Open AccessThe pattern speed of the bar in NGC 4596
Author(s) -
Gerssen Joris,
Kuijken Konrad,
Merrifield Michael R.
Publication year - 1999
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 - 10.1046/j.1365-8711.1999.02627.x
Subject(s) - physics , galaxy , bar (unit) , astrophysics , radius , hubble space telescope , hubble sequence , barred spiral galaxy , disc galaxy , astronomy , galaxy formation and evolution , computer security , computer science , meteorology
The pattern speed is a defining parameter of any barred galaxy. A large number of model‐dependent techniques have therefore been developed to derive the pattern speed. However, the only model‐independent technique for measuring this quantity – the Tremaine–Weinberg method – has hitherto been applied to just one case, the SB0 galaxy NGC 936. In this paper, we apply the technique to a second system, the SBa galaxy NGC 4596. The resulting estimate for the pattern speed is Ω p =52±13 km s −1 kpc −1 . This result is corroborated by a spectrum obtained along the major axis of the bar in this system. The corotation radius associated with this pattern speed lies just beyond the end of the bar indicating a fast bar. Combining the bar major‐axis spectra with data obtained from a Hubble Space Telescope WFPC2 image, we also find strong evidence for a nuclear disc.