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Register a new userGRB171010A / SN2017htp: a GRB-SN at z=0.33
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The number of supernovae known to be connected with long-duration gamma-ray bursts is increasing and the link between these events is no longer exclusively found at low redshift ($z lesssim 0.3$) but is well established also at larger distances. We present a new case of such a liaison at $z = 0.33$ between GRB,171010A and SN,2017htp. It is the second closest GRB with an associated supernova of only three events detected by Fermi-LAT. The supernova is one of the few higher redshift cases where spectroscopic observations were possible and shows spectral similarities with the well-studied SN,1998bw, having produced a similar Ni mass ($M_{rm Ni}=0.33pm0.02 ~rm{M_{odot}}$) with slightly lower ejected mass ($M_{rm ej}=4.1pm0.7~rm{M_{odot}}$) and kinetic energy ($E_{rm K} = 8.1pm2.5 times 10^{51} ~rm{erg}$). The host-galaxy is bigger in size than typical GRB host galaxies, but the analysis of the region hosting the GRB revealed spectral properties typically observed in GRB hosts and showed that the progenitor of this event was located in a very bright HII region of its face-on host galaxy, at a projected distance of $sim$ 10 kpc from its galactic centre. The star-formation rate (SFR$_{GRB} sim$ 0.2 M$_{odot}$~yr$^{-1}$) and metallicity (12 + log(O/H) $sim 8.15 pm 0.10$) of the GRB star-forming region are consistent with those of the host galaxies of previously studied GRB-SN systems.
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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.
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.
We report observations and analysis of the nearby gamma-ray burst GRB,161219B (redshift $z=0.1475$) and the associated Type Ic supernova (SN) 2016jca. GRB,161219B had an isotropic gamma-ray energy of $sim 1.6 times 10^{50}$,erg. Its afterglow is likely refreshed at an epoch preceding the first photometric points (0.6,d), which slows down the decay rates. Combined analysis of the SN light curve and multiwavelength observations of the afterglow suggest that the GRB jet was broad during the afterglow phase (full opening angle $sim 42^circ pm 3^circ$). Our spectral series shows broad absorption lines typical of GRB supernovae (SNe), which testify to the presence of material with velocities up to $sim 0.25$c. The spectrum at 3.73,d allows for the very early identification of a SN associated with a GRB. Reproducing it requires a large photospheric velocity ($35,000 pm 7000$,kms). The kinetic energy of the SN is estimated through models to be KE $approx 4 times 10^{52}$,erg in spherical symmetry. The ejected mass in the explosion was Mej $approx 6.5 pm 1.5$,Msun, much less than that of other GRB-SNe, demonstrating diversity among these events. The total amount of Nifs in the explosion was $0.27 pm 0.05$,Msun. The observed spectra require the presence of freshly synthesised Nifs at the highest velocities, at least 3 times more than a standard GRB-SN. We also find evidence for a decreasing Nifs abundance as a function of decreasing velocity. This suggests that SN,2016jca was a highly aspherical explosion viewed close to on-axis, powered by a compact remnant. Applying a typical correction for asymmetry, the energy of SN,2016jca was $sim$ (1--3) $times 10^{52}$,erg, confirming that most of the energy produced by GRB-SNe goes into the kinetic energy of the SN ejecta.
We present observations of the dark Gamma-Ray Burst GRB 051008 provided by Swift/BAT, Swift/XRT, Konus-WIND, INTEGRAL/SPI-ACS in the high-energy domain and the Shajn, Swift/UVOT, Tautenburg, NOT, Gemini and Keck I telescopes in the optical and near-infrared bands. The burst was detected only in gamma- and X-rays and neither a prompt optical nor a radio afterglow were detected down to deep limits. We identified the host galaxy of the burst, which is a typical Lyman-break Galaxy (LBG) with R-magnitude of 24.06 +/- 0.10. A redshift of the galaxy of z = 2.77 (-0.20,+0.15) is measured photometrically due to the presence of a clear, strong Lyman-break feature. The host galaxy is a small starburst galaxy with moderate intrinsic extinction (A_V = 0.3 mag) and has a SFR of ~ 60 M_Sun / yr typical for LBGs. It is one of the few cases where a GRB host has been found to be a classical Lyman-break galaxy. Using the redshift we estimate the isotropic-equivalent radiated energy of the burst to be E_iso = (1.15 +/- 0.20) x 10^54 erg. We also provide evidence in favour of the hypothesis that the darkness of GRB 051008 is due to local absorption resulting from a dense circumburst medium.
Every GRB model where the progenitor is assumed to be a highly relativistic hadronic jet whose pions, muons and electron pair secondaries are feeding the gamma jets engine, necessarily (except for very fine-tuned cases) leads to a high average neutrino over photon radiant exposure (radiance), a ratio well above unity, though the present observed average IceCube neutrino radiance is at most comparable to the gamma in the GRB one. Therefore no hadronic GRB, fireball or hadronic thin precessing jet, escaping exploding star in tunneled or penetrarting beam, can fit the actual observations. A new model is shown here, based on a purely electronic progenitor jet, fed by neutrons (and relics) stripped from a neutron star (NS) by tidal forces of a black hole or NS companion, showering into a gamma jet. Such thin precessing spinning jets explain unsolved puzzles such as the existence of the X-ray precursor in many GRBs. The present pure electron jet model, disentangling gamma and (absent) neutrinos, explains naturally why there is no gamma GRB correlates with any simultaneous TeV IceCube astrophysical neutrinos. Rare unstable NS companion stages while feeding the jet may lead to an explosion simulating a SN event. Recent IceCube-160731A highest energy muon neutrino event with absent X-gamma traces confirms the present model expectations.
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