Search Publications
The Radius of PSR J0740+6620 from NICER and XMM-Newton Data
Guillemot, L.; Kerr, M.; Ray, P. S. +25 more
PSR J0740+6620 has a gravitational mass of 2.08 ± 0.07 M⊙, which is the highest reliably determined mass of any neutron star. As a result, a measurement of its radius will provide unique insight into the properties of neutron star core matter at high densities. Here we report a radius measurement based on fits of rotating hot spot patte…
A NICER View of the Massive Pulsar PSR J0740+6620 Informed by Radio Timing and XMM-Newton Spectroscopy
Remillard, Ronald A.; Okajima, Takashi; Bogdanov, Slavko +27 more
We report on Bayesian estimation of the radius, mass, and hot surface regions of the massive millisecond pulsar PSR J0740+6620, conditional on pulse-profile modeling of Neutron Star Interior Composition Explorer X-ray Timing Instrument event data. We condition on informative pulsar mass, distance, and orbital inclination priors derived from the jo…
The eROSITA X-ray telescope on SRG
Finoguenov, A.; Böhringer, H.; Haberl, F. +90 more
eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the primary instrument on the Spectrum-Roentgen-Gamma (SRG) mission, which was successfully launched on July 13, 2019, from the Baikonour cosmodrome. After the commissioning of the instrument and a subsequent calibration and performance verification phase, eROSITA started a surv…
A tidal disruption event coincident with a high-energy neutrino
Kilpatrick, Charles D.; Foley, Ryan J.; Cenko, S. Bradley +55 more
Cosmic neutrinos provide a unique window into the otherwise hidden mechanism of particle acceleration in astrophysical objects. The IceCube Collaboration recently reported the likely association of one high-energy neutrino with a flare from the relativistic jet of an active galaxy pointed towards the Earth. However a combined analysis of many simi…
Observational Constraints on Black Hole Spin
Reynolds, Christopher S.
The spin of a black hole is an important quantity to study, providing a window into the processes by which a black hole was born and grew. Furthermore, spin can be a potent energy source for powering relativistic jets and energetic particle acceleration. In this review, I describe the techniques currently used to detect and measure the spins of bl…
X-ray quasi-periodic eruptions from two previously quiescent galaxies
Gromadzki, M.; Salvato, M.; Buchner, J. +21 more
Quasi-periodic eruptions (QPEs) are very-high-amplitude bursts of X-ray radiation recurring every few hours and originating near the central supermassive black holes of galactic nuclei1,2. It is currently unknown what triggers these events, how long they last and how they are connected to the physical properties of the inner accretion f…
VINTERGATAN - I. The origins of chemically, kinematically, and structurally distinct discs in a simulated Milky Way-mass galaxy
Feuillet, Diane K.; Feltzing, Sofia; Ryde, Nils +6 more
Spectroscopic surveys of the Milky Way's stars have revealed spatial, chemical, and kinematical structures that encode its history. In this work, we study their origins using a cosmological zoom simulation, VINTERGATAN, of a Milky Way-mass disc galaxy. We find that in connection to the last major merger at z ∼ 1.5, cosmological accretion leads to …
The Evolutionary Map of the Universe pilot survey
Reiprich, Thomas H.; Koribalski, Bärbel S.; Norris, Ray P. +45 more
We present the data and initial results from the first pilot survey of the Evolutionary Map of the Universe (EMU), observed at 944 MHz with the Australian Square Kilometre Array Pathfinder (ASKAP) telescope. The survey covers $270 deg^2$ of an area covered by the Dark Energy Survey, reaching a depth of 25-30 $µJy beam^{-1}$ rms at a spatial …
Ionized outflows from active galactic nuclei as the essential elements of feedback
Veilleux, Sylvain; Reynolds, Christopher S.; Guainazzi, Matteo +5 more
Outflows from active galactic nuclei (AGNs) are one of the fundamental mechanisms by which the central supermassive black hole interacts with its host galaxy. Detected in ≥50% of nearby AGNs, these outflows have been found to carry kinetic energy that is a large fraction of the AGN power, and thereby give `negative' feedback to their host galaxies…
LOFAR observations of galaxy clusters in HETDEX. Extraction and self-calibration of individual LOFAR targets
Di Gennaro, G.; Brunetti, G.; Rossetti, M. +20 more
Diffuse cluster radio sources, in the form of radio halos and relics, reveal the presence of cosmic rays and magnetic fields in the intracluster medium (ICM). These cosmic rays are thought to be (re)accelerated through the ICM turbulence and shock waves generated by cluster merger events. Here we characterize the presence of diffuse radio emission…