Supernovae

The possibility of a two-bang stellar collapse originating SN 1987a, and having the characteristics of the events recorded in Mont Blanc and Kamiokande, is discussed here. According to the «standard» collapse models of nonrotating stars, which predict the formation of a neutrinosphere with a nondegenerate neutrino gas inside the star, the Mont Blanc and Kamiokande data for the first burst give a too large stellar mass. On the contrary, a degenerate neutrino gas with low temperatureT≈0.5 MeV, and chemical potential μ≈(12÷15), predicts a relatively low total energy outflowW ν≈(2÷6)·1054 erg, and a small number of expected interactions in Kamiokande. A possible scenario is suggested: a massive (M≈20M ⊙) rotating star is fragmented into two pieces, one light and the other heavy, at the onset of the collapse. The massive component collapses to a black hole, and produces the first burst. Neutrinos are trapped inside the collapsing star because of elastic scattering in the outer core off heavy nuclei, withA≳300. It is shown that neutrinos fill up the quantum states, producing a degenerate neutrino gas. The second burst is explained by coalescence of the light fragment (M≈(1÷3)M ⊙) onto the massive black hole. The time delay between the two observed bursts (4.7 h) is mostly connected with gravitational braking, when the light fragment falls down onto the black hole, with an accompanying emission of gravitational waves for times of order of hours.

One of the most important grants of God Almighty to mankind is iron. The reality that there is a Chapter named " Al-Hadid " (Iron) in the Holy Koran can be considered as a sign of its significance. The reality that there is not a Chapter called " adh-Dhahab " (Gold) might be a sign that iron is more crucial than gold since life would go on if gold did not exist but it would not be easy to mention human civilization without iron. Iron is (1) the essential of all of the arts, (2) the source of human development and progress, and (3) in the center of the strength of man. Due to its functions mentioned above and similar ones, the following is stated in the Koran: " …and We sent down Iron, in which is (material for) mighty war, as well as many benefits for mankind... ". The fact that this Verse particularly introduces iron is completely astonishing, taking into account that these findings were realized at the termination of the 20th century.

¿De qué está hecho nuestro universo? Esta no es una pregunta nueva; de una manera u otra, el mismo interrogante ha acompañado a nuestros antepasados curiosos desde la noche de los tiempos. Los estudiosos del cosmos de hoy, sin embargo, creen haber hallado la respuesta. A partir de novedosas teorías y de observaciones y experimentos de gran precisión, se ha establecido un modelo para la evolución y el contenido de este universo, que nuestros abuelos (y, en algunos casos, incluso nuestros padres) jamás habrían podido siquiera imaginar. El resultado, de más está decir, es extraño, muy extraño. Pues todo aquello que nos rodea y aquello que los astrónomos pueden localizar con sus potentes máquinas de atrapar luces lejanas (a veces también llamadas “máquinas del tiempo”) representa un magro porcentaje de todo lo que sabemos –o pensamos que sabemos– que hay allá afuera. Y el resto que no vemos ¿qué es y qué aspecto tiene? Este libro trata precisamente de describir esos componentes oscuros que solo se dejan detectar indirectamente y que se comportan de manera inusual. Se los ha llamado materia y energía oscuras; se trata, sin ninguna duda, de nombres un poco confusos pero que se relacionan fuertemente con nuestra cultura global (pues representan el lado oscuro de nuestro universo).

The accelerating expansion of the universe is the most surprising cosmological discovery in many decades, implying that the universe is dominated by some form of "dark energy" with exotic physical properties, or that Einstein's theory of gravity breaks down on cosmological scales. The profound implications of cosmic acceleration have inspired ambitious experimental efforts to measure the history of expansion and growth of structure with percent-level precision or higher. We review in detail the four most well established methods for making such measurements: Type Ia supernovae, baryon acoustic oscillations (BAO), weak gravitational lensing, and galaxy clusters. We pay particular attention to the systematic uncertainties in these techniques and to strategies for controlling them at the level needed to exploit "Stage IV" dark energy facilities such as BigBOSS, LSST, Euclid, and WFIRST. We briefly review a number of other approaches including redshift-space distortions, the Alcock-Paczynski test, and direct measurements of H_0. We present extensive forecasts for constraints on the dark energy equation of state and parameterized deviations from GR, achievable with Stage III and Stage IV experimental programs that incorporate supernovae, BAO, weak lensing, and CMB data. We also show the level of precision required for other methods to provide constraints competitive with those of these fiducial programs. We emphasize the value of a balanced program that employs several of the most powerful methods in combination, both to cross-check systematic uncertainties and to take advantage of complementary information. Surveys to probe cosmic acceleration produce data sets with broad applications, and they continue the longstanding astronomical tradition of mapping the universe in ever greater detail over ever larger scales.

Novae and supernovae are rare astronomical events that would have had an influence on the sky- watching peoples who witnessed them. Although several bright novae/supernovae have been visible during recorded human history, there are many proposed but no confirmed accounts of supernovae in indigenous oral traditions or material culture. Criteria are established for confirming novae/supernovae in oral traditions and material culture, and claims from around the world are discussed to determine if they meet these criteria. Aboriginal Australian traditions are explored for possible descriptions of novae/supernovae. Although representations of supernovae may exist in Aboriginal traditions, there are currently no confirmed accounts of supernovae in Indigenous Australian oral or material traditions.

The accelerating expansion of the universe is the most surprising cosmological discovery in many decades. In this short review, we briefly summarize theories for the origin of cosmic acceleration and the observational methods being used to test these theories. We then discuss the current observational state of the field, with constraints from the cosmic microwave background (CMB), baryon acoustic oscillations (BAO), Type Ia supernovae (SN), direct measurements of the Hubble constant (H0), and measurements of galaxy and matter clustering. Assuming a flat universe and dark energy with a constant equation-of-state parameter w=P/ρ, the combination of Planck CMB temperature anisotropies, WMAP CMB polarization, the Union2.1 SN compilation, and a compilation of BAO measurements yields w=−1.10+0.08−0.07, consistent with a cosmological constant (w=−1). However, with these constraints the cosmological constant model predicts a value of H0 that is lower than several of the leading recent estimates, and it predicts a parameter combination σ8(Ωm)0.5 that is higher than many estimates from weak gravitational lensing, galaxy clusters, and redshift-space distortions. Individually these tensions are only significant at the ~2σ level, but they arise in multiple data sets with independent statistics and distinct sources of systematic uncertainty. The tensions are stronger with Planck CMB data than they were with WMAP because of the smaller statistical errors and the higher central value of Ωm. With the improved measurements expected from the next generation of data sets, these tensions may diminish, or they may sharpen in a way that points towards a more complete physical understanding of cosmic acceleration.

Nel sottobosco accademico molte teorie alternative crescono e cercano risposte diverse alle domande fondamentali. Oggi parliamo della Cosmologia al Plasma. Alla luce di un universo fondamentalmente elettromagnetico, troviamo risposte diverse anche al mistero più grande di tutti: la Vita.
Parte 1
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According to Feinberg, superluminal neutrino velocity is:

v = +/- c (p^2 / (p^2  - m^2.c^2))^1/2 or equivalently v = c((m^2.c^4 /E^ 2) + 1)^1/2

where E is energy, p is momentum, m is neutrino scalar mass and c is light speed. The view that neutrinos have a negative mass squared are tachyonic and superluminal will be supported in this paper.

Theoretical and experimental neutrino velocities have shown that the transmission of light and neutrinos was not simultaneous for the 1987 supernova. In addition, the 2017 IceCube-170922A observation of blazar TXS 0506+056 has shown that a 290 TeV neutrino was detected before high energy gamma and x-rays during an active phase. These natural phenomena have provided supplementary evidence for the tachyonic neutrino.

According to relativity, a particle with mass cannot travel at the speed of light and must travel at either greater than or less than the speed of light with a negative or a positive mass squared respectively. In light of this, an analysis of major neutrino speed experiments including MINOS (2007), OPERA (2011), OPERA (2012) and ICARUS (2012) has revealed a number of null results.

A reduction of neutrino energy to less than 1 KeV has been suggested to enable experimental superluminal detection.

Erratum: The date of the paper should read 18th October 2019

'Computational History' derives history from data and nowadays, therefore, relies on the technologies of the digital humanities. 'Computational History of Science' addresses questions of history by evaluating historical data, e.g. for tracing back copying traditions and conclude on transfer and transformation of data and knowledge. The term 'Applied Historical Astronomy', in contrast, tries to address questions of contemporary science by evaluating historical data in comparison with most recent data. This opens new possibilities, e.g. in the search for stellar transients among historical data.
In the contribution by Hoffmann & Vogt we will focus on the stellar transients among all the topics mentioned above. Philipp Protte discusses the accuracy of magnitudes and positions in ancient star catalogues, Andreas Schrimpf & Frank Verbunt present an analysis of an early modern star catalogue. Victor Reijs analyses the visibility of celestial objects for naked-eye observers, and Björn Kunzmann showcases some important variable stars in the history of astronomy. Rene Hudec presents astronomical photographic archives as a valuable data source for modern astrophysics. José M. Vaquero discusses the studies on solar observations made during the last four centuries. More technical are the contributions of Georg Zotti on 'Stellarium' and Karsten Markus-Schnabel on data-mining and data-processing technologies. Ido Yavetz & Luca Beisel are developing a digital tool of computational history of science for the simulation of pre-modern astronomical models. Gerd Graßhoff focuses more on the application of computational history with regard to Kepler's Astronomia Nova while Tim Karberg presents an analysis of the astronomical orientation of buildings in the North Sudan.

Wolfschmidt, Gudrun & Susanne M. Hoffmann (ed.):
Applied and Computational Historical Astronomy.
Angewandte und computergestützte historische Astronomie. Proceedings of the Splinter Meeting in the Astronomische Gesellschaft, Sept. 25, 2020. Hamburg: tredition (Nuncius Hamburgensis - Beiträge zur Geschichte der Naturwissenschaften; Bd. 55) 2021.
ISBN 978-3-347-27104-3 (Paperback), 978-3-347-27105-0 (Hardcover), 978-3-347-27106-7 (e-Book), (344 pages, 108 pages in colour). ISBN 978-3-949060-02-1 (computational Book), ©OpenScienceTechnology GmbH Berlin.

Hoffmann, Susanne M. & Gudrun Wolfschmidt:
Introduction to Applied and Computational Historical Astronomy.
In: Wolfschmidt, Gudrun & Susanne M. Hoffmann (ed.):
Applied and Computational Historical Astronomy.
Hamburg: tredition 2021, p. 12-33.

This paper seeks to use data from Colgate University’s Foggy Bottom Observatory to confirm an established relationship between the peak luminosities and light curve shapes of type Ia supernovae. Using this relationship, and the peak apparent brightnesses observed at Foggy Bottom Observatory, the distance to SN 1991M in the galaxy IC 1151 will be determined. The process used will be evaluated for success, and will set the standard for future supernova photometry at Colgate.

There have only been five bright supernovae in the Milky Way in the last millennium (starting in 1006). Of these, the Chinese supernova, which is also known as the ‘Chinese Guest Star’ of 1181AD has remained a mystery. It was originally seen and documented by Chinese and Japanese astronomers in the 12th century who said it was as bright as the planet Saturn and remained visible for six months. They also recorded an approximate location in the sky of the sighting, but no confirmed remnant of the explosion has even been identified by modern astronomers. The other four supernovae are all now well known to modern day science and include the famous Crab nebula.

This project looks into recreating a small scale mimic of the LIGO experiment. An optical Michelson interferometer is used to detect the perturbation caused by monochromatic and non-monochromatic sound waves, deriving from various sources; this is analogous to the gravitational waves radiated from binary star systems or exploding supernovae. The apparatus has successfully detected waves with frequencies up to 2020Hz, whereas the noise inherent in the setup does not allow for frequencies below 50Hz to be picked up. Limitations in resolving power are dependent on the magnitude of the folding frequency used when recording the data. An Arduino is preferable to an oscilloscope when analysing sound waves as it allows for a much larger range of folding frequencies, minimising the error associated with the reading.

When the Arduino works to its theoretical maximum capability, it would take roughly 107 days to correctly identify a frequency of 10-5Hz with a 1% degree of uncertainty, (calculation time not included). To identify frequency peaks the FFT algorithm has been used.
Through showing that the interferometer setup can detect waves with frequencies between 50Hz and 2020Hz, the experiment can be considered as a success, but for lower frequency waves, the noise inherent in the setup must be accounted for, whereas for higher frequencies, a more sensitive detector should be used.

Estrelas são, basicamente, enormes corpos quase esféricos de plasma incandescente. O calor liberado provém de processos nucleares que convertem, principalmente, núcleos de hidrogênio em núcleos de hélio. Esses processos nucleares são descritos pela cadeia próton-próton e pelo ciclo CNO. Ao atingirem o estado de queima de hidrogênio, as estrelas adentram à classe da sequência principal, onde permanecem o maior tempo de suas vidas. O caminho seguido pós sequência principal será determinado pela massa e luminosidade da estrela. Em termos mais gerais, as estrelas podem vir a se tornarem anãs-brancas, estrelas de nêutrons ou buracos ne-gros. Abstract Stars are, basically, huge almost spherical bodies of incandescent plasma. The released heat comes from nuclear processes that mainly convert hydrogen nuclei into helium nuclei. These nuclear processes are described by the proton-proton chain and the CNO cycle. As they reach the hydrogen-burning state, the stars get in to the main sequence class, where they remain the longest of their lives. The path followed by the main sequence will be determined by the mass and luminosity of the star. More generally, stars may become white dwarfs, neutron stars or black holes. Formando uma estrela O processo de formação estelar se inicia em nuvens moleculares densas e frias, proveni-entes de supernovas ou de galáxias starburst. Devido a interação gravitacional a nuvem molecular começa a colapsar seguindo a instabilidade de Jeans, de modo a criar porções aglomeradas de gás, os glóbulos de Bok. Com o colapso desses glóbulos, a energia potencial gravitacional é convertida em calor, de modo a aumentar a temperatura da nuvem. Essa nuvem aquecida da origem a uma protoestrela em seu núcleo quando o equilíbrio hidrostático é atingido. Por equi-líbrio hidrostático, devemos entender o processo em que a radiação proveniente do aumento da temperatura provoca uma expansão na nuvem molecular ao mesmo tempo em que a força gravitacional busca colapsá-la. Quando a força de expansão se iguala a força gravitacional, a protoestrela atinge o equilíbrio hidrostático. Na fase de protoestrela um disco protoplanetário pode existir em torno de seu centro, de modo que poderá vir a formar planetas. Com o aumento da temperatura no núcleo da nuvem os gases em seu interior tornam-se ionizados. O processo seguinte coloca a jovem estrela na fase de sequência principal, de modo que em seu núcleo inicia-se os processos de fusão nuclear, que irão, basicamente, converter núcleos de hidrogênio em núcleos de hélio. O tempo para que uma estrela inicie o processo de fusão do hidrogênio depende da sua massa. Para o Sol, por exemplo, o colapso da nuvem até a entrada na sequência principal durou 30 milhões de anos, enquanto que para estrelas mais massivas o tempo foi bem menor (algumas centenas de milhares de anos). Estrelas prestes a entrar na sequência principal e que possuem massas menores que duas massas solares (2í µí±€ ⊙) são chamadas de T Tauri, enquanto que estrelas mais massivas são deno-minadas como Herbig Ae/Be. O primeiro tipo é o que apresenta o disco protoplanetário circun-dante, enquanto que o segundo tipo é caracterizado por emissões de jatos de gás ao longo de seus eixos de rotação. Essa emissão de jatos reduz o momento angular da estrela, o que acarreta em certa nebulosidade em torno do astro. Nesse caso, a estrela recebe o nome de objeto de Herbig-Haro. A radiação proveniente das estrelas em formação, e também de estrelas próximas, ajudará na expulsão dos gases em torno dela de modo a " limpar " o espaço preenchido pelos protoplanetas.

It is proposed that there has been a longstanding misunderstanding of the relationship between scale factor of the universe and redshift.  It is shown how a value for the matter density, of one quarter of the true value, can result from such a misconception.  Predictions for distance moduli of supernovae against redshift, for a constant rate of expansion, are made and found to be in good agreement with the data.  It is concluded that the expansion of the universe may not be accelerating.

A supermassive rotating toroidal black hole (TBH) is proposed as the fundamental structure of quasars and other jet-producing active galactic nuclei. Rotating protogalaxies gather matter from the central gaseous region leading to the birth of massive toroidal stars, the
internal nuclear reactions of which proceed very rapidly. Once the nuclear fuel is spent, gravitational collapse produces a slender ring-shaped TBH remnant. Transitory electron and neutron degeneracy stabilized collapse phases, although possible, are unlikely owing to the large masses involved thus these events are typically the first supernovae of the host galaxies. Given time, the TBH mass increases through continued accretion by several orders of magnitude, the event horizon swells whilst the central aperture shrinks. The difference in angular velocities between the accreting matter and the TBH induces a magnetic field that is strongest in the region of the central aperture and innermost ergoregion. Owing to the
presence of negative energy states when such a gravitational vortex is immersed in an electromagnetic field, circumstances are near ideal for energy extraction via non-thermal radiation including the Penrose process and superradiant scattering. This establishes a self-sustaining mechanism whereby the transport of angular momentum away from the quasar by relativistic bi-directional jets reinforces both the modulating magnetic field and the TBH/accretion disc angular velocity differential. Continued mass-capture by the TBH results in contraction of the central aperture until the TBH topology transitions to being spheroidal, extinguishing quasar behaviour. Similar mechanisms may be operating in microquasars, supernovae and sources of repeating gamma-ray bursts when neutron density or black hole tori arise. Long-term TBH stability seems to require either a negative cosmological constant, a non-stationary space–time resulting from the presence of accreting matter or the intervention of quantum gravitational effects.

We present spectroscopic VLT/UVES observations of two emerging supernovae, the Type Ia SN 2001el and the Type II SN 2003hn, in the spiral galaxy NGC 1448. Our high resolution and high signal-to-noise spectra display atomic lines of Ca II, Na I, Ti II and K I in the host galaxy. In the line of sight towards SN 2001el, we also detect over a dozen diffuse interstellar bands (DIBs) within NGC 1448. These DIBs have strengths comparable to low reddening galactic lines of sight, albeit with some variations. In particular, a good match is found with the line of sight towards the sigma type diffuse cloud (HD 144217). The DIBs towards SN 2003hn are significantly weaker, and this line of sight has also lower sodium column density. The DIB central velocities show that the DIBs towards SN 2001el are closely related to the strongest interstellar Ca II and Na I components, indicating that the DIBs are preferentially produced in the same cloud. The ratio of the 5797 and 5780 DIB strengths (r~0.14) suggests a rather high UV field in the DIB environment towards SN 2001el. We also note that the extinction estimates obtained from the sodium lines using multiple line fitting agree with reddening estimates based on the colors of the Type Ia SN 2001el.

The work reported in this dissertation concern the study of kinetics, cycles and quantum mechanic processes of nuclear reactions involved in massive stars together with explosive nucleosynthesis phenomena having a key role in supernovae explosion. Four main fields are explored: physics of nuclear reaction, hydrogen burning, CNO cycles and explosive supernovae phenomena. The first chapter provide an overview of the background of the nuclear physics and of the potential approaches to the field as quantum mechanic aspects, cross section and Maxwell-Boltzmann distribution. The next chapter describe the hydrogen burning processes for stars with low mass (our sun), the CNO and hot CNO cycles involved for higher mass stars and other cycles as sodium and magnesium. The third chapter review the helium burning process involved in Red Giants as result of the exhausted hydrogen fuel. A short overview of other helium processes is briefly discussed. The fourth chapter provide a summary of the accepted model of explosive burning process involved in supernovae explosion. Explosive nucleosynthesis together with heavy elements as silicon burning processes are also described.

The work of this dissertation concerns the analysis of the physical properties of 27 Stripped Envelope Supernovae (SE-SNe) using photometric and spectroscopic methods. The first chapter provides an overview of the SE-SNe key features as type classification, light curve properties, spectra profiles, and the explosion mechanisms, including a brief discussion of the possible progenitor stars involved. The second chapter describes and compares four analytical models to compute nickel mass (𝑀𝑁𝑖) and mass ejecta (𝑀𝑒𝑗) highlighting discrepancies of the Khatami’s model between the SNe light curve intensity and velocity rate values. Bolometric light curves for 27 SESNe are computed and key physical properties as nickel mass (𝑀𝑁𝑖) values are estimated and discussed. Spectra analysis including the equivalent width (𝐸𝑊) feature of the Hα and He I lines are briefly discussed, analysing the P-Cygni profile at 6200Ả of the Balmer line. Furthermore, other SE-SNe spectra features as mass ejecta (𝑀𝑒𝑗 ) are calculated analysing the H and He lines strengths and the velocity rate values. Tomographic maps of the nickel mass vs mass ejecta are also included discussing the possible progenitor star origins. The third chapter gives a brief overview of the results obtained and future work. Appendices are also included containing full details of the bolometric light curves, nickel mass (𝑀𝑁𝑖), photospheric velocities (𝑣𝑝ℎ) and the mass ejecta (𝑀𝑒𝑗) calculated values. Uncertainties and error analysis are briefly discussed.

Electroweak parity violating interaction between supernova (SN) neutrinos and electrons of a simple chiral molecule is studied related to the origin of molecular homochirality. Appearance of supernova remnants inside molecular clouds favours the interaction of SN-neutrinos with interstellar molecules, leading to a energetic difference between the two enantiomers of the order of 10–5 eV. This energetic difference is closer to the thermic energy of the interstellar medium, so molecular homochirality could be enhanced in molecular clouds containing supernova remnants inside it due to neutrino interaction.

In this paper we study an anisotropic model generated from a particular Bianchi type-III metric, which is a generalization of Gödel’s metric and an exact solution of Einstein’s field equations. We analyse type Ia supernova data, namely the SDSS sample calibrated with the MLCS2k2 fitter, and we verify in which ranges of distances and redshifts the anisotropy
could be observed. We also consider, in a joint analysis, the position of the first peak in the CMB anisotropy spectrum, as well as current observational constraints on the Hubble
constant. We conclude that a small anisotropy is permitted by the data, and that more accurate measurements of supernova distances above z = 2 might indicate the existence of such anisotropy in the universe.

The spin parameter of the black hole in M33 X-7 has recently been measured to be a*=0.77+-0.05 (Liu et al. 2008). It has been proposed that the spin of the 15.65 M_sun black hole is natal. We show that this is not a viable evolutionary path given the observed binary orbital period of 3.45 days since the explosion that would produce a black hole with the cited spin parameter and orbital period would disrupt the binary. Furthermore, we show that the system has to be evolved through the hypercritical mass transfer of about 5 M_sun from the secondary star to the black hole.

Mankind has been curious about heavens above and the heavenly bodies since a very long time. The most common form of early expression of this date back to almost 20,000 years is in the form of cave paintings and stone etchings. The rock carving found in Burzahama region in Kashmir, India, depicts what is conventionally believed to be a hunting scene along with two very bright objects in the sky. The two objects in this scene have been interpreted as either the Sun and the Moon or two bright stars in close proximity. Here we investigate the possibility that this could be a record of a guest star or supernova in the sky. We search the supernova catalogue to look for a possible supernova that could have had the brightness comparable to that of Sun or Moon and close to ecliptic between 2000 BC and 10,000 BC since the etching is believed to have been done prior to 2000 BC and be visible from Burzahama. Only one Supernova remnant HB9 satisfies this condition. In addition to being dated to...

We present a radiative transfer code to model the nebular phase spectra of supernovae (SNe) in non-local thermodynamic equilibrium (NLTE). We apply it to a systematic study of Type Ia SNe using parameterized 1D models and show how nebular spectral features depend on key physical parameters, such as the time since explosion, total ejecta mass, kinetic energy, radial density profile, and the masses of 56 Ni, intermediate mass elements (IMEs), and stable iron-group elements (IGEs). We also quantify the impact of uncertainties in atomic data inputs. Among the results of the study are: (1) The main features of SNe Ia nebular spectra are relatively insensitive to most physical parameters. Degeneracy among parameters precludes a unique determination of the ejecta properties from spectral fitting. In particular, features can be equally well fit with generic Chandrasekhar mass (M ch), sub-M Ch , and super-M Ch models; (2) A sizable (0.1 M ⊙) central region of stable IGEs, often claimed as evidence for M Ch models, is not essential to fit the optical spectra and may produce an unusual flat-top [CoIII] profile; (3) The strength of [SIII] emission near 9500Å can provide a useful diagnostic of explosion nucleosynthesis; (4) Substantial amounts (0.1 M ⊙) of unburned C/O mixed throughout the ejecta produce [OIII] emission not seen in observations; (5) Shifts in the wavelength of line peaks, sometimes used to infer ejecta geometry, can also arise from line blending effects; (6) The steepness of the ejecta density profile affects the line shapes, with flatter slopes providing better fits to the observations of SN 2011fe, offering a constraint on explosion models; (7) Uncertainties in atomic data affect spectral line ratios by ∼30%, a level similar to the effect of varying physical parameters.

The present scenario for high-luminosity long gamma-ray bursts is strongly influenced by the paper of Fruchter et al. (2006). Whereas the main contention of this paper that these GRBs occur in low-metallicity irregular galaxies is based on a considerable collection of observational results and although the main thesis is doubtless correct, the paper does not explain the dynamics that produces such GRBs and much of the discussion not directly concerning the main thesis is wrong. We propose a dynamics and elucidate how the Fruchter et al. (2006) results may be tested, in our neighborhood in the LMC, suggesting that LMC X-3 is a relic of a high luminosity explosion, probably accompanied by a GRB and hypernova explosion. The way to test our suggestion is to measure the system velocity of the present black hole. We correct errors of the Fruchter et al. paper in stellar evolution, so that the study of GRBs is consistent with it. We show that the subluminous GRB 060218 had a low-mass black hole as central engine.

BVRI and unfiltered MicroObservatory CCD observations of SN 2012aw covering up to 124 days following the explosion of the supernova are reported together with observations submitted to the BAA VSS Online Database. The photometry shows a plateau in the R and I passbands  lasting ~100 days and gradual declines in brightness in the B, V and clear passbands over the same period. The B−V, VR and R−I colour
indices of the plateau show a monotonic evolution toward redder colours throughout the set of observations. Using an established calibration for effective temperature (Teff) based on the V−I colour index, the Teff of the SN ejecta is shown to drop quickly from ~8000K some 4 days after the explosion to ~5500K some 16 days later and then declines more slowly to around 4500K about 110 days after the explosion. With a mid-plateau MV of −16.75±0.2 magnitudes and a well-defined plateau in the VRI passbands lasting ~100 days, SN 2012aw can be considered to represent a typical Type IIP core-collapse SN. The finding that Teff reduces to below the recombination temperature of ionised hydrogen within 20 days of the explosion is consistent with an interpretation that the lightcurve plateau is mainly sustained by hydrogen
recombination emission.

We consider Majorana neutrino conversions inside supernovae by taking into account both flavor mixing and the neutrino magnetic moment. We study the adiabaticity of various possible transitions between the neutrino states for both normal and inverted hierarchy within the various solar neutrino problem solutions. From the final mass spectrum within diffrent scenarios, we infer the consequences of the various conversion effects on the neutronization peak, the nature of final spectra, and the possible Earth matter effect on the final fluxes. This enable us to check the sensibility of the SN neutrino flux on magnetic moment interaction, and narrow down possible scenarios which depend on: the mass spectrum normal or inverted, the solution of the solar neutrino problem; and the value of µB.