ORIGIN: Blind detection of faint emission line galaxies in MUSE datacubes

Abstract

One of the major science cases of the MUSE integral field spectrograph is the detection of Lyman-alpha emitters at high redshifts. The on-going and planned deep fields observations will allow for one large sample of these sources. An efficient tool to perform blind detection of faint emitters in MUSE datacubes is a prerequisite of such an endeavor. Several line detection algorithms exist but their performance during the deepest MUSE exposures is hard to quantify, in particular with respect to their actual false detection rate, or purity. {The aim of this work is to design and validate} an algorithm that efficiently detects faint spatial-spectral emission signatures, while allowing for a stable false detection rate over the data cube and providing in the same time an automated and reliable estimation of the purity. Results on simulated data cubes providing ground truth show that the method reaches its aims in terms of purity and completeness. When applied to the deep 30-hour exposure MUSE datacube in the Hubble Ultra Deep Field, the algorithms allows for the confirmed detection of 133 intermediate redshifts galaxies and 248 Lyman Alpha Emitters, including 86 sources with no HST counterpart. The algorithm fulfills its aims in terms of detection power and reliability. It is consequently implemented as a Python package whose code and documentation are available on GitHub and readthedocs.

Accepted to Astronomy & Astrophysics

References in corpus (7)

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• The MUSE Hubble Ultra Deep Field Survey: I. Survey description, data reduction and source detection
• ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Survey Description
• The MUSE 3D view of the Hubble Deep Field South
• The MUSE Hubble Ultra Deep Field Survey: II. Spectroscopic redshifts and comparisons to color selections of high-redshift galaxies
• The MUSE Hubble Ultra Deep Field Survey: III. Testing photometric redshifts to 30th magnitude
• The correct estimate of the probability of false detection of the matched filter in the detection of weak signals. II. (Further results with application to a set of ALMA and ATCA data)

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• The MUSE Hubble Ultra Deep Field surveys: Data release II
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• The MUSE Extremely Deep Field: the Cosmic Web in Emission at High Redshift
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• The MUSE eXtremely Deep Field: Individual detections of Lyα haloes around rest-frame UV-selected galaxies at z~2.9-4.4
• The MUSE Extremely Deep Field: a first panoramic view of an Mg II emitting intragroup medium
• Recovery and analysis of rest-frame UV emission lines in 2052 galaxies observed with MUSE at $1.5<z<6.4$
• Measuring the average molecular gas content of star-forming galaxies at $z=3-4$
• Clustering dependence on Lyman-$\alpha$ luminosity from MUSE surveys at $3<z<6$
• MusE GAs FLOw and Wind (MEGAFLOW) XII. Rationale and design of a MgII survey of the cool circum-galactic medium with MUSE and UVES: The MEGAFLOW Survey
• MusE GAs FLOw and Wind (MEGAFLOW) XI. Scaling relations between outflows and host galaxy properties
• The MUSE Extremely Deep Field: Classifying the Spectral Shapes of Lya Emitting Galaxies
• Revisiting the Emission Line Source Detection Problem in Integral Field Spectroscopic Data
• Preliminary analysis on the noise characteristics of MWISP data
• HeII emitters at cosmic noon and beyond. Characterising the HeII λ1640 emission with MUSE and JWST/NIRSpec
• Accurate spectroscopic redshift estimation using non-negative matrix factorization: application to MUSE spectra