Related papers: Shocks in nova outflows. I. Thermal emission
We present a set of controlled hydrodynamical simulations to study the effects of strong galactic outflows on the density and temperature structures, and associated X-ray signatures, of extra-planar and circumgalactic gas. We consider three…
On 2004 Dec. 27, the soft gamma repeater (SGR) 1806-20 emitted the brightest giant flare (GF) ever detected from an SGR, with an (isotropic) energy release $\sim 100$ times greater than the only two other known SGR GFs. It was followed by a…
The classical nova V339 Del 2013 is characterized by a 1.5 mag dip of the $V$ light curve owing to a dust shell formation, during which soft X-ray emissions coexist. We present Str\"omgren $y$ band light curve, which represents continuum…
We present time-dependent nova outburst models with optically thick winds for a 1.2 and 1.35 $M_\odot$ white dwarfs (WDs) with a mass accretion rate of $5 \times 10^{-9}~M_\odot$ yr$^{-1}$ and for a 1.3 $M_\odot$ WD with $2 \times…
The physical mechanism driving mass ejection during a nova eruption is still poorly understood. Possibilities include ejection in a single ballistic event, a common envelope interaction, a continuous wind, or some combination of these…
Massive protostars launch accretion-powered, magnetically-collimated outflows, which play crucial roles in the dynamics and diagnostics of the star formation process. Here we calculate the shock heating and resulting free-free radio…
Fast outflows and their interaction with slow shells (generally known as the fossil circumstellar envelope of asymptotic giant branch stars) play an important role in the structure and kinematics of protoplanetary and planetary nebulae…
Tidal disruption event (TDE) can launch an ultrafast outflow. If the black hole is surrounded by large amounts of clouds, outflow-cloud interaction will generate bow shocks, accelerate electrons and produce radio emission. Here we…
The fast recurrent nova V745 Sco was observed in the 3-79 keV X-rays band with NuSTAR 10 days after the optical discovery. The measured X-ray emission is consistent with a collisionally ionized optically thin plasma at temperature of about…
Studies of molecular outflows in high-mass young stellar objects reveal important information about the formation process of massive stars. We therefore selected the close-by IRAS 17233-3606 massive star-forming region to perform SiO…
V745 Sco is a Galactic symbiotic recurrent nova with nova eruptions in 1937, 1989 and 2014. We study the behavior of V745 Sco at radio wavelengths (0.6-37,GHz), covering both its 1989 and 2014 eruptions and informed by optical, X-ray, and…
Fast ejecta expelled in binary neutron star (NS) mergers or energetic supernovae (SNe) should produce late-time synchrotron radio emission as the ejecta shocks into the surrounding ambient medium. Models for such radio flares typically…
We report the results of X-ray and gamma-ray analyses of the classical-nova V1716 Sco using data taken by \verb|Swift|, \verb|NICER|, \verb|NuSTAR| and \verb|Fermi|-LAT. We confirm gamma-ray emission at a significant level exceeding…
A class of very energetic supernovae (hypernovae) is associated with long gamma-ray bursts, in particular with a less energetic but more frequent population of gamma-ray bursts. Hypernovae also appear to be associated with mildly…
Novae are found to have GeV to TeV gamma-ray emission, which reveals the shock acceleration from the white dwarfs. Recently, V1405 Cas was reported to radiated suspicious gamma-ray by \textit{Fermi}-LAT with low significance ($4.1 \sigma$)…
Nova outbursts take place in binary star systems comprising a white dwarf (WD) and either a low-mass Sun-like star (classical novae) or, a red giant. GeV gamma-ray emission has been detected from a dozen of classical novae and from one…
It has recently been discovered that some, if not all, classical novae emit GeV gamma rays during outburst, but the mechanisms involved in the production of the gamma rays are still not well understood. We present here a comprehensive…
We present a simple analytic model for the structure of non-relativistic and relativistic radiation mediated shocks. At shock velocities \beta_s\equiv v_s/c\gtrsim 0.1, the shock transition region is far from thermal equilibrium, since the…
EX Draconis (EX Dra) is a long period dwarf nova showing ~2 mag outburst which lasts for ~7 d and recur on a timescale of (20-30) d. Its deep eclipses allows one to trace the changes in surface brightness and radius of its accretion disk…
When applied to the blast wave formed by the explosion of a massive star as a supernova (SN), the theory of diffusive particle acceleration at shock fronts predicts a very high energy density in cosmic rays. Almost immediately after…