Microlensing optical depth, event rate, and limits on compact objects in dark matter based on 20 yr of OGLE observations of the Small Magellanic Cloud

Abstract

Some previous studies have suggested that massive and intermediate-mass primordial black holes (PBHs) could comprise a substantial fraction of dark matter in the Universe. Such black holes, if they existed in the Milky Way halo, would give rise to long-duration microlensing events that may potentially last for years. However, earlier searches were not sufficiently sensitive to detect such events. Here, we present the results of searches for long-timescale gravitational microlensing events toward the Small Magellanic Cloud (SMC) using nearly 20 years of photometric observations collected by the Optical Gravitational Lensing Experiment (OGLE) from 2001 to 2020. We found six events, three of which are new discoveries. We use a sample of five events to measure the microlensing optical depth toward the SMC $\tau =(0.32\pm 0.18)\times 10^{-7}$ and the event rate $\Gamma =(1.18\pm 0.57)\times 10^{-7}{\mathrm{yr}}^{-1}{\mathrm{star}}^{-1}$. The properties of the detected events are consistent with lenses originating from known stellar populations within the SMC or in the Milky Way disk. No events with timescales longer than 1 yr were detected, which provides competitive limits on the fraction of massive compact objects, including PBHs, in the Milky Way dark matter halo. Together with the earlier OGLE studies of microlensing events in the direction of the Large Magellanic Cloud, these observations rule out PBHs and other compact objects with masses ranging from $10^{-8}$ to $10^3{M}_{\odot }$ as dominant components of dark matter.

published in ApJS

References in corpus (48)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• The Gaia mission
• The Aquarius Project: the subhalos of galactic halos
• The observed properties of dwarf galaxies in and around the Local Group
• Did LIGO detect dark matter?
• Limits on the Macho Content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds
• Primordial Black Hole Scenario for the Gravitational-Wave Event GW150914
• Primordial Black Holes as a dark matter candidate
• Gaia Data Release 2: Kinematics of globular clusters and dwarf galaxies around the Milky Way
• The clustering of massive Primordial Black Holes as Dark Matter: measuring their mass distribution with Advanced LIGO
• Microlensing constraints on primordial black holes with the Subaru/HSC Andromeda observation
• A constant dark matter halo surface density in galaxies
• The Circular Velocity Curve of the Milky Way from $5$ to $25$ kpc
• Gravitational detection of a low-mass dark satellite at cosmological distance
• The Milky Way total mass profile as inferred from Gaia DR2
• No large population of unbound or wide-orbit Jupiter-mass planets
• Detection of a Dark Substructure through Gravitational Imaging
• A distance determination to the Small Magellanic Cloud with an accuracy of better than 2 percent based on late-type eclipsing binary stars
• Observational Evidence for Primordial Black Holes: A Positivist Perspective
• The OGLE View of Microlensing towards the Magellanic Clouds. IV. OGLE-III SMC Data and Final Conclusions on MACHOs
• MOA-2009-BLG-387Lb: A massive planet orbiting an M dwarf
• Implications of High-Resolution Simulations on Indirect Dark Matter Searches
• Rotation curve of the Milky Way from Classical Cepheids
• OGLE-ing the Magellanic System: Optical Reddening Maps of the Large and Small Magellanic Cloud from Red Clump Stars
• First Space-Based Microlens Parallax Measurement: Spitzer Observations of OGLE-2005-SMC-001
• Modelling the line-of-sight contribution in substructure lensing
• POINT-AGAPE Pixel Lensing Survey of M31 : Evidence for a MACHO contribution to Galactic Halos
• Detection of the Keplerian decline in the Milky Way rotation curve
• Microlensing optical depth and event rate toward the Galactic bulge from 8 yr of OGLE-IV observations
• The OGLE View of Microlensing towards the Magellanic Clouds. III. Ruling out sub-solar MACHOs with the OGLE-III LMC data
• No massive black holes in the Milky Way halo
• Gravitational microlensing by dark matter in extended structures
• The OGLE View of Microlensing towards the Magellanic Clouds. I. A Trickle of Events in the OGLE-II LMC data
• Projection effects in the strong lensing study of subhaloes
• Mapping the Milky Way Disk with Gaia DR3: 3D extended kinematic maps and rotation curve to $\approx 30$ kpc
• The total mass and dark halo properties of the Small Magellanic Cloud
• Microlensing towards the SMC: a new analysis of OGLE and EROS results
• Microlensing optical depth and event rate toward the Large Magellanic Cloud based on 20 years of OGLE observations
• MACHOs in M31? Absence of evidence but not evidence of absence
• Substructure Detection Reanalyzed: Dark Perturber shown to be a Line-of-Sight Halo
• The OGLE View of Microlensing towards the Magellanic Clouds. II. OGLE-II SMC data
• Structure of the SMC - Stellar component distribution from 2MASS data
• Pixel lensing: Microlensing towards M31
• Limits on planetary-mass primordial black holes from the OGLE high-cadence survey of the Magellanic Clouds
• Origin of structural and kinematical properties of the Small Magellanic Cloud
• Shining Primordial Black Holes
• On the Galactic rotation curve inferred from the Jeans equations Assessing its robustness using Gaia DR3 and cosmological simulations
• New Self-lensing Models of the Small Magellanic Cloud: Can Gravitational Microlensing Detect Extragalactic Exoplanets?

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