Tracing the Gas in the Merger Arp 105

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Session 107 -- Galaxies: Morphology and Interactions
Display presentation, Thursday, 12, 1995, 9:20am - 6:30pm

[107.15] Tracing the Gas in the Merger Arp 105

Elias Brinks (NRAO), I. Felix Mirabel (Centre d'Etudes de Saclay), Pierre--Alain Duc (Centre d'Etudes de Saclay)

Arp~105 consists of an infrared luminous starburst spiral being torn apart by a massive elliptical, close to the centre of a cluster of galaxies. At the tip of a colossal, 100 kpc long tidal tail which emanates from the spiral and points almost due North, we find an irregular galaxy of Magellanic type. At the opposite end, a thinner and somewhat shorter tidal arm ends in a bright clump of recently formed stars, resembling a blue compact dwarf galaxy. We propose that these small galaxies are recycled objects being formed out of the tidal debris from the spiral. Our observations of the neutral (HI) and molecular (CO) gas in this system show that the collision has caused a marked separation of the cool and cold interstellar gas. The atomic gas from the spiral galaxy has been pulled out into intergalactic space and is mostly concentrated around the star forming small galaxies near the ends of the tidal tails, $\approx 6 \times 10^9$ M$_\odot$ for the northern and $\approx 5 \times 10^8$ M$_\odot$ for the southern object. Some 90\% of the CO is found near the central region of the spiral.

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