J/A+A/415/849 Deprojection of spiral galaxies (Barbera+, 2004)
Deprojecting spiral galaxies using Fourier analysis.
Application to the Frei sample.
Barbera C., Athanassoula E., Garcia-Gomez C.
<Astron. Astrophys. 415, 849 (2004)>
=2004A&A...415..849B 2004A&A...415..849B
ADC_Keywords: Galaxy catalogs ; Morphology
Keywords: galaxies: structure - galaxies : spiral
Abstract:
We present two methods that can be used to deproject spirals, based on
Fourier analysis of their images, and discuss their potential and
restrictions. Our methods perform particularly well for galaxies more
inclined than 50 degrees or for non-barred galaxies more inclined than
35 degrees. They are fast and straightforward to use, and thus ideal
for large samples of galaxies. Moreover, they are very robust for low
resolutions and thus are appropriate for samples of cosmological
interest. The relevant software is available from us upon request. We
use these methods to determine the values of the position and
inclination angles for a sample of 81 spiral galaxies contained in the
Frei et al. (1996AJ....111..174F 1996AJ....111..174F) sample. We compare our results with
the values found in the literature, based on other methods. We find
statistically very good agreement.
Description:
Deprojection angles of each galaxy using the BAG1 and BAG2 methods
plus the deprojection angles found in the literature. The last four
columns of table7a.dat contain the values adopted for the position
angle, its dispersion, the inclination angle and its dispersion in
degrees.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table7a.dat 101 81 Deprojecting information for 81 galaxies
table7b.dat 26 489 Available data in the literature
refs.dat 82 98 References
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Byte-by-byte Description of file: table7a.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- NGC Galaxy name
10- 12 I3 deg PA1a Position angle obtained with BAG1 method
and first filter (Filta)
15- 16 I2 deg IA1a Inclination angle obtained with BAG1 method
and first filter (Filta)
19- 21 I3 deg PA2a ? Position angle obtained with BAG2 method
and first filter (Filta)
24- 25 I2 deg IA2a ? Inclination angle obtained with BAG2 method
and first filter (Filta)
27- 28 A2 --- Filta [gri BJR] Image filter
30- 32 I3 deg PA1b ? Position angle obtained with BAG1 method
and second filter (Filtb)
35- 36 I2 deg IA1b ? Inclination angle obtained with BAG1 method
and second filter (Filtb)
39- 41 I3 deg PA2b ? Position angle obtained with BAG2 method
and second filter (Filtb)
44- 45 I2 deg IA2b ? Inclination angle obtained with BAG2 method
and second filter (Filtb)
47- 48 A2 --- Filtb [gri BJR] Image filter
50- 52 I3 deg PA1c ? Position angle obtained with BAG1 method
and third filter (Filtc)
55- 56 I2 deg IA1c ? Inclination angle obtained with BAG1 method
and third filter (Filtc)
59- 61 I3 deg PA2c ? Position angle obtained with BAG2 method
and third filter (Filtc)
64- 65 I2 deg IA2c ? Inclination angle obtained with BAG2 method
and third filter (Filtc)
67- 68 A2 --- Filtc [gri BJR] Image filter
70- 72 I3 deg mPA1 Mean position angle of BAG1 method
74- 75 I2 deg mIA1 Mean inclination angle of BAG1 method
77 I1 --- w_mIA1 Weight of the averaged deprojection angles
from BAG1
80- 82 I3 deg mPA2 ? Mean position angle of BAG2 method
84- 85 I2 deg mIA2 ? Mean inclination angle of BAG2 method
87 I1 --- w_mIA2 Weight of the averaged deprojection angles
from BAG2
90- 92 I3 deg PA Adopted position angle (1)
94- 95 I2 deg e_PA ? Standard weighted deviation
for the adopted position angle
97- 98 I2 deg IA Adopted inclination angle (1)
100-101 I2 deg e_IA ? Standard weighted Deviation for adopted
inclination angle
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Note (1): Adopted values from BAG1, BAG2 and literature (table7b.dat)
weighed values.
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Byte-by-byte Description of file: table7b.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- NGC Galaxy name
10- 12 I3 deg PAL ? Position angle obtained from the literature
15- 16 I2 deg IAL ? Inclination angle obtained from the literature
18- 19 I2 --- w_PAL Adopted weight for these two previous values
21- 23 A3 --- Type Deprojection method (1)
24- 25 I2 --- r_PAL Code number for literature reference,
in refs.dat file
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Note (1): Methods for obtaining the deprojection angles:
P = Photometry
KC = CO Kynematics
KO = Optical Kynematics
KH = HI Kinematics
KHP = HI Kinematics + Photometry
KS = Long slit Kinematics
S = Spirals
O = Other
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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- 53 A30 --- Aut Author's name
55- 82 A28 --- Com Comments
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Acknowledgements: Carles Barbera
(End) Patricia Bauer [CDS] 07-Nov-2003