NASA | USRA | SOFIA | 2017 May 24
[img3="A BIMA-SONG radio map of the IC 342 central molecular zone; dots indicate locations of SOFIA/GREAT observations. Credits: Röllig et al."]https://www.sofia.usra.edu/sites/defaul ... 267-15.png[/img3][hr][/hr]An international team of researchers used NASA’s Stratospheric Observatory for Infrared Astronomy, SOFIA, to make maps of the ring of molecular clouds that encircles the nucleus of galaxy IC 342. The maps determined the proportion of hot gas surrounding young stars as well as cooler gas available for future star formation. The SOFIA maps indicate that most of the gas in the central zone of IC 342, like the gas in a similar region of our Milky Way Galaxy, is heated by already-formed stars, and relatively little is in dormant clouds of raw material.
At a distance of about 13 million light years, galaxy IC 342 is considered relatively nearby. It is about the same size and type as our Milky Way Galaxy, and oriented face-on so we can see its entire disk in an undistorted perspective. Like our galaxy, IC 342 has a ring of dense molecular gas clouds surrounding its nucleus in which star formation is occurring. However, IC 342 is located behind dense interstellar dust clouds in the plane of the Milky Way, making it difficult to study by optical telescopes.
The team of researchers from Germany and the Netherlands, led by Markus Röllig of the University of Cologne, Germany, used the German Receiver for Astronomy at Terahertz frequencies, GREAT, onboard SOFIA to scan the center of IC 342 at far-infrared wavelengths to penetrate the intervening dust clouds. Röllig’s group mapped the strengths of two far-infrared spectral lines – one line, at a wavelength of 158 microns, is emitted by ionized carbon, and the other, at 205 microns, is emitted by ionized nitrogen.
The 158-micron line is produced both by cold interstellar gas that is the raw material for new stars, and also by hot gas illuminated by stars that have already finished forming. The 205-micron spectral line is only emitted by the hot gas around already-formed young stars. Comparison of the strengths of the two spectral lines allows researchers to determine of the amount of warm gas versus cool gas in the clouds. ...
[C II] 158 μm and [N II] 205 μm Emission from IC 342
Disentangling the Emission from Ionized and Photo-Dissociated Regions - Markus Röllig et al
- Astronomy & Astrophysics 591:A33 (July 2016) DOI: 10.1051/0004-6361/201526267
arXiv.org > astro-ph > arXiv:1604.07362 > 25 Apr 2016 (v1), 26 Apr 2016 (v2)
- Astronomy & Astrophysics 576:A1 (Apr 2015) DOI: 10.1051/0004-6361/201425360
arXiv.org > astro-ph > arXiv:1501.06832 > 27 Jan 2015
NRAO: Magnetic-Field Discovery; Clues to Galaxy-Formation
JPL: Spitzer Sees Spider Web of Stars in Galaxy IC 342
APOD: Hidden Galaxy IC 342[list]
2016 Jan 29
2013 Jul 18
2010 Dec 22
2006 Oct 05 [/list]