The LWA1 is the first LWA station to be completed in April 2011, and is located near the VLA site. LWA1 is a 256 element array, operating as a single-station telescope at frequencies between 10-88 MHz. One additional dipole antenna is placed at a distance of 300 m from the main array. Shared risk operations of the full LWA1 are ongoing alongside with commissioning activities.
This document intends to provide information about the basic functionality of the instrument for observing purposes. This document is under constant revision, and will be updated regularly. The most recent version will be found on the LWA Astronomer web pages http://www.phys.unm.edu/ lwa/astro.html.
Table 1.1 summarizes the observational capabilities of the LWA1 station.
Specification Details Comments Frequency coverage ν 10-88 MHz Number of antennas 257 Number of beams 4 Number of tunings 2 per beam Independently tunable Number of polarizations, Npol 2 per beam per tuning Bandwidth per beam and polarization, B 19.6 MHz ∼16 MHz usable bw due to bandedges Number of channels, Nch 32 Minimum channel width, Δν 7.8125 kHz Transient mode Narrow, TBN 1-100 kHz bandwidth Continuous observing all dipoles Transient mode Wide, TBW 78 MHz bandwidth Short bursts of obserbing Declination range −30∘ to +90∘ Main beam FWHM 2.2∘74 MHz/ν sec2 Z Z is zenith angle SEFD zenith angle Z=[0∘, 65∘]) [3, 17] kJy Frequency independent Thermal noise (at zenith)1 1 Jy For 1s integration, B=16 MHz, Npol=2 and ν=74 MHz Confusion noise (zenith)2 25 Jy/beam for a 2∘ beam at 74 MHz