Kinematics of Eight Nearby Dwarf Galaxies

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Session 108 -- Dwarf and Irregular Galaxies
Display presentation, Saturday, January 15, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[108.02] Kinematics of Eight Nearby Dwarf Galaxies

S.C\^ot\'e, K.C.Freeman (Mount Stromlo Obs.), C.Carignan (Universit\'e de Montr\'eal)

We present neutral hydrogen observations of eight nearby dwarf spirals and dwarf irregulars galaxies with absolute magnitude $M_B$ in the range $-15.5$ to $-11$. NGC625, SDig, ESO471-G6 and ESO245-G5 are members of the Sculptor Group, the most nearby group of galaxies outside the Local Group at 2.5 Mpc; DDO161, ESO325-G11, ESO381-G20, and ESO444-G84 are members of the Centaurus A Group at 3.5 Mpc. These galaxies were mapped in HI with the Australia Telescope (3km and 750m arrays) and with the Very Large Array (B/C and C/D configurations). The HI column density distributions of these objects extend well beyond the optical galaxies, and their HI masses range between $4 \times 10^6 M_{\sun}$ to $3 \times 10^8 M_{\sun}$. The velocity fields of the HI gas in these dwarf galaxies are strongly dominated by rotation (and not chaotic motions), even for the fainter objects. NGC625 however is of the 'tumbling sausage' variety, with its gas rotating around the optical major axis, like for GR8 (Carignan et al 1990).

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