Radio and Optical Spectra of Sources from the Molonglo Deep Survey

1977 ◽  
Vol 3 (2) ◽  
pp. 142-143
Author(s):  
H. S. Murdoch ◽  
G. L. White
Keyword(s):  
Flux Density ◽  
Optical Spectra ◽  
Small Areas ◽  
Preliminary Results ◽  
Position Errors ◽  
Sky Survey ◽  
Deep Survey ◽  
Optical Identifications

We present here preliminary results of further radio and optical work being carried out on the Molonglo Deep Survey (Robertson 1977a, b, c) which reaches a density of ∼ 20,000 sources per sterad at a limiting flux density of 84 mJy at 408 MHz in three small areas of sky at declinations -20° and -62°. The position errors range from 4 to 15 arc sec r.m.s. depending on flux density. Optical identifications are being made by G. W. using the Palomar Sky Survey in the -20° region and the ESO and SRC surveys in the -62° region. In the latter case, where only one colour is available more accurate positions are necessary to identify QSO candidates. The Fleurs synthesis telescope is being used to obtain accurate positions.

The Fleurs Southern Benchmark Program

1989 ◽  
Vol 8 (2) ◽  
pp. 180-183 ◽  
Author(s):  
Michael J. Batty ◽  
Graeme L. White ◽  
John D. Bunton ◽  
David R. Brown ◽  
Julian B. Corben
Keyword(s):  
Flux Density ◽  
Reference Frame ◽  
Radio Sources ◽  
Position Errors ◽  
Significant Bias ◽  
Spectrum Radio ◽  
Sky Survey ◽  
Optical Identifications ◽  
Global Bias

AbstractA program to determine accurate radio positions and optical identifications of southern flat-spectrum radio sources has been undertaken with the six-dish array of the Fleurs synthesis telescope at 1.4 GHz and using the SERC J sky survey. This sample covers the declination range −80° to −50° and comprises all 198 sources from the Parkes catalogue with α of > −0.5 and flux density of 0.25 Jy.The radio astrometric phase of the program is complete. We conclude that by comparison with accurate VLBI positions the FST positions have r.m.s. uncertainties of ∼0″.9. There is no global bias in the FST positions at the 0″.2 to 0″.3 level relative to the JPL VLBI extragalactic reference frame. A comparison with positions from the Parkes catalogue shows that in the southern regions the Parkes catalogue has rms position errors of about 9″. There is no significant bias between the FST and Parkes positions.

scholarly journals Optical Identifications of Radio Sources with Accurate Positions Using the UKST IIIa-J Plates

1984 ◽  
Vol 78 ◽  
pp. 481-487
Author(s):  
Ann Savage ◽  
David L. Jauncey ◽  
Michael J. Batty ◽  
S. Gulkis ◽  
D.D. Morabito ◽  
...  
Keyword(s):  
Radio Sources ◽  
Preliminary Results ◽  
Sky Survey ◽  
Optical Identifications

SummaryThree radio identification programmes are described which are drawn from radio samples with accurate radio positions (< 2" arc rms). Optical identifications are being made on the basis of radio-optical positional coincidence alone, without regard to colour or morphology, using the UKST IIIa-J sky survey to a limiting magnitude of 22.5. Some preliminary results are presented.

scholarly journals A 6-CM Deep Sky Survey

1983 ◽  
Vol 104 ◽  
pp. 81-81
Author(s):  
E. B. Fomalont ◽  
K. I. Kellermann ◽  
J. V. Wall
Keyword(s):  
Radio Source ◽  
Flux Density ◽  
Small Region ◽  
Sky Survey ◽  
Deep Survey

In order to extend radio source counts to lower flux density, we have used the VLA to survey a small region of sky at 4.885 GHz (6 cm) to a limiting flux density of 50 μJy. Details of this deep survey are given in the paper by Kellermann et al. (these proceedings). In addition, we have observed 10 other nearby fields to a limiting flux density of 350 μJy in order to provide better statistics on sources of intermediate flux density.

scholarly journals Radio-Optical Studies of a Complete Sample of Abell Clusters

1982 ◽  
Vol 97 ◽  
pp. 85-86
Author(s):  
B. Y. Mills ◽  
R. W. Hunstead
Keyword(s):  
Optical Spectra ◽  
Complete Sample ◽  
Stellar Objects ◽  
Cluster Membership ◽  
Abell Clusters ◽  
Early Results ◽  
Cluster Area ◽  
Sky Survey ◽  
Optical Identifications ◽  
Low Dispersion

Study of the properties of radio galaxies in clusters is beset with problems of selection and identification. To reduce these problems we have selected a complete sample of Abell clusters and are using optical spectra of identified galaxies to determine their cluster membership. The sample is in a volume of space defined by the limits of coverage and sensitivity of the two Sydney University radiotelescopes and the Anglo-Australian Telescope; it comprises the 42 clusters with δ≤-8° and distance class 4 or closer. Radio maps have been prepared using archive 408 MHz data from the Molonglo Cross. Possible optical identifications have been selected from the Palomar Sky Survey and low-dispersion optical spectra have been taken of these and sometimes other galaxies or stellar objects within the cluster area. When needed, maps of the cluster areas have been produced at 1415 MHz using the Fleurs Synthesis Telescope. Some details of our early results have been published (Mills et al. 1978, 1979) and here a brief summary of the overall statistics is presented. Observations on five clusters remain to be completed but should not greatly affect the present conclusions.

scholarly journals The Molonglo Deep Sky Survey of Radio Sources. II. Declination Zone -62°

1977 ◽  
Vol 30 (2) ◽  
pp. 231 ◽  
Author(s):  
JG Robertson
Keyword(s):  
Flux Density ◽  
Lower Limit ◽  
Solid Angle ◽  
Radio Sources ◽  
Upper Limit ◽  
Sky Survey ◽  
Deep Survey ◽  
The Right

Results are given for the second zone of a deep survey made at 408 MHz with the Molonglo cross. The catalogue lists positions and flux densities for 95 sources, none of which has been previously catalogued, in a solid angle of 5�51 x 10-3 sr. The right ascensions covered (with some excluded areas) are 18h 26m-OOh 06m, with a range in declination of 45'. The lower limit of flux density is 84 inJy. An upper limit of 1000 mJy has also been imposed. The position uncertainties are typically 12''at 100 mJy and 6# at 250 mJy.

scholarly journals The Molonglo Deep Sky Survey of Radio Sources. I. Declination Zone -20°

1977 ◽  
Vol 30 (2) ◽  
pp. 209 ◽  
Author(s):  
JG Robertson
Keyword(s):  
Error Analysis ◽  
Flux Density ◽  
Lower Limit ◽  
Solid Angle ◽  
Radio Sources ◽  
Contour Maps ◽  
Upper Limit ◽  
Sky Survey ◽  
Deep Survey

Results of a deep survey made at 408 MHz with the Molonglo cross are given. The catalogue lists positions and flux densities for a total of 373 radio sources, most of which have not previously been catalogued, in a solid angle of 0�0201 Sf. This covers (with some excluded areas) right ascensions 0l h oom-06h 44m and 13h 45m-17h 19m, with a range in declination of 41'. Eighteen contour maps are given of sources that are extended or have very close companions. A thorough error analysis is given, as well as new operational definitions of completeness and reliability. The lower limit of flux density is 88 mJy, which is five times the r.m.s. error. An upper limit of 1000 mJy has also been imposed. Typical errors in positions are 15" at 100 mJy and 6" at 250 mJy.

scholarly journals TheEUVEOptical Identification Campaign II: Late-Type and White Dwarf Stars

1996 ◽  
Vol 152 ◽  
pp. 491-496
Author(s):  
N. Craig ◽  
A. Fruscione ◽  
J. Dupuis ◽  
M. Mathioudakis ◽  
J.J. Drake ◽  
...  
Keyword(s):  
White Dwarf ◽  
Extreme Ultraviolet ◽  
Late Type ◽  
Dwarf Stars ◽  
White Dwarf Stars ◽  
Sky Survey ◽  
Deep Survey ◽  
Balmer Lines ◽  
Optical Identifications ◽  
Error Circle

We present optical identifications of nine previously unidentified extreme ultraviolet (EUV) sources discovered during theExtreme Ultraviolet Explorer(EUVE) satellite surveys. The all-sky survey detected four of the sources and the more sensitive deep survey detected the other five sources. Three of the four all-sky survey sources, EUVE_J1918+59.9, EUVE_J2249+58.5, and EUVE_J2329+41.4, are listed in present catalogs as having possible associations with optical counterparts but without spectral class. The first two of these sources are hot DA white dwarfs showing an optical spectrum with broad Balmer lines. The source EUVE_J2329+41.4 is listed as having a possible association with an unclassified M star. We show that a pair of dMe stars are actually optical counterparts located within the error circle of theEUVEsource position. The EUVE_J2114+503 remains unidentified even though all the possible candidates have been studied. Based on the count rates we predict a fainter white dwarf or a cataclysmic variable counterpart for this candidate. All five sources discovered with theEUVEdeep survey, EUVE_J0318+184, EUVE_J0419+217, EUVE_J2053−175, EUVE_J2056−171 and EUVE_J2233−096, have been identified as late-type stars. The spectral classes, distances, visual magnitudes, and estimated hydrogen column densities for theseEUVEsources are presented.

scholarly journals Nature of hard X-ray sources from optical identifications of the ASCA Large Sky Survey

1999 ◽  
Vol 320 (4-5) ◽  
pp. 255-256
Author(s):  
M. Akiyama ◽  
K. Ohta ◽  
T. Yamada ◽  
Y. Ueda ◽  
T. Takahashi ◽  
...  
Keyword(s):  
X Ray ◽  
Sky Survey ◽  
Optical Identifications

scholarly journals Synthesis Observations of Southern Radio Sources at 1410 MHz with the Parkes Interferometer. I. Instrument, Reduction, and Preliminary Results

1973 ◽  
Vol 26 (5) ◽  
pp. 661 ◽  
Author(s):  
UJ Schwarz ◽  
DJ Cole ◽  
D Morris
Keyword(s):  
Data Processing ◽  
Computer Control ◽  
Radio Sources ◽  
Preliminary Results ◽  
On Line ◽  
Optical Identifications

Modifications to the Parkes interferometer are described which allow synthesis observations to be made while still retaining the flexibility of frequent baseline changes. Details are given of the receiver with a phase stabilizing device and its performance, on-line computer control, and data processing. Preliminary observations with a resolution of l' of the two sources PKS 2152-69 and 2356-61 and possible optical identifications are discussed briefly.

Studying the Flux Density of Bright Active Galaxies at Different Spectral Bands

2019 ◽  
Vol 16 (1(Suppl.)) ◽  
pp. 0230
Author(s):  
Rashed Et al.
Keyword(s):  
Flux Density ◽  
Galactic Nuclei ◽  
Absolute Magnitude ◽  
Active Galaxies ◽  
X Ray ◽  
Spectral Bands ◽  
Sky Survey ◽  
Multi Wavelength ◽  
Statistical Studies ◽  
Density Ratios

Statistical studies are reported in this article for an active galactic nuclei sample of different type of active galaxies Seyferts 1, Seyferts 2, and Quasars. These sources have been selected from a Catalogue for bright X-ray galaxies. The name of this index is ROSAT Bright Source Catalogue (RBSC) and the NRAO VLA Sky Survey (NVSS). In this research, multi-wavelength observational bands Radio at 1.4 GHz, Optical at 4400 A0, and X-ray at energy 0.1-2.4 KeV have been adopted in this study. The behavior of flux density ratios has been studied ,  with respect to the absolute magnitude . Furthermore, the Seyfert1 and Seyfert 2 objects are combined in one group and the QSOs are collectest in another group. Also, it has been found that the ratios , are increasing towards fainter optical absolute magnitude especially in Quasars.

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