J/A+AS/141/103 BVRI imaging of M 51-type pairs (Laurikainen+, 2000)
BVRI imaging of M 51-type pairs. II. Bulge and disk parameters.
Laurikainen E., Salo H.
<Astron. Astrophys. Suppl. Ser. 141, 103 (2000)>
=2000A&AS..141..103L 2000A&AS..141..103L
ADC_Keywords: Galaxies, photometry ; Photometry, UBVRI
Keywords: galaxies - interactions - photometry - fundamental parameters
Abstract:
We present decompositions of azimuthally averaged surface brightness
profiles in optical B, V, R and I-bands for a sample of 40 M 51-type
interacting galaxies. The profiles were modelled by an exponential
disk and a spherical bulge described either by the R1/4 law or by an
exponential function. Half of the galaxies were well fitted by both
bulge models, whereas for 35% the exponential function was a better
choice. Special care was taken on eliminating superpositions of the
companion galaxies. The mean B-band central surface brightness
µ0was found to be 21.5mag/arcsec2, which is near to the value
originally found by Freeman (1970ApJ...160..811F 1970ApJ...160..811F), but the scatter was
fairly large. Galaxy interactions have strongly modified the disks in
many of the galaxies in the sample. For example, six of them had
extremely flat brightness profiles outside the exponential part of the
disk, and many showed significant isophotal twists.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 33 40 The position angle and inclination of the disk
table2.dat 79 138 The effective and integrated parameters of
the profiles
table3.dat 77 95 Bulge-disk decomposition by model 1
table4.dat 77 131 Bulge-disk decomposition by model 2
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Gal Galaxy name
10 A1 --- l_i1 Limit flag on i1
11- 12 I2 deg i1 ? Method 1 inclination
14- 15 I2 deg e_i1 ? rms uncertainty on i1
17- 18 I2 deg i2 Method 2 inclination (1)
19 A1 --- --- [/]
20- 22 I3 deg PA2 Method 2 position angle
23 A1 --- n_PA2 [?*] Uncertainty flag on PA2 (2)
25- 26 I2 mag/arcsec2 SuBr Surface brightness levels used in the
measurements for method 2
28- 29 I2 deg i3 ? Litterature inclination
(SuBr=25mag/arcsec2) (1)
30 A1 --- --- [/]
31- 33 I3 deg PA3 ? Litterature position angle
(SuBr=25mag/arcsec2)
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Note (1): All inclinations have been corrected by the Hubble formula
as explained in the text
Note (2): * Values are very uncertain.
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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- 8 A8 --- Gal Galaxy name
11 A1 --- Band [BVRI] Filter
13- 17 F5.1 arcsec R25 Radius measured within the isophote having
a surface brightness of 25mag/arcsec2
19- 21 I3 arcsec e_R25 rms uncertainty on R25
22 A1 --- n_R25 [*] *: Extrapolated value
24- 29 F6.3 mag m25 Integrated apparent magnitude measured
within the isophote having a surface
brightness of 25mag/arcsec2
31- 34 F4.2 mag e_m25 rms uncertainty on m25
35 A1 --- n_m25 [*] *: Extrapolated value
37- 40 F4.1 arcsec reff ? Effective radius
42- 45 F4.1 arcsec e_reff ? rms uncertainty on reff
47- 51 F5.2 mag/arcsec2 SuBre ? Effective surface brightness (1)
53- 56 F4.2 mag/arcsec2 e_SuBre ? rms uncertainty on SuBre
58- 62 F5.2 mag mag ? Total integrated apparent magnitude in
band "Band"
64- 67 F4.2 mag e_mag ? rms uncertainty on mag
69- 72 F4.1 mag/arcsec2 SuBr ? Surface brightness levels used in
the measurements
74- 79 F6.2 mag BMAG ? Absolute B magnitude (2)
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Note (1): Total magnitudes and effective surface brightnesses were
generally determined by extrapolation to infinity. However, for
peculiarly flat intensity profiles no extrapolation was made and in
these cases the surface brightnesses used are in SuBr column. When
the measurements were not deep enough to determine well the total
magnitudes, the effective values are omitted.
Note (2): The absolute magnitudes are corrected for Galactic extinction and
redshift, whereas for the apparent magnitudes no corrections were
applied.
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Byte-by-byte Description of file: table3.dat table4.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Gal Galaxy name
10- 11 A2 --- n_Gal [*# 12345] Note on Gal (1)
13 A1 --- Band [BVRI] Filter
15- 18 F4.2 arcsec sigma ? Dispersion of the Gaussian point spread
function, measured from the foreground
stars in the images (only in table3.dat)
20- 23 F4.2 --- Delta ? Unweighted rms residual of the fit:
Δ2={Sum}(µi-µfit)2/N
25- 29 F5.2 mag/arcsec2 SuBr0 ? Central surface brightness
31- 35 F5.2 arcsec h ? Disk scalelength
37- 41 F5.2 mag/arcsec2 <SuBrde> ? Disk mean effective surface brightness
43- 47 F5.2 mag/arcsec2 SuBrde ? Disk effective surface brightness
49- 53 F5.2 arcsec Reffd ? Disk effective radius
55- 59 F5.2 mag/arcsec2 <SuBrbe> Bulge mean effective surface brightness
61- 65 F5.2 mag/arcsec2 SuBrbe Bulge effective surface brightness
67- 71 F5.2 arcsec Reffb Bulge effective radius
73- 76 F4.2 --- Bu/D ? Bulge/disk ratio.
77 A1 --- n_Bu/D [*] Note on bulge/disk (2)
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Note (1): Note on Galaxy as follows:
* = model 1 gives a better fit than model 2
# = Galaxies which had the best fit by model 2
1 = The image of Kar 125 B was not deep enough for bulge-to-disk
decomposition
2 = For Kar 331A no reasonable fit was obtained in V, R and I-bands
and the I-band for Kar 331B is not of good enough quality for
the bulge-to-disk decomposition
3 = Instead of model 1 model 3 was used
4 = Instead of model 2, model 4 was used
5 = The best fit was obtained by using a single exponential function
Note (2): Generally the value is obtained by extrapolating to infinity, but
when marked by an asterisk no extrapolation was done
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History: From A&AS electronic version
References:
Laurikainen et al., Paper I 1998A&AS..129..517L 1998A&AS..129..517L
(End) James Marcout, Patricia Bauer [CDS] 31-Jan-2000