Search for H2 cloudlets in our backyard

Abstract

Several observational lines of evidence imply that a fraction of the dark matter in the Galaxy may be comprised of small cold clouds of molecular hydrogen. Such objects are difficult to detect because of their small size and low temperature, but they can reveal themselves with gamma radiation arising in interactions between such clouds and cosmic rays or as dark shadows cast on the optical, UV and X-ray sky background. In our work we use the data of Fermi LAT 4FGL-DR4 catalogue of gamma-ray sources together with the data of GALEX UV All-Sky Survey to search for small dark clouds of molecular hydrogen in the Solar neighbourhood. This approach allows us to put an upper limit on the local concentration of such objects: $n<2.2\times 10^{-11}{\mathrm{AU}}^{-3}$. Constraints (upper limits) on the total amount of matter in this form bound to the Sun strongly depend on the radial profile of the clouds' distribution and reside in $0.05-30M_{\odot }$ mass range.

References in corpus (18)

• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• Fermi Large Area Telescope Fourth Source Catalog
• Incremental Fermi Large Area Telescope Fourth Source Catalog
• Photodissociation and photoionisation of atoms and molecules of astrophysical interest
• Constraints on primordial black holes as dark matter candidates from star formation
• Real-time detection of an extreme scattering event: constraints on Galactic plasma lenses
• GALEX Diffuse Observations of the Sky: The Data
• Cosmic ray spectrum in the local Galaxy
• Gamma rays as probes of cosmic-ray propagation and interactions in galaxies
• Fermi Large Area Telescope Fourth Source Catalog Data Release 4 (4FGL-DR4)
• Collisional baryonic dark matter halos
• Extreme radio-wave scattering associated with hot stars
• The Atacama Cosmology Telescope: limits on dark matter-baryon interactions from DR4 power spectra
• Dissipative Dark Cosmology: From Early Matter Dominance to Delayed Compact Objects
• Spica and the annual cycle of PKS B1322-110 scintillations
• Probes for Dark Matter Physics
• Cosmic snow clouds: self-gravitating gas spheres manifesting hydrogen condensation
• Cosmological nanolensing by dense gas clouds