J/A+A/428/877 4 nearby galaxies velocities & line-strengths (Krajnovic+, 2004)
HST observations of nuclear stellar disks.
Krajnovic D., Jaffe W.
<Astron. Astrophys. 428, 877 (2004)>
=2004A&A...428..877K 2004A&A...428..877K
ADC_Keywords: Galaxies, nearby ; Velocity dispersion ; Spectroscopy
Keywords: galaxies: elliptical and lenticular, cD - galaxies: nuclei -
galaxies: kinematics and dynamics - galaxies: galaxies: photometry -
galaxies: stellar content - galaxies: evolution
Abstract:
We present observations of four nearby early-type galaxies
previously known (Rest et al., 2001AJ....121.2431R 2001AJ....121.2431R) to have nuclear
stellar disks using two instruments on-board the Hubble Space
Telescope. We observed NGC 4128, NGC 4612, and NGC 5308 with the Wide
Field Planetary Camera 2, and the same three galaxies, plus NGC 4570,
with the Space Telescope Imaging Spectrograph. We have detected a red
nucleus in NGC 4128, a blue nucleus in NGC 4621, and a blue disk in
NGC 5308. Additionally, we have discovered a blue disk-like feature
with position angle ∼15° from the major axis in NGC 4621. In NGC
5308 there is evidence for a blue region along the minor axis. We
discovered a blue transient on the images of NGC 4128 at position
0.14" west and 0.32" north from the nucleus. The extracted kinematic
profiles belong to two groups: fast (NGC 4570 and NGC 5308) and
kinematically disturbed rotators (NGC 4128 and NGC 4621). We report
the discovery of a kinematically decoupled core in NGC 4128. Galaxies
have mostly old (10-14Gyr) stellar populations with large spread in
metallicities (sub- to super-solar). We discuss the possible formation
scenarios, including bar-driven secular evolution and the influence of
mergers, which can explain the observed color and kinematic features.
Description:
Measured kinematics and line-strengths for observed galaxies
using full spectral region in the fit and excluding Mgb region from
the fit.
Objects:
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RA (2000) DE Designation(s)
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12 08 32.2 +68 46 05 NGC 4128 = UGC 7120
12 36 53.6 +07 14 46 NGC 4570 = UGC 7785
12 42 02.4 +11 38 45 NGC 4621 = M 59 = UGC 7858
13 47 00.4 +60 58 23 NGC 5308 = UGC 8722
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 57 48 Measured kinematics and line-strengths for observed
galaxies using full spectral region in the fit
tablea2.dat 57 48 Measured kinematics and line-strengths for observed
galaxies excluding Mgb region from the fit
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Byte-by-byte Description of file: tablea1.dat tablea2.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [NGC]
5- 8 I4 --- NGC NGC number of the object
10- 14 F5.2 arcsec Radius Radius of measurement
17- 20 I4 km/s Vel Mean velocity
24- 25 I2 km/s e_Vel Mean velocity error
29- 31 I3 km/s sigma Velocity dispersion
35- 36 I2 km/s e_sigma Velocity dispersion error
40- 42 F3.1 0.1nm Mgb Mgb line-strength
45- 47 F3.1 0.1nm e_Mgb Mgb line-strength error
50- 52 F3.1 0.1nm Fe5270 Fe5270 line-strength
55- 57 F3.1 0.1nm e_Fe5270 Fe5270 line-strength error
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Acknowledgements: Davor Krajnovic, davor(at)strw.leidenuniv.nl
(End) Patricia Vannier [CDS] 16-Sep-2004