Related papers: Ultra-soft sources as supernova type Ia progenitor…

The expanding ejecta from a classical nova remains hot enough ($\sim10^{4}\, {\rm K}$) to be detected in thermal radio emission for up to years after the cessation of mass loss triggered by a thermonuclear instability on the underlying…

A method is proposed for determining the properties of type Ia supernovae from short-lived precursors -- Prompt SNIa. This method is based on the assumption that this subtype of type Ia supernovae exploded into low-metallicity globular…

Tidal disruption events (TDEs) are usually discovered at X-ray or optical wavelengths through their transient nature. A characteristic spectral feature of X-ray detected TDEs is a "supersoft" X-ray emission, not observed in any other…

Underluminous Thermonuclear Supernovae (uTSNe) are an emerging class of transient events that resemble classic Supernovae Type Ia, but peak at much lower luminosities. Suspected to be the deflagrations of white dwarfs, they directly link…

We analysed archival data of Chandra pre-explosion observations of the position of SN2014J in M82. No X-ray source at this position was detected in the data, and we calculated upper limits on the luminosities of the progenitor. These upper…

Observations of many SNe Ia with the UVOT instrument on the Swift satellite has revealed that there exists order to the differences in the UV-OPT colors of normal SNe. We examine UV-OPT color curves for 25 SNe Ia, dividing them into 4…

We present ultraviolet (UV) and optical photometry and spectra of the 1999aa-like supernova (SN) iPTF14bdn. The UV data were observed using the Swift Ultraviolet/Optical Telescope (UVOT) and constitute the first UV spectral series of a…

A key tracer of the elusive progenitor systems of Type Ia supernovae (SNe Ia) is the detection of narrow blueshifted time-varying Na I D absorption lines, interpreted as evidence of circumstellar material (CSM) surrounding the progenitor…

We present new photometric and spectroscopic observations of SN 2019yvq, a Type Ia supernova (SN Ia) exhibiting several peculiar properties including an excess of UV/optical flux within days of explosion, a high SiII velocity, and a low…

While type Ia Supernovae (SNe Ia) have been used as precise cosmological distance indicators, their progenitor systems remain unresolved. One of the key questions is if there is a non-degenerate companion star at the time of a thermonuclear…

We present well-sampled optical observations of the bright Type Ia supernova (SN~Ia) SN 2011fe in M101. Our data, starting from $\sim16$ days before maximum light and extending to $\sim463$ days after maximum, provide an unprecedented time…

There are two classes of viable progenitors for normal Type Ia supernovae (SNe Ia): systems in which a white dwarf explodes at the Chandrasekhar mass ($M_{ch}$), and systems in which a white dwarf explodes below the Chandrasekhar mass…

We have considered 53 Type Ia supernovae (SNe Ia) observed by the Swift X-Ray Telescope (XRT). None of the SNe Ia are individually detected at any time or in stacked images. Using these data and assuming that the SNe Ia are a homogeneous…

We study populations of soft and super-soft X-ray sources in nearby galaxies of various morphological types with the special emphasis on characterizing populations of stable nuclear burning accreting WDs. Analysing the content of Chandra…

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…

The nature of the progenitors of SNe Ia is not yet fully understood. In the single-degenerate (SD) scenario, the collision of the SN ejecta with its companion star is expected to produce detectable UV emission in the first few days after…

I review various phenomena associated with mass-accreting white dwarfs (WDs) in relation to progenitors of type Ia supernovae (SNe Ia). The WD mass can be estimated from light curve analysis in multiwavelength bands based on the optically…

Type Ia supernovae are bright stellar explosions thought to occur when a thermonuclear runaway consumes roughly a solar mass of degenerate stellar material. These events produce and disseminate iron-peak elements, and properties of their…

SuperSUN, a new superthermal source of ultracold neutrons (UCN) at the Institut Laue-Langevin, exploits inelastic scattering of neutrons in isotopically pure superfluid $^4$He at temperatures below $0.6\,$K. For the first time, continuous…

Thermodynamical explosions of White Dwarfs (WD)are one of the keys to high precision cosmology. Nebular spectra, namely mid-infrared (MIR) with JWST are an effective tool to probe for the multi-dimensional imprints of the explosion physics…