VizieR Online Data Catalog: The Arecibo PPS Survey. I. Harvesting ALFALFA (O'Donoghue+, 2019)
Abstract
All observations were conducted with the single-beam L-band wide (LBW) receiver system. A 1370-1470 MHz filter was used to limit the impact of human-generated radio frequency interference (RFI). At zenith, the gain of LBW is about 10.5 K/Jy and the system temperature is typically 25 K. The LBW observations used a basic pointed total-power (TP) position-switched (ON-OFF) mode of varying bandwidth (see below) in the 1340-1430 MHz ALFALFA frequency range. In TP position switching, a source (the ON scan) is tracked for some time period (usually three to five minutes), then the telescope is slewed back to the original altitude and azimuth location, and tracking of that position (the OFF scan) occurs for the same length of time. A diode of known thermal resistance is fired at the end of each ON/OFF source pair to provide calibration. Application of the TP mode assumes that the OFF scan does not contain a source of H I line emission at the same frequency as the target galaxy. The OFF observation allows for bandpass subtraction since the effects of the instrument and the sky should be identical to the ON observation, but without any source emission. For the observations reported here, we almost always used a three-minute ON-OFF switching. This observing scheme was designed to allow detection of H I masses greater than 107 Mȯ for <S/N> ~5.5, an average velocity width (at half the peak flux) of <W50> ~100 km/s, and a smoothing factor of 1/2 (e.g., Giovanelli et al. 2005AJ....130.2598G, Section 4.1).
(2 data files).- Publication:
-
VizieR Online Data Catalog
- Pub Date:
- May 2019
- DOI:
- 10.26093/cds/vizier.51570081
- Bibcode:
- 2019yCat..51570081O
- Keywords:
-
- Clusters: galaxy;
- Galaxies: radio;
- H I data;
- Surveys