Cross-correlating Dark Sirens and Galaxies: Constraints on H 0 from GWTC-3 of LIGO–Virgo–KAGRA
The Astrophysical Journal American Astronomical Society 975:2 (2024) 189
Abstract:
We apply the cross-correlation technique to infer the Hubble constant (H 0) of the Universe using gravitational-wave (GW) sources without electromagnetic counterparts (dark sirens) from the third GW Transient Catalog (GWTC-3) and the photometric galaxy surveys 2MPZ and WISE-SuperCOSMOS, and combine these with the bright siren measurement of H 0 from GW170817. The posterior on H 0 with only dark sirens is uninformative due to the small number of well-localized GW sources. Using the eight well-localized dark sirens and the binary neutron star GW170817 with electromagnetic counterpart, we obtain a value of the Hubble constant H0=75.4−6+11 km s−1 Mpc−1 (median and 68.3% equal-tailed interval) after marginalizing over the matter density and the GW bias parameters. This measurement is mostly driven by the bright siren measurement, and any constraint from dark sirens is not statistically significant. In the future, with more well-localized GW events, the constraints on expansion history will improve.Ultrahigh-energy cosmic rays from tidally-ignited white dwarfs
Physical Review D American Physical Society 96:10 (2017) 103003
Abstract:
Ultrahigh-energy cosmic rays (UHECRs) can be accelerated by tidal disruption events of stars by black holes. We suggest a novel mechanism for UHECR acceleration wherein white dwarfs (WDs) are tidally compressed by intermediate-mass black holes (IMBHs), leading to their ignition and subsequent explosion as a supernova. Cosmic rays accelerated by the supernova may receive an energy boost when crossing the accretion-powered jet. The rate of encounters between WDs and IMBHs can be relatively high, as the number of IMBHs may be substantially augmented once account is taken of their likely presence in dwarf galaxies. Here we show that this kind of tidal disruption event naturally provides an intermediate composition for the observed UHECRs, and suggest that dwarf galaxies and globular clusters are suitable sites for particle acceleration to ultrahigh energies.CLUSTER–VOID DEGENERACY BREAKING: DARK ENERGY, PLANCK, AND THE LARGEST CLUSTER AND VOID
The Astrophysical Journal Letters American Astronomical Society 820:1 (2016) l7
Probing the circumgalactic baryons through cross-correlations
Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 456:2 (2016) 1495-1507
Flaring of tidally compressed dark-matter clumps
Physical Review D American Physical Society (APS) 93:4 (2016) 043508