Sumi et al. (2011) reported evidence for a large population of planetary-mass objects (PMOs) that are either unbound or orbit host stars in orbits > 10 AU. Their result was deduced from the statistical distribution of durations of…
We report on the mass and distance measurements of two single-lens events from the 2015 \emph{Spitzer} microlensing campaign. With both finite-source effect and microlens parallax measurements, we find that the lens of OGLE-2015-BLG-1268 is…
At cosmological distances, gravitational lensing can provide a direct measurement of supermassive black hole (SMBH) masses irrespective of their luminosities. Here, we directly estimate the mass of a SMBH in the brightest cluster galaxy…
Many black hole (BH) candidates exist, ranging from supermassive ($\sim10^{6}$--$10^{10}$ M$_{\odot}$) to stellar masses ($\sim 1$--$100$ M$_{\odot}$), all of them identified by indirect processes. Although there are no known candidate BHs…
The longest microlensing events provide enough information to estimate the mass and distance of the lens. Among hundreds of millions of stars which were monitored for many years by the OGLE project we selected those with clear parallax…
We present the first space-based microlens parallax measurement of an isolated star. From the striking differences in the lightcurve as seen from Earth and from Spitzer (~1 AU to the West), we infer a projected velocity v_helio,projected ~…
We present a determination of the mass of the supermassive black hole (BH) and the nuclear stellar orbital distribution of the elliptical galaxy Centaurus A (NGC5128) using high-resolution integral-field observations of the stellar…
Gravitational microlensing is unique in detecting binary black (BH) holes with wide (a few au) separations. Models predict that about $1\%$ of microlensing binaries should be due to binary BHs, and yet zero has been robustly identified.…
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…
We investigate the stellar mass - black hole mass ($\mathcal{M}_*-\mathcal{M}_\mathrm{BH}$) relation with type 1 AGN down to $\mathcal{M}_\mathrm{BH}=10^7 M_\odot$, corresponding to a $\simeq -21$ absolute magnitude in rest-frame…