J/MNRAS/423/962 Structure and dynamics of 8 low SB disc galaxies (Morelli+ 2012)
Structure and dynamics of galaxies with a low surface-brightness disc.
II. Stellar populations of bulges.
Morelli L., Corsini E.M., Pizzella A., Dalla Bonta E., Coccato L.,
Mendez-Abreu J., Cesetti M.
<Mon. Not. R. Astron. Soc., 423, 962-982 (2012)>
=2012MNRAS.423..962M 2012MNRAS.423..962M
ADC_Keywords: Galaxies, photometry ; Morphology ; Abundances
Keywords: galaxies: abundances - galaxies: bulges - galaxies: evolution -
galaxies: formation - galaxies: kinematics and dynamics -
galaxies: stellar content
Abstract:
We present the radial profiles of the Hα, Mg and Fe
line-strength indices for a sample of eight spiral galaxies with a
low-surface-brightness stellar disc and a bulge. The correlations
between the central values of the line-strength indices and velocity
dispersion are consistent with those known for early-type galaxies and
bulges of high-surface-brightness galaxies. The age, metallicity and
α/Fe enhancement of the stellar populations in the
bulge-dominated region are obtained using stellar population models
with variable element abundance ratios.
Description:
All the sample galaxies were selected to be spiral galaxies with a
bulge and a LSB disc. Six of these were taken from Paper I (Cat.
J/MNRAS/387/1099), and their broad-band images and long-slit spectra
were already available to us. Therefore, we refer to Paper I (Cat.
J/MNRAS/387/1099) for a detailed description of the photometric and
kinematic data that we use in this paper to measure the line-strength
indices of these galaxies. In addition, two more late-type spirals
were taken from the catalogue of candidate LSB galaxies by Impey et
al. (1996, Cat. J/ApJS/105/209).
The photometric and spectroscopic observations of PGC 26148 and PGC
37759 were carried out with the Very Large Telescope (VLT) of the
European Southern Observatory (ESO) at the Paranal Observatory on 2006
March 23-25 and 2008 February 17-18.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
galaxies.dat 188 8 Parameters of the sample galaxies
tablea1.dat 72 41 Stellar kinematics of the sample galaxies
tablea2.dat 95 283 Line-strength indices of the sample galaxies
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See also:
J/ApJS/105/209 : Low surface brightness galaxies. The catalog (Impey+ 1996)
J/MNRAS/387/1099 : Spectroscopic study of 10 high SB galaxies (Pizzella+, 2008)
(paper I)
Byte-by-byte Description of file: galaxies.dat
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Bytes Format Units Label Explanations
-------------------------------------------------------------------------------
1- 14 A14 --- Name Galaxy name
16- 19 A4 --- MType Morphological classification (1)
21- 23 F3.1 --- TT Numerical morphological (typical error 1.0) (1)
25- 27 F3.1 arcmin Maj Apparent isophotal diameter (2)
28 A1 --- --- [x]
29- 31 F3.1 arcmin Min Apparent isophotal diameter (2)
33- 37 F5.2 mag BTmag Total observed blue magnitude (1)
39- 43 I5 km/s RV Radial velocity with respect to the cosmic
microwave background (CMB) reference frame (1)
45- 49 F5.1 Mpc Dist Distance obtained as VCMB/H0 with H0=75km/s/Mpc
51- 56 F6.2 mag BTMAG Absolute total blue magnitude from BT corrected
for extinction, as in LEDA, and adopting Dist
58- 62 F5.1 km/s sigma Central value of velocity dispersion measured
within an aperture of radius 0.3re
64- 66 F3.1 km/s e_sigma rms uncertainty on sigma
68- 71 F4.2 0.1nm <Fe> Fe line-strength index measured within an
aperture of radius 0.3re
73- 76 F4.2 0.1nm e_<Fe> rms uncertainty on <Fe>
78- 81 F4.2 0.1nm [MgFe] Combined Mg-Fe line-strength index measured
within an aperture of radius 0.3re
83- 86 F4.2 0.1nm e_[MgFe] rms uncertainty on [MgFe]
88- 92 F5.3 mag Mg2 Mg2 line-strength index measured within an
aperture of radius 0.3re
94- 98 F5.3 mag e_Mg2 rms uncertainty on Mg2
100-103 F4.2 0.1nm Mgb Mgb line-strength index measured within an
aperture of radius 0.3re
105-108 F4.2 0.1nm e_Mgb rms uncertainty on Mgb
110-113 F4.2 0.1nm Hb Hβ line-strength index measured within
an aperture of radius 0.3re
115-118 F4.2 0.1nm e_Hb rms uncertainty on Hb
120 I1 --- s [1/2] Source of photometric and spectroscopic
data: 1=Paper I (J/MNRAS/387/1099), 2=this paper
122-124 F3.1 Gyr Age Mean age of the stellar population of the bulge
126-128 F3.1 Gyr e_Age rms uncertainty on Age
130-134 F5.2 [-] [Z/H] Total metallicity of the stellar population
of the bulge
136-139 F4.2 [-] e_[Z/H] rms uncertainty on [Z/H]
141-145 F5.2 [-] [a/Fe] α/Fe enhancement of the stellar population
of the bulge
147-150 F4.2 [-] e_[a/Fe] rms uncertainty on [a/Fe]
152-155 F4.1 arcsec rbd Radius where the surface-brightness
contributions of the bulge and disc are equal
157-161 F5.2 Gyr DAge Gradient of age (3)
163-166 F4.2 Gyr e_DAge rms uncertainty on Age
168-172 F5.2 [-] D[Z/H] Gradient of metallicity (3)
174-177 F4.2 [-] e_D[Z/H] rms uncertainty on D[Z/H]
179-183 F5.2 [-] D[a/Fe] Gradient of α/Fe enhancement (3)
185-188 F4.2 [-] e_D[a/Fe] rms uncertainty on D[alpha/Fe]
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Note (1): from the Lyon Extragalactic Data base (LEDA).
Note (2): measured at a surface-brightness level of µB=25mag/arcsec2
from LEDA.
Note (3): Gradients of age, metallicity and alpha/Fe enhancement of the
stellar populations of the sample bulges derived from the central
values and values at the radius rbd.
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name Galaxy name
15- 16 A2 --- Orient Orientation
(MJ for major axis, MN for minor axis)
18- 23 F6.2 arcsec r Radius
25- 30 F6.1 km/s v Line-of-sight velocity
32- 35 F4.1 km/s e_v rms uncertainty on v
37- 41 F5.1 km/s sigma Velocity dispersion
43- 46 F4.1 km/s e_sigma rms uncertainty on sigma
48- 53 F6.3 --- h3 Third-order Gauss-Hermite moment of the stars
55- 59 F5.3 --- e_h3 rms uncertainty on h3
61- 66 F6.3 --- h4 Fourth-order Gauss-Hermite moment of the stars
68- 72 F5.3 --- e_h4 rms uncertainty on h4
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Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name Galaxy name
16- 25 A10 --- Orient Orientation
(MJ for major axis, MN for minor axis)
27- 32 F6.2 arcsec r Radius
34- 38 F5.3 0.1nm Hb Hβ line-strength index
40- 44 F5.3 0.1nm e_Hb rms uncertainty on Hb
46- 51 F6.3 mag Mg2 Mg2 line-strength index
53- 57 F5.3 mag e_Mg2 rms uncertainty on Mg2
59- 64 F6.3 0.1nm Mgb Mgb line-strength index
66- 70 F5.3 0.1nm e_Mgb rms uncertainty on Mgb
72- 77 F6.3 0.1nm Fe5270 Fe5270Å line-strength index
79- 83 F5.3 0.1nm e_Fe5270 rms uncertainty on Fe5270
85- 89 F5.3 0.1nm Fe5335 Fe5335Å line-strength index
91- 95 F5.3 0.1nm e_Fe5335 rms uncertainty on Fe5335
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History:
From electronic version of the journal
References:
Pizzella et al., Paper I 2008MNRAS.387.1099P 2008MNRAS.387.1099P, Cat. J/MNRAS/387/1099
(End) Patricia Vannier [CDS] 02-Apr-2013