We present the Open Supernova Catalog, an online collection of observations and metadata for presently 36,000+ supernovae and related candidates. The catalog is freely available on the web (https://sne.space), with its main interface having been designed to be a user-friendly, rapidly searchable table accessible on desktop and mobile devices. In addition to the primary catalog table containing supernova metadata, an individual page is generated for each supernova, which displays its available metadata, light curves, and spectra spanning X-ray to radio frequencies. The data presented in the catalog is automatically rebuilt on a daily basis and is constructed by parsing several dozen sources, including the data presented in the supernova literature and from secondary sources such as other web-based catalogs. Individual supernova data is stored in the hierarchical, human- and machine-readable JSON format, with the entirety of each supernova’s data being contained within a single JSON file bearing its name. The setup we present here, which is based on open-source software maintained via git repositories hosted on github, enables anyone to download the entirety of the supernova data set to their home computer in minutes, and to make contributions of their own data back to the catalog via git. As the supernova data set continues to grow, especially in the upcoming era of all-sky synoptic telescopes, which will increase the total number of events by orders of magnitude, we hope that the catalog we have designed will be a valuable tool for the community to analyze both historical and contemporary supernovae.

https://iopscience.iop.org/article/10.3847/1538-4357/835/1/64/pdf

An Open Catalog for Supernova Data

A new class of ultra-long-duration (more than 10,000 seconds) γ-ray bursts has recently been suggested. They may originate in the explosion of stars with much larger radii than those producing normal long-duration γ-ray bursts or in the tidal disruption of a star. No clear supernova has yet been associated with an ultra-long-duration γ-ray burst. Here we report that a supernova (SN 2011kl) was associated with the ultra-long-duration γ-ray burst GRB 111209A, at a redshift z of 0.677. This supernova is more than three times more luminous than type Ic supernovae associated with long-duration γ-ray bursts, and its spectrum is distinctly different. The slope of the continuum resembles those of super-luminous supernovae, but extends further down into the rest-frame ultraviolet implying a low metal content. The light curve evolves much more rapidly than those of super-luminous supernovae. This combination of high luminosity and low metal-line opacity cannot be reconciled with typical type Ic supernovae, but can be reproduced by a model where extra energy is injected by a strongly magnetized neutron star (a magnetar), which has also been proposed as the explanation for super-luminous supernovae.

/pdf/a-very-luminous-magnetar-powered-supernova-associated-with-3h0bmbeb95.pdf

A very luminous magnetar-powered supernova associated with an ultra-long γ-ray burst

We present a detailed report of the connection between long-duration gamma-ray bursts (GRBs) and their accompanying supernovae (SNe). The discussion presented here places emphasis on how observations, and the modelling of observations, have constrained what we know about GRB-SNe. We discuss their photometric and spectroscopic properties, their role as cosmological probes, including their measured luminosity–decline relationships, and how they can be used to measure the Hubble constant. We present a statistical summary of their bolometric properties and use this to determine the properties of the “average” GRB-SN. We discuss their geometry and consider the various physical processes that are thought to power the luminosity of GRB-SNe and whether differences exist between GRB-SNe and the SNe associated with ultra-long-duration GRBs. We discuss how observations of their environments further constrain the physical properties of their progenitor stars and give a brief overview of the current theoretical paradigms of their central engines. We then present an overview of the radioactively powered transients that have been photometrically associated with short-duration GRBs, and we conclude by discussing what additional research is needed to further our understanding of GRB-SNe, in particular the role of binary-formation channels and the connection of GRB-SNe with superluminous SNe.

/pdf/the-observer-s-guide-to-the-gamma-ray-burst-supernova-2onqlxnnsq.pdf

The Observer's Guide to the Gamma-Ray Burst-Supernova Connection

In this review we present a progress report of the connection between long-duration gamma-ray bursts (GRBs) and their accompanying supernovae (SNe). The analysis is from the point of view of an observer, with much of the emphasis placed on how observations, and the modelling of observations, have constrained what we known about GRB-SNe. We discuss their photometric and spectroscopic properties, their role as cosmological probes, including their measured luminosity$-$decline relationships, and how they can be used to measure the Hubble constant. We present a statistical analysis of their bolometric properties, and use this to determine the properties of the "average" GRB-SNe: which has a kinetic energy of $E_{\rm K} \approx 2.5\times10^{52}$ erg, an ejecta mass of $M_{\rm ej} \approx 6$ M$_{\odot}$, a nickel mass of $M_{\rm Ni} \approx 0.4$ M$_{\odot}$, a peak photospheric velocity of $v_{\rm ph} \approx 21,000$ km s$^{-1}$, a peak bolometric luminosity of $L_{\rm p} \approx 1\times10^{43}$ erg s$^{-1}$, and it reaches peak bolometric light in $t_{\rm p} \approx 13$ days. We discuss their geometry, consider the various physical processes that are thought to power the luminosity of GRB-SNe, and whether differences exist between GRB-SNe and the SNe associated with ultra-long duration GRBs. We discuss how observations of the environments of GRB-SNe further constrain the physical properties of their progenitor stars, and give an overview of the current theoretical paradigms of their suspected central engines. We also present an overview of the radioactively powered transients that have been photometrically associated with short-duration GRBs. We conclude the review by discussing what additional research is needed to further our understanding of GRB-SNe, in particular the role of binary-formation channels and the connection of GRB-SNe with superluminous SNe (abridged).

The optical and optical/near-infrared pseudobolometric light curves of 84 stripped-envelope supernovae (SNe) are constructed using a consistent method and a standard cosmology. The light curves are analysed to derive temporal characteristics and peak luminosity L_p, enabling the construction of a luminosity function. Subsequently, the mass of ^(56)Ni synthesised in the explosion, along with the ratio of ejecta mass to ejecta kinetic energy, are found. Analysis shows that host-galaxy extinction is an important factor in accurately determining luminosity values as it is significantly greater than Galactic extinction in most cases. It is found that broad-lined SNe Ic (SNe Ic-BL) and gamma-ray burst SNe are the most luminous subtypes with a combined median L_p, in erg s^(−1), of log(L_p) = 42.99 compared to 42.51 for SNe Ic, 42.50 for SNe Ib, and 42.36 for SNe IIb. It is also found that SNe Ic-BL synthesise approximately twice the amount of ^(56)Ni compared with SNe Ic, Ib, and IIb, with median M_(Ni) = 0.34, 0.16, 0.14, and 0.11 M_⊙, respectively. SNe Ic-BL, and to a lesser extent SNe Ic, typically rise from L_p/2 to L_p more quickly than SNe Ib/IIb; consequently, their light curves are not as broad.

/pdf/the-bolometric-light-curves-and-physical-parameters-of-1m5zb24dol.pdf

The bolometric light curves and physical parameters of stripped-envelope supernovae

We present optical and near-infrared (NIR) photometry for three gamma-ray burst supernovae (GRB-SNe): GRB 120729A, GRB 130215A / SN 2013ez and GRB 130831A / SN 2013fu. In the case of GRB 130215A / SN 2013ez, we also present optical spectroscopy at t-t0=16.1 d, which covers rest-frame 3000-6250 Angstroms. Based on Fe II (5169) and Si (II) (6355), our spectrum indicates an unusually low expansion velocity of 4000-6350 km/s, the lowest ever measured for a GRB-SN. Additionally, we determined the brightness and shape of each accompanying SN relative to a template supernova (SN 1998bw), which were used to estimate the amount of nickel produced via nucleosynthesis during each explosion. We find that our derived nickel masses are typical of other GRB-SNe, and greater than those of SNe Ibc that are not associated with GRBs. For GRB 130831A / SN 2013fu, we use our well-sampled R-band light curve (LC) to estimate the amount of ejecta mass and the kinetic energy of the SN, finding that these too are similar to other GRB-SNe. For GRB 130215A, we take advantage of contemporaneous optical/NIR observations to construct an optical/NIR bolometric LC of the afterglow. We fit the bolometric LC with the millisecond magnetar model of Zhang & Meszaros (2001), which considers dipole radiation as a source of energy injection to the forward shock powering the optical/NIR afterglow. Using this model we derive an initial spin period of P=12 ms and a magnetic field of B=1.1 x 10^15 G, which are commensurate with those found for proposed magnetar central engines of other long-duration GRBs.

/pdf/a-trio-of-grb-sne-grb-120729a-grb-130215a-sn-2013ez-and-grb-4zurc2then.pdf

Y. Krugl

Papers

A Trio of GRB-SNe: GRB 120729A, GRB 130215A / SN 2013ez and GRB 130831A / SN 2013fu