J/A+A/636/A74 HARPS radial velocity database (Trifonov+, 2020)
A public HARPS radial velocity database corrected for systematic errors.
Trifonov T., Tal-Or L., Zechmeister M., Kaminski A., Zucker S., Mazeh T.
<Astron. Astrophys. 636, A74 (2020)>
=2020A&A...636A..74T 2020A&A...636A..74T (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Radial velocities
Keywords: techniques: radial velocities - astronomical data bases -
stars: individual: GJ 253 - planetary systems
Abstract:
The High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph
is mounted since 2003 at the ESO 3.6m telescope in La Silla and
provides state-of-the-art stellar radial velocity (RV) measurements
with a precision down to ∼1m/s. The spectra are extracted with a
dedicated data-reduction software (DRS) and the RVs are computed by
cross correlating with a numerical mask.
The aim of this study is three-fold: (i) Create an easy access to the
public HARPS RV data set. (ii) Apply the new public SpEctrum Radial
Velocity AnaLyser (SERVAL) pipeline to the spectra, and produce a more
precise RV data set. (iii) Check whether the precision of the RVs can
be further improved by correcting for small nightly systematic
effects.
For each star observed with HARPS, we downloaded the publicly
available spectra from the ESO archive, and recomputed the RVs with
SERVAL. This was based on fitting each observed spectrum with a high
signal-to-noise ratio template created by co-adding all the available
spectra of that star. We then computed nightly zero points (NZPs) by
averaging the RVs of quiet stars.
Analysing the RVs of the most RV-quiet stars, whose RV scatter is
<5m/s, we find that SERVAL RVs are on average more precise than DRS
RVs by a few percent. Investigating the NZP time series, we find three
significant systematic effects, whose magnitude is independent of the
software used for the RV derivation: (i) stochastic variations with a
magnitude of ∼1m/s; (ii) longterm variations, with a magnitude of
∼1m/s and a typical timescale of a few weeks; and (iii) 20-30NZPs
significantly deviating by few m/s. In addition, we find small
(≲1m/s) but significant intra-night drifts in DRS RVs before the 2015
intervention, and in SERVAL RVs after it. We confirm that the fibre
exchange in 2015 caused a discontinuous RV jump, which strongly
depends on the spectral type of the observed star: from ∼14m/s for
late F-type stars, to ~-3m/sx for M dwarfs. The combined effect of
extracting the RVs with SERVAL and correcting them for the systematics
we find is an improved average RV precision: ∼5% improvement for
spectra taken before the 2015 intervention, and ∼15% improvement for
spectra taken after it. To demonstrate the quality of the new RV data
set, we present an updated orbital solution of the GJ 253 two-planet
system.
Our NZP-corrected SERVAL RVs can be retrieved from a user-friendly,
public database. It provides more than 212000 RVs for about 3000
stars along with many auxiliary information, such as the NZP
corrections, various activity indices, and DRS-CCF products.
Description:
Once public, HARPS spectra can be queried and downloaded
from the ESO archive using the generic query form
(http://archive.eso.org/wdb/wdb/adp/phase3_main/form), which provides
access to all phase 3 data reduced by HARPS' data reduction software
(DRS v3.5).
we present an independent systematic analysis of the HARPS spectral
archive. In particular, we re-calculated Doppler velocity measurements
of the publicly accessible spectra, and performed stellar line
analysis, which is important for validating planetary induced Doppler
signals. For this part of the analysis, we applied the SERVAL RV
pipeline, with which we derived slightly more precise RV measurements
when compared to those derived by the official ESO-DRS pipeline.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 174 2912 List of target
rvbank.dat 915 212562 Individual radial velocity measurements and
auxiliary data for all targets
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See also:
http://archive.eso.org/wdb/wdb/adp/phase3_main/form : ESO data Products
Home Page
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Target name
17- 18 I2 h RAh Rihgt ascension (J2000)
20- 21 I2 min RAm Rihgt ascension (J2000)
23- 29 F7.4 s RAs Rihgt ascension (J2000)
31 A1 --- DE- Declination sign (J2000)
32- 33 I2 deg DEd Declination (J2000)
35- 36 I2 arcmin DEm Declination (J2000)
38- 43 F6.3 arcsec DEs Declination (J2000)
45- 64 A20 --- SpType MK spectral type
66- 71 F6.1 K Teff ? Effective temperature
73- 78 F6.3 mag Bmag ? B magnitude
80- 85 F6.3 mag Vmag ? V magnitude
87- 92 F6.3 mag Gmag ? Gaia magnitude
94-100 F7.2 pc Dist ? Distance
102-137 A36 --- FileName1 Name of the ascii file with RV data
in original site (1)
139-174 A36 --- FileName2 Name of the csv file with RV data
in original site (1)
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Note (1): Individual files available at
http://www2.mpia-hd.mpg.de/homes/trifonov/HARPS_RVBank.html
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Byte-by-byte Description of file: rvbank.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Target name
16- 28 F13.5 d BJD Barycentric Julian date
30- 41 F12.3 m/s DRVmlcnzp ?=-9999999 Differential RV from SERVAL
corrected for BERV, SA, drift, NZP,
NZPdrift, -pre and -post calculated
separately) (RVmlcnzp)
43- 54 F12.3 m/s e_DRVmlcnzp ?=-9999999 Differential radial velocity
error (eRVmlc_nzp)
56- 68 F13.3 m/s RVdrsnzp ?=-9999999 Radial velocity from DRS
corrected for BERV, SA, drift, NZP,
NZPdrift, corrected, -pre and -post
calculated separately) (RVdrsnzp)
70- 81 F12.3 m/s e_RVdrsnzp ?=-9999999 Radial velocity error
(eRVdrs_nzp)
83-105 F23.16 m/s DRVmlc Differential RV from SERVAL corrected for
BERV, SA, drift, (non-NZP corrected),
-pre and -post calculated separately
(RV_mlc)
107-129 F23.14 m/s e_DRVmlc ?=-9999999 Differential SERVAL radial
velocity error (eRVmlc)
131-152 F22.12 m/s RVdrs ?=-9999999 RV from DRS corrected for BERV,
SA, drift, (non-NZP corrected), -pre and
-post calculated separately) (RV_drs)
154-175 F22.13 m/s e_RVdrs ?=-9999999 DRS radial velocity error
(eRVdrs)
177-199 F23.16 m/s DRVmlcj Differential RV from SERVAL corrected for
BERV, SA, drift, (non-NZP corrected, joint
RV calculation with -pre and -post fibre
upgrade data) (RVmlcj)
201-223 F23.14 m/s e_DRVmlcj ?=-9999999 Differential radial velocity
error (eRVmlc_j)
225-253 F29.21 m/s CRX Chromatic index from SERVAL
255-277 F23.17 m/s e_CRX Chromatic index error
279-308 F30.24 m/s.km/s dLW Differential line width from SERVAL
310-336 F27.23 m/s.km/s e_dLW Differential line width error
338-357 F20.17 --- Halpha Halpha index from SERVAL
359-381 F23.20 --- e_Halpha [] Halpha index error
383-403 F21.18 --- NaD1 NaD1 index
405-427 F23.20 --- e_NaD1 [] NaD1 index error
429-449 F21.18 --- NaD2 NaD2 index
451-473 F23.20 --- e_NaD2 [] NaD2 index error
475-477 I3 --- Flag [0/128] SERVAL flag bitwise flag (1)
479-499 F21.12 km/s FWHMDRS ?=-9999999 Full width half maximum from DRS
501-523 F23.14 --- Contrast ?=-9999999 Constrast from DRS
(CONTRAST_DRS)
525-545 E21.18 m/s BIS ?=-9999999 Bisector span measurement
from DRS
547-556 F10.3 km/s RVguess ?=-99999 User guess for absolute RV
from DRS
558-562 F5.1 m/s.km/s SNRDRS Signal-to-noise ratio in order 55 from DRS
564-576 F13.5 d BJDDRS Barycentric Julian date from DRS
578-596 F19.15 km/s BERV Barycentric Earth radial velocity
598-617 F20.16 km/s BERVDRS Barycentric Earth radial velocity from DRS
619-630 F12.3 m/s DRIFT ?=-9999999 drift measure
632-639 I8 m/s E_DRIFT [-9999999] drift measure error (not used)
641-652 F12.3 m/s SA ?=-9999999 Contribution from secular
acceleration
654-665 F12.3 m/s NZPmlc ?=-9999999 NZP for BJD (NZP_mlc)
667-678 F12.3 m/s dNZPmlc ?=-9999999 Contribution from intra-night
systematics (dNZP_mlc)
680-691 F12.3 --- NZPdrs ?=-9999999 NZP for DRS (NZP_drs)
693-700 I8 --- dNZPdrs [-9999999] Contribution from intra-night
systematics (dNZP_drs) (not used)
702-706 F5.2 --- TMmean Flux weighted mean point
708-716 F9.4 s ExpTime Exposure time
718-741 F24.15 m/s MLCRX ML Chromatic index (Slope over logarithmic
wavelength)
743-763 F21.12 m/s E_MLCRX ?=-9999999 Error for MLCRX (slope error)
765-787 A23 "datime" TimeId Identifier for file (time stamp)
789-796 I8 --- DriftLamp [-9999999] FP,ThAr? (DRIFT_LAMP) (not used)
798-805 A8 --- MASK DRS MASK for CCF
807-820 A14 --- PROGID Program ID
822-837 A16 --- PROGPI Program PI name
839-846 I8 m/s.km/s AIRMASS ?=-9999999 Airmass
848-864 A17 --- OBJAB [HARPSechobs_all]
866-889 A24 --- THARFP THARFP
891-915 A25 --- DPRTYPE Type
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Note (1): Bitwise flag as follows:
0 = normal (reliable) spectra
1 = nosci frame, e.g. calibration files
2 = spectra taken in "I2" mode
4 = spectra taken in "eggs" mode
16 = coordinates too much off
32 = spectra not within a nautical twilight (daytime)
64 = spectra with too low S/N
128 = spectra with too high S/N
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Acknowledgements:
Trifon Trifonov, trifonov(at)mpia.de
(End) Patricia Vannier [CDS] 02-Mar-2020