Automated Classification of Astronomical Spectra
Open Access
- Author:
- Debski, Maya
- Area of Honors:
- Astronomy and Astrophysics
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Donald P Schneider, Thesis Supervisor
Jane Camilla Charlton, Thesis Honors Advisor - Keywords:
- spectroscopic redshift
large sky survey
galaxies
stars
optical spectra - Abstract:
- The Hobby-Eberly Telescope VIRUS Parallel Survey (HETVIPS) is a blind spectroscopic program that sparsely covers approximately two-thirds of the celestial sphere and consists of roughly 118 million fiber spectra. The spectra were taken in parallel mode with the Visible Integral-field Replicable Unit Spectrograph (VIRUS) instrument when the HET was observing a primary target with other HET facility instruments. VIRUS can simultaneously obtain approximately 35,000 spectra covering 3470 A to 5540 ˚ A at a spectral resolution of ˚ ≈ 800. Although the vast majority of these spectra cover blank sky, we used the Pan-STARRS1 Data Release 2 Stacked Catalog to identify objects encompassed in the HETVIPS pointings and extract their spectra. This paper presents the first HETVIPS data release, containing 212,619 flux-calibrated spectra obtained through 31 May 2021, as well as a description of the data processing technique. The spectra were extracted from 118 million fiber observations. Each of the object spectra were classified, resulting in a catalog of 32,824 galaxies, 1,338 quasars, 111,575 stars, and 66,882 unknown sources. Applying tools from the HETVIPS catalog, I combine the power of blind integral field unit (IFU) spectroscopy from the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) with sources detected in the novel Low Frequency Array (LOFAR) to construct the HETDEX-LOFAR Spectroscopic Redshift Catalog. Starting from the first data release of the LOFAR Two-metre Sky Survey (LoTSS), including a value-added catalog with photometric redshifts, I extracted 18,267 HETDEX spectra. Using an automatic classifying algorithm, I assigned a star, galaxy, or quasar label along with a velocity/redshift. I supplemented these classifications with the continuum and emission line catalogs of the internal, third data release from HETDEX (HDR3). I measured 4,349 new redshifts; in combination with the value-added catalog, the final spectroscopic redshift sample 6,016 sources. This new catalog of distances facilitates research to determine the [O II] emission properties of radio galaxies from 0.0 < z < 0.5 and the Lyman-alpha emission characteristics of both radio galaxies and quasars from 1.9 < z < 3.5, and allows the study of radio-loud stars in our own galaxy.