No Arabic abstract
Long-duration gamma-ray bursts (GRBs) at z < 1 are in most cases found to be accompanied by bright, broad-lined Type Ic supernovae (SNe Ic-BL). The highest-energy GRBs are mostly located at higher redshifts, where the associated SNe are hard to detect observationally. Here we present early and late observations of the optical counterpart of the very energetic GRB 130427A. Despite its moderate redshift z = 0.3399+/-0.0002, GRB 130427A is at the high end of the GRB energy distribution, with an isotropic-equivalent energy release of Eiso ~ 9.6x10^53 erg, more than an order of magnitude more energetic than other GRBs with spectroscopically confirmed SNe. In our dense photometric monitoring, we detect excess flux in the host-subtracted r-band light curve, consistent with what expected from an emerging SN, ~0.2 mag fainter than the prototypical SN 1998bw. A spectrum obtained around the time of the SN peak (16.7 days after the GRB) reveals broad undulations typical of SNe Ic-BL, confirming the presence of a SN, designated SN 2013cq. The spectral shape and early peak time are similar to those of the high expansion velocity SN 2010bh associated with GRB 100316D. Our findings demonstrate that high-energy long-duration GRBs, commonly detected at high redshift, can also be associated with SNe Ic-BL, pointing to a common progenitor mechanism.
We present the spectroscopic discovery of a broad-lined Type Ic supernova (SN 2010bh) associated with the nearby long-duration gamma-ray burst (GRB) 100316D. At z = 0.0593, this is the third-nearest GRB-SN. Nightly optical spectra obtained with the Magellan telescopes during the first week after explosion reveal the gradual emergence of very broad spectral features superposed on a blue continuum. The supernova features are typical of broad-lined SNe Ic and are generally consistent with previous supernovae associated with low-redshift GRBs. However, the inferred velocities of SN 2010bh at 21 days after explosion are a factor of ~2 times larger than those of the prototypical SN 1998bw at similar epochs, with v ~ 26,000 km/s, indicating a larger explosion energy or a different ejecta structure. A near-infrared spectrum taken 13.8 days after explosion shows no strong evidence for He I at 1.083 microns, implying that the progenitor was largely stripped of its helium envelope. The host galaxy is of low luminosity (M_R ~ -18.5 mag) and low metallicity (Z < 0.4 Z_solar), similar to the hosts of other low-redshift GRB-SNe.
We observed the afterglow of GRB 130427A with the RATIR instrument on the 1.5-m Harold L. Johnson telescope of the Observatorio Astronomico Nacional on Sierra San Pedro Martir. Our homogenous $griZYJH$ photometry extends from the night of burst to three years later. We fit a model for the afterglow. There is a significant positive residual which matches the behavior of SN 1998bw in the $griZ$ filters; we suggest that this is a photometric signature of the supernova SN 2013cq associated with the GRB. The peak absolute magnitude of the supernova is $M_r=-18.43pm0.11$.
SN2010ah, a very broad-lined type Ic SN discovered by the Palomar Transient Factory, was interesting because of its relatively high luminosity and the high velocity of the absorption lines, which was comparable to that of GRB/SNe, suggesting a high explosion kinetic energy. However, no GRB was detected in association with the SN. Here, the properties of SN2010ah are determined with higher accuracy than previous studies through modelling. New Subaru telescope photometry is presented. A bolometric light curve is constructed taking advantage of the spectral similarity with SN1998bw. Radiation transport tools are used to reproduce the spectra and the light curve. The results thus obtained regarding ejecta mass, composition and kinetic energy are then used to compute a synthetic light curve. This is in reasonable agreement with the early bolometric light curve of SN2010ah, but a high abundance of 56Ni at high velocity is required to reproduce the early rise, while a dense inner core must be used to reproduce the slow decline at late phases. The high-velocity 56Ni cannot have been located on our line of sight, which may be indirect evidence for an off-axis, aspherical explosion. The main properties of SN2010ah are: ejected mass ~ 3 Mo; kinetic energy ~10^52 erg, M(56Ni) ~ 0.25 Mo. The mass located at v >~ 0.1c is ~0.2 Mo. Although these values, in particular the kinetic energy, are quite large for a SN Ic, they are all smaller (especially the ejecta mass) than those typical of GRB/SNe. This confirms the tendency for these quantities to correlate, and suggests that there are minimum requirements for a GRB/SN, which SN2010ah may not meet although it comes quite close. Depending on whether a neutron star or a black hole was formed following core collapse, SN2010ah was the explosion of a CO core of ~ 5-6 Mo, pointing to a progenitor mass of ~24 - 28 Mo.
Long-duration gamma-ray bursts (GRBs) have been found to be associated with broad-lined type-Ic supernovae (SNe), but only a handful of cases have been studied in detail. Prompted by the discovery of the exceptionally bright, nearby GRB130427A (redshift z=0.3399), we aim at characterising the properties of its associated SN2013cq. This is the first opportunity to test directly the progenitors of high-luminosity GRBs. We monitored the field of the Swift long duration GRB130427A using the 3.6-m TNG and the 8.2-m VLT during the time interval between 3.6 and 51.6 days after the burst. Photometric and spectroscopic observations revealed the presence of the type Ic SN2013cq. Spectroscopic analysis suggests that SN2013cq resembles two previous GRB-SNe, SN1998bw and SN2010bh associated with GRB980425 and XRF100316D, respectively. The bolometric light curve of SN2013cq, which is significantly affected by the host galaxy contribution, is systematically more luminous than that of SN2010bh ($sim$ 2 mag at peak), but is consistent with SN1998bw. The comparison with the light curve model of another GRB-connected SN2003dh, indicates that SN2013cq is consistent with the model when brightened by 20%. This suggests a synthesised radioactive $^{56}$Ni mass of $sim 0.4 M_odot$. GRB130427A/SN2013cq is the first case of low-z GRB-SN connection where the GRB energetics are extreme ($E_{rm gamma, iso} sim 10^{54}$ erg). We show that the maximum luminosities attained by SNe associated with GRBs span a very narrow range, but those associated with XRFs are significantly less luminous. On the other hand the isotropic energies of the accompanying GRBs span 6 orders of magnitude (10$^{48}$ erg $< E_{rm gamma, iso} <$ 10$^{54}$ erg), although this range is reduced when corrected for jet collimation. The GRB total radiated energy is in fact a small fraction of the SN energy budget.
On 2018 July 28, GRB 180728A triggered textit{Swift} satellites and, soon after the determination of the redshift, we identified this source as a type II binary-driven hypernova (BdHN II) in our model. Consequently, we predicted the appearance time of its associated supernova (SN), which was later confirmed as SN 2018fip. A BdHN II originates in a binary composed of a carbon-oxygen core (CO$_{rm core}$) undergoing SN, and the SN ejecta hypercritically accrete onto a companion neutron star (NS). From the time of the SN shock breakout to the time when the hypercritical accretion starts, we infer the binary separation $simeq 3 times 10^{10}$ cm. The accretion explains the prompt emission of isotropic energy $simeq 3 times 10^{51}$ erg, lasting $sim 10$ s, and the accompanying observed blackbody emission from a thermal convective instability bubble. The new neutron star ($ u$NS) originating from the SN powers the late afterglow from which a $ u$NS initial spin of $2.5$ ms is inferred. We compare GRB 180728A with GRB 130427A, a type I binary-driven hypernova (BdHN I) with isotropic energy $> 10^{54}$ erg. For GRB 130427A we have inferred an initially closer binary separation of $simeq 10^{10}$ cm, implying a higher accretion rate leading to the collapse of the NS companion with consequent black hole formation, and a faster, $1$ ms spinning $ u$NS. In both cases, the optical spectra of the SNe are similar, and not correlated to the energy of the gamma-ray burst. We present three-dimensional smoothed-particle-hydrodynamic simulations and visualisations of the BdHNe I and II.