Search Publications
The Man behind the Curtain: X-Rays Drive the UV through NIR Variability in the 2013 Active Galactic Nucleus Outburst in NGC 2617
Im, M.; Choi, C.; Yoon, Y. +44 more
After the All-Sky Automated Survey for SuperNovae discovered a significant brightening of the inner region of NGC 2617, we began a ~70 day photometric and spectroscopic monitoring campaign from the X-ray through near-infrared (NIR) wavelengths. We report that NGC 2617 went through a dramatic outburst, during which its X-ray flux increased by over …
Short-Duration Gamma-Ray Bursts
Berger, Edo
Gamma-ray bursts (GRBs) display a bimodal duration distribution with a separation between the short- and long-duration bursts at about 2 s. The progenitors of long GRBs have been identified as massive stars based on their association with Type Ic core-collapse supernovae (SNe), their exclusive location in star-forming galaxies, and their strong co…
The McGill Magnetar Catalog
Kaspi, V. M.; Olausen, S. A.
We present a catalog of the 26 currently known magnetars and magnetar candidates. We tabulate astrometric and timing data for all catalog sources, as well as their observed radiative properties, particularly the spectral parameters of the quiescent X-ray emission. We show histograms of the spatial and timing properties of the magnetars, comparing …
Toward the Standard Population Synthesis Model of the X-Ray Background: Evolution of X-Ray Luminosity and Absorption Functions of Active Galactic Nuclei Including Compton-thick Populations
Ueda, Yoshihiro; Akiyama, Masayuki; Miyaji, Takamitsu +2 more
We present the most up to date X-ray luminosity function (XLF) and absorption function of active galactic nuclei (AGNs) over the redshift range from 0 to 5, utilizing the largest, highly complete sample ever available obtained from surveys performed with Swift/BAT, MAXI, ASCA, XMM-Newton, Chandra, and ROSAT. The combined sample, including that of …
The Second Fermi GBM Gamma-Ray Burst Catalog: The First Four Years
Collazzi, Andrew C.; Goldstein, Adam; Preece, Robert D. +30 more
This is the second of a series of catalogs of gamma-ray bursts (GRBs) observed with the Fermi Gamma-ray Burst Monitor (GBM). It extends the first two-year catalog by two more years, resulting in an overall list of 953 GBM triggered GRBs. The intention of the GBM GRB catalog is to provide information to the community on the most important observabl…
A fast and long-lived outflow from the supermassive black hole in NGC 5548
Kaastra, J. S.; Harrison, F. A.; Nandra, K. +31 more
Supermassive black holes in the nuclei of active galaxies expel large amounts of matter through powerful winds of ionized gas. The archetypal active galaxy NGC 5548 has been studied for decades, and high-resolution x-ray and ultraviolet (UV) observations have previously shown a persistent ionized outflow. An observing campaign in 2013 with six spa…
Magnetic Fields in Relativistic Collisionless Shocks
Santana, Rodolfo; Barniol Duran, Rodolfo; Kumar, Pawan
We present a systematic study on magnetic fields in gamma-ray burst (GRB) external forward shocks (FSs). There are 60 (35) GRBs in our X-ray (optical) sample, mostly from Swift. We use two methods to study epsilon B (fraction of energy in magnetic field in the FS): (1) for the X-ray sample, we use the constraint that the observed flux …
Cobalt-56 γ-ray emission lines from the type Ia supernova 2014J
Sunyaev, R.; Sazonov, S.; Churazov, E. +8 more
A type Ia supernova is thought to be a thermonuclear explosion of either a single carbon-oxygen white dwarf or a pair of merging white dwarfs. The explosion fuses a large amount of radioactive 56Ni (refs 1-3). After the explosion, the decay chain from 56Ni to 56Co to 56Fe generates γ-ray photons, which a…
Time-dependent modeling of TeV-detected, young pulsar wind nebulae
Torres, D. F.; de Oña Wilhelmi, E.; Cillis, A. +1 more
The increasing sensitivity of instruments at X-ray and TeV energies has revealed a large number of nebulae associated with bright pulsars. Despite this large data set, the observed pulsar wind nebulae (PWNe) do not show a uniform behavior and the main parameters driving features like luminosity, magnetization, and others are still not fully unders…
Early 56Ni decay gamma rays from SN2014J suggest an unusual explosion
Diehl, Roland; Grebenev, Sergei A.; Greiner, Jochen +7 more
Type Ia supernovae result from binary systems that include a carbon-oxygen white dwarf, and these thermonuclear explosions typically produce 0.5 solar mass of radioactive 56Ni. The 56Ni is commonly believed to be buried deeply in the expanding supernova cloud. In SN2014J, we detected the lines at 158 and 812 kiloelectron volt…