Publication

Dynamics of Starbursting Dwarf Galaxies

Lelli, F., Verheijen, M. A., Fraternali, F. & Sancisi, R., Jan-2013, In : Bulletin of the American Astronomical Society.

Research output: Contribution to journalMeeting AbstractAcademic

The mechanisms that trigger strong bursts of star formation in dwarf galaxies are poorly understood. Blue Compact Dwarfs (BCDs) are nearby starburst galaxies that may hold the key to understand these mechanisms. We are studying a sample of 18 BCDs using both new and archival HI data. In several cases we find that BCDs have a steeply-rising rotation curve that flattens in the outer parts. This points to a strong central concentration of mass. We introduce a new parameter to quantify the central mass concentration in dwarf galaxies (BCDs and irregulars): the circular-velocity gradient V(Rd)/Rd, where Rd is the galaxy scale-length. We find that V(Rd)/Rd correlates with i) the central surface brightness; ii) the mean HI surface density over the stellar disk; and iii) the SFR density. BCDs have higher V(Rd)/Rd than typical irregulars, suggesting that the starburst activity is closely linked with the gravitational potential and the concentration of gas. We decompose the rotation curves of BCDs into mass components and find that baryons (stars and gas) are dynamically important. This is remarkable, as dwarf galaxies are commonly thought to be entirely dominated by dark matter. We discuss the implications of these results on the evolution of dwarf galaxies and in particular on the properties of the progenitors and descendants of BCDs.
Original languageEnglish
JournalBulletin of the American Astronomical Society
Publication statusPublished - Jan-2013
EventAmerican Astronomical Society, AAS Meeting #221, #107.02 - Long Beach, California, United States
Duration: 6-Jan-201310-Jan-2013

Event

American Astronomical Society, AAS Meeting #221, #107.02

06/01/201310/01/2013

Long Beach, California, United States

Event: Conference

ID: 19698601