J/ApJS/107/239 327MHz survey of the galactic plane (Taylor+ 1996)
A Westerbork synthesis radio telescope 327 MHz survey of the galactic plane.
Taylor A.R., Goss W.M., Coleman P.H., van Leeuwen J., Wallace B.J.
<Astrophys. J. Suppl. Ser. 107, 239 (1996)>
=1996ApJS..107..239T 1996ApJS..107..239T
ADC_Keywords: Radio sources ; H II regions
Keywords: HII regions - Planetary nebulae: general -
radio continuum: general - surveys
Abstract (from the authors)
The Westerbork Synthesis Radio Telescope (WSRT) in the Netherlands has
been used to survey a section of the galactic plane at a radio
frequency of 327MHz. Twenty-three overlapping synthesis fields were
observed, covering galactic co-ordinates 43°<l<91°,
|b|<1.6°. Each field was observed at two epochs, several years
apart, to identify variable sources. Intensity data from the separate
epochs were combined, and the resulting images mosaiced to produce a
single image of the entire survey region. Sensitivity of the mosaic is
typically a few mJy. Resolution is 1' by 1'cosec(dec).
The survey image provides our first high resolution view of the Galaxy
at low radio frequencies, and includes sections of the Sagittarius and
Cygnus arms. These sections contain numerous extended features, among
them supernova remnants, HII regions, "bubbles" of thermal emission,
and large patches of amorphous galactic thermal emission. The
inter-arm region is characterized by lower densities of extended
features, but numerous discrete compact radio sources, most of which
are background objects such as quasars and other types of active
galactic nuclei. However, the resolution, sensitivity and low
frequency of this survey make it ideal for detecting weak, non-thermal
compact galactic sources, e.g. compact, low surface brightness SNRs
and radio stars.
Inspection of the survey image has produced a catalog of nearly 4000
discrete sources with sizes less than about 3'.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
wsrt.dat 84 3984 Catalogue of small diameter sources
table1.dat 79 120 *IRAS identification
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Note on table1.dat: the source W2033+4124 is not in the published table
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See also:
http://www.ras.ucalgary.ca/wsrt_survey.html : Images and FITS files
Byte-by-byte Description of file: wsrt.dat
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Bytes Format Units Label Explanations
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1- 1 A1 --- --- [W]
2- 11 A10 --- WSRT Name of source
13- 14 I2 h RAh Right Ascension 1950 (hours)
16- 17 I2 min RAm Right Ascension 1950 (minutes)
19- 23 F5.2 s RAs [0,60] Right Ascension 1950 (seconds)
26- 29 F4.2 s e_RAs Mean error on RA
31 A1 --- DE- Declination 1950 (sign)
32- 33 I2 deg DEd Declination 1950 (degrees)
35- 36 I2 arcmin DEm Declination 1950 (minutes)
38- 39 I2 arcsec DEs [0/60] Declination 1950 (seconds)
41- 43 I3 arcsec e_DEs Mean error on Declination
45- 49 I5 mJy S327 Flux density at 327MHz
51- 54 I4 mJy e_S327 Mean error on S327
55 A1 --- n_WSRT [*] Flag when the source is in table1.dat
57- 59 I3 arcsec MajDiam ? Diameter (major)
61- 63 I3 arcsec MinDiam ? Diameter (minor)
65- 67 I3 deg PA [0/180]? Position Angle
69- 76 F8.4 deg GLON Galactic longitude
77- 84 F8.4 deg GLAT Galactic latitude
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- WSRT Name of radio source
12- 15 F4.1 arcsec Sep Separation from IRAS position
17- 20 I4 mJy S327 Flux density at 327MHz
22- 24 I3 mJy e_S327 rms uncertainty on S327MHz
26- 30 F5.1 Jy S12um Flux density at 12µm
32- 37 F6.1 Jy S25um Flux density at 25µm
39- 45 F7.1 Jy S60um Flux density at 60µm
47- 53 F7.1 Jy S100um Flux density at 100µm
55- 59 F5.2 --- [25/12] S25um/S12um ratio, log scale
61- 65 F5.2 --- [60/25] S60um/S25um ratio, log scale
67- 73 F7.1 --- [60/S327] S60um/S327MHz ration
75- 79 F5.2 --- SI ? Radio spectral index
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History:
* February 1997: wsrt.dat copied from
http://www.ras.ucalgary.ca/wsrt/wsrt.cat in February
and table1 supplied by Russ Taylor
* 20-May-2000 : errors in the units if IRAS fluxes corrected.
Flag "n_WSRT" added in wsrt.dat (thanks to H. Andernach's remarks)
(End) Francois Ochsenbein [CDS] 25-Feb-1997