VLA observations of compact radio sources in the galactic plane - A search for Crab-like supernova remnants

1984 ◽  
Vol 89 ◽  
pp. 819 ◽  
Author(s):  
D. J. Helfand ◽  
D. Chance ◽  
R. H. Becker ◽  
R. L. White
1990 ◽  
Vol 140 ◽  
pp. 63-64
Author(s):  
N. Junkes ◽  
E. Fürst ◽  
W. Reich

Data from the Effelsberg Galactic plane survey at 11 cm wavelength have been used to produce a survey of polarized intensity in the first Galactic quadrant. Besides polarized sources (Supernova remnants and extragalactic objects) extended polarized emission features are visible, which are not connected to distinct radio sources. To decide whether these features reflect characteristics of the local field or the distant spiral structure of the Galaxy we performed an integration of polarized intensities as a function of Galactic longitude. An anticorrelation with the thermal background component suggests a distance of more than 6 kpc for some components of the polarized emission. This enables us to derive an upper limit for the uniform component of the Galactic magnetic field.


1973 ◽  
Vol 26 (3) ◽  
pp. 379 ◽  
Author(s):  
JR Dickel ◽  
DK Milne ◽  
AR Kerr ◽  
JG Ables

Brightness distributions and flux densities at 8�8 GHz are presented for 12 small-diameter radio sources near the galactic plane. Each of these sources has been classified at one time or another as a supernova remnant. For one source, G295� 2 - 0�6, the flux density at 8�8 GHz confirms the thermal spectrum suggested by lower frequency measurements and indicates that it is not a supernova remnant. Another source, G309� 6+ 1�7, is thought to be extragalactic.


1969 ◽  
Vol 22 (5) ◽  
pp. 613 ◽  
Author(s):  
DK Milne

Brightness distributions and flux densities at 5000 MHz are presented for 17 nonthermal sources (possible supernova remnants) together with their spectra derived from these and other observations. For most sources a comparison has been made between the brightness distribution at 5000 MHz and that obtained with comparable resolution at 408 MHz with the Molonglo 1 mile Cross.


1998 ◽  
Vol 179 ◽  
pp. 103-105
Author(s):  
S.A. Trushkin

Now in radio continuum surveys more than 10,000 radio sources have discovered in the Milky Way plane but the Galactic origin only of a small part of them has been determined. The problem comes from the absence of estimates of source distance and the optical identification even for bright radio sources, and the most of sources have not spectral data at 2-3 frequencies. As followed some hundreds of sources have not classified as thermal or non-thermal. Now we don't know the full number of supernova remnants (SNRs) in the Galaxy. The simple estimates show that a sample of Galactic SNRs is not full as for weak and extended (> 15′) as for bright and compact (< 3′) SNRs (Trushkin 1993).


1992 ◽  
Vol 10 (1) ◽  
pp. 21-23
Author(s):  
J. L. Caswell ◽  
R. T. Stewart

Abstractstrong non-thermal radio sources at low galactic latitude may be young galactic supernova remnants or else distant extragalactic objects located in the direction of the galactic plane merely by chance. Here, we have imaged G321.48 + 1.02 with the Australia Telescope in order to distinguish between these alternatives for this source.


Author(s):  
A Ingallinera ◽  
G Umana ◽  
C Trigilio ◽  
R Norris ◽  
T M O Franzen ◽  
...  

Abstract We present a catalogue of a large sample of extended radio sources in the SCORPIO field, observed and resolved by the Australia Telescope Compact Array. SCORPIO, a pathfinder project for addressing the early operations of the Australia SKA Pathfinder, is a survey of ∼5 square degrees between 1.4 and 3.1 GHz, centered at l = 343.5○, b = 0.75○ and with an angular resolution of about 10 arcsec. It is aimed at understanding the scientific and technical challenges to be faced by future Galactic surveys. With a mean sensitivity around $100\ \mu \mathrm{Jy\ beam}^{-1}$ and the possibility to recover angular scales at least up to 4 arcmin, we extracted 99 extended sources, 35 of them detected for the first time. Among the 64 known sources 55 had at least a tentative classification in literature. Studying the radio morphology and comparing the radio emission with infrared we propose as candidates 6 new H ii regions, 2 new planetary nebulae, 2 new luminous blue variable or Wolf–Rayet stars and 3 new supernova remnants. This study provides an overview of the potentiality of future radio surveys in terms of Galactic source extraction and characterization and a discussion on the difficulty to reduce and analyze interferometric data on the Galactic plane.


2019 ◽  
Vol 623 ◽  
pp. A105 ◽  
Author(s):  
X. Y. Gao ◽  
P. Reich ◽  
L. G. Hou ◽  
W. Reich ◽  
J. L. Han

Context. Large-scale radio continuum surveys provide data to get insights into the physical properties of radio sources. H II regions are prominent radio sources produced by thermal emission of ionised gas around young massive stars. Aims. We identify and analyse H II regions in the Sino-German λ6 cm polarisation survey of the Galactic plane. Methods. Objects with flat radio continuum spectra together with infrared and/or Hα emission were identified as H II regions. For H II regions with small apparent sizes, we cross-matched the λ6 cm small-diameter source catalogue with the radio H II region catalogue compiled by Paladini and the infrared H II region catalogue based on the WISE data. Effelsberg λ21 cm and λ11 cm continuum survey data were used to determine source spectra. High angular resolution data from the Canadian Galactic Plane Survey and the NRAO VLA Sky Survey were used to solve the confusion when low angular resolution observations were not sufficient. Extended H II regions were identified by eye by overlaying the Paladini and the WISE H II regions onto the λ6 cm survey images for coincidences. The TT-plot method was employed for spectral index verification. Results. A total of 401 H II regions were identified and their flux densities were determined with the Sino-German λ6 cm survey data. In the surveyed area, 76 pairs of sources are found to be duplicated in the Paladini H II region catalogue, mainly due to the non-distinction of previous observations with different angular resolutions and 78 objects in their catalogue are misclassified as H II regions, being actually planetary nebulae, supernova remnants, or extragalactic sources that have steep spectra. More than 30 H II regions and H II region candidates from our λ6 cm survey data, especially extended ones, do not have counterparts in the WISE H II region catalogue, of which 9 are identified for the first time. Our results imply that some more Galactic H II regions still await to be discovered and the combination of multi-domain observations is important for H II region identification. Based on the newly derived radio continuum spectra and the evidence of infrared emission, the previously identified SNRs G11.1−1.0, G20.4+0.1 and G16.4−0.5 are believed to be H II regions.


1997 ◽  
Vol 14 (1) ◽  
pp. 73-76 ◽  
Author(s):  
A. J. Green

AbstractThe Molonglo Observatory Synthesis Telescope (MOST) has been upgraded to increase the diameter of the field of view from 70′ to 2·7°. A survey of the Galactic Plane is proposed to completely cover the region 240° ≤ l ≤ 365°, ∣ b ∣ ≤ 10° with a (1σ) sensitivity of 1–2 mJy. The results will provide a major resource for the investigation of supernova remnants, HII regions and transient radio sources. They will also be correlated with the galaxy search from the HI multibeam survey to be conducted at the Parkes telescope.


2008 ◽  
Vol 4 (S259) ◽  
pp. 455-466 ◽  
Author(s):  
JinLin Han

AbstractThe magnetic structure in the Galactic disk, the Galactic center and the Galactic halo can be delineated more clearly than ever before. In the Galactic disk, the magnetic structure has been revealed by starlight polarization within 2 or 3 kpc of the Solar vicinity, by the distribution of the Zeeman splitting of OH masers in two or three nearby spiral arms, and by pulsar dispersion measures and rotation measures in nearly half of the disk. The polarized thermal dust emission of clouds at infrared, mm and submm wavelengths and the diffuse synchrotron emission are also related to the large-scale magnetic field in the disk. The rotation measures of extragalactic radio sources at low Galactic latitudes can be modeled by electron distributions and large-scale magnetic fields. The statistical properties of the magnetized interstellar medium at various scales have been studied using rotation measure data and polarization data. In the Galactic center, the non-thermal filaments indicate poloidal fields. There is no consensus on the field strength, maybe mG, maybe tens of μG. The polarized dust emission and much enhanced rotation measures of background radio sources are probably related to toroidal fields. In the Galactic halo, the antisymmetric RM sky reveals large-scale toroidal fields with reversed directions above and below the Galactic plane. Magnetic fields from all parts of our Galaxy are connected to form a global field structure. More observations are needed to explore the untouched regions and delineate how fields in different parts are connected.


2009 ◽  
Vol 5 (H15) ◽  
pp. 808-808
Author(s):  
Emma de Oña-Wilhelmi

AbstractThe H.E.S.S. Galactic Plane Survey (GPS) has revealed a large number of Galactic Sources, including Pulsar Wind Nebulae (PWN), Supernova Remnants (SNRs), giant molecular clouds, star formation regions and compact binary systems, as well as a number of unidentified objects, or dark sources, for which no obvious counterparts at other wavelengths have yet been found. We will review the latest results from the GPS observations and discuss the most interesting cases.


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