2005/02/22 by Martin Haas Rolf Chini Ulrich Klaas, Klaas, Martin Haas Rolf Chini Ulrich
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0502464
4 pages, 3 figures (colour Fig. 2 in low resolution), accepted by A&A
arxiv created 2005/02/22 · openalex publication_date 2005/02/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The collision of gas-rich galaxies is believed to produce strong shocks\nbetween their gas clouds which cause the onset of the observed bursts of\nextended star formation. However, the so far observed shock signatures in\ncolliding galaxies can be explained essentially by winds from already existing\nmassive stars and supernovae and thus do not give any evidence for an\noutstanding pre-starburst phase. Either pre-starburst gas shocks are too\nshort-lived to be detected or one has to modify our perception of colliding\ngalaxies. A dedicated analysis of ISOCAM-CVF mid-infrared spectral maps led us\nto the discovery of exceptional H2 v=0-0 S(3) lambda = 9.66 um line emission\nfrom the "Antennae" galaxy pair, which is at an early stage of galaxy\ncollision. Its H2 line luminosity, normalized by the far-infrared luminosity,\nexceeds that of all other known galaxies and the strongest H2 emission is\nspatially displaced from the known starbursts regions. This implies that most\nof the excited H2 gas in the Antennae must be shocked due to the collision of\nthe two galaxies. These observations indicate that the outstanding phase of\npre-starburst shocks exists, and that they might be a key to our understanding\nof the formation of the first proto-galaxies.\n