학술논문
The HETDEX Survey: Emission Line Exploration and Source Classification
Document Type
Working Paper
Author
Davis, Dustin; Gebhardt, Karl; Cooper, Erin Mentuch; Ciardullo, Robin; Fabricius, Maximilian; Farrow, Daniel J.; Feldmeier, John J.; Finkelstein, Steven L.; Gawiser, Eric; Gronwall, Caryl; Hill, Gary J.; Hopp, Ulrich; House, Lindsay R.; Jeong, Donghui; Kollatschny, Wolfram; Komatsu, Eiichiro; Landriau, Martin; Liu, Chenxu; Saito, Shun; Tuttle, Sarah; Wold, Isak G. B.; Zeimann, Gregory R.; Zhang, Yechi
Source
Subject
Language
Abstract
The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) is an untargeted spectroscopic survey that aims to measure the expansion rate of the Universe at $z \sim 2.4$ to 1% precision for both $H(z)$ and $D_A(z)$. HETDEX is in the process of mapping in excess of one million Lyman Alpha emitting (LAE) galaxies and a similar number of lower-z galaxies as a tracer of the large-scale structure. The success of the measurement is predicated on the post-observation separation of galaxies with Ly$\alpha$ emission from the lower-$z$ interloping galaxies, primarily [OII], with low contamination and high recovery rates. The Emission Line eXplorer (ELiXer) is the principal classification tool for HETDEX, providing a tunable balance between contamination and completeness as dictated by science needs. By combining multiple selection criteria, ELiXer improves upon the 20 Angstrom rest-frame equivalent width cut commonly used to distinguish LAEs from lower-$z$ [OII] emitting galaxies. Despite a spectral resolving power, R $\sim800$, that cannot resolve the [OII] doublet, we demonstrate the ability to distinguish LAEs from foreground galaxies with 98.1% accuracy. We estimate a contamination rate of Ly$\alpha$ by [OII] of 1.2% and a Ly$\alpha$ recovery rate of 99.1% using the default ELiXer configuration. These rates meet the HETDEX science requirements.
Comment: 38 pages, 11 figures
Comment: 38 pages, 11 figures