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17th of November 2017
A deep Parkes HI survey of the Sculptor group and filament: HI mass function and environment
by Tobias Westmeier (ICRAR/UWA)
Using deep HI observations with the Parkes radio telescope in combination with archival data, Westmeier et al. (2017) have created the deepest HI survey to date of the nearby Sculptor group and associated Sculptor filament. More than a quarter of the 31 HI sources detected in the field are new HI detections. With a low-mass slope of α = −1.10+0.20−0.11 the resulting HI mass function is significantly flatter than the global HI mass function from HIPASS or ALFALFA and consistent with the flat slopes previously found in other low-density group environments. Some physical process, such as ram pressure, photoionisation or star formation, must therefore have removed neutral gas predominantly from low-mass galaxies within the Sculptor filament and similar group environments. The results of this work will be published in the December issue of MNRAS.

Figure caption: (A) HI peak flux density map of the Sculptor group region. Blue circles mark HI detections from this work. (B) View of the survey cone showing the HI detections along the Sculptor filament out to a distance of 15 Mpc. (C) HI mass function of the Sculptor filament (black data points) with fitted Schechter function (red line) plus 68% and 95% confidence intervals (shaded regions). The HIPASS and ALFALFA Schechter fits from Zwaan et al. (2005) and Martin et al. (2010) are included for comparison.

Reference: Westmeier, T., Obreschkow, D., Calabretta, M., Jurek, R., Koribalski, B. S., Meyer, M., Musaeva, A., Popping, A., Staveley-Smith, L., Wong, O. I., Wright, A., 2017, MNRAS, 472, 4832 (DOI | ADS| arXiv)

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