Goddard Robotic Telescope - Optical Follow-up of GRBs and Coordinated Observations of AGNs -

TL;DR

The paper describes the development and operation of the Goddard Robotic Telescope, a fully automated system designed for optical follow-up of GRBs and AGNs, filling a coverage gap in the eastern U.S. and enabling coordinated observations with space telescopes.

Contribution

Introduction of a new 14-inch automated robotic telescope at Goddard for GRB follow-up and AGN monitoring, enhancing global observational coverage.

Findings

Operates since 2009 with remote control capabilities.

Achieves a limiting magnitude of ~15.4 in 30s exposure, reaching ~18 mag in 600s.

Provides valuable data for transient astronomical events.

Abstract

Since it is not possible to predict when a Gamma-Ray Burst (GRB) will occur or when Active Galactic Nucleus (AGN) flaring activity starts, follow-up/monitoring ground telescopes must be located as uniformly as possible all over the world in order to collect data simultaneously with Fermi and Swift detections. However, there is a distinct gap in follow-up coverage of telescopes in the eastern U.S. region based on the operations of Swift. Motivated by this fact, we have constructed a 14" fully automated optical robotic telescope, Goddard Robotic Telescope (GRT), at the Goddard Geophysical and Astronomical Observatory. The aims of our robotic telescope are 1) to follow-up Swift/Fermi GRBs and 2) to perform the coordinated optical observations of Fermi Large Area Telescope (LAT) AGN. Our telescope system consists of off-the-shelf hardware. With the focal reducer, we are able to match the field of view of Swift narrow instruments (20' x 20'). We started scientific observations in mid-November 2008 and GRT has been fully remotely operated since August 2009. The 3 sigma upper limit in a 30-second exposure in the R filter is ~15.4 mag; however, we can reach to ~18 mag in a 600-second exposures. Due to the weather condition at the telescope site, our observing efficiency is 30-40% on average.