Shock-induced Star Formation Research Articles

Observations of Atomic Gas in Photodissociation Regions

At the interface between an HII region and a molecular cloud, lies a neutral gas layer which is subject to both an intense radiation field, and to shocks arising from the expansion of the ionisation front of the HII region. The gas in these regions is highly excited, hot, and may be fairly dense. We present the first high resolution images of atomic carbon towards a sample of ionisation front sources. This study has relevance to our understanding of shock induced star formation, the formation and destruction of molecular species under extreme conditions, shock processes in the ISM, and the energy balance in molecular clouds.

Star formation in radio galaxies at large redshift

view Abstract Citations (151) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Star Formation in Radio Galaxies at Large Redshift De Young, David S. Abstract Optical continuum and emission-line observations of many high-redshift radio galaxies show a morphology which aligns the optical emission along the axis of the extended radio source. Shock-induced star formation has been suggested as a source of this emission, and calculations have been performed to test this hypothesis. Numerical simulations of high-energy radio jets passing through a dense protogalactic gas have been performed, with subsequent cooling and collapse of star formation. The resulting distribution of stars is elongated along the axis of the radio source but is also always highly limb-brightened in the direction normal to the radio axis. With a star formation efficiency of 10%, simulations for different jet velocities, densities, and star formation thresholds show that ~ 10^10^ M_sun_ in stars can be formed by this process over 10^8^ yr. Publication: The Astrophysical Journal Pub Date: July 1989 DOI: 10.1086/185484 Bibcode: 1989ApJ...342L..59D Keywords: Radio Galaxies; Red Shift; Star Formation; Emission Spectra; Radio Jets (Astronomy); Spatial Distribution; Visible Spectrum; Astrophysics; STARS: FORMATION; RADIO SOURCES: GALAXIES full text sources ADS | data products SIMBAD (1) NED (1)

Shock-induced star formation in G357.7 – 0.1?

Recent studies using the Very Large Array (VLA) telescope have revealed the existence of two unusual extended non-thermal sources, G357.7–0.1 and G5.3–1.0 (refs 1,2). Classified earlier as supernova remnants (SNRs), these sources have a marked axial symmetry and compact sources on the axis at one edge. We have now looked for counterparts of these sources in the Infrared Astronomical Satellite (IRAS) Point Source Catalogue and find an IRAS source showing the characteristic spectrum of an early type star embedded in a dusty cloud, coincident with the compact source in G357.7–0.1. We propose that the compact object is an O star whose formation was triggered by the shock front of the diffuse radio source.

Observations of the shock in a region of shock-induced star formation - NGC 281

view Abstract Citations (23) References (15) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Observations of the shock in a region of shock-induced star formation: NGC 281. Elmegreen, B. G. ; Moran, J. M. Abstract Evidence for the cooled postshock layer situated between the expanding H II region NGC 281 and an adjacent molecular cloud is shown by a well-sampled map of (C-12)O and (C-13)O line profiles having 0.16-km/s resolution. The shocked region shows a higher (C-12)O temperature and column density than the unshocked cloud, and the shock velocity is 1.5 to 2 km/s, depending on position. An H2O maser located at the site of peak shock activity was observed at three epochs separated by 4.5 and 10 months, respectively. The H2O line velocities and strengths show considerable variation, but the strongest emission line is always within + or - 1 km/s of the neutral cloud velocities. It is suggested that the associated maser source is a middle- to late-type B star that was formed in the shock-compressed gas. Publication: The Astrophysical Journal Pub Date: January 1979 DOI: 10.1086/182874 Bibcode: 1979ApJ...227L..93E Keywords: B Stars; Compressed Gas; Shock Waves; Star Formation; Water Masers; Carbon Monoxide; H Ii Regions; Line Spectra; Propagation Velocity; Radio Emission; Astrophysics; Interstellar Matter:Star Formation; Shock Waves:Star Formation; Star Formation:Water Masers full text sources ADS |