Relativistic reflection features are commonly observed in the X-ray spectra of accreting black
holes. In the presence of high quality data and with the correct astrophysical model, X-ray …

Black holes are among the most extreme objects that can be found in the Universe and an
ideal laboratory for testing fundamental physics. Here, the basic properties of black holes as …

We report the detection of coherent pulsations from the ultraluminous X-ray source (ULX)
NGC 7793 P13. The≈ 0.42 s nearly sinusoidal pulsations were initially discovered in …

Black-hole (BH) high-mass X-ray binary (HMXB) systems are likely to be the progenitors of
BH-BH mergers detected in gravitational waves by LIGO/Virgo/KAGRA (LVK). Yet merging …

The evolution of massive stars is influenced by the mass lost to stellar winds over their
lifetimes. These winds limit the masses of the stellar remnants (such as black holes) that the …

We present the analysis of the first Nuclear Spectroscopic Telescope Array observations (∼
220 ks), simultaneous with the last Suzaku observations (∼ 50 ks), of the active galactic …

Ultraluminous pulsars are a definite proof that persistent super-Eddington accretion occurs
in nature. They support the scenario according to which most Ultraluminous X-ray Sources …

Cygnus X-1 is a well-studied persistent black hole X-ray binary. Recently, the three
parameters needed to estimate the black hole spin of this system, namely the black hole …

Ultralight scalars, if they exist as theorized, could form clouds around rapidly rotating black
holes. Such clouds are expected to emit continuous, quasimonochromatic gravitational …

Current-and next-generation gravitational-wave observatories may reveal new, ultralight
bosons. Through the superradiance process, these theoretical particle candidates can form …