Machine Learning–based Photometric Redshifts for Galaxies in the North Ecliptic Pole Wide Field: Catalogs of Spectroscopic and Photometric Redshifts
We perform an MMT/Hectospec redshift survey of the North Ecliptic Pole Wide (NEPW) field covering 5.4 deg ^2 and use it to estimate the photometric redshifts for the sources without spectroscopic redshifts. By combining 2572 newly measured redshifts from our survey with existing data from the litera...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal Supplement Series |
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| Online Access: | https://doi.org/10.3847/1538-4365/adb42a |
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| author | Taewan Kim Jubee Sohn Ho Seong Hwang Simon C.-C. Ho Denis Burgarella Tomotsugu Goto Tetsuya Hashimoto Woong-Seob Jeong Seong Jin Kim Matthew A. Malkan Takamitsu Miyaji Nagisa Oi Hyunjin Shim Hyunmi Song Narae Hwang Byeong-Gon Park |
| author_facet | Taewan Kim Jubee Sohn Ho Seong Hwang Simon C.-C. Ho Denis Burgarella Tomotsugu Goto Tetsuya Hashimoto Woong-Seob Jeong Seong Jin Kim Matthew A. Malkan Takamitsu Miyaji Nagisa Oi Hyunjin Shim Hyunmi Song Narae Hwang Byeong-Gon Park |
| author_sort | Taewan Kim |
| collection | DOAJ |
| description | We perform an MMT/Hectospec redshift survey of the North Ecliptic Pole Wide (NEPW) field covering 5.4 deg ^2 and use it to estimate the photometric redshifts for the sources without spectroscopic redshifts. By combining 2572 newly measured redshifts from our survey with existing data from the literature, we create a large sample of 4421 galaxies with spectroscopic redshifts in the NEPW field. Using this sample, we estimate photometric redshifts of 77,755 sources in the band-merged catalog of the NEPW field with a random forest model. The estimated photometric redshifts are generally consistent with the spectroscopic redshifts, with a dispersion of 0.028, an outlier fraction of 7.3%, and a bias of −0.01. We find that the standard deviation of the prediction from each decision tree in the random forest model can be used to infer the fraction of catastrophic outliers and the measurement uncertainties. We test various combinations of input observables, including colors and magnitude uncertainties, and find that the details of these various combinations do not change the prediction accuracy much. As a result, we provide a catalog of 77,755 sources in the NEPW field, which includes both spectroscopic and photometric redshifts up to z ∼ 2. This data set has significant legacy value for studies in the NEPW region, especially with upcoming space missions such as JWST, Euclid, and SPHEREx. |
| format | Article |
| id | doaj-art-1dcb175b179240938eba4e896e932bcd |
| institution | DOAJ |
| issn | 0067-0049 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Supplement Series |
| spelling | doaj-art-1dcb175b179240938eba4e896e932bcd2025-08-20T02:50:49ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492025-01-0127724110.3847/1538-4365/adb42aMachine Learning–based Photometric Redshifts for Galaxies in the North Ecliptic Pole Wide Field: Catalogs of Spectroscopic and Photometric RedshiftsTaewan Kim0https://orcid.org/0009-0001-3758-9440Jubee Sohn1https://orcid.org/0000-0002-9254-144XHo Seong Hwang2https://orcid.org/0000-0003-3428-7612Simon C.-C. Ho3https://orcid.org/0000-0002-8560-3497Denis Burgarella4https://orcid.org/0000-0002-4193-2539Tomotsugu Goto5Tetsuya Hashimoto6https://orcid.org/0000-0001-7228-1428Woong-Seob Jeong7https://orcid.org/0000-0002-2770-808XSeong Jin Kim8https://orcid.org/0000-0001-9970-8145Matthew A. Malkan9https://orcid.org/0000-0001-6919-1237Takamitsu Miyaji10https://orcid.org/0000-0002-7562-485XNagisa Oi11Hyunjin Shim12https://orcid.org/0000-0002-4179-2628Hyunmi Song13https://orcid.org/0000-0002-4362-4070Narae Hwang14https://orcid.org/0000-0002-2013-1273Byeong-Gon Park15https://orcid.org/0000-0002-6982-7722Astronomy Program, Department of Physics and Astronomy, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea ; hhwang@astro.snu.ac.krAstronomy Program, Department of Physics and Astronomy, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea ; hhwang@astro.snu.ac.kr; SNU Astronomy Research Center, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of KoreaAstronomy Program, Department of Physics and Astronomy, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea ; hhwang@astro.snu.ac.kr; SNU Astronomy Research Center, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; Australian Astronomical Optics–Macquarie University , 105 Delhi Road, North Ryde, NSW 2113, AustraliaResearch School of Astronomy and Astrophysics, The Australian National University , Canberra, ACT 2611, Australia; ARC Centre of Excellence for All-Sky Astrophysics in 3 Dimensions (ASTRO 3D) , ACT 2611, Australia; OzGrav: The Australian Research Council Centre of Excellence for Gravitational Wave Discovery , Hawthorn, VIC 3122, AustraliaAix Marseille Université , CNRS, Laboratoire d’Astrophysique de Marselle UMR 7326, 13388 Marseille, FranceInstitute of Astronomy, National Tsing Hua University , 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan (R.O.C.)Department of Physics, National Chung Hsing University , No. 145, Xingda Road, South Dist., Taichung, 40227, Taiwan (R.O.C.)Korea Astronomy and Space Science Institute , 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Republic of KoreaDepartment of Physics, National Chung Hsing University , No. 145, Xingda Road, South Dist., Taichung, 40227, Taiwan (R.O.C.)Department of Physics and Astronomy, University of California, Los Angeles , Los Angeles, CA 90095-1547, USAInstituto de Astronomía Ensenada, Km. 107 Carretera Tijuana-Ensenada, Ensenada, 22860 BC, MexicoSpace Information Center, Hokkaido Information University , Nishi-Nopporo 59-2, Ebetsu, Hokkaido 069-8585, JapanDepartment of Earth Science Education, Kyungpook National University , 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of KoreaDepartment of Astronomy and Space Science, Chungnam National University , Daejeon 34134, Republic of KoreaKorea Astronomy and Space Science Institute , 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Republic of KoreaKorea Astronomy and Space Science Institute , 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Republic of KoreaWe perform an MMT/Hectospec redshift survey of the North Ecliptic Pole Wide (NEPW) field covering 5.4 deg ^2 and use it to estimate the photometric redshifts for the sources without spectroscopic redshifts. By combining 2572 newly measured redshifts from our survey with existing data from the literature, we create a large sample of 4421 galaxies with spectroscopic redshifts in the NEPW field. Using this sample, we estimate photometric redshifts of 77,755 sources in the band-merged catalog of the NEPW field with a random forest model. The estimated photometric redshifts are generally consistent with the spectroscopic redshifts, with a dispersion of 0.028, an outlier fraction of 7.3%, and a bias of −0.01. We find that the standard deviation of the prediction from each decision tree in the random forest model can be used to infer the fraction of catastrophic outliers and the measurement uncertainties. We test various combinations of input observables, including colors and magnitude uncertainties, and find that the details of these various combinations do not change the prediction accuracy much. As a result, we provide a catalog of 77,755 sources in the NEPW field, which includes both spectroscopic and photometric redshifts up to z ∼ 2. This data set has significant legacy value for studies in the NEPW region, especially with upcoming space missions such as JWST, Euclid, and SPHEREx.https://doi.org/10.3847/1538-4365/adb42aRedshift surveysGalaxiesGalaxy spectroscopy |
| spellingShingle | Taewan Kim Jubee Sohn Ho Seong Hwang Simon C.-C. Ho Denis Burgarella Tomotsugu Goto Tetsuya Hashimoto Woong-Seob Jeong Seong Jin Kim Matthew A. Malkan Takamitsu Miyaji Nagisa Oi Hyunjin Shim Hyunmi Song Narae Hwang Byeong-Gon Park Machine Learning–based Photometric Redshifts for Galaxies in the North Ecliptic Pole Wide Field: Catalogs of Spectroscopic and Photometric Redshifts The Astrophysical Journal Supplement Series Redshift surveys Galaxies Galaxy spectroscopy |
| title | Machine Learning–based Photometric Redshifts for Galaxies in the North Ecliptic Pole Wide Field: Catalogs of Spectroscopic and Photometric Redshifts |
| title_full | Machine Learning–based Photometric Redshifts for Galaxies in the North Ecliptic Pole Wide Field: Catalogs of Spectroscopic and Photometric Redshifts |
| title_fullStr | Machine Learning–based Photometric Redshifts for Galaxies in the North Ecliptic Pole Wide Field: Catalogs of Spectroscopic and Photometric Redshifts |
| title_full_unstemmed | Machine Learning–based Photometric Redshifts for Galaxies in the North Ecliptic Pole Wide Field: Catalogs of Spectroscopic and Photometric Redshifts |
| title_short | Machine Learning–based Photometric Redshifts for Galaxies in the North Ecliptic Pole Wide Field: Catalogs of Spectroscopic and Photometric Redshifts |
| title_sort | machine learning based photometric redshifts for galaxies in the north ecliptic pole wide field catalogs of spectroscopic and photometric redshifts |
| topic | Redshift surveys Galaxies Galaxy spectroscopy |
| url | https://doi.org/10.3847/1538-4365/adb42a |
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