Poster Presentation Astronomical Society of Australia Annual Scientific Meeting including HWWS 2013

Exploring the Ursa Major region (#274)

Kathrin Wolfinger 1
  1. Swinburne, Hawthorn, VIC, Australia

The Ursa Major region is an ideal target to study the effect of environment on the evolution of gas-rich galaxies as it is nearby and most of the known members are late-type galaxies that are rich in neutral hydrogen (HI). I investigate 480 deg2 and a heliocentric velocity range from 300-1900 km/s using data from the HI Jodrell All Sky Survey (HIJASS). The surveyed region includes the Ursa Major cluster (17.1 Mpc3 ), the Canes Venatici groups (4.1 Mpc1 ) and the less dense filament connecting the Ursa Major and Virgo cluster (16.7 Mpc2 ).

In this talk I will present an overview of the region: (i) the peak-flux limited catalogue containing 166 HI sources, 10 of which are first time detections in HI including a candidate galaxy/tidal tail/HI stream, (ii) intriguing objects such as HIJASS detections with HI extensions/plumes and (iii) candidate regions for galaxy-galaxy interactions4 . Furthermore I will show preliminary results from my studies regarding substructures in the region and their dynamics to investigate if Ursa Major is an unevolved and newly forming cluster in the context of hierarchical structure formation.

  1. Karachentsev I. D. et al., 2003, A&A, 398, 467
  2. Mei S. et al., 2007, ApJ, 655, 144
  3. Tully R. B. et al., 2008, ApJ, 686, 1523
  4. Wolfinger K. et al., 2013, MNRAS, 428, 1790