相关论文: Hubble Space Telescope Far Ultraviolet Spectroscop…

(Abridged) We report on the analysis of high-speed photometry of the dwarf nova EX Dra through its outburst cycle with eclipse mapping techniques. The eclipse maps show evidence of the formation of a one-armed spiral structure in the disc…

Pre-outburst signal (a decrease of the optical brightness) just before the outburst is clearly detected in the observations of the T CrB obtained before and during the 1946 outburst. A similar decrease is also visible in the light curve of…

Our long-term photometric monitoring of southern nova-like cataclysmic variables with the 1.3-m SMARTS telescope found BB Doradus fading from V ~ 14.3 towards a deep low state at V ~ 19.3 in April 2008. Here we present time-resolved optical…

YZ Ret (Nova Reticuli 2020) is the first VY Scl-type nova-like variable observed to undergo a classical nova eruption. Following the outburst, timing analysis of 20-s cadence TESS data revealed a periodicity at approximately 42 s,…

We report first results from a large project to measure black hole (BH) mass in high accretion rate active galactic nuclei (AGNs). Such objects may be different from other AGNs in being powered by slim accretion disks and showing saturated…

We present multi-epoch, time-resolved optical spectroscopic observations of the dwarf nova HT Cas, obtained during 1986, 1992, 1995 and 2005 with the aim to study the properties of emission structures in the system. We determined that the…

Theoretical light curves of four recurrent novae in outburst are modeled to obtain various physical parameters. They are those with a red giant companion, T CrB, RS Oph, V745 Sco, and V3890 Sgr. Our model includes irradiations of the…

We present a spectral analysis of the dereddened FUSE and HST/STIS spectra separately and combined together assuming E(B-V)=0.1 & 0.2. Overall, we find that the model fits are in much better agreement with the dereddened spectra when E(B-V)…

We present high-speed, three-colour photometry of the eclipsing cataclysmic variables GY Cnc, IR Com and HT Cas. We find that the sharp eclipses in GY Cnc and IR Com are due to eclipses of the white dwarf. There is some evidence for a…

In recent years, recurrent nova eruptions are often observed very intensely in wide range of wavelengths from radio to optical to X-rays. Here I present selected highlights from recent multi-wavelength observations. The enigma of T Pyx is…

TWA 27B (2M1207b) is the first directly-imaged planetary-mass (MP ~ 5 MJ) companion (Chauvin et al. 2004) and was observed at 0.9--5.3 micron with JWST/NIRSpec (Luhman et al. 2023). To understand the accretion properties of TWA 27B, we…

Nova Her 2021 (V1674 Her), which erupted on 2021 June 12, reached naked-eye brightness and has been detected from radio to $\gamma$-rays. An extremely fast optical decline of 2 magnitudes in 1.2 days and strong Ne lines imply a high-mass…

We estimate the accretion rates onto the supermassive black holes that power 20 of the highest-redshift quasars, at z>5.8, including the quasar with the highest redshift known to date -- ULAS J1120 at z=7.09. The analysis is based on the…

We have carried out a synthetic spectral analysis of archival IUE spectra of the old nova V841 Oph (Nova Oph 1848) taken 15 years apart. The spectra reveal a rising continuum shortward of 1560\AA, a C {\sc iv} P-Cygni profile indicative of…

We present timing and spectral analysis results of the {\it NICER} and {\it NuSTAR} observations of the dwarf nova MASTER OT J030227.28$+$191754.5 during the 2021--2022 outburst. The soft X-ray component was found to be dominated by…

An X-ray flash, expected in a very early phase of a nova outburst, was at last detected with the {\it SRG}/eROSITA in the classical nova YZ Reticuli 2020. The observed flash timescale, luminosity, and blackbody temperature substantially…

Estimates of the accretion rate in symbiotic recurrent novae (RNe) often fall short of theoretical expectations by orders of magnitude. This apparent discrepancy can be resolved if the accumulation of mass by the white dwarf (WD) is highly…

HD 142527 is a young pre-main sequence star with properties indicative of the presence of a giant planet or/and a low-mass stellar companion. We have analyzed an X-Shooter/Very Large Telescope spectrum to provide accurate stellar parameters…

A theoretical light curve for the 1999 outburst of U Scorpii is presented in order to obtain various physical parameters of the recurrent nova. Our U Sco model consists of a very massive white dwarf (WD) with an accretion disk and a…

A distinguishing trait of the three known Galactic recurrent novae with the shortest orbital periods, T Pyx, IM Nor, and CI Aql, is that their optical decline time-scales are significantly longer than those of the other recurrent systems.…