Related papers: Was there a (super)nova in 1408?
The results of the first synoptic survey of novae in the barred spiral and starburst galaxy, M83 (NGC 5236), are presented. A total of 19 novae and one background supernova were discovered during the course of a nearly seven-year survey…
We study three transient X-ray sources, that were bright in the central region of M31 galaxy in the year 2000. Observations with Chandra and XMM-Newton allowed us for the first time in the history of X-ray astronomy, to build light curves…
The 135 classical novae that we have discovered in M87 with two $\textit{Hubble Space Telescope}$ imaging surveys appear to be strongly concentrated along that galaxy's jet. Detailed simulations show that the likelihood that this…
We report photometric and spectroscopic observations of the optical transient LSQ13zm. Historical data reveal the presence of an eruptive episode (that we label as `2013a') followed by a much brighter outburst (`2013b') three weeks later,…
Nova V2491 Cyg was discovered on April 10.72 UT 2008 (Nakano, 2008). Here we present spectrophotometric premises that V2491 Cyg can be a good candidate for recurrent nova (RNe). Its properties are compared to five well known RNe with red…
We have obtained snapshot images of a transient X-ray source in M31 from Chandra ACIS-I and the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The Chandra position of the X-ray nova was R.A.=00:42:56.038 +/-0.08'',…
Nova outbursts are the result of strong thermonuclear runaways on the surface of a white dwarf accreting Hydrogen-rich material from a small mass companion. These giant explosions cause the star to increase its brightness by hundreds of…
Massive stars end their lives in spectacular supernova explosions. Identifying the progenitor star is a test of stellar evolution and explosion models. Here we show that the progenitor star of the supernova SN 2008bk has now disappeared,…
We present the results of a long-term monitoring campaign of the H\alpha line in a sample of bright OB-supergiants (O7.5-B9) that aims at detecting rotationally modulated changes potentially related to the existence of large-scale wind…
Supernova 2006gy in the galaxy NGC 1260 is the most luminous one recorded \cite{2006CBET..644....1Q, 2006CBET..647....1H, 2006CBET..648....1P, 2006CBET..695....1F}. Its progenitor might have been a very massive ($>100$ \msun) star…
The work is devoted to the study of the peculiar variable star Khavchenko 1 in Auriga. It was discovered by the 7th grade student Sergey Khavchenko in 2020. The brightness of the star varies with an amplitude of about 0.4 magnitude and the…
We have serendipitously discovered that Leoncino Dwarf, an ultra-faint, low-metallicity record-holder dwarf galaxy, may have hosted a transient source, and possibly exhibited a change in morphology, a shift in the center of brightness, and…
The Palomar Transient Factory (PTF) is systematically charting the optical transient and variable sky. A primary science driver of PTF is building a complete inventory of transients in the local Universe (distance less than 200 Mpc). Here,…
Kilonova explosions typically release $\sim 10^{50-51}$ erg in kinetic energy, which is sufficient to constitute a kilonova remnant (KNR); however, it has not yet been confirmed. In this work, we investigate the probable association between…
The Galactic transient V1309 Sco was the result of a merger in a low-mass star system, while V838 Mon was thought to be a similar merger event from a more massive B-type progenitor. In this paper we study an optical/IR transient discovered…
We detected the second historical outburst of the 1920 nova IM Nor. Accurate astrometry of the outbursting object revealed the true quiescent counterpart having a magnitude of R=17.0 mag and B=18.0 mag. We show that the quiescent…
We present the results of X-ray observations of four bright transients sources detected in the July 2004 XMM-Newton observations of the central bulge of M31. Two X-ray sources, XMMU J004315.5+412440 and XMMU J004144.7+411110, were…
The progenitors of SN 2008S and the 2008 transient in NGC300 were dust-enshrouded, with extremely red mid-infrared (MIR) colors and relatively low luminosities. The transients were optically faint (-13 < M_V < -15) compared to normal…
We present the results of a study of the variability of X-ray sources in the central 30' of the nearby Andromeda Galaxy (M31) based on XMM Performance Verification observations. Two observations of this field, with a total exposure time of…
We present optical and near-infrared (IR) photometry and near-IR spectroscopy of SN 2004am, the only optically detected supernova (SN) in M 82. These demonstrate that SN 2004am was a highly reddened type II-P SN similar to the low…