USuRPER: Unit-Sphere Representation PERiodogram for full spectra

Abstract

We introduce an extension of the periodogram concept to time-resolved spectroscopy. USuRPER -- Unit Sphere Representation PERiodogram -- is a novel technique which opens new horizons in the analysis of astronomical spectra. It can be used to detect a wide range of periodic variability of the spectrum shape. Essentially, the technique is based on representing spectra as unit vectors in a multidimensional hyperspace, hence its name. It is an extension of the phase-distance correlation (PDC) periodogram we had introduced in previous papers, to very high-dimensional data like spectra. USuRPER takes into account the overall shape of the spectrum, sparing the need to reduce it into a single quantity like radial velocity or temperature. Through simulations we demonstrate its performance in various types of spectroscopic variability -- single-lined and double-lined spectroscopic binary stars and pulsating stars. We also show its performance on actual data of a rapidly oscillating Ap (roAp) star. USuRPER is a new tool to explore large time-resolved spectroscopic databases, e.g. APOGEE, LAMOST and the RVS spectra of Gaia. We have made available to the community a public GitHub repository with a Python implementation of USuRPER, to experiment with it and apply it to a wide range of spectroscopic time series.

arXiv comment7 pages, 10 figures. A&A accepted. The code is available at: https://github.com/SPARTA-dev/SPARTA

References in corpus (16)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Astropy: A Community Python Package for Astronomy
• The NumPy array: a structure for efficient numerical computation
• The Gaia mission
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• Measuring and testing dependence by correlation of distances
• A new extensive library of PHOENIX stellar atmospheres and synthetic spectra
• The Apache Point Observatory Galactic Evolution Experiment (APOGEE)
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• Distance covariance in metric spaces
• A fast algorithm for computing distance correlation
• Pulsation tomography of rapidly oscillating Ap stars. Resolving the third dimension in peculiar pulsating stellar atmospheres
• The discovery of high-amplitude 10.9-minute oscillations in the cool magnetic Ap star HD 115226
• Detection of Periodicity Based on Independence Tests - III. Phase Distance Correlation Periodogram
• Discovery of the spectroscopic binary nature of six southern Cepheids
• Detection of Periodicity Based on Independence Tests - IV. Phase Distance Correlation Periodogram for Two-Dimensional Astrometry

Cited by in corpus (10)

• A transiting warm giant planet around the young active star TOI-201
• TESS Cycle 1 observations of roAp stars with 2-min cadence data
• SOAP-GPU: Efficient Spectral Modelling of Stellar Activity Using Graphical Processing Units
• Ultraviolet Spectropolarimetry: on the origin of rapidly rotating B stars
• Improving Earth-like planet detection in radial velocity using deep learning
• New Periodograms Separating Orbital Radial Velocities and Spectral Shape Variation
• Adaptation of the Phase Distance Correlation Periodogram to Account for Measurement Uncertainties
• Constraining an exoplanets magnetic field using star-planet interactions
• The VELOCE modulation zoo III. Detecting additional pulsation modes in optical spectra of classical Cepheids using semi-partial distance correlation periodograms
• Model Independent Periodogram for Scanning Astrometry