Abstract
We report the discovery of extended star formation in the prominent tidal arms near NGC 3077 (member of the M 81 triplet). 36 faint compact star forming regions were identified, covering an area of 4 × 6 kpc2. HII regions are only found near the southern rim of the tidal HI arm where the HI column density reaches values above 1 × 1021 cm−2. This threshold is very similar to what is found in ‘normal’ galactic environments. We derive a total star formation rate of 2.6 × 10−3M⊙ yr−1 in the tidal feature. We also present the first high-resolution observations of molecular gas in this region. The molecular gas emission can be separated into at least 5 distinct complexes most of which do not coincide with sites of star formation. The reservoir of neutral and molecular gas in the tidal arm is huge (~5 × 108M⊙); star formation may continue at the given rate for a Hubble time. We conclude that wide-spread low-level star formation may be a common phenomenon in tidal HI tails, however it will be difficult to detect in interacting systems that are further away.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
