相关论文: Outbursts of EX Hydrae Revisited

We report photometry and spectroscopy of the outburst of the young stellar object ESO-Halpha 99. The outburst was first noticed in Gaia alert Gaia18dvc and later by ATLAS. We have established the outburst light curve with archival ATLAS…

We report six BeppoSAX X-ray observations of VW Hydri during and after the outburst of Sep 23 1998. The outburst flux is lower than the quiescent flux in the entire observed energy band (0.1-10 keV), in agreement with earlier observations.…

We present optical and NIR spectroscopic observations of U Sco 2010 outburst. From the analysis of lines profiles we identify a broad and a narrow component and show that the latter originates from the reforming accretion disk. We show that…

The outbursts of the dwarf nova WZ Sagittae occur on timescales which are much longer than expected from the standard thermal viscous disc instability model, which correctly reproduces the outburst behaviour of many other dwarf novae. In…

In 2021, the high-mass X-ray binary EXO 2030+375 underwent a giant X-ray outburst, the first since 2006, that reached a peak flux of ${\sim}600\,\mathrm{mCrab}$ (3-50\,keV). The goal of this work is to study the spectral evolution over the…

Novae are thermonuclear eruptions on accreting white dwarfs in interacting binaries. Although most of the accreted envelope is expelled, the mechanism -- impulsive ejection, multiple outflows or prolonged winds, or a common-envelope…

We examine the dynamical behavior of accretion flow around XTE J1859+226 during the 1999 outburst by analyzing the entire outburst data ($\sim$ 166 days) from RXTE Satellite. Towards this, we study the hysteresis behavior in the hardness…

Protostellar jets and outflows are signposts of active star formation. In H II regions, molecular tracers like CO only reveal embedded portions of the outflow. Outside the natal cloud, outflows are dissociated, ionized, and eventually…

The 1998 outburst of XTE J1550-564 started with a hard X-ray spike, rising in less than a day and declining after 3-4 days; at the same time, the soft X-ray flux was rising with a longer timescale (~ 10 days). We suggest that the soft and…

Using SpeX at the NASA Infrared Telescope Facility and the Spitzer Infrared Spectrograph, we have obtained infrared spectra from 0.7 to 30um for three young brown dwarfs in the TW Hydra Association (~10 Myr), 2M J1207-3932, 2M J1139-3159,…

Since its discovery, 1E 1048.1$-$5937 has been one of the most active magnetars, both in terms of radiative outbursts, and changes to its spin properties. Here we report on a continuing monitoring campaign with the Neil Gehrels Swift…

We present a type-I outburst of the high-mass X-ray binary EXO 2030+375, detected during INTEGRAL's Performance and Verification Phase in December 2002 (on-source time about 10e+06 seconds). In addition, six more outbursts have been…

Despite early theoretical expectations that large-scale, massive outflows would be triggered by accretion onto black holes and neutron stars, their presence was not firmly established until the 2000s. Since then, these accretion disc winds…

We use the best available X-ray data from the intermediate polar EX Hydrae to study the cooling-flow model often applied to interpret the X-ray spectra of these accreting magnetic white dwarf binaries. First, we resolve a long-standing…

Superorbital periods that are observed in the brightness of Be/X-ray binaries may be driven by a misaligned and precessing Be star disc. We examine how the precessing disc model explains the superorbital variation of (i) the magnitude of…

We present two epochs of observations of TW Hya from the high-dispersion near-IR spectrograph ARIES at the MMT. We detect strong emission from the Brackett gamma transition of hydrogen, indicating an accretion rate substantially larger than…

Young close binaries clear central cavities in their surrounding circumbinary disk from which the stars can still accrete material. This process takes place within the very first astronomical units, and is still not well constrained as the…

We present time-resolved optical spectroscopy of the dwarf nova GW Librae during its rare April 2007 super-outburst and compare these with quiescent epochs. The data provide the first opportunity to track the evolution of the principal…

We model the intermediate-mass black hole HLX-1, using the Hubble Space Telescope, XMM-Newton and Swift. We quantify the relative contributions of a bluer component, function of X-ray irradiation, and a redder component, constant and likely…

Many astrophysical sources, e.g., cataclysmic variables, X-ray binaries, active galactic nuclei, exhibit a wind outflow, when they reveal a multicolor blackbody spectrum, hence harboring a geometrically thin Keplerian accretion disk. Unlike…