Real-Time Survey for Rapid Source Variability in Astronomical Objects using the Very Large Array

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

The study of sources showing rapidly time variability is one of last frontiers of astronomy. This covers a wide range of wavelengths. In the radio range, variations had been found for our Sun in the 1940s. In the 1960s, slow time variations of astronomical sources were discovered. Later, radio sources emitting regular pulses were found. In the last few years, non-repeating, bursting sources have been found. One group of the most energetic radio sources is Fast Radio Bursts, or FRBs. FRBs are a rare phenomenon. The study of FRBs is a new one, and their distance and exact location is an open question. If the FRBs are located in other galaxies, the energy of such outbursts would reach the limits of possible emission mechanisms. The appeal of transient phenomena should provide wide public interest. There will be student in topics such as time variable astrophysics, high performance computing and efficient algorithms. This project will construct a system to search for transient phenomena during scheduled imaging observations made with the Very Large Array (VLA). Images are produced from the average of data over many hours. However, the evidence for rapid variations is lost in the averaging process. This project will construct a system designed to search the data for variability on time scales from 50 milliseconds to minutes, in parallel with scheduled astronomical programs. These searches will be carried out in real time. With the real-time system, only those samples showing significant bursts of radio energy would be stored. This system will be in use at all times when standard scientific programs are carried out, that is, a commensal system. In this, the data stream from the VLA will be searched for significant, short term bursts of radio energy with a powerful, especially designed system. This will not affect the normal scientific observations made with the VLA. The VLA can easily provide FRB positions that have errors smaller than 1 arc second, allowing optical identifications. This system will take advantage of the large amount of observing time available at the VLA, including the 6000 hours to be allocated to the already-planned VLA Sky Survey. This project is a precursor for larger facilities planned for the future, such as the Square Kilometer Array. There will be many opportunities for student training in the algorithms used to search for transient events in large data sets, and there will be outreach at the website of the National Radio Astronomy Observatory.