Kinematical Study of Old HII Regions and Optical Counterpart to the DRAO Canadian Galactic Plane Survey

1998 ◽  
Vol 15 (1) ◽  
pp. 60-63 ◽  
Author(s):  
Steve Godbout ◽  
Gilles Joncas ◽  
Laurent Drissen
Keyword(s):  
Interstellar Medium ◽  
Preliminary Data ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Hii Regions ◽  
Data Sets ◽  
Optical Counterpart ◽  
Molecular Material ◽  
Kinematical Behaviour

AbstractThis project aims to tackle a few unresolved problems related to the interstellar medium (ISM) by acting as an optical counterpart to the Canadian Galactic Plane Survey (CGPS). We have three main objectives: (1) the study of large/old HII regions; (2) observations of targets-of-opportunity that may be found by the CGPS; (3) comparison of the kinematics of extragalactic (M33) and galactic HII regions. (1) Old HII regions having large spatial extents will be observed to establish their kinematical structure when almost no molecular material is left to produce photodissociated flows. Does turbulence play a role in these objects as for younger nebulae? (2) Ionised nebulae observed by the CGPS that are peculiar, either morphologically or by special association with neutral hydrogen, will also be observed. (3) The kinematical behaviour of old HII regions in M33 will be compared with that of galactic HII regions. With both data sets in hand we will check if HII regions, like supernovae, dump energy into the neutral ISM. The instrument used as well as some very preliminary data are presented.

scholarly journals The Molonglo Galactic Plane Survey: MGPS2

2002 ◽  
Vol 199 ◽  
pp. 259-261
Author(s):  
A. J. Green
Keyword(s):  
Interstellar Medium ◽  
Supernova Remnant ◽  
Galactic Plane ◽  
Hii Regions ◽  
Radio Galaxies ◽  
Radio Continuum ◽  
The Galaxy ◽  
First Results ◽  
Made In

A survey of the southern Galactic Plane is being made in the radio continuum at 843 MHz with the Molonglo Observatory Synthesis Telescope. The area to be covered is 240° ≤ l ≤ 365°, |b| ≤ 10° with a resolution of 43″ × 43″cosec|δ| and a 3σ rms noise of ≤ 5 mJy/beam. This survey (MGPS2) will be used to search for possible new supernova remnant candidates, to image other discrete sources such as HII regions and radio galaxies located behind the Galaxy, and to study the structure of the interstellar medium. Comparison with a first epoch survey (MGPS1) will also be made. Some of the first results from MGPS2 are presented.

scholarly journals THE SINO-GERMAN λ6 CM POLARIZATION SURVEY OF THE GALACTIC PLANE: A SUMMARY

2013 ◽  
Vol 23 ◽  
pp. 82-91 ◽  
Author(s):  
J. L. HAN ◽  
W. REICH ◽  
X. H. SUN ◽  
X. Y. GAO ◽  
L. XIAO ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Interstellar Medium ◽  
Radio Telescope ◽  
Supernova Remnants ◽  
Galactic Plane ◽  
High Sensitivity ◽  
Hii Regions ◽  
Galactic Latitude ◽  
Galactic Longitude ◽  
Individual Objects

We have finished the λ6 cm polarization survey of the Galactic plane using the Urumqi 25 m radio telescope. It covers 10° ≤ l ≤ 230° in Galactic longitude and |b| ≤ 5° in Galactic latitude. The new polarization maps not only reveal new properties of the diffuse magnetized interstellar medium, but also are very useful for studying individual objects such as HII regions, which may act as Faraday screens with strong regular magnetic fields inside, and supernova remnants for their polarization properties and spectra. The high sensitivity of the survey enables us to discover two new SNRs G178.2–4.2 and G25.3–2.1 and a number of HII regions.

Interstellar gas in the central region of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Interstellar Gas ◽  
Hydrogen Recombination ◽  
The Galaxy ◽  
Centre Region ◽  
The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

Southern Hemisphere Seti Survey: Five Years of Project Meta II

1997 ◽  
Vol 161 ◽  
pp. 611-621
Author(s):  
Guillermo A. Lemarchand ◽  
Fernando R. Colomb ◽  
E. Eduardo Hurrell ◽  
Juan Carlos Olalde
Keyword(s):  
Southern Hemisphere ◽  
Scattering Theory ◽  
Galactic Plane ◽  
Narrow Band ◽  
Neutral Hydrogen ◽  
Sky Survey ◽  
Inertial Frames ◽  
Interstellar Scattering ◽  
Extraterrestrial Origin ◽  
Spectral Channels

AbstractProject META II, a full sky survey for artificial narrow-band signals, has been conducted from one of the two 30-m radiotelescopes of the Instituto Argentino de Radioastronomía (IAR). The search was performed near the 1420 Mhz line of neutral hydrogen, using a 8.4 million channels Fourier spectrometer of 0.05 Hz resolution and 400 kHz instantaneous bandwidth. The observing frequency was corrected both for motions with respect to three astronomical inertial frames, and for the effect of Earths rotation, which provides a characteristic changing signature for narrow-band signals of extraterrestrial origin. Among the 2 × 1013spectral channels analyzed, 29 extra-statistical narrow-band events were found, exceeding the average threshold of 1.7 × 10−23Wm−2. The strongest signals that survive culling for terrestrial interference lie in or near the galactic plane. A description of the project META II observing scheme and results is made as well as the possible interpretation of the results using the Cordes-Lazio-Sagan model based in interstellar scattering theory.

The HRS GTO program to study the neutral hydrogen column density and D/H ratio in the local interstellar medium

1986 ◽  
Vol 6 (2) ◽  
pp. 91-94
Author(s):  
J.L. Linsky, ◽  
W.B. Landsman ◽  
B.D. Savage ◽  
S.R. Heap ◽  
A.M. Smith ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Column Density ◽  
Neutral Hydrogen ◽  
Local Interstellar Medium ◽  
Hydrogen Column Density

Discovery of Three Large HII Regions in the Galactic Plane

2008 ◽  
Vol 8 (5) ◽  
pp. 575-579 ◽  
Author(s):  
Wei-Bin Shi ◽  
Xiao-Hui Sun ◽  
Jin-Lin Han ◽  
Xu-Yang Gao ◽  
Li Xiao
Keyword(s):  
Galactic Plane ◽  
Hii Regions

scholarly journals Massive stars shaping the ISM: H I holes and shells in nearby galaxies

1999 ◽  
Vol 193 ◽  
pp. 636-644
Author(s):  
Elias Brinks ◽  
Fabian Walter
Keyword(s):  
Interstellar Medium ◽  
Dwarf Galaxy ◽  
Massive Stars ◽  
Neutral Hydrogen ◽  
Neutral Medium ◽  
Stellar Winds ◽  
X Ray ◽  
Left Behind ◽  
Neutral Gas ◽  
Nearby Galaxies

Neutral hydrogen (H I) is a magnificent tool when studying the structure of the interstellar medium (ISM) as it is relatively easily observable and can be mapped at good spatial and velocity resolution with modern instruments. Moreover, it traces the cool (∼ 100 K) and warm (∼ 5000 K) neutral gas which together make up about 60%, or the bulk, of the ISM. The currently accepted picture is that stellar winds and subsequent supernovae are the origin for the clearly defined holes or bubbles within the more or less smooth neutral medium. The H I can therefore serve indirectly as a tracer of the hot interstellar medium (HIM) left behind after the most massive stars within an OB association have gone off as supernovae. A splendid example is the dwarf galaxy IC 2574 for which we discuss H I, optical and X-ray observations.

scholarly journals Search for HI Bubbles Around WR Stars: WR 149

1996 ◽  
Vol 169 ◽  
pp. 619-620
Author(s):  
C. Cappa de Nicolau ◽  
V.S. Niemela ◽  
U. Herbstmeier ◽  
B. Koribalski
Keyword(s):  
Interstellar Medium ◽  
Neutral Hydrogen ◽  
Gas Bubbles ◽  
Stellar Winds ◽  
Hydrogen Distribution ◽  
Neutral Gas ◽  
Rayet Star

The interaction of strong stellar winds with the interstellar medium creates large cavities or interstellar bubbles surrounded by expanding outer shells. 21-cm line (HI) observations have revealed the presence of such neutral gas bubbles around several WR stars (e.g. Niemela & Cappa de Nicolau 1991 and references therein; Dubner et al. 1992).Continuing our search for HI bubbles around WR stars, we have analyzed the neutral hydrogen distribution in the vicinity of the Wolf-Rayet star WR149, a highly reddened WN6-7 star located at 6.5 kpc in the direction (l,b) = (89.°53,+0.°65).

scholarly journals Planckearly results. XXI. Properties of the interstellar medium in the Galactic plane

2011 ◽  
Vol 536 ◽  
pp. A21 ◽  
Author(s):  
◽  
A. Abergel ◽  
P. A. R. Ade ◽  
N. Aghanim ◽  
M. Arnaud ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Galactic Plane

scholarly journals HII regions and star formation in the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 139-144 ◽  
Author(s):  
Robert C. Kennicutt
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Massive Star ◽  
Massive Stars ◽  
Hii Regions ◽  
Magellanic Clouds ◽  
H Ii Regions ◽  
Distant Galaxies ◽  
Close Range ◽  
Mass Functions

The H II regions in the Magellanic Clouds provide an opportunity to characterize the global star formation properties of a galaxy at close range. They also provide a unique laboratory for testing empirical tracers of the massive star formation rates and initial mass functions in more distant galaxies, and for studying the dynamical interactions between massive stars and the interstellar medium. This paper discusses several current studies in these areas.

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