Detecting isolated stellar-mass black holes by the Roman telescope

Abstract

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 seen by Roman and estimate the errors in the physical parameters of the lens objects, including their masses, distances, and proper motions through calculating Fisher and Covariance matrices. Since the ~2.3-year time gap between Roman's first three observing seasons and the others may lower the efficiency of realizing microlensing events and characterizing ISMBHs, we additionally consider a scenario where we add a small amount of additional observations -- one hour of observations every 10 days when the Bulge is observable during the large time gap -- which is equivalent to a total of about one additional day of observations with the Roman telescope. These extra observations increase Roman's efficiency for characterizing ISMBHs by ~$1-2\%$ and, more importantly, improve the robustness of the results by avoiding possible degenerate solutions. By considering uniform, and power-law mass functions ($dN/dM{M}^{-\alpha }$, $\alpha =2,1,0.5$) for ISMBHs in the range of $[2,50]M_{\odot }$, we conclude that the Roman telescope will determine the physical parameters of the lenses within $<5\%$ uncertainty, with efficiencies of $21\%$, and $16$-$18\%$, respectively. By considering these mass functions, we expect that the Roman telescope during its mission will detect and characterize $3$-$4$, $15$-$17$ and $22$-$24$ ISMBHs through astrometric microlensing, with the relative errors for all physical parameters less than $1,5,10\%$, respectively. Microlensing events owing to ISMBHs with a mass $\simeq 10$-$25M_{\odot }$ and located close to the observer with $D_l\lesssim 0.5D_s$ while the source is inside the Galactic disk can be characterized with least errors.

15 pages, 6 figures (23 panels), accepted for publication in AJ

References in corpus (18)

• Refined Mass and Geometric Measurements of the High-Mass PSR J0740+6620
• The origins of massive black holes
• Formation of massive black holes in rapidly growing pre-galactic gas clouds
• OGLE-IV: Fourth Phase of the Optical Gravitational Lensing Experiment
• An isolated mass gap black hole or neutron star detected with astrometric microlensing
• Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey II: Free-Floating Planet Detection Rates
• A Search for Stellar-Mass Black Holes via Astrometric Microlensing
• Systematic errors as a source of mass discrepancy in black hole microlensing event OGLE-2011-BLG-0462
• Measuring the Galactic Distribution of Transiting Planets with WFIRST
• The Black Hole Mass Function Across Cosmic Times I. Stellar Black Holes and Light Seed Distribution
• Formation of Mass-gap Black Holes from Neutron Star X-ray Binaries with Super-Eddington Accretion
• On the detection of free-floating planets through microlensing towards the Magellanic Clouds
• Detection of Exoplanet as a Binary Source of Microlensing Events in WFIRST Survey
• Search for primordial black hole dark matter with X-ray spectroscopic and imaging satellite experiments and prospects for future satellite missions
• Detecting isolated stellar-mass black holes in the absence of microlensing parallax effect
• Sensitivity to habitable planets in the \textit{Roman} microlensing survey
• Binary astrometric microlensing with Gaia
• Detecting the inner regions of discs around sources of microlensing with Roman Space Telescope

Cited by in corpus (5)

• Gravitational lensing of a Schwarzschild-like black hole in Kalb-Ramond gravity
• Gravitational lens effect of a holonomy corrected Schwarzschild black hole
• Disentangling the Black Hole Mass Spectrum with Photometric Microlensing Surveys
• The Galactic Center with Roman
• Astrometric microlensing probes of the isolated neutron star population with Roman