Open AccessLifetime of nuclear velocity dispersion drops in barred galaxies
Author(s) -
Wozniak Hervé,
Champavert Nicolas
Publication year - 2006
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.10359.x
Subject(s) - physics , astrophysics , drop (telecommunication) , star formation , velocity dispersion , bulge , galaxy , astronomy , telecommunications , computer science
We have made hydro/ N ‐body simulations with and without star formation to shed some light on the conditions under which a central kinematically cold stellar component (characterized by a velocity dispersion drop or σ‐drop) could be created in a hot medium (e.g. a bulge) and survive enough time to be observed. We found that the time‐scale for a σ‐drop formation could be short (less than 500 Myr), whereas its lifetime could be long (more than 1 Gyr) provided that the central region is continuously or regularly fed by fresh gas which leads to a continuous star formation activity. Star formation in the central region, even at a low rate as 1 M ⊙ yr −1 , is mandatory to sustain a permanent σ‐drop by replacing heated particles by new low‐σ ones. We moreover show that as soon as star formation is switched off, the σ‐drop begins to disappear.