Related papers: VVV-WIT-01: highly obscured classical nova or prot…

M31 RV is a red transient that erupted in 1988 in the Andromeda bulge, reaching a luminosity intermediate between novae and supernovae. It was cool throughout its outburst, unlike a normal classical nova. In 2006, Bond & Siegel examined…

Classical novae are thermonuclear explosions that occur on the surfaces of white dwarf stars in interacting binary systems (Bode & Evans 2008). It has long been thought that the luminosity of classical novae is powered by continued nuclear…

The windows of low extinction in the Milky Way (MW) plane are rare but important because they enable us to place structural constraints on the opposite side of the Galaxy, which has hitherto been done rarely. We use the near-infrared…

NSV 10934 was discovered as a large-amplitude suspected variable star of unknown classification. We noticed that the object is identified with a bright ROSAT X-ray source (1RXS J184050.3-834305). Systematic monitoring of this object by the…

A luminous optical transient (OT) that appeared in NGC 300 in early 2008 had a maximum brightness, M_V ~ -12 to -13, intermediate between classical novae and supernovae. We present ground-based photometric and spectroscopic monitoring and…

We imaged the error box of a gamma-ray burst of the short (0.5 s), hard type (GRB 000313), with the BOOTES-1 experiment in southern Spain, starting 4 min after the gamma-ray event, in the I-band. A bright optical transient (OT 000313) with…

M87 has been monitored with a cadence of 5 days over a 9 month-long span through the near-ultraviolet (NUV:F275W) and optical (F606W) filters of the Wide Field Camera 3 (WFC3) of the $\textit{Hubble Space Telescope}$. This unprecedented…

We have observed four low-luminosity active galactic nuclei classified as Type 1 LINERs with the X-ray Telescope (XRT) and the UltraViolet-Optical Telescope (UVOT) onboard Swift, in an attempt to clarify the main powering mechanism of this…

Classical novae are eruptions on the surface of a white dwarf in a binary system. The material ejected from the white dwarf surface generally forms an axisymmetric shell of gas and dust around the system. The three-dimensional structure of…

We present the results of the first {\it XMM-Newton} observation of the interacting type IIn supernova 1995N, performed in July 2003. We find that the 0.2--10.0 keV unabsorbed flux dropped at a value of $\simeq 1.8 \times 10^{-13}$ erg…

We report extensive new photometry and spectroscopy of the highly variable young stellar object PTF 10nvg including optical and near-infrared time series data as well as mid-infrared and millimeter data. Following the previously reported…

XMMSL1 J171900.4-353217 is a very-faint X-ray transient that was discovered in 2010 March when it exhibited an outburst. We report on 7 observations, obtained with the X-Ray Telescope (XRT) aboard the Neil Gehrels {\it{Swift}} Observatory…

\swift \xrt observations of the \hi line source \VV were performed on April 22 and April 26, 2008 for a total exposure time of 9.2ks. This is the first pointed X-ray observation of \VV, a putative dark galaxy in the Virgo cluster, and no…

We investigate the photometric characteristics of a sample of Intermediate Luminosity Red Transients (ILRTs), a class of elusive objects with peak luminosity between that of classical novae and standard supernovae. We present the…

Context. The Vista Variables in the Via Lactea (VVV) near-infrared variability survey explores some of the most complex regions of the Milky Way bulge and disk in terms of high extinction and high crowding. Aims. We add a new wavelength…

Recent Swift X-ray monitoring campaigns of novae have revealed extreme levels of variability during the early super-soft-source (SSS) phase. The first time this was observed was during the 2006 outburst of the recurrent nova RS Oph which…

We present Hubble Space Telescope imaging confirming the optical disappearance of the failed supernova (SN) candidate identified by Gerke et al. (2015). This $\sim 25~M_{\odot}$ red supergiant experienced a weak $\sim 10^{6}~L_{\odot}$…

An anomalous transient in the early Hubble-type (S0) galaxy Messier 85 (M85) in the Virgo cluster was discovered by Kulkarni et al. (2007) on 7 January 2006 that had very low luminosity (peak absolute R-band magnitude MR of about -12) that…

We present the spectroscopic and photometric study of five intermediate-luminosity red transients (ILRTs), namely AT 2010dn, AT 2012jc, AT 2013la, AT 2013lb, and AT 2018aes. They share common observational properties and belong to a family…

We report on optical spectroscopic and photometric follow-up observations of the eROSITA discovered transient SRGt 062340.2-265751 and show that it displays the characteristics of a nova-like cataclysmic variable (CV), with possible…