scholarly journals Background and First Results from the New AAO/UKST Hα Survey

1998 ◽  
Vol 15 (1) ◽  
pp. 28-32 ◽  
Author(s):  
Quentin A. Parker ◽  
Steven Phillipps
Keyword(s):  
Galactic Plane ◽  
Interference Filter ◽  
Low Noise ◽  
Area Coverage ◽  
Coverage Depth ◽  
Fine Grain ◽  
Sensitivity Peak ◽  
The Galaxy ◽  
First Results ◽  
The Uk

AbstractThe UK Schmidt Telescope (UKST) of the Anglo-Australian Observatory (AAO) has just embarked on a new Hα survey of the Southern Galactic Plane, Magellanic Clouds and selected regions using a specially designed, high-specification, monolithic, interference filter. It is probably the largest of its kind for astronomy. It is being used in combination with Kodak Tech Pan film-based emulsion. This emulsion not only has a useful sensitivity peak at Hα but also possesses extremely fine grain and an exceptionally high DQE for the hypersensitised product (∼10%). This leads to excellent imaging, sensitivity and low noise. It is clear that CCDs cannot yet match the wide-area coverage, uniformity and resolution of the UKST/Tech Pan combination for undertaking such a survey. The survey will initially include about 233 Galactic Plane and 40 Magellanic Cloud fields on 4-degree centres and will take about 3 years to complete. Some preliminary images from the new survey are presented and compared with the best previously available from the UKST. Examples of the first survey discoveries, new resolved Galactic planetary nebulae, are also given. This survey will have an unprecedented combination of area coverage, depth and resolution, superior to those of any previous optical survey of ionised gas in the Galaxy. Many new discoveries and research avenues are expected.

scholarly journals A UKST Hα Survey of the Galactic Plane

1997 ◽  
Vol 14 (1) ◽  
pp. 123-124 ◽  
Author(s):  
Q. A. Parker ◽  
Q. S. Phillipps
Keyword(s):  
High Resolution ◽  
Galactic Plane ◽  
Interference Filter ◽  
Low Noise ◽  
Magellanic Clouds ◽  
Area Coverage ◽  
Coverage Depth ◽  
Fine Grain ◽  
The Galaxy ◽  
Peak Sensitivity

AbstractWe describe a major Anglo-Australian project to undertake a UKST Ha survey of the Southern Galactic plane, Magellanic clouds and selected regions. The survey will use a new 12 × 12 inch monolithic Hα interference filter of high specification and Tech Pan film which offers significant advantages over other emulsions due to its peak sensitivity at Ha and its extremely fine grain, high resolution, exceptional DQE, excellent imaging and low noise. A survey of unprecedented area coverage, depth and resolution should result, superior to any previous optical survey of ionised gas in the galaxy. It is certain to lead to exciting new discoveries and new avenues of research.

scholarly journals An Hα Survey of the Galactic Plane

1998 ◽  
Vol 179 ◽  
pp. 179-181
Author(s):  
Q.A. Parker ◽  
S. Phillipps
Keyword(s):  
Galactic Plane ◽  
Narrow Band ◽  
Interference Filter ◽  
Low Noise ◽  
Magellanic Clouds ◽  
Coverage Depth ◽  
Ionized Gas ◽  
Fine Grain ◽  
The Galaxy ◽  
Very High

We describe a major new Anglo-Australian proposal for a U.K. Schmidt Telescope (UKST) Hα survey of the Southern Galactic plane, Magellanic clouds and selected regions. The agreed survey will use a new 12 × 12 inch monolithic Hα interference filter of very high specification in combination with Tech Pan film. Tech Pan offers significant advantages for this work due to an inherent sensitivity at Hα and its extremely fine grain, high resolution, exceptional DQE, excellent imaging and low noise (e.g., Parker et al. 1994). The combination of Tech Pan and a narrow band Hα filter will provide a survey of unprecendented area coverage, depth and resolution, superior to any previous optical survey of ionized gas in the galaxy. It should to lead to exciting new discoveries and avenues of research.

scholarly journals Detailed distributions of the CO J = (2 − 1)/J = (1 − 0) intensity ratios toward a large area of the central molecular zone

2013 ◽  
Vol 9 (S303) ◽  
pp. 106-108
Author(s):  
Kazufumi Torii ◽  
Rei Enokiya ◽  
Yasuo Fukui ◽  
Hiroaki Yamamoto ◽  
Akiko Kawamura ◽  
...  
Keyword(s):  
Angular Resolution ◽  
Galactic Center ◽  
Galactic Plane ◽  
Area Coverage ◽  
High Angular Resolution ◽  
Molecular Gas ◽  
Large Area ◽  
First Results ◽  
Intensity Ratios ◽  
Sgr A

AbstractWe present the first results of the new CO J = (2 − 1) observations toward the central molecular zone (CMZ) using the NANTEN2 telescope at an angular resolution of 100″. Large area coverage of 4° × 2° in l and b and a high angular resolution of 100″ enable us to investigate detailed structures of the molecular gas in the CMZ including peculiar molecular filaments perpendicularly to the Galactic plane to b > |0.5°|. The major components of the CMZ, e.g., Sgr A, Sgr B and Sgr C cloud complexes, show high CO J = (2 − 1)/J = (1 − 0) ratios around 0.9, indicating highly excited conditions of the molecular gas, while the local foreground components show less than 0.4. The molecular filaments show the typical ratios of 0.6–0.7 indicate that they are indeed located in the Galactic center.

scholarly journals ATLASGAL, the APEX Telescope Large Area Survey of the Galaxy

2009 ◽  
Vol 5 (H15) ◽  
pp. 780-780
Author(s):  
F. Schuller ◽  
K. M. Menten ◽  
F. Wyrowski ◽  
H. Beuther ◽  
S. Bontemps ◽  
...  
Keyword(s):  
Galactic Plane ◽  
High Mass ◽  
Current Status ◽  
Continuum Emission ◽  
Mass Star ◽  
Large Area ◽  
Submillimeter Wavelengths ◽  
The Galaxy ◽  
First Results ◽  
Area Survey

AbstractSubmillimeter continuum emission traces high molecular column densities and, thus, dense cloud regions in which new stars are forming. Surveys of the Galactic plane in such emission have the potential of delivering an unbiased view of high-mass star formation throughout the Milky Way. Here we present the scope, current status and first results of ATLASGAL, an ongoing survey of the Galactic plane using the Large APEX Bolometer Camera (LABOCA) on the Atacama Pathfinder Experiment (APEX) telescope at the Chajnantor plateau in Chile. Aimed at mapping 360 square degrees at 870 μm, with a uniform sensitivity of 50 mJy/beam, this survey will provide the first unbiased sample of cold dusty clumps in the Galaxy at submillimeter wavelengths. These will be targets for molecular line follow-up observations and high resolution studies with ALMA and the EVLA.

scholarly journals The Mopra Southern Galactic Plane CO Survey

2013 ◽  
Vol 30 ◽  
Author(s):  
Michael G. Burton ◽  
C. Braiding ◽  
C. Glueck ◽  
P. Goldsmith ◽  
J. Hawkes ◽  
...  
Keyword(s):  
Molecular Clouds ◽  
Gamma Ray ◽  
Galactic Plane ◽  
Molecular Gas ◽  
Number Density ◽  
Analysis Methodology ◽  
The Galaxy ◽  
First Results ◽  
Molecular Masses ◽  
Velocity Channel

AbstractWe present the first results from a new carbon monoxide (CO) survey of the southern Galactic plane being conducted with the Mopra radio telescope in Australia. The 12CO, 13CO, and C18O J = 1–0 lines are being mapped over the $l = 305^{\circ }\text{--} 345^{\circ }, b = \pm 0.5^{\circ }$ portion of the fourth quadrant of the Galaxy, at 35 arcsec spatial and 0.1 km s−1 spectral resolution. The survey is being undertaken with two principal science objectives: (i) to determine where and how molecular clouds are forming in the Galaxy and (ii) to probe the connection between molecular clouds and the ‘missing’ gas inferred from gamma-ray observations. We describe the motivation for the survey, the instrumentation and observing techniques being applied, and the data reduction and analysis methodology. In this paper, we present the data from the first degree surveyed, $l = 323^{\circ } \text{--} 324^{\circ }, b = \pm 0.5^{\circ }$. We compare the data to the previous CO survey of this region and present metrics quantifying the performance being achieved; the rms sensitivity per 0.1 km s−1 velocity channel is ~1.5 K for ${\rm ^{12}CO}$ and ~0.7 K for the other lines. We also present some results from the region surveyed, including line fluxes, column densities, molecular masses, ${\rm ^{12}CO/^{13}CO}$ line ratios, and ${\rm ^{12}CO}$ optical depths. We also examine how these quantities vary as a function of distance from the Sun when averaged over the 1 square degree survey area. Approximately 2 × 106M⊙ of molecular gas is found along the G323 sightline, with an average H2 number density of $n_{\text{H}_2} \sim 1$ cm−3 within the Solar circle. The CO data cubes will be made publicly available as they are published.

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 Autonomous Gaussian decomposition of the Galactic Ring Survey

2019 ◽  
Vol 633 ◽  
pp. A14 ◽  
Author(s):  
M. Riener ◽  
J. Kainulainen ◽  
H. Beuther ◽  
J. D. Henshaw ◽  
J. H. Orkisz ◽  
...  
Keyword(s):  
Velocity Dispersion ◽  
Velocity Structure ◽  
Galactic Plane ◽  
Emission Lines ◽  
Data Sets ◽  
Gas Kinematics ◽  
The Galaxy ◽  
First Results ◽  
Physical Information ◽  
Gaussian Decomposition

The analysis of large molecular line surveys of the Galactic plane is essential for our understanding of the gas kinematics on Galactic scales and, in particular, its link with the formation and evolution of dense structures in the interstellar medium. An approximation of the emission peaks with Gaussian functions allows for an efficient and straightforward extraction of useful physical information contained in the shape and Doppler-shifted frequency of the emission lines contained in these enormous data sets. In this work, we present an overview and the first results of a Gaussian decomposition of the entire Galactic Ring Survey (GRS) 13CO (1–0) data that consists of about 2.3 million spectra. We performed the decomposition with the fully automated GAUSSPY+ algorithm and fitted about 4.6 million Gaussian components to the GRS spectra. These decomposition results enable novel and unexplored ways to interpret and study the gas velocity structure. We discuss the statistics of the fit components and relations between the fitted intensities, velocity centroids, and velocity dispersions. We find that the magnitude of the velocity dispersion values increase towards the inner Galaxy and around the Galactic midplane, which we speculate is partly due to the influence of the Galactic bar and regions with higher non-thermal motions located in the midplane, respectively. We also used our decomposition results to infer global properties of the gas emission and find that the number of fit components used per spectrum is indicative of the amount of structure along the line of sight. We find that the emission lines from regions located on the far side of the Galaxy show increased velocity dispersion values, which are likely due to beam averaging effects. We demonstrate how this trend has the potential to aid in characterising Galactic structure by disentangling emission that belongs to the nearby Aquila Rift molecular cloud from emission that is more likely associated with the Perseus and Outer spiral arms. With this work, we also make our entire decomposition results available.

scholarly journals An Imaging Survey of Northern Galactic Hα Emission with Arcminute Resolution

1998 ◽  
Vol 15 (1) ◽  
pp. 147-148 ◽  
Author(s):  
Brian Dennison ◽  
John H. Simonetti ◽  
Gregory A. Topasna
Keyword(s):  
Galactic Plane ◽  
Background Radiation ◽  
Emission Measure ◽  
High Sensitivity ◽  
Interference Filter ◽  
Low Noise ◽  
High Quantum Efficiency ◽  
Star Forming ◽  
Microwave Background Radiation ◽  
Line Imaging

AbstractWe present preliminary results from a high-resolution, high-sensitivity imaging survey of the northern galactic Hα emission. The survey is carried out using the Spectral Line Imaging Camera (SLIC) which incorporates a fast (f/1·2) lens attached to a cryogenic CCD in combination with a narrowband interference filter. The pixel size is 1·6 arcminutes and the diameter of each field is 10°. The fast optics, narrow bandpass (1·7 nm) filter, and high quantum-efficiency, low-noise CCD yield a high brightness sensitivity to Hα emission on arcminute scales. This gives an equivalent sensitivity to emission measure structure below 1 pc cm−6. Some faint features detected include a supershell connected with the star forming region W4 extending 7° above the galactic plane, and filaments possibly related to galactic loops II and III. In addition, we have carried out deep observations of fields in which anisotropies in the cosmic microwave background radiation have been detected. Our observations place stringent limits upon the contribution to the apparent microwave fluctuations from free–free emission in the galactic foreground.

A survey of trigonometric parallaxes and proper motions with the UK Schmidt Telescope: I. Methods and first results for stars brighter than B = 14 in a field near the South Galactic Pole

1978 ◽  
Vol 48 ◽  
pp. 48
Author(s):  
C. A. Murray ◽  
P. M. Corben
Keyword(s):  
Proper Motion ◽  
Atmospheric Dispersion ◽  
Random Errors ◽  
Schmidt Telescope ◽  
The South ◽  
The Galaxy ◽  
First Results ◽  
Trigonometric Parallaxes ◽  
Pilot Investigation ◽  
The Uk

AbstractIn an attempt to investigate the statistics of stars in the solar neighbourhood, independent of the bias toward high velocity stars introduced by selection of stars with large proper motion, a major astrometric investigation is being carried out at RGO using U.K. Schmidt plates measured on the GALAXY machine.So far more than 15000 objects brighter than B = 18 in a field near the South Galactic Pole have been measured on more than 50 plates taken between 19 74 and 1977.This paper describes the methods of analysis and the results of a pilot investigation on nearly 900 stars with B < 14. The measurements show a very high degree of internal consistence, demonstrating the astrometric excellence of the U.K. Schmidt telescope and the GALAXY machine; random errors of measurement are found to be about ±0075 (=1.1.μm) per coordinate over the whole area (4° x 4°) measured, using a simple linear plate constant model for all plates. The external error of a single component of proper motion is estimated to be ± 0013 which is exactly consistent with the internal measurement error. The external error of a parallax in the present data is about ± 0018 whereas that predicted from the errors of measurement, and the self-consistency of two subsets of the data, is ± 0013; it is shown that the discrepancy can be largely accounted for by the random errors (± O11) in the B-V colours used in computing the effect of atmospheric dispersion, and should be reduced when better photometry becomes available.

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.

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