Related papers: V5116 Sgr, an Eclipsing Supersoft Post-Outburst No…

We report on the fast Nova Sgr 2016 N.4 being surprisingly trapped in a long-lasting and bright plateau (Delta I >= 10 mag above quiescence) six years past the nova eruption. Very few other novae experience a similar occurrence. We carried…

Two XMM observations of the fast classical nova V2491Cyg were carried out on days 39.93 and 49.62 after discovery, during the supersoft source (SSS) phase, yielding simultaneous X-ray and UV light curves and high-resolution X-ray spectra.…

The recurrent symbiotic nova V745 Sco exploded on 2014 February 6 and was observed on February 22 and 23 by the Chandra X-ray Observatory Transmission Grating Spectrometers. By that time the supersoft source phase had already ended and…

(...) Since 1998, only half a dozen spectroscopically confirmed associations have been discovered and XRF 100316D associated with the type-Ic SN 2010bh at z = 0.059 is among the latest. We began observations with GROND 12 hours after the…

We present results from the XMM observations of the dwarf nova YZ Cnc in a quiescent state. We have performed a detailed time series analysis of the resulting light curves. Unusually, we do not detect any orbital modulation in the UV, with…

We report on the spectral evolution of the enigmatic, very slow nova V5558 Sgr, based on the low-resolution spectra obtained at the Fujii-Bisei Observatory and the Bisei Astronomical Observatory, Japan during a period of 2007 April 6 to…

We present the results of our analysis of new optical, ultraviolet (UV) and X-ray observations of a highly variable source $-$ AX J1549.8$-$5416. Both the detection of several fast rise, exponential decay outbursts in the optical light…

The analyses of X-ray emission from classical novae during the outburst stage have shown that the soft X-ray emission below 1 keV, which is thought to originate from the photosphere of the white dwarf, is inconsistent with the simple…

The 2021 outburst of the symbiotic recurrent nova RS Oph was monitored with the Neutron Star Interior Composition Explorer Mission (NICER) in the 0.2-12 keV range from day one after the optical maximum, until day 88, producing an…

V4743 Sgr (Nova Sgr 2002 No. 3) was discovered on 20 September 2002. We obtained a 5ks ACIS-S spectrum in November 2002 and found that the nova was faint in X-rays. We then obtained a 25ks CHANDRA LETGS observation on 19 March 2003. By this…

The recurrent symbiotic nova RS Oph reoccurred after 21 years on 12 February 2006. In contrast to the 1985 outburst, much denser coverage with X-ray observations was achieved. Swift observed RS Oph up to several times a day while Chandra…

The March 2011 outburst of the poorly-studied cataclysmic variable NSV 1436 offered an opportunity to decide between dwarf nova and recurrent nova classifications. We use seven daily observations in the X-ray and UV by the Swift satellite,…

Classical novae occur in close binary systems (main-sequence star + white dwarf). V4743 Sgr is a very fast nova exhibiting a X-ray spectrum which is consistent with a view on the optically thick atmosphere of an extremely hot white dwarf…

The sky region containing the soft gamma-ray repeater SGR 1627-41 has been observed three times with XMM-Newton in February and September 2004. SGR 1627-41 has been detected with an absorbed flux of ~9x10^{-14} erg cm^{-2} s^{-1} (2-10…

We present ground-based and HST optical and infrared observations of XRF 100316D / SN 2010bh. It is seen that the optical light curves of SN 2010bh evolve at a faster rate than the archetype GRB-SN 1998bw, but at a similar rate to SN…

We present X-ray observations of novae V2491 Cyg and KT Eri about 9 years post-outburst, of the dwarf nova and post-nova candidate EY Cyg, and of a VY Scl variable. The first three objects were observed with XMM-Newton, KT Eri also with the…

Photometric observations of V4633 Sgr (Nova Sagittarii 1998) during 1998-2005 reveal the presence of a stable photometric periodicity at P1=180.8 min which is probably the orbital period of the underlying binary system. A second period was…

We have monitored the return to quiescence of novae previously observed in outburst as supersoft X-ray sources, with optical photometry of the intermediate polar (IP) V4743 Sgr and candidate IP V2491 Cyg, and optical spectroscopy of these…

For several novae, a bright X-ray source with a spectrum resembling the class of Super Soft X-ray Sources (SSS) has been observed a few weeks to months after outburst. Novae are powered by explosive nuclear burning on the surface of a white…

Detection of X-rays from classical novae, both in outburst and post-outburst, provides unique and crucial information about the explosion mechanism. Soft X-rays reveal the hot white dwarf photosphere, whenever hydrogen (H) nuclear burning…