Astrophysics - High Energy Astrophysical Phenomena

The Swift/BAT Hard X-Ray Transient Monitor

The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day …

Discovery and Redshift of an Optical Afterglow in 71 deg$^2$: iPTF13bxl and GRB 130702A

We report the discovery of the optical afterglow of the γ-ray burst (GRB) 130702A, identified upon searching 71 deg$^2$ surrounding the Fermi Gamma-ray Burst Monitor (GBM) localization. Discovered and characterized by the intermediate Palomar …

Discovery, Progenitor and Early Evolution of a Stripped Envelope Supernova iPTF13bvn

The intermediate Palomar Transient Factory reports our discovery of a young supernova, iPTF13bvn, in the nearby galaxy, NGC 5806 (22.5 Mpc). Our spectral sequence in the optical and infrared suggests a Type Ib classification. We identify a blue …

Keck Observations of 160 Gamma-Ray Burst Host Galaxies

We present a preliminary data release from our multi-year campaign at Keck Observatory to study the host galaxies of a large sample of Swift-era gamma-ray bursts via multi-color ground-based optical imaging and spectroscopy. With over 160 targets …

Discovery of a Cosmological, Relativistic Outburst via its Rapidly Fading Optical Emission

We report the discovery by the Palomar Transient Factory (PTF) of the transient source PTF11agg, which is distinguished by three primary characteristics: (1) bright (R $_peak$ = 18.3 mag), rapidly fading (ΔR = 4 mag in Δt = 2 days) optical transient …

SN 2011ht: confirming a class of interacting supernovae with plateau light curves (Type IIn-P)

We present photometry and spectroscopy of the Type IIn supernova (SN) 2011ht, identified previously as a possible SN impostor. The light curve exhibits an abrupt transition from a well-defined ̃120 d plateau to a steep bolometric decline, plummeting …

An outburst from a massive star 40 days before a supernova explosion

Some observations suggest that very massive stars experience extreme mass-loss episodes shortly before they explode as supernovae, as do several models. Establishing a causal connection between these mass-loss episodes and the final explosion would …

Late-time Radio Emission from X-Ray-selected Tidal Disruption Events

We present new observations with the Karl G. Jansky Very Large Array of seven X-ray-selected tidal disruption events (TDEs). The radio observations were carried out between 9 and 22 years after the initial X-ray discovery, and thus probe the …

X-Ray Emission from Supernovae in Dense Circumstellar Matter Environments: A Search for Collisionless Shocks

The optical light curve of some supernovae (SNe) may be powered by the outward diffusion of the energy deposited by the explosion shock (the so-called shock breakout) in optically thick (τ >åisebox-0.5ex 30) circumstellar matter (CSM). Recently, …

The Luminous Infrared Host Galaxy of Short-duration GRB 100206A

The known host galaxies of short-hard gamma-ray bursts (GRBs) to date are characterized by low to moderate star formation rates (SFRs) and a broad range of stellar masses, in general agreement with models associating the phenomenon with an old …