HiFLEx—A Highly Flexible Package to Reduce Cross-dispersed Echelle Spectra

Errmann, R.; Cook, Neil J.; Anglada-Escudé, G.; Sithajan, Sirinrat; Mkrtichian, D. E.; Semenko, E. A.; Martin, W.; Tanvir, Tabassum S.; Feng, Fabo; Collett, J. L.; Jones, H. R. A.

doi:10.1088/1538-3873/ab8783

Cited by 10 publications

(10 citation statements)

References 26 publications

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“…Only point (2), corresponding to a better extraction of the RV content of a spectra, has not been intensively studied in the last decade. Only a few papers have recently addressed this question (Dumusque 2018;Errmann et al 2020;Zechmeister et al 2020;Trifonov et al 2020). However, this step is essential for better understanding stellar activity if an improvement in RV precision can be obtained.…”

Section: Introductionmentioning

confidence: 99%

YARARA: Significant improvement in RV precision through post-processing of spectral time series

Cretignier

Dumusque

Hara

et al. 2021

A&A

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Aims. Even the most precise radial-velocity instruments gather high-resolution spectra that present systematic errors that a data reduction pipeline cannot identify and correct for efficiently by simply analysing a set of calibrations and a single science frame. In this paper we aim at improving the radial-velocity precision of HARPS measurements by 'cleaning' individual extracted spectra using the wealth of information contained in spectral time series. Methods. We developed YARARA, a post-processing pipeline designed to clean high-resolution spectra of instrumental systematics and atmospheric contamination. Spectra are corrected for: tellurics, interference patterns, detector stitching, ghosts, and fibre B contaminations, as well as more advanced spectral line-by-line corrections. YARARA uses principal component analysis on spectral time series with prior information to disentangle contaminations from real Doppler shifts. We applied YARARA to three systems, HD10700, HD215152, and HD10180, and compared our results to the standard HARPS data reduction software and the SERVAL post-processing pipeline.Results. We ran YARARA on the radial-velocity dataset of three stars intensively observed with HARPS: HD10700, HD215152, and HD10180. For HD10700, we show that YARARA enables us to obtain radial-velocity measurements that present an rms smaller than 1 m s −1 over the 13 years of the HARPS observations, which is 20% and 10% better than the HARPS data reduction software and the SERVAL post-processing pipeline, respectively. We also injected simulated planets into the data of HD10700 and demonstrated that YARARA does not alter pure Doppler-shifted signals. For HD215152, we demonstrated that the 1-year signal visible in the periodogram becomes marginal after processing with YARARA and that the signals of the known planets become more significant. Finally, for HD10180, the six known exoplanets are well recovered, although different orbital parameters and planetary masses are provided by the new reduced spectra. Conclusions. The post-processing correction of spectra using spectral time series allows the radial-velocity precision of HARPS data to be significantly improved and demonstrates that for the extremely quiet star HD10700 a radial-velocity rms better than 1 m/s can be reached over the 13 years of HARPS observations. Since the processing proposed in this paper does not absorb planetary signals, its application to intensively followed systems is promising and will certainly result in advances in the detections of the lightest exoplanets.

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Section: Introductionmentioning

confidence: 99%

YARARA: Significant improvement in RV precision through post-processing of spectral time series

Cretignier

Dumusque

Hara

et al. 2021

A&A

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“…5. Additionally, a new and more precise radial velocity of this star was obtained by Errmann et al (2020). In Fig.…”

Section: Example Results In Detail: Past Dynamics Of Comet C/2015 Xy1...mentioning

confidence: 99%

Galactic and stellar perturbations of long period comet motion -- Practical considerations

Dybczyński,

Breiter

2021

Preprint

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Context. Due to our increasing knowledge on the Galactic and stellar neighborhood of the Solar System, modern long-period comet motion studies have to take into account both stellar perturbations and the overall Galactic potential. Aims. Our aim is to propose algorithms and methods to perform numerical integration of a Solar System small body equations of motion much faster and at the same time with greater precision. Methods. We propose a new formulation of the equations of motion formulated in the Solar System barycentric frame but accurately accounting for the differential perturbations caused by the Galactic potential. To use these equations effectively we provide numerical ephemerides of the Galactic positions of the Sun and a set of potential stellar perturbers. Results. The proposed methods offer the precision higher by several orders of magnitude and simultaneously greatly reduce the necessary CPU time. The application of this approach is presented with the example of a detailed dynamical study of the past motion of comet C/2015 XY1.

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“…The philosophy has been that once a wavelength solution exists for one configuration a new nearby solution might be found relatively easily given knowledge of the expected known wavelength spectral lines. The data reduction software known as HIFLEx is available on github 4 and described in Errmann et al (2020).…”

Section: Data Reduction and Analysismentioning

confidence: 99%

“…Our currently preferred methodology for achieving efficient focal reduction is through efficient tapering of the input fibre from the telescope as presented by Choochalerm et al (2020). Alongside these efforts we have developed a data reduction pipeline (Errmann et al 2020) which can be used for EXOhSPEC but is specifically built with the flexibility to examine data from our laboratory prototypes. In Section 2, we outline and present the basic spectrograph, considering its design and components.…”

Section: Introductionmentioning

confidence: 99%

A small actively-controlled high-resolution spectrograph based on off-the-shelf components

Jones,

Martin,

Anglada-Escudé

et al. 2020

Preprint

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We present the design and testing of a prototype in-plane echelle spectrograph based on an actively controlled fibre-fed double-pass design. This system aims to be small and efficient with the minimum number of optical surfaces -currently a collimator/camera lens, cross-dispersing prism, grating and a reflector to send light to the detector. It is built from catalogue optical components and has dimensions of approximately 20×30 cm. It works in the optical regime with a resolution of >70,000. The spectrograph is fed by a bifurcated fibre with one fibre to a telescope and the other used to provide simultaneous Thorium Argon light illumination for wavelength calibration. The positions of the arc lines on the detector are processed in real time and commercial auto-guiding software is used to treat the positions of the arc lines as guide stars. The guiding software sends any required adjustments to mechanical piezo-electric actuators which move the mirror sending light to the camera removing any drift in the position of the arc lines. The current configuration using an sCMOS detector provides a precision of 3.5 milli-pixels equivalent to 4 m/s in a standard laboratory environment.

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HiFLEx—A Highly Flexible Package to Reduce Cross-dispersed Echelle Spectra

Cited by 10 publications

References 26 publications

YARARA: Significant improvement in RV precision through post-processing of spectral time series

YARARA: Significant improvement in RV precision through post-processing of spectral time series

Galactic and stellar perturbations of long period comet motion -- Practical considerations

A small actively-controlled high-resolution spectrograph based on off-the-shelf components

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