Update on the GRB universal scaling EX,iso_{\rm{X,iso}}-Eγ,iso_{\rm{\gamma,iso}}-Epk_{\rm{pk}} with ten years of SwiftSwift data

From a comprehensive statistical analysis of $Swift$ X-ray light-curves of gamma-ray bursts (GRBs) collected from December 2004 to the end of 2010, we found a three-parameter correlation between the isotropic energy emitted in the rest frame 1-10$^4$ keV energy band during the prompt emission (E$_{\rm{\gamma,iso}}$), the rest frame peak of the prompt emission energy spectrum (E$_{\rm{pk}}$), and the X-ray energy emitted in the rest frame 0.3-30 keV observed energy band (E$_{\rm{X,iso}}$), computed excluding the contribution of the flares. In this paper, we update this correlation with the data collected until June 2014, expanding the sample size with $\sim$35% more objects, where the number of short GRBs doubled. With this larger sample we confirm the existence of a universal correlation that connects the prompt and afterglow properties of long and short GRBs. We show that this correlation does not depend on the X-ray light-curve morphology and that further analysis is necessary to firmly exclude possible biases derived by redshift measurements. In addition we discuss about the behavior of the peculiar objects as ultra-long GRBs and we propose the existence of an intermediate group between long and short GRBs. Interestingly, two GRBs with uncertain classification fall into this category. Finally, we discuss the physics underlying this correlation, in the contest of the efficiency of conversion of the prompt $\gamma$-ray emission energy into the kinetic energy of the afterglow, the photosferic model, and the cannonball model.Comment: 11 pages, 5 figures, accepted for publication in MNRA

High-Energy Emission from Interacting Supernovae: New Constraints on Cosmic-Ray Acceleration in Dense Circumstellar Environments

Supernovae (SNe) with strong interactions with circumstellar material (CSM) are promising candidate sources of high-energy neutrinos and gamma rays, and have been suggested as an important contributor to Galactic cosmic rays beyond 1 PeV. Taking into account the shock dissipation by a fast velocity component of SN ejecta, we present comprehensive calculations of the non-thermal emission from SNe powered by shock interactions with a dense wind or CSM. Remarkably, we consider electromagnetic cascades in the radiation zone and subsequent attenuation in the pre-shock CSM. A new time-dependent phenomenological prescription provided by this work enables us to calculate gamma-ray, hard X-ray, radio, and neutrino signals, which originate from cosmic rays accelerated by the diffusive shock acceleration mechanism. We apply our results to SN IIn 2010jl and SN Ib/IIn 2014C, for which the model parameters can be determined from the multi-wavelength data. For SN 2010jl, the more promising case, by using the the latest Fermi Large Area Telescope (LAT) Pass 8 data release, we derive new constraints on the cosmic-ray energy fraction, <0.05-0.1. We also find that the late-time radio data of these interacting SNe are consistent with our model. Further multi-messenger and multi-wavelength observations of nearby interacting SNe should give us new insights into the diffusive shock acceleration in dense environments as well as pre-SN mass-loss mechanisms.Comment: 16 pages, 10 figures, 3 tables, accepted for publication in ApJ. Results and conclusions unchange

Unveiling the Engines of Fast Radio Bursts, Super-Luminous Supernovae, and Gamma-Ray Bursts

Young, rapidly spinning magnetars are invoked as central engines behind a diverse set of transient astrophysical phenomena, including gamma-ray bursts (GRB), super-luminous supernovae (SLSNe), fast radio bursts (FRB), and binary neutron star (NS) mergers. However, a barrier to direct confirmation of the magnetar hypothesis is the challenge of directly observing non-thermal emission from the central engine at early times (when it is most powerful and thus detectable) due to the dense surrounding ejecta. We present CLOUDY calculations of the time-dependent evolution of the temperature and ionization structure of expanding supernova or merger ejecta due to photo-ionization by a magnetar engine, in order to study the escape of X-rays (absorbed by neutral gas) and radio waves (absorbed by ionized gas), as well as to assess the evolution of the local dispersion measure due to photo-ionization. We find that ionization breakout does not occur if the engine's ionizing luminosity decays rapidly, and that X-rays typically escape the oxygen-rich ejecta of SLSNe only on $\sim 100 \, {\rm yr}$ timescales, consistent with current X-ray non-detections. We apply these results to constrain engine-driven models for the binary NS merger GW170817 and the luminous transient ASASSN-15lh. In terms of radio transparency and dispersion measure constraints, the repeating FRB 121102 is consistent with originating from a young, $\gtrsim 30-100 \, {\rm yr}$, magnetar similar to those inferred to power SLSNe. We further show that its high rotation measure can be produced within the same nebula that is proposed to power the quiescent radio source observed co-located with FRB 121102. Our results strengthen previous work suggesting that at least some FRBs may be produced by young magnetars, and motivate further study of engine powered transients.Comment: submitted to MNRAS; comments welcom