The Expanded Very Large Array

Abstract

In almost 30 years of operation, the Very Large Array (VLA) has proved to be a remarkably flexible and productive radio telescope. However, the basic capabilities of the VLA have changed little since it was designed. A major expansion utilizing modern technology is currently underway to improve the capabilities of the VLA by at least an order of magnitude in both sensitivity and in frequency coverage. The primary elements of the Expanded Very Large Array (EVLA) project include new or upgraded receivers for continuous frequency coverage from 1 to 50 GHz, new local oscillator, intermediate frequency, and wide bandwidth data transmission systems to carry signals with 16 GHz total bandwidth from each antenna, and a new digital correlator with the capability to process this bandwidth with an unprecedented number of frequency channels for an imaging array. Also included are a new monitor and control system and new software that will provide telescope ease of use. Scheduled for completion in 2012, the EVLA will provide the world research community with a flexible, powerful, general-purpose telescope to address current and future astronomical issues.Comment: Added journal reference: published in Proceedings of the IEEE, Special Issue on Advances in Radio Astronomy, August 2009, vol. 97, No. 8, 1448-1462 Six figures, one tabl

A Vla Survey for Faint Compact Radio Sources in the Orion Nebula Cluster

“…Previous studies have used the Very Large Array (VLA) to search for compact radio sources in the ONC (e.g., Felli et al 1993a;Zapata et al 2004a), and fluxes produced by those studies have been used to correct for free-free contamination in disk mass studies (e.g., Eisner et al 2008;Mann & Williams 2010;Mann et al 2014). The expanded capabilities of the VLA correlator (Perley et al 2009), now enable surveys of much higher sensitivity than were previously possible. More recent surveys have taken advantage of this increase in sensitivity to map star-forming regions, including the ONC at 4.5 and 7.5 GHz (Dzib et al 2013;Kounkel et al 2014;Forbrich et al 2016).…”

Maser observations with new instruments

“…JVLA (Perley et al(2009), Perley et al(2011) has begun providing exciting science results as demonstrated in data presented by many at this Symposium even before it reaches its full upgraded potential. The several order of magnitude increase in correlator capacity promises delivery of sensitive spectroscopy at high spectral and spatial resolution.…”

Digital Signal Processing

“…This versatility is necessary because the widths of spectral features are influenced by Doppler shifts, which are proportional to the rest frequencies of the lines and the velocities of the emitting atoms and molecules. The correlator of the upgraded VLA system (Perley et al 2009) is fundamentally an XF design, as is the ALMA system, following its digital filter (Escoffier et al 2000).…”

“…Examples of recirculating lag correlators are described by Ball (1973) and Okumura et al (2000). The WIDAR correlator on the VLA uses recirculation (Perley et al 2009). …”

“…Carlson and Dewdney (2000) have described an all-digital development of the frequency demultiplexing principle used in the hybrid correlator. This is used with the expanded VLA (Perley et al 2009), and the system is described as a WIDAR correlator. Broadband signals are digitized at full bandwidth, divided into frequency channels using digital filters, and resampled at the appropriate lower rate before cross-correlation between all antenna pairs.…”