Search Publications
Fast radio bursts at the dawn of the 2020s
Lorimer, D. R.; Hessels, J. W. T.; Petroff, E.
Since the discovery of the first fast radio burst (FRB) in 2007, and their confirmation as an abundant extragalactic population in 2013, the study of these sources has expanded at an incredible rate. In our 2019 review on the subject, we presented a growing, but still mysterious, population of FRBs—60 unique sources, 2 repeating FRBs, and only 1 i…
Polarized x-rays constrain the disk-jet geometry in the black hole x-ray binary Cygnus X-1
Ingram, Adam; Wu, Kinwah; Enoto, Teruaki +111 more
A black hole x-ray binary (XRB) system forms when gas is stripped from a normal star and accretes onto a black hole, which heats the gas sufficiently to emit x-rays. We report a polarimetric observation of the XRB Cygnus X-1 using the Imaging X-ray Polarimetry Explorer. The electric field position angle aligns with the outflowing jet, indicating t…
Primordial black hole production during first-order phase transitions
Cai, Rong-Gen; Guo, Zong-Kuan; Liu, Jing +2 more
A novel mechanism for the primordial black hole (PBH) production is proposed as a natural and inevitable consequence of general first-order phase transitions without reference to specific underlying particle physics models. We obtain mutual predictions and constraints between primordial black holes and gravitational waves from phase transitions in…
Hunt for light primordial black hole dark matter with ultrahigh-frequency gravitational waves
Franciolini, Gabriele; Maharana, Anshuman; Muia, Francesco
Light primordial black holes may comprise a dominant fraction of the dark matter in our Universe. This paper critically assesses whether planned and future gravitational wave detectors in the ultrahigh-frequency band could constrain the fraction of dark matter composed of subsolar primordial black holes. Adopting the state-of-the-art description o…
Parameter estimation with gravitational waves
Christensen, Nelson; Meyer, Renate
The new era of gravitational wave astronomy truly began on September 14, 2015, with the detection of GW150914, the sensational first direct observation of gravitational waves from the inspiral and merger of two black holes by the two Advanced LIGO detectors. In the subsequent first three observing runs of the LIGO-Virgo network, gravitational wave…
Sensitivities on nonspinning and spinning primordial black hole dark matter with global 21-cm troughs
Laha, Ranjan; Saha, Akash Kumar
Detection of the global 21 cm signal arising from neutral hydrogen can revolutionize our understanding of the standard evolution of the Universe after recombination. In addition, it can also be an excellent probe of dark matter (DM). Among all the DM candidates, primordial black holes (PBHs) are one of the most well motivated. Hawking emission fro…
Irreducible Axion Background
Rodd, Nicholas L.; Langhoff, Kevin; Outmezguine, Nadav Joseph
Searches for dark matter decaying into photons constrain its lifetime to be many orders of magnitude larger than the age of the Universe. A corollary statement is that the abundance of any particle that can decay into photons over cosmological timescales is constrained to be much smaller than the cold dark-matter density. We show that an irreducib…
Dark dimension, the swampland, and the dark matter fraction composed of primordial black holes
Anchordoqui, Luis A.; Antoniadis, Ignatios; Lüst, Dieter
Very recently, it was suggested that combining the swampland program with the smallness of the dark energy and confronting these ideas to experiment lead to the prediction of the existence of a single extra dimension (dubbed the dark dimension) with characteristic length scale in the micron range. We show that the rate of Hawking radiation slows d…
Primordial black holes in nonminimal derivative coupling inflation with quartic potential and reheating consideration
Karami, Kayoomars; Heydari, Soma
We investigate the generation of primordial black holes (PBHs) with the aid of gravitationally increased friction mechanism originated from the nonminimal field derivative coupling (NMDC) to gravity framework, with the quartic potential. Applying the coupling parameter as a two-parted function of inflaton field and fine-tuning of five parameter as…
Primordial black holes and gravitational waves in hybrid inflation with chaotic potentials
Ahmed, Waqas; Junaid, M.; Zubair, Umer
We study the formation of primordial black hole (PBH) dark matter and the generation of scalar induced secondary gravitational waves (SIGWs) in a non-supersymmetric model of hybrid inflation with chaotic (polynomial-like) potential, including one-loop radiative corrections. A radiatively corrected version of these models is entirely consistent wit…