Related papers: A very luminous, highly extinguished, very fast no…

Recurrent novae are binary stars in which a white dwarf accretes matter from a less evolved companion, either a red giant or a main-sequence star. They have dramatic optical brightenings of around 5-6 mag in V in less than a day, several…

We present time-resolved photometry of V1494 Aql (Nova Aql 1999 No. 2: http://www.kusastro.kyoto-u.ac.jp/vsnet/Novae/v1494aql.html) between 2001 November and 2003 June. The object is confirmed to be an eclipsing nova with a period of…

We present our analysis of the Type II supernova DLT16am (SN~2016ija). The object was discovered during the ongoing $\rm{D}<40\,\rm{Mpc}$ (DLT40) one day cadence supernova search at $r\sim20.1\,\rm{mag}$ in the `edge-on' nearby…

V5116 Sgr (Nova Sgr 2005 No. 2), discovered on 2005 July 4, was observed with XMM-Newton in March 2007, 20 months after the optical outburst. The X-ray spectrum shows that the nova had evolved to a pure supersoft X-ray source, with no…

We analyzed optical, UV, and X-ray light curves of 14 recurrent and very fast novae in our galaxy, Magellanic Clouds, and M31, and obtained their distances and white dwarf (WD) masses. Among the 14 novae, we found that eight novae host very…

V5579 Sgr was a fast nova discovered in 2008 April 18.784 UT. We present the optical spectroscopic observations of the nova observed from the Castanet Tolosan, SMARTS and CTIO observatories spanning over 2008 April 23 to 2015 May 11. The…

SN 2001em is a peculiar supernova, originally classified as Type Ib/c. About two years after the SN it was detected in the radio, showing a rising radio flux with an optically thin spectral slope, and it also displayed a large X-ray…

We report spectroscopic observations of the $H\alpha$ emission line of the recurrent nova RS~Oph obtained between 12 and 23 August 2021 during the recent outburst. On the basis of the sharp P~Cyg profile superimposed onto the strong H-alpha…

I review X-ray observations of classical and recurrent novae in outburst. Significant X-ray flux is emitted by the nova shell, with a peak luminosity up to 10**35 erg/cm**2/s in the 0.2-10 keV range.In recurrent nova systems, or in novae…

The extensive grid of numerical simulations of nova eruptions of Yaron et al.(2005) first predicted that some classical novae might deviate significantly from the Maximum Magnitude - Rate of Decline (MMRD) relation, which purports to…

We report combined optical and X-ray observations of nova M31N 2007-12b. Optical spectroscopy obtained 5 days after the 2007 December outburst shows evidence of very high ejection velocities (FWHM H$\alpha \simeq 4500$ km s$^{-1}$). In…

We present the results of optical photometry of the recurrent nova CI Aql in later phase of the outburst which occurred in 2000. Our observation revealed that the object reached the quiescent level between 2001 December and 2002 April and…

Following on our initial absorption-line analysis of fifteen novae spectra we present additional evidence for the existence of two distinct components of novae ejecta having different origins. As argued in Paper I one component is the…

We report a series of extensive photometric and spectroscopic observations of the luminous M31 nova M31N 2007-11d. Our photometric observations coupled with previous measurements show that the nova took at least four days to reach peak…

We present the results of the study of the red nova PSN J14021678+5426205 based on the observations carried out with the Russian 6-m telescope (BTA) along with other telescopes of SAO RAS and SAI MSU. To investigate the nova progenitor, we…

The spectroscopic observations of two novae namely V1065 CEN and V1280 SCO were made by 45 cm Cassegrain telescope in high resolution ($\lambda/\delta\lambda$=22000) at H$\alpha$ (6563 \r{A}) region. V1065 CEN is He/N-type spectra which…

In our ongoing study of eta Carinae's light echoes, there is a relatively bright echo that has been fading slowly, reflecting the 1845-1858 plateau of the eruption. A separate paper discusses its detailed evolution, but here we highlight…

All novae recur, but only a handful have been observed in eruption more than once. These systems, the recurrent novae (RNe), are among the most extreme examples of novae. RNe have long been thought of as potential type Ia supernova…

Nova explosions occur on accreting white dwarfs. A thermonuclear runaway in the H-rich accreted envelope causes its ejection without destroying the white dwarf, and an increase in the luminosity by several magnitudes. Accretion is…

We present early spectral observations of the very slow Galactic nova Gaia22alz, over its gradual rise to peak brightness that lasted 180 days. During the first 50 days, when the nova was only 3--4 magnitudes above its normal brightness,…