On the Automated and Objective Detection of Emission Lines in Faint-Object Spectroscopy

Sungryong Hong; Arjun Dey; Moire Kathleen Murphy Prescott

doi:10.1086/679285

On the Automated and Objective Detection of Emission Lines in Faint-Object Spectroscopy

Sungryong Hong, Arjun Dey, Moire Kathleen Murphy Prescott

DARK

3 Citationer (Scopus)

Abstract

Modern spectroscopic surveys produce large spectroscopic databases, generally with sizes well beyond the scope of manual investigation. The need arises, therefore, for an automated line detection method with objective indicators for detection significance. In this paper, we present an automated and objective method for emission line detection in spectroscopic surveys and apply this technique to observed spectra from a Lyα emitter survey at z ∼ 2:7, obtained with the Hectospec spectrograph on the MMT Observatory (MMTO). The basic idea is to generate on-source (signal plus noise) and off-source (noise only) mock observations using Monte Carlo simulations, and calculate completeness and reliability values, ðC;RÞ, for each simulated signal. By comparing the detections from real data with the Monte Carlo results, we assign the completeness and reliability values to each real detection. From 1574 spectra, we obtain 881 raw detections and, by removing low reliability detections, we finalize 652 detections from an automated pipeline. Most of high completeness and reliability detections, ðC;RÞ≈ ð1:0; 1:0Þ, are robust detections when visually inspected; the low C and R detections are also marginal on visual inspection. This method of detecting faint sources is dependent on the accuracy of the sky subtraction.

Originalsprog	Engelsk
Tidsskrift	Publications of the Astronomical Society of the Pacific
Vol/bind	126
Udgave nummer	945
Sider (fra-til)	1048-1067
ISSN	0004-6280
DOI	https://doi.org/10.1086/679285
Status	Udgivet - 20 nov. 2014

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10.1086/679285

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title = "On the Automated and Objective Detection of Emission Lines in Faint-Object Spectroscopy",

abstract = "Modern spectroscopic surveys produce large spectroscopic databases, generally with sizes well beyond the scope of manual investigation. The need arises, therefore, for an automated line detection method with objective indicators for detection significance. In this paper, we present an automated and objective method for emission line detection in spectroscopic surveys and apply this technique to observed spectra from a Lyα emitter survey at z ∼ 2:7, obtained with the Hectospec spectrograph on the MMT Observatory (MMTO). The basic idea is to generate on-source (signal plus noise) and off-source (noise only) mock observations using Monte Carlo simulations, and calculate completeness and reliability values, {\dh}C;R{\TH}, for each simulated signal. By comparing the detections from real data with the Monte Carlo results, we assign the completeness and reliability values to each real detection. From 1574 spectra, we obtain 881 raw detections and, by removing low reliability detections, we finalize 652 detections from an automated pipeline. Most of high completeness and reliability detections, {\dh}C;R{\TH}≈ {\dh}1:0; 1:0{\TH}, are robust detections when visually inspected; the low C and R detections are also marginal on visual inspection. This method of detecting faint sources is dependent on the accuracy of the sky subtraction.",

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AU - Dey, Arjun

AU - Prescott, Moire Kathleen Murphy

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Y1 - 2014/11/20

N2 - Modern spectroscopic surveys produce large spectroscopic databases, generally with sizes well beyond the scope of manual investigation. The need arises, therefore, for an automated line detection method with objective indicators for detection significance. In this paper, we present an automated and objective method for emission line detection in spectroscopic surveys and apply this technique to observed spectra from a Lyα emitter survey at z ∼ 2:7, obtained with the Hectospec spectrograph on the MMT Observatory (MMTO). The basic idea is to generate on-source (signal plus noise) and off-source (noise only) mock observations using Monte Carlo simulations, and calculate completeness and reliability values, ðC;RÞ, for each simulated signal. By comparing the detections from real data with the Monte Carlo results, we assign the completeness and reliability values to each real detection. From 1574 spectra, we obtain 881 raw detections and, by removing low reliability detections, we finalize 652 detections from an automated pipeline. Most of high completeness and reliability detections, ðC;RÞ≈ ð1:0; 1:0Þ, are robust detections when visually inspected; the low C and R detections are also marginal on visual inspection. This method of detecting faint sources is dependent on the accuracy of the sky subtraction.

AB - Modern spectroscopic surveys produce large spectroscopic databases, generally with sizes well beyond the scope of manual investigation. The need arises, therefore, for an automated line detection method with objective indicators for detection significance. In this paper, we present an automated and objective method for emission line detection in spectroscopic surveys and apply this technique to observed spectra from a Lyα emitter survey at z ∼ 2:7, obtained with the Hectospec spectrograph on the MMT Observatory (MMTO). The basic idea is to generate on-source (signal plus noise) and off-source (noise only) mock observations using Monte Carlo simulations, and calculate completeness and reliability values, ðC;RÞ, for each simulated signal. By comparing the detections from real data with the Monte Carlo results, we assign the completeness and reliability values to each real detection. From 1574 spectra, we obtain 881 raw detections and, by removing low reliability detections, we finalize 652 detections from an automated pipeline. Most of high completeness and reliability detections, ðC;RÞ≈ ð1:0; 1:0Þ, are robust detections when visually inspected; the low C and R detections are also marginal on visual inspection. This method of detecting faint sources is dependent on the accuracy of the sky subtraction.

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DO - 10.1086/679285

M3 - Journal article

SN - 0004-6280

VL - 126

SP - 1048

EP - 1067

JO - Publications of the Astronomical Society of the Pacific

JF - Publications of the Astronomical Society of the Pacific

IS - 945

ER -

On the Automated and Objective Detection of Emission Lines in Faint-Object Spectroscopy

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