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J/ApJ/513/168  HST observations of carbon in spiral galaxies  (Garnett+, 1999)

Carbon in spiral galaxies from Hubble space telescope spectroscopy Garnett D.R., Shields G.A., Peimbert M., Torres-Peimbert S., Skillman E.D., Dufour R.J., Terlevich E., Terlevich R.J. <Astrophys. J. 513, 168 (1999)> =1999ApJ...513..168G
ADC_Keywords: Abundances ; Galaxies, spectra ; Spectra, ultraviolet Mission_Name: HST Keywords: galaxies: abundances - galaxies: evolution - galaxies: individual (M101, NGC 2403) - galaxies: ISM - galaxies: spiral Abstract: We present measurements of the gas-phase abundance ratio C/O in six H II regions in the spiral galaxies M101 and NGC 2403, based on ultraviolet spectroscopy using the Faint Object Spectrograph on the Hubble Space Telescope. The ratios of C to O increase systematically with O/H in both galaxies, from log(C/O){~=}-0.8 at log(O/H){~=}-4.0 to log(C/O){~=}-0.1 at log(O/H){~=}-3.4. C/N shows no correlation with O/H. The rate of increase of C/O is somewhat uncertain because of uncertainty as to the appropriate UV reddening law and uncertainty in the metallicity dependence on grain depletions. However, the trend of increasing C/O with O/H is clear, confirming and extending the trend in C/O indicated previously from observations of irregular galaxies. Our data indicate that the radial gradients in C/H across spiral galaxies are steeper than the gradients in O/H. Comparing the data to chemical-evolution models for spiral galaxies shows that models in which the massive star yields do not vary with metallicity predict radial C/O gradients that are much flatter than the observed gradients. Description: All six regions were scanned over the full wavelength region from 1600 to 6900 Å with the four medium-resolution gratings G190H, G270H, G400H, and G570H, observed through the 0.86'' square (C-1) upper aperture. Objects: ----------------------------------------- RA (2000) DE Designation(s) ----------------------------------------- 14 04 29.02 +54 23 48.8 M101-NGC 5471 14 03 01.16 +54 14 27.0 M101-NGC 5455 14 03 41.62 +54 19 04.4 M101-NGC 5461 07 36 28.63 +65 33 49.0 NGC 2403-VS9 07 36 52.13 +65 36 48.5 NGC 2403-VS38 07 37 06.82 +65 36 38.7 NGC 2403-VS44 ----------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 99 152 Spectra for M101 and NGC 2403 HII regions
See also: J/AJ/104/92 : HII Regions Properties in M101 (Scowen+ 1992) J/A+AS/91/285 : HII galaxies spectrophotometric catalogue (Terlevich+, 1991) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 8 A8 --- Name H II region name 11- 18 A8 --- Ion Ion 20- 23 I4 0.1nm Wave Wavelength of Ion 30 A1 --- l_Flux Indicates a lower limit in Flux 31- 35 F5.3 --- Flux Observed flux relative to Hβ 37- 41 F5.3 --- e_Flux ? Uncertainty (1σ) in Flux 45 A1 --- l_F3.1 Indicates a lower limit in F3.1 46- 50 F5.3 --- F3.1 Extinction Corrected flux (R=3.1) relative to Hβ 53- 57 F5.3 --- e_F3.1 ? Uncertainty (1σ) in F3.1 60 A1 --- l_F5 Indicates a lower limit in F5 61- 65 F5.3 --- F5 Extinction Corrected flux (R=5) relative to Hβ 69- 73 F5.3 --- e_F5 ? Uncertainty (1σ) in F5 76- 79 F4.2 mag A3.1 Extinction (R=3.1) at Hβ 81- 84 F4.2 mag e_A3.1 Uncertainty in A3.1 90- 93 F4.2 mag A5 Extinction (R=5) at Hβ 96- 99 F4.2 mag e_A5 Uncertainty in A5
History: From ApJ electronic edition
(End) Greg Schwarz [AAS] 02-Mar-2000
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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