Found 17 talks width keyword supernovae

Exciting things may have happened sometimes to the stars we see in the sky today. For example, Betelgeuse, also known as Alpha-Ori, an M-type red supergiant, the 10th brightest sky in the sky (usually), may well have been a binary star in the past. Its rapid rotation, peculiarly large Galactic velocity, and unusual chemical abundances all point to it being kicked out from the birth environment and merging as a binary star. By comparing a Monte-Carlo stellar cluster population model with the observed populations of Galactic O- and B- type stars (progenitors of red supergiants), I will show that the story of Betelgeuse is not at all uncommon. In distant galaxies, closely related scenarios may give rise to peculiar core-collapse supernovae. I will conclude by briefly discussing how the diversity of such binary and triple stellar evolution histories reflects in the variety of the currently discovered core-collapse supernovae.

Cosmological observations (redshifts, cosmic microwave background radiation, abundance of light elements, formation and evolution of galaxies, large-scale structure) find explanations within the standard Lambda-CDM model, although many times after a number of ad hoc corrections. Nevertheless, the expression ‘crisis in cosmology’ stubbornly reverberates in the scientific literature: the higher the precision with which the standard cosmological model tries to fit the data, the greater the number of tensions that arise. Moreover, there are alternative explanations for most of the observations. Therefore, cosmological hypotheses should be very cautiously proposed and even more cautiously received.

There are also sociological and philosophical arguments to support this scepticism. Only the standard model is considered by most professional cosmologists, while the challenges of the most fundamental ideas of modern cosmology are usually neglected. Funding, research positions, prestige, telescope time, publication in top journals, citations, conferences, and other resources are dedicated almost exclusively to standard cosmology. Moreover, religious, philosophical, economic, and political ideologies in a world dominated by anglophone culture also influence the contents of cosmological ideas.

We introduce the strong CP problem and the existence of the Axion as a possible solution. 

We discuss the possibility that axions are the dark matter of the Universe and the possible ways to

detect it or disprove it using: direct laboratory experiments as well as astrophysical and cosmological

Until the advent in the late 1990’s of sensitive submillimetre arrays such as SCUBA, it was generally thought that the main sources for the interstellar dust found in galaxies were the dusty outflows from evolved AGB stars and M supergiants, although a dust contribution from supernovae had long been predicted on theoretical grounds. The detection at submillimetre wavelengths of very large dust masses in some high redshift galaxies emitting less than a billion years after the Big Bang led to a more serious consideration of core-collapse supernovae (CCSNe) from massive stars as major dust contributors. KAO and Spitzer mid-infrared observations confirmed that CCSN ejecta could form dust but it was not until the Herschel mission and subsequent ALMA observations that direct evidence has been obtained for the presence of significantly large masses of cold dust in young CCSN remnants. As well as using infrared spectral energy distributions to measure the amounts of dust forming in CCSN ejecta, dust masses can also be quantified from the analysis of red-blue asymmetries in their late-time optical emission line profiles. I will describe current results from these methods for estimating ejecta dust masses, and their implications.

The existence of apparently isolated massive stars has been recognized for some time, and various explanations have been proposed to explain these ranging from isolated star formation to variouscluster ejection mechanisms. In this talk I will present recent results from Gaia and Hubble on stellar dynamics within the Tarantula Nebula/30 Doradus region of the Large Magellanic Cloud. I will discuss how these complementary datasets have improved our knowledge of this nearby mini-starburst. The first results indicate the existence of a few stars in the region with masses ~100 solar masses that have been ejected from the central dense cluster R136. Ejection velocities appear torange from a few 10s of km/s to ~100 km/s. Given the extreme youth of R136 it is therefore likely that the mechanism of ejection was via the dynamical interaction channel rather than the binary supernova ejection scenario.

Supernova SN1987A in the Large Magellanic Cloud offers an unprecedented opportunity to tackle fundamental issues of supernova explosions: dust and molecule formation, interaction with the circumstellar medium, particle acceleration, pulsar formation, etc. Since 2011, instruments like ALMA have been fundamental for such endeavor. Tomographic techniques have recently permitted to obtain 3D-images of the molecular emission. High-resolution images of dust emission have recently been obtained. All those results, compared with predictions from hydro-dynamical simulations, are paving the way to a better understanding of supernovae explosions. In the talk, the main results will be highlighted with emphasis on the advances produced since 2017 in the understanding of the structure of the inner ejecta or debris.

I will describe the roles of jets in several quite different astrophysical systems. These include exploding core collapse supernovae, expelling common envelopes, and heating gas in clusters of galaxies. Hot bubbles inflated by jets seem to be a key ingredient in the interaction of jets with the ambient gas. The understanding that jets can efficiently interact with the ambient gas leads to new notions, such as the jittering jets model to explode massive stars, and the grazing envelope evolution(GEE) that can replace the common envelope evolution in some cases.

With the aim of testing the relation between supernova (SN) rate and star formation rate, we conducted a SN search in a sample of local starburst galaxies (SBs) where both star formation rates and extinction are extremely high. The search was performed in the near-infrared, where the bias due to extinction is reduced using HAWK-I on the VLT. We discovered six SNe, in excellent agreement with expectations, when considering that, even in our search, about 60% of events remain hidden in the nuclear regions due to a combination of reduced search efficiency and very high extinction.
In addition I will present my plans for next months at IAC for the "Starbursts and EMIR project". I will participate in the commissioning of the instrument at La Palma, collaborating in the development of the ETC and I  will compile a catalog of starbursts for EMIR with the aim to study their imprint in the cosmic evolution of galaxies.

The Astrophysics Research Institute (ARI) was established at LJMU in 1992. Today the Institute comprises around 70 staff and research students working on topics ranging from stellar evolution to cosmology. In this talk I will give an overview and some highlights of the work undertaken in recent years on Classical and Recurrent novae by the nova group of the ARI. This involves multi-frequency observations of both Galactic novae and those in Local Group galaxies and includes topics such as the exploration of their potential links to the progenitors of Type Ia supernovae. Along the way, I will briefly describe the work of the Liverpool Telescope on La Palma, one of whose primary science drivers is the efficient and effective observation of transient objects such as these, and look forward to our plans for the development of an even larger and faster-reacting robotic telescope at ORM - currently codenamed 'LT2".

Type-Ia supernovae (SNIa) are believed to be thermonuclear explosions of accreting carbon-oxygen white dwarfs that reach the Chandrasekhar mass limit of about 1.39 solar masses. However, the nature of the companion star is still under debate, i.e. to be either a dwarf, a sub giant, or a giant star (single-degenerate channel), or another white dwarf (double-degenerate channel). Both channels have been proposed but their relative frequency remains unclear. We have been exploring regions close to the center of supernova remnants of Galactic SNe to search for the companion of these type-Ia SNe. I will show the very recent results we have found in two Galactic type-Ia SNe.