J/AJ/128/2170 Hα imaging of irregular galaxies (Hunter+, 2004)
Star formation properties of a large sample of irregular galaxies.
Hunter D.A., Elmegreen B.G.
<Astron. J., 128, 2170-2205 (2004)>
=2004AJ....128.2170H 2004AJ....128.2170H
ADC_Keywords: Photometry, H-alpha ; Galaxies, photometry
Keywords: galaxies: irregular - stars: formation
Abstract:
We present the results of Hα imaging of a large sample of
irregular galaxies. Our sample includes 94 galaxies with morphological
classifications of Im, 26 blue compact dwarfs (BCDs), and 20 Sm
systems. The sample spans a large range in galactic parameters,
including integrated absolute magnitude (MV of -9 to -19), average
surface brightness (20-27mag/arcsec2), current star formation
activity (0-1.3M☉/yr/kpc2), and relative gas content
(0.02-5M☉/LB). The Hα images were used to measure the
integrated star formation rates, determine the extents of star
formation in the disks, and compare azimuthally averaged radial
profiles of current star formation to older starlight.
Description:
The Hα images were obtained in 22 observing runs from 1988 to
1998.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 77 140 Hα Photometry, Star Formation Rates,
Hα Extents
table4.dat 41 140 Other Parameters
refs.dat 84 25 References
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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- 3 A3 --- MType Galaxy type
5- 15 A11 --- Name Galaxy name
17- 21 F5.2 [10-7W] logHa Logarithm of the reddening-corrected
Hα luminosity
23- 26 F4.2 [10-7W] e_logHa ? Error in logHa
28- 32 F5.2 [solMass/yr] logMd ? Logarithm of the star formation rate
34- 38 F5.2 [solMass/yr/kpc2] logM25 ? Logarithm of the integrated star
formation rate normalized to the
area of the galaxy within R25
40- 44 F5.2 [solMass/yr/kpc2] logMD ? Logarithm of the integrated star
formation rate normalized to the
area of the galaxy within RD
46- 50 F5.2 [yr] logtau ? Logarithm of the time to exhaust
the total current galaxy gas content
at the current star formation rate
52- 56 F5.2 arcmin RHa ? Semimajor axis of largest ellipse that
contains Hα emission (1)
58- 61 F4.2 arcmin RHII ? Semimajor axis of largest ellipse that
contains the center of a discrete
Hα region (1)
63- 66 F4.2 --- RHII/R25 ? Ratio of the furthest detectable
discrete Hα region radius to
the B-band surface brightness of
25mag/arcsec2 radius
68- 71 F4.2 --- RHII/RH ? Ratio of the furthest detectable
discrete Hα region radius
to the Holmberg radius
73- 76 F4.2 --- RHII/RD ? Ratio of the furthest detectable
discrete Hα region radius
to disk scale length
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Note (1):
99.99 = The Hα potentially extended beyond the region that we imaged.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- MType Galaxy type
5- 15 A11 --- Name Galaxy name
17- 21 F5.2 kpc R25 ? B-band 25mag/arcsec2 radius
23- 26 F4.2 kpc RD ? Disk scale length
28- 33 F6.2 mag VMAG ? Absolute V-band magnitude
35- 38 F4.2 [solMass] logM ? Logarithm of the total galactic atomic gas
mass (1)
40- 41 I2 --- r_logM ? The HI mass reference
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Note (1): The HI mass has been multiplied by 1.34 to account for He.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 22 A19 --- Bibcode Bibcode
24- 43 A20 --- Aut Author's name
45- 84 A40 --- Com Comments
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 20-Apr-2005