J/A+A/318/416 Radial velocities & photometry of classical Cepheids (Pont+ 1997)
Rotation of the outer disc from classical Cepheids.
Pont F., Queloz D., Bratschi P., Mayor M.
<Astron. Astrophys. 318, 416 (1997)>
=1997A&A...318..416P 1997A&A...318..416P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Radial velocities ; Photometry
Keywords: stars: distance - kinematics - Cepheids -
Galaxy: kinematics and dynamics
Description:
Radial velocities and distances have been measured for a sample of 48
remote classical Cepheids located in the outer disc of the Galaxy
(118deg<l<274deg). The distances are determined from BVI photometry,
with semi-empirical metallicity corrections calibrated on the
Magellanic Clouds. Using these Cepheids as tracers, the rotation curve
of the disc is determined between R0 and 2R0. The result is a flat
rotation curve about 30km/s lower than theta0, Vrot=193±4km/s
for R0≡8.5kpc and theta0=220kms/s assumed, or Vrot=167±4km/s
for R0=8kpc and theta0=200km/s. The possible presence of
non-axisymmetric components in the rotation of the outer disc is
considered. We find a very small or vanishing value for any radial
motion of the LSR or expansion/contraction motion.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
coravel 32 141 Coravel measurements
elodie 35 163 Elodie measurements
photom 49 224 Photometric measurements
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Byte-by-byte Description of file: coravel
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Bytes Format Units Label Explanations
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1- 11 F11.3 d HJD Heliocentric Julian date
13- 18 F6.2 km/s RV Radial velocity
20- 23 F4.2 km/s e_RV ? rms uncertainty on RV
25- 30 A6 --- Name Object name
32 A1 --- Com Comment (1)
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Note (1): a: uncertain cross-correlation function
b: doubtful identification
c: almost certainly mistaken identification
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Byte-by-byte Description of file: elodie
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Bytes Format Units Label Explanations
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1- 11 F11.3 d HJD Heliocetric Julian date
13- 20 F8.3 km/s RV Radial velocity
22- 26 F5.3 km/s e_RV rms uncertainty in RV (photon noise only)
28- 35 A8 --- Name Object name
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Byte-by-byte Description of file: photom
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Object name
10- 19 F10.2 d HJD Heliocentric Julian date
21- 26 F6.3 mag Vmag V (Geneva) filter
28- 33 F6.3 mag V-B V-B (Geneva) filter
35- 39 F5.3 mag V-R V-R (Gunn) filter
41- 45 F5.3 mag V-I V-I (Cousins) filer
48- 49 A2 --- Com Comment (1)
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Note (1): a: low number of counts on B, uncertainty larger than 3%
b: low number of counts on V
c: observing run with too little standards observed, values
with higher errors.
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(End) Patricia Bauer [CDS] 28-Jun-1996