LINESTACKER: A spectral line stacking tool for interferometric data
Journal article, 2020

LINESTACKER is a new open access and open source tool for stacking of spectral lines in interferometric data. LINESTACKER is an ensemble of CASA tasks, and can stack both 3D cubes or already extracted spectra. The algorithm is tested on increasingly complex simulated data sets, mimicking Atacama Large Millimeter/submillimeter Array, and Karl G. Jansky Very Large Array observations of [C II] and CO(3-2) emission lines, from z ∼ 7 and z ∼ 4 galaxies, respectively. We find that the algorithm is very robust, successfully retrieving the input parameters of the stacked lines in all cases with an accuracy ≳90 per cent. However, we distinguish some specific situations showcasing the intrinsic limitations of the method. Mainly that high uncertainties on the redshifts (∆z > 0.01) can lead to poor signal-to-noise ratio improvement, due to lines being stacked on shifted central frequencies. Additionally, we give an extensive description of the embedded statistical tools included in LINESTACKER: mainly bootstrapping, rebinning, and subsampling. Velocity rebinning is applied on the data before stacking and proves necessary when studying line profiles, in order to avoid artificial spectral features in the stack. Subsampling is useful to sort the stacked sources, allowing to find a subsample maximizing the searched parameters, while bootstrapping allows to detect inhomogeneities in the stacked sample. LINESTACKER is a useful tool for extracting the most from spectral observations of various types.

Galaxies: statistics

Techniques: interferometric

Radio lines: galaxies

Methods: data analysis

Galaxies: high-redshift

Submillimetre: galaxies

Author

Jean Baptiste Jolly

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Kirsten Kraiberg Knudsen

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Flora Stanley

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 499 3 3992-4010

Galaxy evolution: Tracing the gas fraction of star-forming galaxies

Swedish Research Council (VR) (2015-05580), 2016-01-01 -- 2019-12-31.

Subject Categories

Astronomy, Astrophysics and Cosmology

Bioinformatics (Computational Biology)

Signal Processing

DOI

10.1093/mnras/staa2908

More information

Latest update

12/29/2020