The COSMOS-Legacy survey is a 4.6 Ms Chandra program that has imaged 2.2 deg 2 of the
COSMOS field with an effective exposure of $\simeq 160$ ks over the central 1.5 deg 2 and …

Abstract We present Event Horizon Telescope (EHT) 1.3 mm measurements of the radio
source located at the position of the supermassive black hole Sagittarius A*(Sgr A*) …

Fast radio bursts (FRBs) are flashes of unknown physical origin. The majority of FRBs have
been seen only once, although some are known to generate multiple flashes,. Many models …

Observations of quasars reveal that many supermassive black holes (BHs) were in place
less than 700 Myr after the Big Bang. However, the origin of the first BHs remains a mystery …

We report spectroscopic and photometric follow-up of a dormant black hole (BH) candidate
from Gaia DR3. The system, which we call Gaia BH2, contains a∼ 1 M⊙ red giant and a …

Hard X-ray (≥ 10 keV) observations of active galactic nuclei (AGNs) can shed light on some
of the most obscured episodes of accretion onto supermassive black holes. The 70-month …

We present Event Horizon Telescope (EHT) 1.3 mm measurements of the radio source
located at the position of the supermassive black hole Sagittarius A*(Sgr A*), collected …

Ultraluminous x-ray sources (ULXs) in nearby galaxies shine brighter than any x-ray source
in our Galaxy. ULXs are usually modeled as stellar-mass black holes (BHs) accreting at very …

Context. Relativistic electrons and magnetic fields permeate the intra-cluster medium (ICM)
and manifest themselves as diffuse sources of synchrotron emission observable at radio …

The coronal activity–rotation relationship is considered to be a proxy for the underlying
stellar dynamo responsible for magnetic activity in solar and late-type stars. While this has …