# gamma-ray sources

## GRB 180620A: Evidence for Late-time Energy Injection

The early optical emission of gamma-ray bursts (GRBs) gives an opportunity to understand the central engine and first stages of these events. About 30% of GRBs present flares whose origin is still a subject of discussion. We present optical …

## Revealing the First Stellar and Supermassive Black Holes to EXIST

The epochs of origin of the first stars and galaxies, and subsequent growth of the first supermassive black holes, are among the most fundamental questions. Observations of the highest redshift Gamma-Ray Bursts (GRBs) will be the most compelling in …

## Can We Trust GRB High Energy Correlations?

We show that several GRB correlations have common features indicative of an origin in selection effects. We focus on the possible origin of the Epk-Eiso correlation in Swift data due to detector threshold truncation. The existence of faint Swift …

## Gamma-ray Bursts, Classified Physically

From Galactic binary sources, to extragalactic magnetized neutron stars, to long-duration GRBs without associated supernovae, the types of sources we now believe capable of producing bursts of gamma- rays continues to grow apace. With this emergent …

## Real-time Transient Classification Pipeline

The Transients Classification Pipeline (TCP) is a Berkeley-led project which federates data streams from multiple surveys and observatories, classifies with machine learning and astronomer defined science priors, and broadcasts sources of interest to …

## Resolving The ISM Surrounding GRBs with Afterglow Spectroscopy

We review current research related to spectroscopy of gamma-ray burst (GRB) after-glows with particular emphasis on the interstellar medium (ISM) of the galaxies hosting these high redshift events. These studies reveal the physical conditions of …

## Unraveling the dynamics and kinematics of GRB hosts with high resolution spectroscopy

In the last years the research on GRB host galaxies has proceeded to more detailed studies both using high resolution afterglow spectroscopy and spatially resolved spectra of nearby hosts. High resolution spectra give a detailed picture of the …

## XRF 060428B: Observational evidence for a strongly lensed burst

Long-duration GRBs and X-ray flashes (XRFs softer-spectrum brethren of long GRBs) are thought to occur following the core-collapse of massive stars. We report here on observations of a recent X-ray flash (XRF 060428B) that occurred 2.6$^″$ in …

## Constraints on the Diverse Progenitors of GRBs from the Large-Scale Environments

The pursuit of the progenitors of short duration-hard spectrum gamma-ray bursts (SHBs) draws strongly upon similar quests for the origin of supernovae (SNe) and long duration-soft spectrum GRBs (LSBs). Indeed the notion that, in the absence of …

## Rapidly Detecting Extincted Bursts with KAIT and PAIRITEL

Ground-based robotic telescopes have proven essential in the first 6 months of Swift operation. The robotic optical 0.7m Katzman Automatic Imaging Telescope (KAIT) and the robotic infra-red 1.3m Peters Automated Infrared Imaging Telescope (PAIRITEL) …