We present the detection of extended ( \sim 30 kpc ^ { 2 } ) dust emission in the tidal H I arm near NGC 3077 ( member of the M 81 triplet ) using SPIRE on board Herschel .
Dust emission in the tidal arm is typically detected where the H I column densities are > 10 ^ { 21 } cm ^ { -2 } .
The SPIRE band ratios show that the dust in the tidal arm is significantly colder ( \sim 13 K ) than in NGC 3077 itself ( \sim 31 K ) , consistent with the lower radiation field in the tidal arm .
The total dust mass in the tidal arm is \sim 1.8 \times 10 ^ { 6 } M _ { \odot } ( assuming \beta =2 ) , i.e .
substantially larger than the dust mass associated with NGC 3077 ( \sim 2 \times 10 ^ { 5 } M _ { \odot } ) .
Where dust is detected , the dust–to–gas ratio is 6 \pm 3 \times 10 ^ { -3 } , consistent within the uncertainties with what is found in NGC 3077 and nearby spiral galaxies with Galactic metallicities .
The faint H II regions in the tidal arm can not be responsible for the detected enriched material and are not the main source of the dust heating in the tidal arm .
We conclude that the interstellar medium ( atomic H I , molecules and dust ) in this tidal feature was pre–enriched and stripped off NGC 3077 during its recent interaction ( \sim 3 \times 10 ^ { 8 } yr ago ) with M 82 and M 81 .
This implies that interaction can efficiently remove heavy elements and enriched material ( dust , molecular gas ) from galaxies .
As interactions were more frequent at large lookback times , it is conceivable that they could substantially contribute ( along with galactic outflows ) to the enrichment of the intergalactic medium .