WALLABY Pilot Survey: Public data release of ∼ 1800 H i sources and high-resolution cut-outs from Pilot Survey Phase 2

• Published in: Publications of the Astronomical Society of Australia 2024-11, Vol.41, Article e088
• Main Authors: Murugeshan, C., Deg, N., Westmeier, T., Shen, A. X., For, B.-Q., Spekkens, K., Wong, O. I., Staveley-Smith, L., Catinella, B., Lee-Waddell, K., Dénes, H., Rhee, J., Cortese, L., Goliath, S., Halloran, R., van der Hulst, J. M., Kamphuis, P., Koribalski, B. S., Kraan-Korteweg, R. C., Lelli, F., Venkataraman, P., Verdes-Montenegro, L., Yu, N.
• Format: Article
• Language: English
• ISSN: 1323-3580; 1448-6083
• DOI: 10.1017/pasa.2024.91

We present the Pilot Survey Phase 2 data release for the Wide-field ASKAP L-band Legacy All-sky Blind surveY (WALLABY), carried-out using the Australian SKA Pathfinder (ASKAP). We present 1760 H i detections (with a default spatial resolution of 30′′) from three pilot fields including the NGC 5044 and NGC 4808 groups as well as the Vela field, covering a total of $\sim 180$ deg $^2$ of the sky and spanning a redshift up to $z \simeq 0.09$ . This release also includes kinematic models for over 126 spatially resolved galaxies. The observed median rms noise in the image cubes is 1.7 mJy per 30′′ beam and 18.5 kHz channel. This corresponds to a 5 $\sigma$ H i column density sensitivity of $\sim 9.1\times10^{19}(1 + z)^4$ cm $^{-2}$ per 30′′ beam and $\sim 20$ km s $^{-1}$ channel and a 5 $\sigma$ H i mass sensitivity of $\sim 5.5\times10^8 (D/100$ Mpc) $^{2}$ M $_{\odot}$ for point sources. Furthermore, we also present for the first time 12′′ high-resolution images (“cut-outs”) and catalogues for a sub-sample of 80 sources from the Pilot Survey Phase 2 fields. While we are able to recover sources with lower signal-to-noise ratio compared to sources in the Public Data Release 1, we do note that some data quality issues still persist, notably, flux discrepancies that are linked to the impact of side lobes associated with the dirty beams due to inadequate deconvolution. However, in spite of these limitations, the WALLABY Pilot Survey Phase 2 has already produced roughly a third of the number of HIPASS sources, making this the largest spatially resolved H i sample from a single survey to date.