We present detailed analysis of mid-infrared (MIR) data for 9 type II-P supernovae from the public Spitzer database. Spectral energy distributions (SEDs) from observed fluxes are fitted with simple models to get basic information about the dust as the presumed source of MIR radiation. We found two SNe, 2005ad and 2005af, which likely have newly-formed dust in their environment, while in the other seven cases the observed MIR flux may originate from pre-existing circumstellar or interstellar dust.

During the late stages of stellar evolution in massive stars (carbon fusion and later), the fusion and neutrino luminosities in the core of the star exceed the Eddington luminosity. This can drive vigorous convective motions which in turn excite a super-Eddington flux in internal gravity waves. We show that an interesting fraction of the energy in excited gravity waves can, in some cases, convert into sound waves as the gravity waves propagate (tunnel) towards the stellar surface. The subsequent dissipation of the sound waves can unbind up to several M⊙ of the stellar envelope. This wave-driven mass loss can explain the existence of extremely large stellar mass loss rates just prior to core-collapse, which are inferred via circumstellar interaction in some core-collapse supernovae (e.g., SNe 2006gy and PTF 09uj).

We calculate a new equation of state for baryons at sub-nuclear densities for the use in core-collapse simulations of massive stars. The formulation is the nuclear statistical equilibrium description and the liquid drop approximation of nuclei. The model free energy to minimize is calculated by relativistic mean field theory for nucleons and the mass formula for nuclei with atomic number up to ~ 1000. We have also taken into account the pasta phase. We find that the free energy and other thermodynamical quantities are not very different from those given in the standard EOSs that adopt the single nucleus approximation. On the other hand, the average mass is systematically different, which may have an important effect on the rates of electron captures and coherent neutrino scatterings on nuclei in supernova cores.

We investigate explosive nucleosynthesis during neutrino-driven, aspherical supernova (SN) explosion aided by standing accretion shock instability (SASI), based on two-dimensional hydrodynamic simulations of the explosion of 11, 15, 20, 25, 30 and 40M⊙ stars with zero metallicity. The magnitude and asymmetry of the explosion energy are estimated with simulations, for a given set of neutrino luminosities and temperatures, not as in the previous study in which the explosion is manually and spherically initiated by means of a thermal bomb or a piston and also some artificial mixing procedures are applied for the estimate of abundances of the SN ejecta.

By post-processing calculations with a large nuclear reaction network, we have evaluated abundances and masses of ejecta from the aspherical SNe. We find that matter mixing induced via SASI is important for the abundant production of nuclei with atomic number ≥ 21, in particular Sc, which is underproduced in the spherical models without artificial mixing. We also find that the IMF-averaged abundances are similar to those observed in extremely metal poor stars. However, observed [K/Fe] cannot be reproduced with our aspherical SN models.

We have obtained optical integral field spectroscopy of the explosion sites of more than 25 nearby type-IIP/IIL/Ib/Ic supernovae using UH88/SNIFS, and additionally Gemini/GMOS IFU. This technique enables us to obtain both spatial and spectral information of the immediate environment of the supernovae. Using strong line method we measured the metallicity of the star cluster present at the explosion site, presumably the coeval parent stellar population of the supernova progenitor, and comparison with simple stellar population models gives age estimate of the cluster. With this method we were able to put constraints on the metallicity and age of the progenitor star. The age, i.e. lifetime, of the progenitor corresponds to the initial mass of the star. By far this is the most direct measurement of supernova progenitor metallicity and, if the cluster-progenitor association is confirmed, provides reliable determination of the initial mass of supernova progenitor stars.

We present early time (~0-50 days) bolometric light curves of UV-bright Core Collapse Supernovae observed with the Swift UV/Optical Telescope. We also generate pseudo-bolometric light curves from Swift UV and optical data and examine these by subtype as well as the observed and interpolated UV and IR flux contributions by epoch and bolometric corrections at early times from UV data.

Gamma-ray bursts (GRBs) observed up to redshifts z > 9.3 are fascinating objects to study due to their still unexplained relativistic outburst mechanisms and a possible use to test cosmological models. Our analysis of all GRB afterglows with known redshifts and definite plateau (100 GRBs) reveals not only that the luminosity L*X(Ta) - break time T*a correlation, called hereafter LT, (Dainotti et al. 2010a) is confirmed with higher value of the Spearman correlation coefficient for the new updated sample, but also reveals its intrinsic nature throughout the analysis of the Efron & Petrosian (1992) test. The above mentioned test is performed to check if there is redshift evolution in both the luminosity and time. This test shows that the correlation still holds probing that its nature is intrinsic and it is not due to selection biases. The novelty of this approach is that the Efron & Petrosian method has been applied for the first time for a two parameter correlation that involves not only luminosities, but also time. Notwithstanding the intrinsic nature of the correlation, the correction of the observables for the effect of redshift evolution does not lead to a significantly tighter correlation and thus to a better redshift estimator. Therefore, the usage of the L*a correlation is limited, at least with the present data analysis, to constrain physical models of plateau emission. With an enlarged data sample in the future the aim will be to make the luminosity time correlation a useful redshift estimator.

Host galaxies are an excellent means of probing the natal environments that generate gamma-ray bursts (GRBs). Recent work on the host galaxies of short-duration GRBs has offered new insights into the parent stellar populations and ages of their enigmatic progenitors. Similarly, surveys of long-duration GRB (LGRB) host environments and their ISM properties have produced intriguing new results with important implications for long GRB progenitor models. These host studies are also critical in evaluating the utility of LGRBs as potential tracers of star formation and metallicity at high redshifts. I will summarize the latest research on LGRB host galaxies, and discuss the resulting impact on our understanding of these events' progenitors, energetics, and cosmological applications.

An observational study is presented of the spectral evolution of gamma-ray burst (GRB) prompt emissions with the Suzaku Wide-band All-sky Monitor (WAM). We selected 6 bright GRBs exhibiting 7 well-separated fast-rise-exponential-decay (FRED) shaped light curves to investigate spectral changes by evaluating exponential decay time constants of the energy-resolved light curves. In addition, we carried out time-resolved spectroscopy of two of them which were located with accuracy sufficient to evaluate the time-resolved spectra with precise energy response matrices. The two imply different emission mechanisms; the one is well reproduced with a cooling blackbody radiation model with a power-law component, while the other prefers non-thermal emission model with a decaying turn over energy.

The galaxies hosting the most energetic explosions in the universe, the gamma-ray bursts (GRBs), are generally found to be low-mass, metal-poor, blue and star forming. However, the majority of the targets investigated so far (less than 100) are at relatively low redshift, z < 2. We know that at low redshift, the cosmic star formation is predominantly in small galaxies. Therefore, at low redshift, long-duration GRBs, which are associated with massive stars, are expected to be in small galaxies. Preliminary investigations of the stellar mass function of z < 1.5 GRB hosts does not indicate that these galaxies are different from the general population of nearby star-forming galaxies. At high-z, it is still unclear whether GRB hosts are different. Recent results indicate that a fraction of them might be in dusty regions of massive galaxies. Remarkable is the a super-solar metallicity measured in the interstellar medium of a z = 3.57 GRB host.

We performed Rapid-Response Mode (RRM) VLT/UVES high-resolution UV/ optical spectroscopy of the GRB 080310 afterglow, starting 13 min after the burst trigger, in order to investigate the ISM in the GRB host galaxy. The four spectra show remarkable features at zGRB, including a low log N(H i) = 18.7 and time-variable absorption from ground-state and excited levels of Fe ii and Fe iii, the latter being observed for the first time in a GRB afterglow. These observations indicate i) ongoing photo-ionization of the surrounding gas due to the GRB radiation and ii) Fe and Cr overabundances in the host galaxy ISM. We derive ionic column densities through a four-component Voigt-profile fit of the absorption lines and investigate the pre-burst ionization level of the gas with CLOUDY photo-ionization modelling. The resulting intrinsic [Si/Fe] = −1.4 ([C/H] = −1.3, [O/H] < −0.8, [Si/H] = −1.2, [Cr/H] = +0.7 and [Fe/H] = +0.2) for the whole line profile - and even more extreme for one of the absorption components - cannot be explained with current models of SN yields. Dust destruction may contribute to the marked iron overabundance, possibly induced by the burst. The overall high iron enhancement along the line-of-sight also suggests little recent star formation in the host galaxy.

The status and prospects for gamma-ray bursts (GRBs) as cosmological probes are reviewed. Long duration GRBs can potentially be used as an indicator of star formation rate (SFR), though GRB rate might be systematically different from SFR, by the effect of e.g. metallicity. There are several papers claiming that the cosmic GRB rate history is different from that of SFR in the sense that GRB rate is relatively higher than SFR at higher redshifts, which may be explained by the metallicity effect. However, considering the large uncertainties about the efficiency of GRB afterglow detection and redshift determination, it would be conservative to state that the observed GRB rate is roughly consistent with the star formation history. GRBs can also be used as a unique and powerful tool to reveal the reionization history. However, there is practically no progress in this direction since the first GRB-based useful constraint on reionization in 2005 (GRB 050904). The bottleneck now is the insufficient sensitivity of near-infrared spectroscopy, even with 8m class telescopes. The planned 30m class telescopes will bring the next breakthruough. Finally, GRBs can potentially be used as a standard candle to study cosmology by a geometrical test. However, there are still many steps for GRBs to overcome before it produces a result that has strong impact on the cosmology community in the precision cosmology era.

The locations of long GRBs and stripped supernovae are compared to those of their favored progenitors, WR stars, and their sub-classes. Compared to Leloudas et al. (2010), we have doubled the number of galaxies with suitable WR data. In the combined sample, WC stars are found, on average, in brighter locations than WN stars. The WN distribution is fully consistent with the one of SNe Ib, while it is inconsistent with those of SNe II, Ic and GRBs. The WC distribution is both consistent with SNe Ib and Ic. It is inconsistent with SNe II, and marginally consistent with GRBs. Furthermore, we present a spectroscopic study of the locations of SNe Ib/c. The average metallicity in the environments of SNe Ic is found to be a little higher than for SNe Ib, but the difference is small and not significant within our sample. Under the assumption that the SN regions were formed in an instantaneous burst of star formation, we find that a fraction of them appear older than what is allowed in order to host SNe Ib/c from single massive stars. Within this framework, these SNe must come from lower mass binaries.

The GRB-SNe connection has been strengthened since 2008 by the detection of 6 additional GRB-SNe at both local and cosmological redshifts. This review summarizes the recent observations of SNe associated with GRBs 081007, 090618, 091127, 100316D, 101219B and 111211A, as well as the observations of SN 2008D, which was associated with a bright X-ray flash (XRF 080109) and may represent a link between “plain” SN and GRB-SNe. It is now clear that most – if not all – long-duration GRBs are produced by the core collapse of massive stars.

While the connection between Long Gamma-Ray Bursts (GRBs) and Type Ib/c Supernovae (SNe Ib/c) from stripped stars has been well-established, one key outstanding question is what conditions and factors lead to each kind of explosion in massive stripped stars. One promising line of attack is to investigate what sets apart SNe Ib/c with GRBs from those without GRBs. Here, I briefly present two observational studies that probe the SN properties and the environmental metallicities of SNe Ib/c (specifically broad-lined SNe Ic) with and without GRBs. I present an analysis of expansion velocities based on published spectra and on the homogeneous spectroscopic CfA data set of over 70 SNe of Types IIb, Ib, Ic and Ic-bl, which triples the world supply of well-observed Stripped SNe. Moreover, I demonstrate that a meta-analysis of the three published SN 1b/c metallicity data sets when including only values at the SN positions to probe natal oxygen abundances, indicates at very high significance that indeed SNe Ic erupt from more metal-rich environments than SNe Ib, while SNe Ic-bl with GRBs still prefer, on average, more metal-poor sites than those without GRBs.

At the end of IAU Symposium 279, Shri Kulkarni delivered the concluding remarks. This paper presents a summary of his comments as interpreted by the Chairs of the Science Organizing Committee.

The immensely bright and intrinsically simple afterglow spectra of gamma-ray bursts (GRBs) have proven to be highly effective probes of the interstellar dust and gas in distant, star-forming galaxies. Despite significant progress, many aspects of the host galaxy attenuating material are still poorly understood. There is considerable discrepancy between the amount of X-ray and optical afterglow absorption, with the former typically an order of magnitude higher than what would be expected from the optical line absorption of neutral element species. Similar inconsistencies exist between the abundance of interstellar dust derived from spectroscopic and photometric data, and the relation between the line-of-sight and integrated host galaxy interstellar medium (ISM) remains unclear. In these proceedings we present our analysis on both spectroscopic and photometric multi-wavelength GRB afterglow data, and summarise some of the more recent results on the attenuation properties of the ISM within GRB host galaxies.

Using three-dimensional (special relativistic) magnetohydrodynamics simulations, the amplification of magnetic field behind strong shock wave is studied. In supernova remnants and gamma-ray bursts, strong shock waves propagate through an inhomogeneous density field. When the shock wave hit a density bump or density dent, the Richtmyer-Meshkov instability is induced that cause a deformation of the shock front. The deformed shock leaves vorticity behind the shock wave that amplifies the magnetic field due to the stretching of field lines.

We present the results from our Swift/VLT legacy survey, a VLT Large Programme aimed at characterizing the host galaxies of a homogeneously selected sample of Swift gamma-ray bursts (GRBs). The immediate goals are to determine the host luminosity function, study the effects of reddening, determine the fraction of Lyα emitters in the hosts, and obtain redshifts for targets without a reported one. We have carefully selected a sample, obeying strict and well-defined criteria: 69 targets in total. Among the results is a large optical detection rate, the lack of extremely red objects (only one possible case in the sample), and 15 new GRB redshifts with the mean redshift of the host sample assessed to be 〈z〉 ≳ 2.2.

Based on our multi-dimensional neutrino-radiation hydrodynamic simulations, we report several cutting-edge issues about the long-veiled explosion mechanism of core-collapse supernovae (CCSNe). In this contribution, we pay particular attention to whether three-dimensional (3D) hydrodynamics and/or general relativity (GR) would or would not help the onset of explosions. Our results from the first generation of full GR 3D simulations including approximate neutrino transport are quite optimistic, indicating that both of the two ingredients can foster neutrino-driven explosions. We give an outlook with a summary of the most urgent tasks to draw a robust conclusion to our findings.