J/ApJS/178/1 Distribution of HII regions in disk galaxies (Sanchez+, 2008)
The fractal distribution of H II regions in disk galaxies.
Sanchez N., Alfaro E.J.
<Astrophys. J. Suppl. Ser., 178, 1-19 (2008)>
=2008ApJS..178....1S 2008ApJS..178....1S
ADC_Keywords: Galaxy catalogs ; H II regions
Keywords: catalogs - galaxies: structure, ISM: H II regions - stars: formation
Abstract:
It is known that interstellar gas has a fractal structure in a wide
range of spatial scales with a fractal dimension that seems to be a
constant around Df∼2.7. It is expected that stars forming from this
fractal medium exhibit similar fractal patterns. Here we address this
issue by quantifying the degree to which star-forming events are
clumped. We develop, test, and apply a precise and accurate technique
to calculate the correlation dimension Dc of the distribution of HII
regions in a sample of disk galaxies.
Description:
We have compiled literature data for positions of HII regions in
external galaxies. Here we present the set of HII region catalogues
for a sample of 101 disk galaxies (93 spirals and 8 irregulars). For
each galaxy several properties are given including the calculated
fractal (correlation) dimension of the distribution of HII regions.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 80 101 Properties of the galaxies in the sample
table3.dat 41 101 Calculated fractal dimensions
hii/* . 101 HII regions individual data
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Galaxy name
13- 16 A4 --- MType Morphological Hubble type
19- 23 F5.1 deg PA Position angle
26- 29 F4.1 deg IA Inclination angle
32- 34 F3.1 --- TType Morphological de Vaucouleurs type
37- 38 I2 --- Arm ? Spiral arm class
41- 45 F5.1 Mpc Dist Distance to the galaxy
48- 53 F6.2 mag BMAG ? B-band absolute magnitude
56- 60 F5.2 kpc R25 25mag/arcsec2 isophotal radius
63- 67 F5.1 km/s Vrot ? Maximum rotation velocity
corrected for inclination
69- 80 A12 --- FileName Name of the file containing the HII region
data, in the "hii" subdirectory
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Galaxy name
13- 16 I4 --- HII Number of catalogued HII regions
19- 22 F4.2 --- Dc Calculated correlation (fractal) dimension
25- 28 F4.2 --- e_Dc Estimated uncertainty in Dc
31- 34 F4.2 kpc Rmin Minimum spatial scale of the distribution
37- 41 F5.2 kpc Rmax Maximum spatial scale of the distribution
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Byte-by-byte Description of file: hii/*
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Bytes Format Units Label Explanations
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1- 7 F7.2 kpc Xpos X position of HII region with respect to
the galaxy centre
11- 17 F7.2 kpc Ypos Y position of HII region with respect to
the galaxy centre
21 I1 --- Flag [0/1] HII region excluded (0) or included (1)
in the calculation of Dc
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Acknowledgements:
Nestor Sanchez, nestor(at)iaa.es
(End) Patricia Vannier [CDS] 08-Sep-2008