J/A+A/502/951 HARPS observations of nine galactic Cepheids (Nardetto+, 2009)
High resolution spectroscopy for Cepheids distance determination.
V. Impact of the cross-correlation method on the p-factor and the
gamma-velocities.
Nardetto N., Gieren W., Kervella P., Fouque P., Storm J., Pietrzynski G.,
Mourard D., Queloz D.
<Astron. Astrophys. 502, 951 (2009)>
=2009A&A...502..951N 2009A&A...502..951N
ADC_Keywords: Stars, variable ; Spectroscopy ; Radial velocities
Keywords: techniques: spectroscopic - stars: atmospheres - stars: oscillations -
stars: variables: Cepheids - stars: distances
Abstract:
We observed eight galactic Cepheids with the HARPS spectrograph. For
each star, we derive an interpolated cross-correlated radial velocity
curve using the HARPS pipeline. Pulsating phases and HARPS radial
velocity measurements can be found in Table 1.
The cross correlation method is widely used to derive the radial
velocity curve of Cepheids when the signal to noise ratio of the
spectra is low. However, if it is used with an inac curate projection
factor, it might introduce some biases in the Baade-Wesselink (BW)
methods of determining the distance of Cepheids. In addition, it might
affect the average value of the radial velocity curve (or
gamma-velocity) important for Galactic structure studies.
See the paper for details and results.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 29 8 The Cepheids studied listed with increasing period
table45.dat 25 119 HARPS cross-correlated radial velocities of
eight Cepheids
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See also:
J/A+A/453/309 : HARPS observations of nine galactic Cepheids (Nardetto+ 2006)
J/A+A/489/1255 : HARPS observations of eight galactic Cepheids (Nardetto+ 2008)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Star name
10- 17 F8.5 d Per Period
19- 20 I2 % D4896 Depth of the FeI 4896.439Å spectral line
22- 25 F4.1 km/s DRVc Amplitude of the radial velocity curve of
FeI 4896.439Å
27- 29 F3.1 km/s e_DRVc rms uncertainty on DRVc
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Byte-by-byte Description of file: table45.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Star name
10- 13 F4.2 --- Phase Pulsating phase (1)
15- 20 F6.2 km/s RVcc Cross-correlated radial velocity
22- 25 F4.2 km/s e_RVcc rms uncertainty on RVcc
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Note (1): Ephemeris can be found in Nardetto et al. 2006, Cat. J/A+A/453/309
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Acknowledgements:
N. Nardetto, nnardetto(at)astro-udec.cl
References:
Nardetto et al., Paper I 2006A&A...453..309N 2006A&A...453..309N, Cat. J/A+A/453/309
Nardetto et al., Paper II 2007A&A...471..661N 2007A&A...471..661N
Nardetto et al., Paper III 2008A&A...489.1255N 2008A&A...489.1255N, Cat. J/A+A/489/1255
Nardetto et al., Paper IV 2008A&A...489.1263N 2008A&A...489.1263N
(End) Patricia Vannier [CDS] 04-Jul-2009