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J/AJ/138/1203    Star formation regions in nearby dwarf galaxies (Melena+, 2009)

Bright ultraviolet regions and star formation characteristics in nearby dwarf galaxies Melena N.W., Elmegreen B.G., Hunter D.A., Zernow L. <Astron. J. 138, 1203 (2009)> =2009AJ....138.1203M
ADC_Keywords: Galaxies, nearby ; Ultraviolet ; Photometry, UBV Keywords: galaxies: dwarf - galaxies: irregular - galaxies: star clusters Abstract: We compare star formation in the inner and outer disks of 11 dwarf irregular galaxies (dIm) within 3.6Mpc. The regions are identified on Galaxy Evolution Explorer near-UV images, and modeled with UV, optical, and near-IR colors to determine masses and ages. A few galaxies have made 105-106M complexes in a starburst phase, while others have not formed clusters in the last 50Myr. The maximum region mass correlates with the number of regions as expected from the size-of-sample effect. We find no radial gradients in region masses and ages, even beyond the realm of Hα emission, although there is an exponential decrease in the luminosity density and number density of the regions with radius. Hα is apparently lacking in the outer parts only because nebular emission around massive stars is too faint to see. The outermost regions for the five galaxies with HI data formed at average gas surface densities of 1.9-5.9M_☉/pc2. Description: In this paper, we compare the properties of individual star-forming regions in outer and inner disks of a sample of dwarf galaxies. The young regions are identified on Galaxy Evolution Explorer (GALEX) near-UV (NUV) images archives. We use far-UV (FUV) and NUV, UBV, and some JHK colors to model the masses and ages of the regions. Our investigation includes approximately 2000 separate star-forming regions. With these data we compare mass, age, and several other key properties of star-forming regions in inner and outer disks. GALEX images were taken simultaneously in two channels: FUV, with a bandpass of 1350-1750Å, an effective wavelength of 1516Å, and a resolution of 4.0" and NUV with a bandpass of 1750-2800Å, an effective wavelength of 2267Å, and a resolution of 5.6". File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 81 11 Galaxy sample table3.dat 119 1622 Region photometry
See also: J/A+A/495/447 : PN and HII regions in NGC6822 (Hernandez-Martinez+, 2009) J/ApJ/706/599 : Hα and UV SFR in the local volume (Lee+, 2009) J/ApJS/162/49 : UBV imaging of irregular galaxies (Hunter+, 2006) J/AJ/132/378 : HST and UV photometry of NGC 6822 (Bianchi+, 2006) J/AJ/121/2020 : CTIO and WFPC2 photometry in NGC 6822 (Bianchi+, 2001) J/AJ/105/894 : Star formation in DDO 210 and NGC 3109 (Greggio+ 1993) J/A+AS/125/293 : NGC 2366, NGC 2403 + NGC 4236 HK' photometry (Pierini+ 1997) J/AJ/110/2715 : UBV photometry in NGC 6822, M31 and M33 (Massey+ 1995) J/AJ/109/173 : BVR photometry of NGC 6822 (Marconi+ 1995) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 8 A8 --- Name Galaxy name (1) 10- 54 A45 --- OName Other name(s) 56- 58 F3.1 Mpc Dist Distance 60- 63 F4.2 mag E(B-V) Foreground reddening from Burstein & Heiles, 1984ApJS...54...33B 65- 69 F5.1 mag VMag Absolute V-band magnitude 71- 74 F4.2 arcmin RD ? Disk scale length determined from V-band images 76- 78 I3 deg PA [-85,88] Galactic position angle of the major axis determined from V-band images 80- 81 I2 deg i Inclination of galactic disk
Note (1): Quantities taken from Hunter & Elmegreen (2006, Cat. J/ApJS/162/49).
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 8 A8 --- Name Galaxy name 10- 12 I3 --- Reg Star-forming region number 14- 15 I2 h RAh Hour of Right Ascension (J2000) 17- 18 I2 min RAm Minute of Right Ascension (J2000) 20- 23 F4.1 s RAs Second of Right Ascension (J2000) 25 A1 --- DE- Sign of the Declination (J2000) 26- 27 I2 deg DEd Degree of Declination (J2000) 29- 30 I2 arcmin DEm Arcminute of Declination (J2000) 32- 33 I2 arcsec DEs Arcsecond of Declination (J2000) 35- 38 F4.2 kpc R Distance from galaxy center (1) 40- 44 F5.2 --- R/RD Same as R but divided by disk scale length (2) 46- 50 F5.1 pc radius Star-forming region radius (3) 52- 56 F5.1 mag NUVMag Absolute GALEX NUV filter AB magnitude 58- 61 F4.2 mag e_NUVMag The 1σ error in NUVMag 63- 67 F5.2 mag F-N Intrinsic GALEX (FUV-NUV) color index 69- 72 F4.2 mag e_F-N The 1σ error in F-N 74- 78 F5.1 mag VMag Absolute V filter AB magnitude 80- 82 F3.1 mag e_VMag The 1σ error in VMag 84- 88 F5.2 mag B-V Intrinsic (B-V) color index 90- 93 F4.2 mag e_B-V The 1σ error in B-V 95- 99 F5.2 mag U-B Intrinsic (U-B) color index 101-104 F4.2 mag e_U-B The 1σ error in U-B 106-109 F4.2 [Msun] logM Log star-forming region mass (4) 111-114 F4.2 [yr] logA Log star-forming region age (4) 116-119 F4.2 mag RMS rms deviation between observed & modeled colors
Note (1): In the plane of the galaxy, using the galactic parameters given in Table 1. Note (2): From Hunter & Elmegreen (2006, Cat. J/ApJS/162/49). Note (3): The identifying regions are polygons, and the radius is the square-root of the area of the region divided by π. Note (4): From the best fit model to the colors and luminosity.
Nomenclature Notes: Regions are <[MEH2009] {Name} NNN> in Simbad. History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 23-Jan-2012
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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