NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-05-25 T04:24:20 PDT
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For refcode 2014ApJ...787..103H:
Retrieve 80 NED objects in this reference.
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NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
2014ApJ...787..103H Star Formation and the Interstellar Medium in Nearby Tidal Streams (SAINTS): Spitzer Mid-infrared spectroscopy and Imaging of Intergalactic Star-forming Objects Higdon, S. J. U.; Higdon, J. L.; Smith, B. J.; Hancock, M. Abstract. A spectroscopic analysis of 10 intergalactic star-forming objects (ISFOs) and a photometric analysis of 67 ISFOs in a sample of 14 interacting systems is presented. The majority of the ISFOs have relative polycyclic aromatic hydrocarbon (PAH) band strengths similar to those of nearby spiral and starburst galaxies. In contrast to what is observed in blue compact dwarfs (BCDs) and local giant H II regions in the Milky Way (NGC 3603) and the Magellanic Clouds (30 Doradus and N 66), the relative PAH band strengths in ISFOs correspond to models with a significant PAH Ion fraction (<50%) and bright emission from large PAHs (~100 carbon atoms). The [Ne III]/[Ne II] and [S IV]/[S III] line flux ratios indicate moderate levels of excitation with an interstellar radiation field that is harder than the majority of the Spitzer Infrared Nearby Galaxies Survey and starburst galaxies, but softer than BCDs and local giant H II regions. The ISFO neon line flux ratios are consistent with a burst of star formation lsim6 million years ago. Most of the ISFOs have ~10^6^ M_sun_ of warm H_2_ with a likely origin in photo-dissociation regions (PDRs). Infrared Array Camera photometry shows the ISFOs to be bright at 8 micron, with one-third having [4.5] - [8.0] > 3.7, i.e., enhanced non-stellar emission, most likely due to PAHs, relative to normal spirals, dwarf irregulars, and BCD galaxies. The relative strength of the 8 micron emission compared to that at 3.6 micron or 24 micron separates ISFOs from dwarf galaxies in Spitzer two-color diagrams. The infrared power in two-thirds of the ISFOs is dominated by emission from grains in a diffuse interstellar medium. One in six ISFOs have significant emission from PDRs, contributing ~30%-60% of the total power. ISFOs are young knots of intense star formation. Key words: galaxies: dwarf, galaxies: formation, galaxies: individual: Arp 72 Arp 84 Arp 87 Arp 105 Arp 242 Arp 284 Stephan's Quintet NGC 5291, galaxies: interactions, infrared: galaxies
Retrieve 80 NED objects in this reference.
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