J/A+A/516/A4 NGC1600, NGC4125, NGC7619 extended spectroscopy (Pu+, 2010)
Radially extended kinematics and stellar populations of the massive ellipticals
NGC1600, NGC4125 and NGC7619.
Constraints on the outer dark halo density profile.
Pu S.B., Saglia R.P., Thomas J., Fabricius M., Bender R., Han Z.
<Astron. Astrophys. 516, A4 (2010)>
=2010A&A...516A...4P 2010A&A...516A...4P
ADC_Keywords: Galaxies, spectra ; Morphology ; Radial velocities ;
Velocity dispersion
Keywords: galaxies: elliptical and lenticular, cD - Galaxy: abundances -
galaxies: kinematic and dynamics -
galaxies, individual: NGC1600, NGC4125, NGC7619
Abstract:
We present high quality long slit spectra along the major and minor
axes out to 1.5-2Re (14-22kpc) of three bright elliptical galaxies
(NGC1600, NGC4125, NGC7619) obtained at the Hobby-Eberly Telescope
(HET). We derive stellar kinematic profiles and Lick/IDS indices
(Hβ, Mgb, Fe_{5015}, Fe_{5270}, Fe_{5335}, Fe_{5406}). Moreover,
for NGC4125 we derive gas kinematics and emission line strengths. We
model the absorption line strengths using Simple Stellar Populations
models that take into account the variation of α/Fe and derive
ages, total metallicity and element abundances. Overall, we find that
the three galaxies have old and α/Fe overabundant stellar
populations with no significant gradients. The metallicity is
supersolar at the center with a strong negative radial gradient. For
NGC4125, several pieces of evidence point to a recent dissipational
merger event. We calculate the broad band color profiles with the help
of SSP models. All of the colors show sharp peaks at the center of the
galaxies, mainly caused by the metallicity gradients, and agree well
with the measured colors. Using the Schwarzschild's axisymmetric orbit
superposition technique, we model the stellar kinematics to constrain
the dark halos of the galaxies. We use the tight correlation between
the Mgb strength and local escape velocity to set limits on their
extent by testing different halo sizes. Logarithmic halos cut at 60kpc
minimize the overall scatter of the Mgb-Vesc relation. Larger cutoff
radii are found if the dark matter density profile is decreasing more
steeply at large radii.
Description:
The stellar kinematics (Table 3) and the Lick absorption line strength
indices (Table 6) of NGC1600, NGC4125, NGC7619; the gas kinematics the
equivalent widths of Hβ gas emission line, plus the EW ratios
[OIII]/Hβ and [NI]/Hβ of NGC4125 (Table 4) presented here
have been measured from spectra taken with the Hobby-Eberly Telescope
and the Low Resolution Spectrograph. We observed the major and minor
axes of these galaxies with a slit width of 3-arcsec, a spectral
resolution of sigma∼120km/s and covering the spectral range
4790-5850Å, with seeing values between 1.4 and 2.57-arcsec.
Objects:
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RA (2000) DE Designation(s)
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04 31 39.9 -05 05 10 NGC1600 = NGC 1600
12 08 06.3 +65 10 27 NGC4125 = NGC 4125
23 20 14.7 +08 12 23 NGC7619 = NGC 7619
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 95 351 Stellar kinematics along major and minor axes of
NGC1600, NGC4125, NGC7619
table4.dat 79 95 Gas kinematics and emission equivalent width and
ratios along major and minor axes of NGC4125
table6.dat 129 352 Lick indices along major and minor axes of
NGC1600, NGC4125, NGC7619
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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- 7 A7 --- Galaxy Galaxy name
9- 15 F7.2 arcsec R Distance from the galaxy center (G1)
17- 19 I3 deg PA Position angle (G2)
21- 27 F7.2 km/s RV Stellar radial velocity, positive receiding
29- 34 F6.2 km/s e_RV Error on stellar radial velocity
36- 41 F6.2 km/s e:RV Systematic error on stellar radial velocity due
to the sky subtraction
44- 49 F6.2 km/s sigma Stellar velocity dispersion
51- 56 F6.2 km/s e_sigma Error on stellar velocity dispersion
58- 63 F6.2 km/s e:sigma Systematic error on stellar velocity dispersion
to the sky subtraction
65- 69 F5.2 --- H3 3rd order Hermite coefficient
71- 74 F4.2 --- e_H3 Error on 3rd order Hermite coefficient
76- 79 F4.2 --- e:H3 Systematic error on 3rd order Hermite
coefficient to the sky subtraction
81- 85 F5.2 --- H4 4th order Hermite coefficient
87- 90 F4.2 --- e_H4 Error on 4th order Hermite coefficient
92- 95 F4.2 --- e:H4 Systematic error on 4th order Hermite
coefficient due to the sky subtraction
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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- 7 A7 --- Galaxy Galaxy name
10- 14 F5.1 arcsec R Distance from the center
16- 18 I3 deg PA Position angle (G2)
20- 25 F6.1 km/s Vgas Gas radial velocity, positive receiding
28- 31 F4.1 km/s e_Vgas Error on gas radial velocity
33- 37 F5.1 km/s sig.gas Gas velocity dispersion
40- 43 F4.1 km/s e_sig.gas Error on gas velocity dispersion
45- 49 F5.2 0.1nm Hbe Equivalent width of the Hβ gas emission
52- 55 F4.2 0.1nm e_Hbe Error on EW of the Hβ gas emission
58- 61 F4.2 --- OH Ratio [OIII]/Hβ of the gas emission EWs
64- 67 F4.2 --- e_OH Error on OH
70- 73 F4.2 --- NH Ratio [NI]/Hβ of the gas emission EWs
76- 79 F4.2 --- e_NH Error on NH
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Galaxy Galaxy name
9- 15 F7.2 arcsec R Distance from the center (G1)
17- 19 I3 deg PA Position angle (G2)
21- 25 F5.2 0.1nm Hb Hβ line strength
28- 31 F4.2 0.1nm e_Hb Error on the Hβ line strength
33- 37 F5.2 0.1nm e:Hb Systematic error on the Hβ line
strength due to the sky subtraction
39- 43 F5.2 0.1nm Mgb Mgb line strength
46- 49 F4.2 0.1nm e_Mgb Error on the Mgb line strength
51- 55 F5.2 0.1nm e:Mgb Systematic error on the Mgb line
strength due to the sky subtraction
57- 61 F5.2 0.1nm Fe1 Fe5015 line strength
64- 67 F4.2 0.1nm e_Fe1 Error on the Fe5015 line strength
69- 73 F5.2 0.1nm e:Fe1 Systematic error on the Fe5015 line
strength due to the sky subtraction
75- 79 F5.2 0.1nm Fe2 Fe5270 line strength
82- 85 F4.2 0.1nm e_Fe2 Error on the Fe5270 line strength
87- 91 F5.2 0.1nm e:Fe2 Systematic error on the Fe5270 line
strength due to the sky subtraction
93- 97 F5.2 0.1nm Fe3 Fe5335 line strength
100-103 F4.2 0.1nm e_Fe3 Error on the Fe5335 line strength
105-109 F5.2 0.1nm e:Fe3 Systematic error on the Fe5335 line
strength due to the sky subtraction
111-115 F5.2 0.1nm Fe4 Fe5406 line strength
118-121 F4.2 0.1nm e_Fe4 Error on the Fe5406 line strength
125-129 F5.2 0.1nm e:Fe4 Systematic error on the Fe5406 line
strength due to the sky subtraction
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Global notes:
Note (G1): slit data with R<0" correspond to:
* NGC1600: North-East side along the major axis (PA=9) and on the
North-West side along the minor axis (PA=99).
* NGC4125: South-West side along the major axis (PA=82) and on the
South-East side along the minor axis (PA=172).
* NGC7619: North-East side along the major axis (PA=36) and on the
North-West side along the minor axis (PA=126).
Note (G2): Position angles of our galaxies:
NGC1600 = [major, minor] are [9, 99]
NGC4125 = [major, minor] are [82, 172]
NGC7619 = [major, minor] are [36, 126]
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Acknowledgements:
Pu Shibi, pushibi(at)ynao.ac.cn
Roberto Saglia, saglia(at)mpe.mpg.de
(End) Pu Shibi [[YNAO, China], Patricia Vannier [CDS] 19-Apr-2010