Astronomy and Astrophysics – Astronomy
Scientific paper
May 2001
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001aas...198.8501s&link_type=abstract
American Astronomical Society, 198th AAS Meeting, #85.01; Bulletin of the American Astronomical Society, Vol. 33, p.912
Astronomy and Astrophysics
Astronomy
Scientific paper
We have studied the molecular gas properties of 30 barred and 15 unbarred spirals to a) better understand the interplay between molecular gas and star formation, b) better constrain models of gas flow in bars, c) quantify the role of the bar in the re-distribution of gas, and d) test the secular evolutionary sequence predicted by models. In the central 500 pc, we find that the mean nuclear gas surface density of barred spirals (<Σ nuc>=309+/-71 M&sun; pc-2) is three times higher than that of unbarred spirals (<Σ nuc>=107+/-29 M&sun; pc-2). 9/11 bars with Σ nuc > 300 M&sun; pc-2 are early types. We suggest that differences in Σ nuc explain the observed variation in the circumnuclear star formation activity in barred and unbarred spirals. Barred spirals also have a higher central concentration of gas than unbarred spirals, providing further statistical evidence of bar-induced gas transport. The central gas concentration is correlated with the bulge size but not the bar length, indicating that the ILR, bar ellipticity and circumnuclear star formation play important roles in determining the gas accumulation. We show that star formation must be taken into account if models are to reproduce the observed gas morphologies. We find that the majority of the Hα emission in bars is on the leading side of the dust lane, with an average linear offset of 417+/-57 pc near the bar ends. To explain the offset, we propose that stars may form in dust spurs, regions of high density/low shear, upstream of the dust lanes. Finally, we classify the molecular gas distributions in bars, and find that they are consistent with the predicted secular evolutionary sequence. However, the data show that not every late type bar evolves into an early type, and/or bar-induced gas inflow is periodic.
No associations
LandOfFree
Molecular Gas Properties of Barred Spirals: (SONG Results) does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Molecular Gas Properties of Barred Spirals: (SONG Results), we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Molecular Gas Properties of Barred Spirals: (SONG Results) will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1271209