Search Publications
New physics in light of the H0 tension: An alternative view
Vagnozzi, Sunny
The strong discrepancy between local and early-time (inverse distance ladder) estimates of the Hubble constant H0 could be pointing towards new physics beyond the concordance Λ CDM model. Several attempts to address this tension through new physics rely on extended cosmological models, featuring extra free parameters beyond the six Λ CD…
I N T E G R A L constraints on primordial black holes and particle dark matter
Slatyer, Tracy R.; Muñoz, Julian B.; Laha, Ranjan
The International Gamma-Ray Astrophysics Laboratory (I N T E G R A L ) satellite has yielded unprecedented measurements of the soft gamma-ray spectrum of our Galaxy. Here we use those measurements to set constraints on dark matter (DM) that decays or annihilates into photons with energies E ≈0.02 - 2 MeV . First, we revisit the constraints on part…
Cosmography in f (Q ) gravity
Wang, Deng; Sahoo, P. K.; Mandal, Sanjay
Cosmography is an ideal tool to investigate the cosmic expansion history of the Universe in a model-independent way. The equations of motion in modified theories of gravity are usually very complicated; cosmography may select practical models without imposing arbitrary choices a priori. We use the model-independent way to derive f (z ) and its der…
Can late dark energy transitions raise the Hubble constant?
Raveri, Marco; Hu, Wayne; Benevento, Giampaolo
Late times dark energy transitions at redshifts z ≪0.1 can raise the predicted value of the Hubble constant to the SH0ES value, 74.03 ±1.42 (km s-1 Mpc-1) or more, while providing an equally good fit as Λ CDM at 67.73 ±0.41 to higher redshift data, in particular from the cosmic microwave background and baryon acoustic oscilla…
Axion and neutrino bounds improved with new calibrations of the tip of the red-giant branch using geometric distance determinations
Capozzi, Francesco; Raffelt, Georg
The brightness of the tip of the red-giant branch (TRGB) allows one to constrain novel energy losses that would lead to a larger core mass at helium ignition and, thus, to a brighter TRGB than expected by standard stellar models. The required absolute TRGB calibrations strongly improve with reliable geometric distances that have become available f…
Updated constraints on asteroid-mass primordial black holes as dark matter
Profumo, Stefano; Guhathakurta, Puragra; McKinnon, Kevin +3 more
Microlensing of stars places significant constraints on subplanetary-mass compact objects, including primordial black holes, as dark matter candidates. As the lens' Einstein radius in the source plane becomes comparable to the size of the light source, however, source amplification is strongly suppressed, making it challenging to constrain lenses …
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…