J/MNRAS/526/5187 Star-forming complex S254-S258 HII regions (Kirsanova+, 2023)
3D structure of H II regions in the star-forming complex S254-S258.
Kirsanova M.S., Moiseev A.V., Boley P.A.
<Mon. Not. R. Astron. Soc., 526, 5187-5202 (2023)>
=2023MNRAS.526.5187K 2023MNRAS.526.5187K (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, IR ; H II regions ; Interstellar medium ; Abundances ;
Spectra, optical
Keywords: techniques: imaging spectroscopy - stars: massive -
stars: winds, outflows - dust, extinction - ISM: H II regions
Abstract:
The S254-258 star-forming complex is a place of massive star formation
where five OB-stars have created HII regions, visible as optical
nebulae, and disrupted the parental molecular gas. In this work, we
study the 3D structure of these HII regions using optical spectroscopy
and tunable-filter photometry with the 6- and 1-m telescopes of the
Special Astrophysical Observatory of the Russian Academy of Sciences.
We construct maps of the optical extinction and find that the HII
emission is attenuated by neutral material with 2≤AV≤5mag. The
typical electron density in S255, and S257 is ∼100cm-3, with
enhancements up to 200cm-3 in their borders, and up to 400cm-3
toward the dense molecular cloud between them, where active star
formation is taking place. We show that either a model of a clumpy
dense neutral shell, where UV photons penetrate through and ionize the
gas, or a stellar wind, can explain the shell-like structure of the
ionized gas. S255 is surrounded by neutral material from all sides,
but S257 is situated on the border of a molecular cloud and does not
have dense front and rear walls. The compact HII regions S256 and S258
are deeply embedded in the molecular clouds.
Description:
We present fits-files with the images of the S255 HII regions using
filters centred on the H-alpha, H-beta, NII, OIII and SII lines, as
well as optical spectra of S255, S256, S257 and S258.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
listimg.dat 108 6 List of fits images
fits/* . 6 Individual fits images
listsp.dat 123 4 List of spectra
sp/* . 4 Individual fits spectra
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Byte-by-byte Description of file: listimg.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 24 F5.3 arcsec/pix scale Scale of the image
26- 28 I3 --- Nx Number of pixels along X-axis
30- 32 I3 --- Ny Number of pixels along Y-axis
34- 43 A10 "date" Obs.date Observation date
45- 48 I4 Kibyte size Size of FITS file
50- 72 A23 --- FileName Name of FITS file, in subdirectory fits
74-108 A35 --- Title Title of the FITS file
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Byte-by-byte Description of file: listsp.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Name Source name
9- 10 I2 h RAh Simbad right ascension (J2000)
12- 13 I2 min RAm Simbad right ascension (J2000)
15- 19 F5.2 s RAs Simbad right ascension (J2000)
20 A1 --- DE- Simbad declination sign (J2000)
21- 22 I2 deg DEd Simbad declination (J2000)
24- 25 I2 arcmin DEm Simbad declination (J2000)
27- 30 F4.1 arcsec DEs Simbad declination (J2000)
32- 35 I4 --- Nx Number of pixels along X-axis
37- 39 I3 --- Ny Number of pixels along Y-axis
41- 50 A10 "date" Obs.date Observation date
52- 55 I4 0.1nm bAWAV Lower value of wavelength interval
57- 63 F7.2 0.1nm BAWAV Upper value of wavelength interval
65- 68 F4.2 0.1nm dAWAV Wavelength resolution
70- 74 I5 Kibyte size Size of FITS file
76- 94 A19 --- FileName Name of FITS file, in subdirectory sp
96-123 A28 --- Title Title of the FITS file
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Acknowledgements:
Maria Kirsanova, Maria.kirsanova(at)gmail.com
(End) Patricia Vannier [CDS] 12-Jan-2024