Microlensing constraints on axion stars including finite lens and source size effects

Abstract

A fraction of light scalar dark matter, especially axions, may organize into Bose-Einstein condensates, gravitationally bound clumps, "boson stars", and be present in large number in galactic halos today. We compute the expected number of gravitational microlensing events of clumps composed of the ordinary QCD axion and axion-like-particles and derive microlensing constraints from the EROS-2 survey and the Subaru Hyper Suprime-Cam observation. We perform a detailed lensing calculation, including the finite lens and source size effects in our analysis. We constrain the axion mass in terms of the fraction of dark matter collapsed into clumps, the individual clump densities, and the axion self-coupling. We also consider and constrain clumps composed of a generic scalar dark matter candidate with repulsive self-interactions. Our analysis opens up a new window for the potential discovery of dark matter.

20 pages, 12 figures, v2: Updated towards version accepted for publication in Physical Review D

References in corpus (15)

• Limits on the Macho Content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds
• Constraints on Earth-mass primordial black holes from OGLE 5-year microlensing events
• Dilute and dense axion stars
• Microlensing and dynamical constraints on primordial black hole dark matter with an extended mass function
• Relativistic axions from collapsing Bose stars
• OGLE-IV: Fourth Phase of the Optical Gravitational Lensing Experiment
• The Need for Speed: Escape velocity and dynamical mass measurements of the Andromeda galaxy
• Merger of Dark Matter Axion Clumps and Resonant Photon Emission
• Quantum and Classical Behavior in Interacting Bosonic Systems
• A Model of Anthropic Reasoning, Addressing the Dark to Ordinary Matter Coincidence
• Evolution and thermalization of dark matter axions in the condensed regime
• Radio signatures from encounters between Neutron Stars and QCD-Axion Minihalos around Primordial Black Holes
• Axions: From Magnetars and Neutron Star Mergers to Beam Dumps and BECs
• Boson star and dark matter
• Correlated gravitational wave and microlensing signals of macroscopic dark matter

Cited by in corpus (16)

• Observational Evidence for Primordial Black Holes: A Positivist Perspective
• Dark Photon Stars: Formation and Role as Dark Matter Substructure
• Possible evidence of QCD axion stars in HSC and OGLE microlensing events
• Lensing constraints on ultradense dark matter halos
• Maximum mass of relativistic self-gravitating Bose-Einstein condensates with repulsive or attractive $|\phi {|}^4$ self-interaction
• Gravitational microlensing by dressed primordial black holes
• Constraining axion and compact dark matter with interstellar medium heating
• New scenario of QCD axion clump formation I: Linear analysis
• Axion star condensation around primordial black holes and microlensing limits
• New Light on Dark Extended Lenses with the Roman Space Telescope
• Novel standard candle: Collapsing axion stars
• Microlensing of dark matter models in the Milky Way
• Can QCD Axion Stars explain Subaru HSC microlensing?
• Detecting dilute axion stars constrained by fast radio bursts in the Solar System via stimulated decay
• Caustic crossings in giant arcs with extended dark matter objects
• Constraints on extended axion structures from the lensing of fast radio bursts