相关论文: Radiative diffusion in a time-dependent outflow: a…

The jets of blazars are renowned for their multi-wavelength flares and rapid extreme variability; however, there are still some important unanswered questions about the physical processes responsible for these spectral and temporal changes…

Luminous Fast Blue Optical Transients (LFBOTs) - the prototypical example being AT2018cow - are a rare class of events whose origins are poorly understood. They are characterised by rapid evolution, featureless blue spectra at early times,…

Optical Transients from gamma-ray burst sources, in addition to offering a distance determination, convey important information on the physics of the emission mechanism, and perhaps also about the underlying energy source. As the gamma-ray…

FU Orionis systems are young stars undergoing outbursts of disc accretion and where the optical spectrum contains lines associated with both the disc photosphere and a wind component. Previous observations of the prototype FU Orionis have…

A star that wanders too close to a massive black hole (BH) is shredded by the BH's tidal gravity. Stellar gas falls back to the BH, releasing a flare of energy. In anticipation of upcoming transient surveys, we predict the light curves and…

Fast radio bursts are radio transients observed mainly around 1.5 GHz. Their peak frequency decreases at a rate of 100 ~ 500 MHz/s and some of them have a broader pulse with an exponentially decaying tail. Common assumptions for fast radio…

We have observed 99 mid-infrared-bright, massive young stellar objects and compact HII regions drawn from the Red MSX source (RMS) survey in the J=3$-$2 transition of $^{12}$CO and $^{13}$CO, using the James Clerk Maxwell Telescope. 89…

Galactic outflows play a major role in the evolution of galaxies, but the underlying physical processes are poorly understood. This is mainly because we have little information about the outflow structure, especially on large scales. In…

We discuss the evolution of cosmological gamma-ray burst remnants, consisting of the cooling and expanding fireball ejecta together with any swept-up external matter, after the gamma-ray event. We show that significant optical emission is…

Warm absorber spectra contain bound-bound and bound-free absorption features seen in the X-ray and UV spectra from many active galactic nuclei (AGN). The widths and centroid energies of these features indicate they occur in outflowing gas,…

Modern wide-field high-cadence surveys have revealed the significant diversity of optical transient phenomena in their luminosity and timescale distributions, which led to the discovery of some mysterious fast optical transients (FOTs).…

The discovery of numerous luminous, super-early galaxies at $z>10$ by JWST has revealed a striking diversity in their ultraviolet (UV) properties, ranging from extremely blue, dust-poor systems to a smaller population of significantly…

We present spectra of the optical transient (OT) associated with GRB 021004. The spectra show a blue continuum with superposed absorption features and one emission line. We confirm two intervening metal-line systems at z = 1.380 and z =…

(ABRIDGED)- The physical mechanism responsible for the short outbursts in a recently recognized class of High Mass X-ray Binaries, the Supergiant Fast X-ray Transients (SFXTs), is still unknown. Two main hypotheses have been proposed to…

Fast Radio Bursts (FRBs) are short lived ($\sim$ msec), energetic transients (having a peak flux density of $\sim$ Jy) with no known prompt emission in other energy bands. We present results of a search for prompt X-ray emissions from 41…

In the last decade a number of rapidly evolving transients have been discovered that are not easily explained by traditional supernovae models. We present optical and UV data on onee such object, SN 2018gep, that displayed a fast rise with…

Evidence for shocks in nova outflows include (1) multiple velocity components in the optical spectra; (2) keV X-ray emission weeks to months after the outburst; (3) early radio flare on timescales of months, in excess of that predicted from…

The prompt gamma-ray emission in gamma-ray bursts is believed to be produced by internal shocks within a relativistic unsteady outflow. The recent detection of prompt optical emission accompanying the prompt gamma-ray emission appears to be…

We investigate numerically the ability of three models (jet, structured outflow, energy injection) to accommodate the optical light-curve breaks observed in 10 GRB afterglows (980519, 990123, 990510, 991216, 000301c, 000926, 010222, 011211,…

In this paper we reexamine the optical depth of ultrarelativistic spherically symmetric outflows and reevaluate the photospheric radius for each model during both the acceleration and coasting phases. It is shown that for both the wind and…