CLASS Survey Description: Coronal-line Needles in the SDSS Haystack
Coronal lines are a powerful, yet poorly understood, tool to identify and characterize active galactic nuclei. There have been few large-scale surveys of coronal lines in the general galaxy population in the literature so far. Using a novel preselection technique with a flux-to-rms ratio ${ \mathcal...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal Supplement Series |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4365/acb0d2 |
| _version_ | 1827827762858033152 |
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| author | Michael Reefe Remington O. Sexton Sara M. Doan Shobita Satyapal Nathan J. Secrest Jenna M. Cann |
| author_facet | Michael Reefe Remington O. Sexton Sara M. Doan Shobita Satyapal Nathan J. Secrest Jenna M. Cann |
| author_sort | Michael Reefe |
| collection | DOAJ |
| description | Coronal lines are a powerful, yet poorly understood, tool to identify and characterize active galactic nuclei. There have been few large-scale surveys of coronal lines in the general galaxy population in the literature so far. Using a novel preselection technique with a flux-to-rms ratio ${ \mathcal F }$ , followed by Markov Chain Monte Carlo fitting, we searched for the full suite of 20 coronal lines in the optical spectra of almost 1 million galaxies from the Sloan Digital Sky Survey Data Release 8. We present a catalog of the emission-line parameters for the resulting 258 galaxies with detections. The Coronal Line Activity Spectroscopic Survey includes line properties, host-galaxy properties, and selection criteria for all galaxies in which at least one line is detected. This comprehensive study reveals that a significant fraction of coronal-line activity is missed in past surveys based on a more limited set of coronal lines; ∼60% of our sample do not display the more widely surveyed [Fe x ] λ 6374. In addition, we discover a strong correlation between coronal-line and Wide-field Infrared Survey Explorer W2 luminosities, suggesting that the mid-infrared flux can be used to predict coronal-line fluxes. For each line we also provide a confidence level that the line is present, generated by a novel neural network, trained on fully simulated data. We find that after training the network to detect individual lines using 100,000 simulated spectra, we achieve an overall true-positive rate of 75.49% and a false-positive rate of only 3.96%. |
| first_indexed | 2024-03-12T03:37:11Z |
| format | Article |
| id | doaj.art-e99863c124c94a05ac3bad56d4e3392d |
| institution | Directory Open Access Journal |
| issn | 0067-0049 |
| language | English |
| last_indexed | 2024-03-12T03:37:11Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Supplement Series |
| spelling | doaj.art-e99863c124c94a05ac3bad56d4e3392d2023-09-03T13:08:57ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492023-01-0126512110.3847/1538-4365/acb0d2CLASS Survey Description: Coronal-line Needles in the SDSS HaystackMichael Reefe0https://orcid.org/0000-0003-4701-8497Remington O. Sexton1https://orcid.org/0000-0003-3432-2094Sara M. Doan2https://orcid.org/0000-0003-3152-4328Shobita Satyapal3https://orcid.org/0000-0003-2277-2354Nathan J. Secrest4https://orcid.org/0000-0002-4902-8077Jenna M. Cann5https://orcid.org/0000-0003-1051-6564George Mason University , Department of Physics and Astronomy, MS3F3, 4400 University Drive, Fairfax, VA 22030, USA; Massachusetts Institute of Technology , Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USAGeorge Mason University , Department of Physics and Astronomy, MS3F3, 4400 University Drive, Fairfax, VA 22030, USA; U.S. Naval Observatory , 3450 Massachusetts Avenue NW, Washington, DC 20392-5420, USAGeorge Mason University , Department of Physics and Astronomy, MS3F3, 4400 University Drive, Fairfax, VA 22030, USAGeorge Mason University , Department of Physics and Astronomy, MS3F3, 4400 University Drive, Fairfax, VA 22030, USAU.S. Naval Observatory , 3450 Massachusetts Avenue NW, Washington, DC 20392-5420, USANASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771 USACoronal lines are a powerful, yet poorly understood, tool to identify and characterize active galactic nuclei. There have been few large-scale surveys of coronal lines in the general galaxy population in the literature so far. Using a novel preselection technique with a flux-to-rms ratio ${ \mathcal F }$ , followed by Markov Chain Monte Carlo fitting, we searched for the full suite of 20 coronal lines in the optical spectra of almost 1 million galaxies from the Sloan Digital Sky Survey Data Release 8. We present a catalog of the emission-line parameters for the resulting 258 galaxies with detections. The Coronal Line Activity Spectroscopic Survey includes line properties, host-galaxy properties, and selection criteria for all galaxies in which at least one line is detected. This comprehensive study reveals that a significant fraction of coronal-line activity is missed in past surveys based on a more limited set of coronal lines; ∼60% of our sample do not display the more widely surveyed [Fe x ] λ 6374. In addition, we discover a strong correlation between coronal-line and Wide-field Infrared Survey Explorer W2 luminosities, suggesting that the mid-infrared flux can be used to predict coronal-line fluxes. For each line we also provide a confidence level that the line is present, generated by a novel neural network, trained on fully simulated data. We find that after training the network to detect individual lines using 100,000 simulated spectra, we achieve an overall true-positive rate of 75.49% and a false-positive rate of only 3.96%.https://doi.org/10.3847/1538-4365/acb0d2Active galaxiesDwarf galaxiesStarburst galaxiesGalaxy evolutionInfrared galaxiesSolar coronal lines |
| spellingShingle | Michael Reefe Remington O. Sexton Sara M. Doan Shobita Satyapal Nathan J. Secrest Jenna M. Cann CLASS Survey Description: Coronal-line Needles in the SDSS Haystack The Astrophysical Journal Supplement Series Active galaxies Dwarf galaxies Starburst galaxies Galaxy evolution Infrared galaxies Solar coronal lines |
| title | CLASS Survey Description: Coronal-line Needles in the SDSS Haystack |
| title_full | CLASS Survey Description: Coronal-line Needles in the SDSS Haystack |
| title_fullStr | CLASS Survey Description: Coronal-line Needles in the SDSS Haystack |
| title_full_unstemmed | CLASS Survey Description: Coronal-line Needles in the SDSS Haystack |
| title_short | CLASS Survey Description: Coronal-line Needles in the SDSS Haystack |
| title_sort | class survey description coronal line needles in the sdss haystack |
| topic | Active galaxies Dwarf galaxies Starburst galaxies Galaxy evolution Infrared galaxies Solar coronal lines |
| url | https://doi.org/10.3847/1538-4365/acb0d2 |
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