Related papers: On an apparent dearth of recurrent nova super-remn…

The standard model for Type II supernovae explosion, confirmed by the detection of the neutrinos emitted during the supernova explosion, predicts the formation of a compact object, usually assumed to be a neutron star. However, the lack of…

We present the discovery of two new dwarf galaxies, Andromeda XXI and Andromeda XXII, located in the surroundings of the Andromeda and Triangulum galaxies (M31 and M33). These discoveries stem from the first year data of the Pan-Andromeda…

Using the Subaru 8.2m Telescope with an IRCS Echelle spectrograph, we obtained high-resolution (R=10,000) near-infrared (1.01-1.38 \mu m) spectra of images A and B of the gravitationally lensed QSO B1422+231 (z=3.628) consisting of four…

We report a discovery of a new X-ray-selected supernova remnant (SNR) candidate SRGe~J0023+3625 = G116.6-26.1 found in the SRG/eROSITA all-sky survey. The source features a large angular extent ($\sim 4$ deg in diameter), nearly circular…

We present a survey of optically emitting supernova remnants (SNRs) in M31 based on H$\alpha$ and [SII] images in the Local Group Survey. Using these images, we select objects that have [SII]:H$\alpha$ $>$ 0.4 and circular shapes. We find…

Shell-type supernova remnants (SNRs) are considered prime candidates for the acceleration of Galactic cosmic rays (CRs) up to the knee of the CR spectrum at $\mathrm{E} \approx \mathrm{3}\times \mathrm{10}^\mathrm{15}$ eV. Our Milky Way…

AT2016dah and AT2017fyp are fairly typical Andromeda Galaxy (M31) classical novae. AT2016dah is an almost text book example of a 'very fast' declining, yet uncommon, Fe II'b' (broad-lined) nova, discovered during the rise to peak optical…

We have used MERLIN, at 1.4 and 5 GHz, to search for radio supernovae (RSNe) and supernova remnants (SNRs) in the unobscured irregular dwarf galaxy NGC1569, and in particular in the region of its super star clusters (SSCs) A and B.…

Supernovae near the galactic center evolve differently from regular galactic supernovae. This is mainly due to the environment into which the supernova remnants propagate. Instead of a static, uniform density medium, SNRs near the galactic…

We report on observations of the Galactic supernova remnant (SNR) G299.2$-$2.9 with the {\it Chandra X-Ray Observatory}. The high resolution images with {\it Chandra} resolve the X-ray-bright knots, shell, and diffuse emission extending…

High resolution ALMA observations of the recent (2.52 yrs old) shell of Nova V5668 Sgr (2015) show a highly structured ionised gas distribution with small (10$^{15}$ cm) clumps. These are the smallest structures ever observed in the remnant…

We have carried out a study of the X-ray properties of the supernova remnant (SNR) population in M33 with XMM-Newton, comprising deep observations of 8 fields in M33 covering all of the area within the D$_{25}$ contours, and with a typical…

The relatively nearby spiral galaxy NGC~6946 is one of the most actively star forming galaxies in the local Universe. Ten supernovae (SNe) have been observed since 1917, and hence NGC6946 surely contains a large number of supernova remnants…

The Large Magellanic Cloud (LMC) hosts a rich and varied population of supernova remnants (SNRs). Optical, X-ray, and radio observations are required to identify these SNRs, as well as to ascertain the various processes responsible for the…

The deepest X-ray images of M31, obtained with XMM-Newton, are examined in this paper to derive spectral and statistical properties of the population of the softest X-ray sources. Classifying supersoft X-ray sources (SSS) with criteria…

We present optical light curves of twenty-nine novae in M31 during the 2009 and 2010 observing seasons of the Palomar Transient Factory (PTF). The dynamic and rapid cadences in PTF monitoring of M31, from one day to even ten minutes,…

We present a detailed study of the 2017 eruption of the classical nova ASASSN-17pf (LMCN 2017-11a), which is located in the Large Magellanic Cloud, including data from AAVSO, ASAS-SN, SALT, SMARTS, SOAR, and the Neil Gehrels \textit{Swift}…

Classical novae (CNe) have been found to represent the major class of supersoft X-ray sources (SSS) in our neighbour galaxy M 31. We determine properties and evolution of the two first SSSs ever discovered in the M 31 globular cluster (GC)…

Using a combination of ground-based and HST imaging, we have constructed a catalog of 179 supernova remnants (SNRs) and SNR candidates in the nearby spiral galaxy M51. Follow-up spectroscopy of 66 of the candidates confirms 61 of these as…

We report the discovery and multicolor (VRIW) photometry of a rare explosive star MASTER OT J004207.99+405501.1 - a luminous red nova - in the Andromeda galaxy M31N2015-01a. We use our original light curve acquired with identical MASTER…