A VLT VIMOS study of the anomalous BCD Mrk 996: mapping the ionized gas kinematics and abundances
James, B. L × Tsamis, Y. G Barlow, M. J Westmoquette, M. S Walsh, J. R Cuisinier, F Exter, Katrina #
Wiley-blackwell publishing, inc
Monthly notices of the royal astronomical society vol:398 issue:1 pages:2-22
A study of the blue compact dwarf (BCD) galaxy Mrk 996 based on high-resolution optical Very Large Telescope Visible Multi-Object Spectrograph integral field unit spectroscopy is presented. Mrk 996 displays multicomponent line emission, with most line profiles consisting of a narrow, central Gaussian [full width at half-maximum (FWHM) similar to 110 km s(-1)] with an underlying broad component (FWHM similar to 400 km s(-1)). The broad HI Balmer component splits into two separate broad components inside a 1.5-arcsec radius from the nucleus; these are attributed to a two-armed minispiral. This spiral-like nucleus rotates in the same sense as the extended narrow line ionized gas but is offset by similar to 50 km s(-1) from the systemic velocity of the galaxy. The rotation curve of Mrk 996 derived from the H alpha narrow component yields a total mass of 5 x 10(8) M-circle dot within a radius of 3 kpc. From the H alpha luminosity we infer a global star formation rate of similar to 2 M-circle dot yr(-1).