@misc{10481/28395,
year = {2008},
url = {http://hdl.handle.net/10481/28395},
abstract = {We present new results for the molecular gas, dust emission and the ionized gas in J1023+1952, an HI rich intergalactic star-forming tidal dwarf galaxy candidate. It is located at the projected intersection of two faint stellar tidal streams wrapped around the interacting pair of galaxies NGC 3227/6 (Arp~94). Using the IRAM 30m telescope, emission from CO(1-0) and CO(2-1) was detected across the entire extent of the neutral hydrogen cloud associated with J1023+1952, a region of the size of 8.9$ x 5.9 kpc, as well as in the nuclear region and outer disk of NGC 3227. The molecular gas is found to be abundant over the entire HI cloud, with H2-to-HI gas mass ratios between 0.5 and 1.7. New Spitzer mid-infrared observations at 3.6, 4.5, 5.8, 8.0, 15 and 24mu show that young SF is restricted to the southern part of the cloud. Despite the relatively uniform H$_2$ and HI column density across the cloud, young SF occurs only where the velocity dispersion in the CO and HI is a factor of $\sim$two lower (FWHM of 30 - 70 \kms) than elsewhere in the cloud (FWHM of 80 - 120 \kms). Thus the kinematics of the gas, in addition to its column density, seems to be a crucial factor in triggering SF. Optical/infrared spectral energy distributions (SEDs) and Halpha photometry confirm that all the knots are young, with a tentative age sequence from the south-west (oldest knots) to the north-east (youngest). Optical spectroscopy of the brightest SF region allowed us to determine the metallicity (12+log(O/H) = 8.6 +- 0.2) and the extinction ($A_B$=2.4). This shows that J1023+1952 is made from metal-enriched gas which is inconsistent with the hypothesis that it represents a pre-existing dwarf galaxy. Instead, it must be formed from recycled, metal-enrichd gas, expelled from NGC 3227 or NGC 3226 in a previous phase of the interaction.},
organization = {U. L. acknowledges financial support from the research project AYA 2005-07516-C02-01 and ESP 2004-06870-C02-02 from the Spanish Ministerio de Ciencia y Educación and from the Junta de Anaducía. C. G. M. acknowledges financial support from the Royal Society and the RCUK.},
publisher = {American Astronomical Society; Institute of Physics (IOP)},
keywords = {Molecular data},
keywords = {Galaxies},
keywords = {Active},
keywords = {Interactions},
keywords = {ISM},
keywords = {Arp 94},
keywords = {J1023+1952},
keywords = {NGC 3227},
title = {Molecular gas and dust in Arp 94: the formation of a recycled galaxy in an interacting system},
doi = {10.1086/590420},
author = {Lisenfeld , Ute and Mundell, C. and Shinnerer, E. and Appleton, P. N. and Allsopp, J.},
}