Search Publications
Science with the TianQin Observatory: Preliminary results on Galactic double white dwarf binaries
Huang, Shun-Jia; Hu, Yi-Ming; Korol, Valeriya +6 more
We explore the prospects of detecting Galactic double white dwarf (DWD) binaries with the space-based gravitational wave (GW) observatory TianQin. In this work, we analyze both a sample of currently known DWDs and a realistic synthetic population of DWDs to assess the number of guaranteed detections and the full capacity of the mission. We find th…
Primordial black holes and secondary gravitational waves from k and G inflation
Gao, Qing; Zhang, Chao; Gong, Yungui +3 more
The possibility that in the mass range around 10-12 M⊙ most of dark matter is constituted of primordial black holes (PBHs) is a very interesting topic. To produce PBHs with this mass, the primordial scalar power spectrum needs to be enhanced to the order of 0.01 at the scale k ∼1012 Mpc-1. The enhanced p…
NuSTAR tests of sterile-neutrino dark matter: New Galactic bulge observations and combined impact
Wik, Daniel R.; Krivonos, Roman; Beacom, John F. +4 more
We analyze two dedicated NuSTAR observations with exposure ∼190 ks located ∼1 0 ° from the Galactic plane, one above and the other below, to search for x-ray lines from the radiative decay of sterile-neutrino dark matter. These fields were chosen to minimize astrophysical x-ray backgrounds while remaining near the densest region of the dark matter…
Velocity substructure from Gaia and direct searches for dark matter
Belokurov, Vasily; Evans, N. Wyn; Myeong, GyuChul +2 more
Data from the Gaia satellite show that the solar neighborhood of the Milky Way's stellar halo is imprinted with substructure from several accretion events. Evidence of these events is found in "the shards," stars clustering with high significance in both action space and metallicity. Stars in the shards share a common origin, likely as ancient sat…
Ghostly galaxies as solitons of Bose-Einstein dark matter
Broadhurst, Tom; Smoot, George F.; De Martino, Ivan +2 more
The large dark cores of common dwarf galaxies are unexplained by the standard heavy particle interpretation of dark matter. This puzzle is exacerbated by the discovery of a very large but barely visible, dark matter dominated galaxy Antlia II orbiting the Milky Way, uncovered by tracking star motions with the Ĝaia satellite. Although Antlia II has…
Primordial black holes and oscillating gravitational waves in slow-roll and slow-climb inflation with an intermediate noninflationary phase
Wu, Puxun; Yu, Hongwei; Fu, Chengjie
We propose a new single field inflation model in which the usual slow-roll inflation is joined to a new period of slow-climb and slow-roll inflation through a short intermediate noninflationary phase. We then show that primordial curvature perturbations can be enhanced at small scales, a sizable amount of primordial black holes (PBHs) can be produ…
Primordial black holes and gravitational waves in nonstandard cosmologies
Mohanty, Subhendra; Parashari, Priyank; Bhattacharya, Sukannya
For primordial black holes (PBHs) to form a considerable fraction of cold dark matter, the required amplitude of primordial scalar perturbations is quite large (Pζ(k )∼10-2) if PBH is formed in radiation epoch. In alternate cosmological histories, where additional epoch of arbitrary equation of state precede radiation epoch, …
Testing interacting dark matter and dark energy model with cosmological data
Chen, Xuelei; Ma, Yin-Zhe; Cheng, Gong +2 more
We investigate the model of dark matter-dark energy (DM-DE) interaction with coupling strength proportional to the multiplication of dark sector densities with different power indices Q =γ ρcαρdβ. We first investigate the modification of the cosmic expansion history, and then further develop the formalis…
Constraints on dark matter-nucleon effective couplings in the presence of kinematically distinct halo substructures using the DEAP-3600 detector
Willis, J.; Chen, Y.; Ward, M. +86 more
DEAP-3600 is a single-phase liquid argon detector aiming to directly detect weakly interacting massive particles (WIMPs), located at SNOLAB (Sudbury, Canada). After analyzing data taken during the first year of operation, a null result was used to place an upper bound on the WIMP-nucleon, spin-independent, isoscalar cross section. This study reint…
Testing general relativity with x-ray reflection spectroscopy: The Konoplya-Rezzolla-Zhidenko parametrization
Tripathi, Ashutosh; Abdikamalov, Askar B.; Ayzenberg, Dimitry +6 more
X-ray reflection spectroscopy is a promising technique for testing general relativity in the strong-field regime as it can be used to test the Kerr black hole hypothesis. In this context, the parametrically deformed black hole metrics proposed by Konoplya, Rezzolla, and Zhidenko [Phys. Rev. D 93, 064015 (2016), 10.1103/PhysRevD.93.064015] form an …