Detecting dark objects with plasma microlensing by their gravitational wakes
arXiv:2409.16348 · doi:10.3847/1538-4357/ad96b1
Abstract
A moving mass makes a gravitational wake in the partially ionized interstellar medium, which acts as a lens for radio-frequency light. Consequently, plasma microlensing could complement gravitational microlensing in the search for invisible massive objects, such as stellar remnants or compact dark matter. This work explores the spatial structure of the plasma lens associated with a gravitational wake. Far away from the moving mass, the characteristic lensing signal is the steady demagnification or magnification of a radio source as the wake passes in front of it at the speed of sound. Sources can be plasma lensed at a much greater angular distance than they would be gravitationally lensed to the same degree by the same object. However, only the wakes of objects greatly exceeding stellar mass are expected to dominate over the random turbulence in the interstellar medium.
arXiv comment19 pages, 8 figures. Introduction has been expanded to clarify the physical setup. Accepted by ApJ
References in corpus (21)
- The MACHO Project: Microlensing Results from 5.7 Years of LMC Observations
- Limits on the Macho Content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds
- Dynamical Friction in a Gaseous Medium
- A Review of Bondi--Hoyle--Lyttleton Accretion
- The OGLE View of Microlensing towards the Magellanic Clouds. IV. OGLE-III SMC Data and Final Conclusions on MACHOs
- Black Hole, Neutron Star and White Dwarf Candidates from Microlensing with OGLE-III
- An isolated mass gap black hole or neutron star detected with astrometric microlensing
- Gravitational Microlensing Events Due to Stellar Mass Black Holes
- The Gaussian Plasma Lens in Astrophysics. Refraction
- Optical Gravitational Lensing Experiment. OGLE-1999-BUL-32: the Longest Ever Microlensing Event -- Evidence for a Stellar Mass Black Hole?
- The NANOGrav Nine-Year Data Set: Measurement and Interpretation of Variations in Dispersion Measures
- Pulsar Observations of Extreme Scattering Events
- No massive black holes in the Milky Way halo
- Electron Density Structure of the Local Galactic Disk
- Real-time detection of an extreme scattering event: constraints on Galactic plasma lenses
- Microlensing Searches for Exoplanets
- Dynamic spectral mapping of interstellar plasma lenses
- Lensing constraints on ultradense dark matter halos
- Extreme scattering events from axisymmetric plasma lenses
- Plasma microlensing dynamic spectrum probing fine structures in the ionized interstellar medium
- The imprint of dark subhaloes on the circumgalactic medium