Related papers: White dwarf dynamical interactions and fast optica…
We explain the early excess emission of the Type Ia supernova 2018oh by an interaction of the supernova ejecta with disk-originated matter (DOM). Such DOM can form in the merger process of two white dwarfs (WDs) in the double degenerate…
We explore the observational appearance of the merger of a low-mass star with a white dwarf (WD) binary companion. We are motivated by Schreiber et al. (2016), who found that multiple tensions between the observed properties of cataclysmic…
Type Ia supernovae (SNe Ia) exhibit a wide diversity of peak luminosities and light curve shapes: the faintest SNe Ia are 10 times less luminous and evolve more rapidly than the brightest SNe Ia. Their differing characteristics also extend…
We present deep optical B, V, R images of a sample of 10 interacting systems which were selected for their resemblance to disturbed galaxies at high redshift. Photometry is performed on knots in the tidal features of the galaxies. We…
The progenitor systems and explosion mechanism of Type Ia supernovae are still unknown. Currently favoured progenitors include double-degenerate systems consisting of two carbon-oxygen white dwarfs with thin helium shells. In the…
We investigate whether nearby white dwarfs (WDs) can constrain dark matter (DM) interactions with ordinary matter. As experimental sensitivity improves, driven by the Gaia mission, the sample volume of nearby WDs has been increasing over…
We have found a new evolutionary path to Type Ia supernovae (SNe Ia) which has been overlooked in previous work. In this scenario, a carbon-oxygen white dwarf (C+O WD) is originated, not from an asymptotic giant branch star with a C+O core,…
I examine the hypothesis that many of the high velocity white dwarfs observed by Oppenheimer et al. (2001) are the remnants of donor stars from binaries that produced type Ia supernovae via the `single degenerate' channel. If this channel…
Recent searches by unbiased, wide-field surveys have uncovered a group of extremely luminous optical transients. The initial discoveries of SN 2005ap by the Texas Supernova Search and SCP-06F6 in a deep Hubble pencil beam survey were…
The Catalina Real-time Transient Survey (CRTS) carried out a public survey for optical transients between 2007 and 2019, discovering more than 16,000 transient candidates. Here we present the spectra and highlight the results of the…
Bright optical transients (i.e. transients typically visible with the naked eye) are populated mainly by novae eruptions plus a few supernovae (among which the SN1987a event). One bright nova happen every two years, either in the North ot…
Type Ia supernovae are bright stellar explosions distinguished by standardizable light curves that allow for their use as distance indicators for cosmological studies. Despite their highly successful use in this capacity, the progenitors of…
We systematically investigate the mergers of neutron star-white dwarf binaries from beginning to end, with focus on the properties of the inflows and outflows in accretion disks and their electromagnetic emissions. Using population…
Recently two fast X-ray transients (XT1 and XT2) have been reported from the search in the Chandra Deep Field (CDF) data. Each transient shows an initial plateau lasting around hundreds to thousands seconds followed by a rapid decay in the…
From the spectra and light curves it is clear that SNIa events are thermonuclear explosions of white dwarfs. However, details of the explosion are highly under debate. Here, we present detailed models which are consistent with respect to…
Type Iax supernovae (SN Iax), also called SN 2002cx-like supernovae, are the largest class of peculiar white dwarf (thermonuclear) supernovae, with over fifty members known. SN Iax have lower ejecta velocity and lower luminosities, and…
Wide-field optical surveys have begun to uncover large samples of fast (t_rise < 5d), luminous (M_peak < -18), blue transients. While commonly attributed to the breakout of a supernova shock into a dense wind, the great distances to the…
Numerical and observational evidence suggests that massive white dwarfs dominate the innermost regions of core-collapsed globular clusters by both number and total mass. Using NGC 6397 as a test case, we constrain the features of white…
The mergers of neutron stars (NSs) and white dwarfs (WDs) could give rise to explosive transients, potentially observable with current and future transient surveys. However, the expected properties and distribution of such events is not…
The current data acquisition rate of astronomical transient surveys and the promise for significantly higher rates during in the next decade necessitate the development of novel approaches to analyze astronomical data sets and promptly…