Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-08-08
Astron.J.132:2289-2295,2006
Astronomy and Astrophysics
Astrophysics
Accepted for publication in the Astronomical Journal
Scientific paper
10.1086/508273
We report the detection of ongoing star formation in the prominent tidal arms near NGC 3077 (member of the M 81 triplet). In total, 36 faint compact HII regions were identified, covering an area of ~4x6 kpc^2. Most of the HII regions are found at HI column densities above 1x10^21 cm^-2 (on scales of 200 pc), well within the range of threshold columns measured in normal galaxies. The HII luminosity function resembles the ones derived for other low-mass dwarf galaxies in the same group; we derive a total star formation rate of 2.6x10^-3 M_sun/yr in the tidal feature. We also present new high-resolution imaging of the molecular gas distribution in the tidal arm using CO observations obtained with the OVRO interferometer. We recover about one sixth of the CO flux (or M_H2~2x10^6 M_sun, assuming a Galactic conversion factor) originally detected in the IRAM 30m single dish observations, indicating the presence of a diffuse molecular gas component in the tidal arm. The brightest CO peak in the interferometer map (comprising half of the detected CO flux) is coincident with one of the brightest HII regions in the feature. Assuming a constant star formation rate since the creation of the tidal feature (presumably ~3x10^8 years ago), a total mass of ~7x10^5 M_sun has been transformed from gas into stars. Over this period, the star formation in the tidal arm has resulted in an additional enrichment of Delta(Z)>0.002. The reservoir of atomic and molecular gas in the tidal arm is ~3x10^8 M_sun, allowing star formation to continue at its present rate for a Hubble time. Such wide-spread, low-level star formation would be difficult to image around more distant galaxies but may be detectable through intervening absorption in quasar spectra.
Martin Christopher L.
Ott Jorgen
Walter Fabian
No associations
LandOfFree
Extended Star Formation and Molecular Gas in the Tidal Arms near NGC3077 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 Extended Star Formation and Molecular Gas in the Tidal Arms near NGC3077, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Extended Star Formation and Molecular Gas in the Tidal Arms near NGC3077 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-248420