Exploring Unobscured Quasi-stellar Objects in the Southern Hemisphere with KS4

We present a catalog of unobscured quasi-stellar object (QSO) candidates in the Southern Hemisphere from the early interim data of the KMTNet Synoptic Survey of Southern Sky (KS4). The KS4 data covers ∼2500 deg ^2 sky area, reaching 5 σ detection limits of ∼22.1–22.7 AB mag in the BVRI bands. Combin...

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Main Authors: Yongjung Kim, Minjin Kim, Myungshin Im, Seo-Won Chang, Mankeun Jeong, Woowon Byun, Joonho Kim, Dohyeong Kim, Hyunjin Shim, Hyunmi Song
Format: Article
Language:English
Published: IOP Publishing 2024-01-01
Series:The Astrophysical Journal Supplement Series
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Online Access:https://doi.org/10.3847/1538-4365/ad89be
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author Yongjung Kim
Minjin Kim
Myungshin Im
Seo-Won Chang
Mankeun Jeong
Woowon Byun
Joonho Kim
Dohyeong Kim
Hyunjin Shim
Hyunmi Song
author_facet Yongjung Kim
Minjin Kim
Myungshin Im
Seo-Won Chang
Mankeun Jeong
Woowon Byun
Joonho Kim
Dohyeong Kim
Hyunjin Shim
Hyunmi Song
author_sort Yongjung Kim
collection DOAJ
description We present a catalog of unobscured quasi-stellar object (QSO) candidates in the Southern Hemisphere from the early interim data of the KMTNet Synoptic Survey of Southern Sky (KS4). The KS4 data covers ∼2500 deg ^2 sky area, reaching 5 σ detection limits of ∼22.1–22.7 AB mag in the BVRI bands. Combining this with available infrared photometric data from the surveys covering the southern sky, we select the unobscured QSO candidates based on their colors and spectral energy distribution fitting results. The final catalog contains 72,964 unobscured QSO candidates, of which only 0.4% are previously identified as QSOs based on spectroscopic observations. Our selection method achieves an 87% recovery rate for spectroscopically confirmed bright QSOs at z < 2 within the KS4 survey area. In addition, the number count of our candidates is comparable to that of spectroscopically confirmed QSOs from the Sloan Digital Sky Survey in the northern sky. These demonstrate that our approach is effective in searching for unobscured QSOs in the southern sky. Future spectrophotometric surveys covering the southern sky will enable us to discern their true nature and enhance our understanding of QSO populations in the Southern Hemisphere.
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spelling doaj-art-17fdd28e12424a63859ae61405d0e4fd2024-12-06T06:33:14ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492024-01-0127524610.3847/1538-4365/ad89beExploring Unobscured Quasi-stellar Objects in the Southern Hemisphere with KS4Yongjung Kim0https://orcid.org/0000-0003-1647-3286Minjin Kim1https://orcid.org/0000-0002-3560-0781Myungshin Im2https://orcid.org/0000-0002-8537-6714Seo-Won Chang3https://orcid.org/0000-0002-3118-8275Mankeun Jeong4https://orcid.org/0009-0003-1280-0099Woowon Byun5https://orcid.org/0000-0002-7762-7712Joonho Kim6https://orcid.org/0000-0002-1294-168XDohyeong Kim7https://orcid.org/0000-0002-6925-4821Hyunjin Shim8https://orcid.org/0000-0002-4179-2628Hyunmi Song9https://orcid.org/0000-0002-4362-4070Korea Astronomy and Space Science Institute , Daejeon 34055, Republic of Korea ; yjkim.ast@gmail.comDepartment of Astronomy and Atmospheric Sciences, College of Natural Sciences, Kyungpook National University , Daegu 41566, Republic of Korea ; mkim.astro@gmail.comSNU Astronomy Research Center, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; Astronomy Program, Department of Physics & Astronomy, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of KoreaSNU Astronomy Research Center, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; Astronomy Program, Department of Physics & Astronomy, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of KoreaSNU Astronomy Research Center, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; Astronomy Program, Department of Physics & Astronomy, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of KoreaKorea Astronomy and Space Science Institute , Daejeon 34055, Republic of Korea ; yjkim.ast@gmail.comDaegu National Science Museum , 20, Techno-daero 6-gil, Yuga-myeon, Dalseong-gun, Daegu 43023, Republic of KoreaDepartment of Earth Sciences, Pusan National University , Busan 46241, Republic of KoreaDepartment of Earth Science Education, Kyungpook National University , Daegu 41566, Republic of KoreaDepartment of Astronomy and Space Science, Chungnam National University , Daejeon 34134, Republic of KoreaWe present a catalog of unobscured quasi-stellar object (QSO) candidates in the Southern Hemisphere from the early interim data of the KMTNet Synoptic Survey of Southern Sky (KS4). The KS4 data covers ∼2500 deg ^2 sky area, reaching 5 σ detection limits of ∼22.1–22.7 AB mag in the BVRI bands. Combining this with available infrared photometric data from the surveys covering the southern sky, we select the unobscured QSO candidates based on their colors and spectral energy distribution fitting results. The final catalog contains 72,964 unobscured QSO candidates, of which only 0.4% are previously identified as QSOs based on spectroscopic observations. Our selection method achieves an 87% recovery rate for spectroscopically confirmed bright QSOs at z < 2 within the KS4 survey area. In addition, the number count of our candidates is comparable to that of spectroscopically confirmed QSOs from the Sloan Digital Sky Survey in the northern sky. These demonstrate that our approach is effective in searching for unobscured QSOs in the southern sky. Future spectrophotometric surveys covering the southern sky will enable us to discern their true nature and enhance our understanding of QSO populations in the Southern Hemisphere.https://doi.org/10.3847/1538-4365/ad89beQuasarsPhotometryCatalogsGalaxies
spellingShingle Yongjung Kim
Minjin Kim
Myungshin Im
Seo-Won Chang
Mankeun Jeong
Woowon Byun
Joonho Kim
Dohyeong Kim
Hyunjin Shim
Hyunmi Song
Exploring Unobscured Quasi-stellar Objects in the Southern Hemisphere with KS4
The Astrophysical Journal Supplement Series
Quasars
Photometry
Catalogs
Galaxies
title Exploring Unobscured Quasi-stellar Objects in the Southern Hemisphere with KS4
title_full Exploring Unobscured Quasi-stellar Objects in the Southern Hemisphere with KS4
title_fullStr Exploring Unobscured Quasi-stellar Objects in the Southern Hemisphere with KS4
title_full_unstemmed Exploring Unobscured Quasi-stellar Objects in the Southern Hemisphere with KS4
title_short Exploring Unobscured Quasi-stellar Objects in the Southern Hemisphere with KS4
title_sort exploring unobscured quasi stellar objects in the southern hemisphere with ks4
topic Quasars
Photometry
Catalogs
Galaxies
url https://doi.org/10.3847/1538-4365/ad89be
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