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J/A+A/373/1032      Radio emission from planetary nebulae    (Siodmiak+, 2001)

An analysis of the observed radio emission from planetary nebulae. Siodmiak N., Tylenda R. <Astron. Astrophys. 373, 1032 (2001)> =2001A&A...373.1032S
ADC_Keywords: Planetary nebulae ; Radio lines ; Stars, diameters Keywords: planetary nebulae: general - radio continuum: ISM - ISM: dust, extinction Abstract: We have analysed the radio fluxes for 264 planetary nebulae for which reliable measurements of fluxes at 1.4 and 5 GHz, and of nebular diameters are available. For many of the investigated nebulae, the optical thickness is important, especially at 1.4 GHz. Simple models like the one specified only by a single optical thickness or spherical, constant density shells do not account satisfactorily for the observations. Also an r-2 density distribution is ruled out. A reasonable representation of the observations can be obtained by a two-component model having regions of two different values of optical thickness. We show that the nebular diameters smaller than 10" are uncertain, particularly if they come from photographic plates or Gaussian fitting to the radio profile. While determining the interstellar extinction from an optical to radio flux ratio, caution should be paid regarding optical thickness effects in the radio. We have developed a method for estimating the value of self absorption. At 1.4 GHz self absorption of the flux is usually important and can exceed a factor of 10. At 5 GHz self absorption is negligible for most of the objects, although in some cases it can reach a factor of 2. The Galactic bulge planetary nebulae when used to calibrate the Shklovsky method give a mean nebular mass of 0.14M. The statistical uncertainty of the Shklovsky distances is smaller than a factor of 1.5. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 82 264 Observational data table1.tex 122 465 LaTeX version of table1 refs.dat 155 36 References
See also: V/84 : Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (Acker+, 1992) VII/34 : ESO/Uppsala Survey of the ESO(B) Atlas (Lauberts 1982) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 10 A10 --- PNG PNG designation 12- 21 A10 --- Name Usual name 23- 28 F6.1 mJy F1.4GHz Flux measurement at 1.4GHz from Condon & Kaplan (1998, Cat. J/ApJS/117/361) 30- 35 F6.1 mJy F5GHz Flux at 5GHz 37- 43 A7 --- r_F5GHz References for F5GHz in refs.dat file 46- 51 F6.2 arcsec DiamRad ? Angular diameter from radio observations 52 A1 --- n_DiamRad [+] +: more reliable measurement 54- 57 A4 --- r_DiamRad References for DiamRad in refs.dat file 58 A1 --- l_DiamOpt Limit flag on DiamOpt 59- 63 F5.1 arcsec DiamOpt ? Nebular diameter from optical observations 65 A1 --- n_DiamOpt [+] +: more reliable measurement 66- 67 A2 --- ST [ST ] ST: stellar 69- 75 A7 --- r_DiamOpt References for diamOpt in refs.dat file 77- 82 F6.2 arcsec Diam Adopted diameter
Byte-by-byte Description of file: refs.dat
Bytes Format Units Label Explanations
1- 2 A2 --- Ref Reference code 4- 22 A19 --- BibCode BibCode 24- 42 A19 --- Aut Author's name 44-155 A112 --- Com Comments
Acknowledgements: Natasza Siodmiak
(End) Patricia Bauer [CDS] 15-Aug-2001
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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