VizieR Online Data Catalog: Oph A mosaic image (Coutens+, 2019)

This mosaic image of the Oph A YSO cluster was obtained with the VLA in most extended A array configuration, which provides a projected baseline range from 310m to 34300m. It is the result of the combination of five epochs of observations between 2 December 2016 and 22 January 2017

This mosaic image of the Oph A YSO cluster was obtained with the VLA in most extended A array configuration, which provides a projected baseline range from 310m to 34300m. It is the result of the combination of five epochs of observations between 2 December 2016 and 22 January 2017. We used the 3-bit samplers and configured the correlator to have 4GHz of continuous bandwidth coverage centered on the sky frequency of 10GHz (X band) divided into 32 contiguous spectral windows. The pointing centers of our observations are given in Table 2. They are separated by 2.6', while the primary beam FWHM is 4.2'. In each epoch of observation, the total on-source observing time for each pointing was 312 seconds. The quasar J1625-2527 was observed approximately every 275 seconds for complex gain calibration. We observed 3C286 as the absolute flux reference. The joint imaging of these mosaic fields forms an approximately parallelogram-shaped, mosaic field of view, of which the width and height are ~6'. We calibrated the data manually using the CASA software package, following standard data calibration procedures. The imaging was done with Briggs robust = 2.0 weighting, gridder='mosaic', specmode='mfs', and nterms=1. At the average observing frequency, we obtained a synthesized θ_maxxθ_min~0.4"x0.2" and a maximum detectable angular scale of ~5"'(or ~700au). After primary beam correction, we achieved a root-mean-square (RMS) noise level of ~5μJy/beam at the center of our mosaic field, degraded to ~28μJy/beam toward the edges of the mosaic. The flux calibration uncertainty is expected to be about 5%.

(2 data files).