Optical+Near-IR Analysis of a Newly Confirmed Einstein Ring at z ∼ 1 from the Kilo-Degree Survey: Dark Matter Fraction, Total and Dark Matter Density Slope, and Initial Mass Function
We report the spectroscopic confirmation of a bright blue Einstein ring in the Kilo-Degree Survey (KiDS) footprint: the Einstein “blue eye.” Spectroscopic data from X-Shooter at the Very Large Telescope (VLT) show that the lens is a typical early-type galaxy (ETG) at z _l = 0.9906, while the backgr...
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2025-01-01
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| author | Rui Li Nicola R. Napolitano Giuseppe D’Ago Vyacheslav N. Shalyapin Kai Zhu Xiaotong Guo Ran Li Léon V. E. Koopmans Chiara Spiniello Crescenzo Tortora Francesco La Barbera Haicheng Feng Liang Gao Zhiqi Huang Koen Kuijken Hui Li Linghua Xie Mario Radovich Alexey Sergeyev |
| author_facet | Rui Li Nicola R. Napolitano Giuseppe D’Ago Vyacheslav N. Shalyapin Kai Zhu Xiaotong Guo Ran Li Léon V. E. Koopmans Chiara Spiniello Crescenzo Tortora Francesco La Barbera Haicheng Feng Liang Gao Zhiqi Huang Koen Kuijken Hui Li Linghua Xie Mario Radovich Alexey Sergeyev |
| author_sort | Rui Li |
| collection | DOAJ |
| description | We report the spectroscopic confirmation of a bright blue Einstein ring in the Kilo-Degree Survey (KiDS) footprint: the Einstein “blue eye.” Spectroscopic data from X-Shooter at the Very Large Telescope (VLT) show that the lens is a typical early-type galaxy (ETG) at z _l = 0.9906, while the background source is a Ly α emitter at z _s = 2.823. The reference lens modeling was performed on a high-resolution Y- band adaptive-optics image from HAWK-I at VLT. Assuming a singular isothermal ellipsoid total mass density profile, we inferred an Einstein radius R _Ein = 10.47 ± 0.06 kpc. The average slope of the total mass density inside the Einstein radius, as determined by a joint analysis of lensing and isotropic Jeans equations, is ${\gamma }_{\mathrm{tot}}=2.1{4}_{-0.07}^{+0.06}$ , showing no systematic deviation from the slopes of lower-redshift galaxies. This can be the evidence of ETGs developing through dry mergers plus moderate dissipationless accretion. Stellar population analysis with eight-band ( gri ZYJHK _s ) photometries from KiDS and VIKING shows that the total stellar mass of the lens is M * = (3.95 ± 0.35) × 10 ^11 M _⊙ (Salpeter initial mass function (IMF)), implying a dark matter fraction inside the effective radius of f _DM = 0.307 ± 0.151. We finally explored the dark matter halo slope and found a strong degeneracy with the dynamic stellar mass. Dark matter adiabatic contraction is needed to explain the posterior distribution of the slope, unless an IMF heavier than Salpeter is assumed. |
| format | Article |
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| institution | Kabale University |
| issn | 2041-8205 |
| language | English |
| publishDate | 2025-01-01 |
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| series | The Astrophysical Journal Letters |
| spelling | doaj-art-7b5ad2b9ae6c4d21a53175ea5b93c8a32025-08-20T03:31:34ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019872L3110.3847/2041-8213/ade680Optical+Near-IR Analysis of a Newly Confirmed Einstein Ring at z ∼ 1 from the Kilo-Degree Survey: Dark Matter Fraction, Total and Dark Matter Density Slope, and Initial Mass FunctionRui Li0https://orcid.org/0000-0002-3490-4089Nicola R. Napolitano1https://orcid.org/0000-0003-0911-8884Giuseppe D’Ago2https://orcid.org/0000-0001-9697-7331Vyacheslav N. Shalyapin3https://orcid.org/0000-0003-3062-7835Kai Zhu4https://orcid.org/0000-0002-2583-2669Xiaotong Guo5https://orcid.org/0000-0002-2338-7709Ran Li6Léon V. E. Koopmans7Chiara Spiniello8https://orcid.org/0000-0002-3909-6359Crescenzo Tortora9https://orcid.org/0000-0001-7958-6531Francesco La Barbera10Haicheng Feng11https://orcid.org/0000-0002-1530-2680Liang Gao12Zhiqi Huang13https://orcid.org/0000-0003-3070-3412Koen Kuijken14https://orcid.org/0000-0002-3827-0175Hui Li15Linghua Xie16https://orcid.org/0000-0002-2831-8630Mario Radovich17https://orcid.org/0000-0002-3585-866XAlexey Sergeyev18Institute for Astrophysics, School of Physics, Zhengzhou University , Zhengzhou, 450001, People’s Republic of China ; liruiww@gmail.comDepartment of Physics “E. Pancini,” University Federico II , Via Cinthia 6, 80126-I, Naples, Italy ; nicolarosario.napolitano@unina.it; School of Physics and Astronomy, Sun Yat-sen University , Zhuhai Campus, 2 Daxue Road, Xiangzhou District, Zhuhai, People’s Republic of China; CSST Science Center for Guangdong-Hong Kong-Macau Great Bay Area , Zhuhai, 519082, People’s Republic of ChinaInstitute of Astronomy, University of Cambridge , Madingley Road, Cambridge, CB3 0HA, UKDepartamento de Fí sica Moderna, Universidad de Cantabria , Avda. de Los Castros s/n, E-39005 Santander, Spain; O.Ya. Usikov Institute for Radiophysics and Electronics , National Academy of Sciences of Ukraine, 12 Acad. Proscury St., UA-61085 Kharkiv, UkraineDepartment of Astronomy, Tsinghua University , Beijing 100084, People’s Republic of ChinaInstitute of Astronomy and Astrophysics, Anqing Normal University , Anqing, Anhui 246133, People’s Republic of ChinaSchool of Physics and Astronomy, Beijing Normal University , Beijing 100875, People’s Republic of China; School of Astronomy and Space Science, University of Chinese Academy of Science , Beijing 100049, People’s Republic of ChinaKapteyn Astronomical Institute, University of Groningen , P.O.Box 800, 9700AV Groningen, The NetherlandsDepartment of Physics, University of Oxford , Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK; INAF—Osservatorio Astronomico di Capodimonte , Salita Moiariello 16, 80131—Napoli, ItalyINAF—Osservatorio Astronomico di Capodimonte , Salita Moiariello 16, 80131—Napoli, ItalyINAF—Osservatorio Astronomico di Capodimonte , Salita Moiariello 16, 80131—Napoli, ItalyYunnan Observatories, Chinese Academy of Sciences , Kunming, 650011, Yunnan, People’s Republic of ChinaInstitute for Astrophysics, School of Physics, Zhengzhou University , Zhengzhou, 450001, People’s Republic of China ; liruiww@gmail.com; School of Physics and Astronomy, Beijing Normal University , Beijing 100875, People’s Republic of ChinaSchool of Physics and Astronomy, Sun Yat-sen University , Zhuhai Campus, 2 Daxue Road, Xiangzhou District, Zhuhai, People’s Republic of ChinaLeiden Observatory, Leiden University , P.O.Box 9513, 2300RA Leiden, The NetherlandsInstitute for Astrophysics, School of Physics, Zhengzhou University , Zhengzhou, 450001, People’s Republic of China ; liruiww@gmail.comSchool of Physics and Astronomy, Sun Yat-sen University , Zhuhai Campus, 2 Daxue Road, Xiangzhou District, Zhuhai, People’s Republic of ChinaINAF—Osservatorio Astronomico di Padova , via dell’Osservatorio 5, 35122 Padova, ItalyUniversité Côte d’Azur , Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, France; V. N. Karazin Kharkiv National University , Kharkiv, 61022, Ukraine; Institute of Radio Astronomy of National Academy of Science of Ukraine , Mystetstv 4, UkraineWe report the spectroscopic confirmation of a bright blue Einstein ring in the Kilo-Degree Survey (KiDS) footprint: the Einstein “blue eye.” Spectroscopic data from X-Shooter at the Very Large Telescope (VLT) show that the lens is a typical early-type galaxy (ETG) at z _l = 0.9906, while the background source is a Ly α emitter at z _s = 2.823. The reference lens modeling was performed on a high-resolution Y- band adaptive-optics image from HAWK-I at VLT. Assuming a singular isothermal ellipsoid total mass density profile, we inferred an Einstein radius R _Ein = 10.47 ± 0.06 kpc. The average slope of the total mass density inside the Einstein radius, as determined by a joint analysis of lensing and isotropic Jeans equations, is ${\gamma }_{\mathrm{tot}}=2.1{4}_{-0.07}^{+0.06}$ , showing no systematic deviation from the slopes of lower-redshift galaxies. This can be the evidence of ETGs developing through dry mergers plus moderate dissipationless accretion. Stellar population analysis with eight-band ( gri ZYJHK _s ) photometries from KiDS and VIKING shows that the total stellar mass of the lens is M * = (3.95 ± 0.35) × 10 ^11 M _⊙ (Salpeter initial mass function (IMF)), implying a dark matter fraction inside the effective radius of f _DM = 0.307 ± 0.151. We finally explored the dark matter halo slope and found a strong degeneracy with the dynamic stellar mass. Dark matter adiabatic contraction is needed to explain the posterior distribution of the slope, unless an IMF heavier than Salpeter is assumed.https://doi.org/10.3847/2041-8213/ade680Dark matterGravitational lensingGalaxy dynamicsGalaxy formationGalaxy evolution |
| spellingShingle | Rui Li Nicola R. Napolitano Giuseppe D’Ago Vyacheslav N. Shalyapin Kai Zhu Xiaotong Guo Ran Li Léon V. E. Koopmans Chiara Spiniello Crescenzo Tortora Francesco La Barbera Haicheng Feng Liang Gao Zhiqi Huang Koen Kuijken Hui Li Linghua Xie Mario Radovich Alexey Sergeyev Optical+Near-IR Analysis of a Newly Confirmed Einstein Ring at z ∼ 1 from the Kilo-Degree Survey: Dark Matter Fraction, Total and Dark Matter Density Slope, and Initial Mass Function The Astrophysical Journal Letters Dark matter Gravitational lensing Galaxy dynamics Galaxy formation Galaxy evolution |
| title | Optical+Near-IR Analysis of a Newly Confirmed Einstein Ring at z ∼ 1 from the Kilo-Degree Survey: Dark Matter Fraction, Total and Dark Matter Density Slope, and Initial Mass Function |
| title_full | Optical+Near-IR Analysis of a Newly Confirmed Einstein Ring at z ∼ 1 from the Kilo-Degree Survey: Dark Matter Fraction, Total and Dark Matter Density Slope, and Initial Mass Function |
| title_fullStr | Optical+Near-IR Analysis of a Newly Confirmed Einstein Ring at z ∼ 1 from the Kilo-Degree Survey: Dark Matter Fraction, Total and Dark Matter Density Slope, and Initial Mass Function |
| title_full_unstemmed | Optical+Near-IR Analysis of a Newly Confirmed Einstein Ring at z ∼ 1 from the Kilo-Degree Survey: Dark Matter Fraction, Total and Dark Matter Density Slope, and Initial Mass Function |
| title_short | Optical+Near-IR Analysis of a Newly Confirmed Einstein Ring at z ∼ 1 from the Kilo-Degree Survey: Dark Matter Fraction, Total and Dark Matter Density Slope, and Initial Mass Function |
| title_sort | optical near ir analysis of a newly confirmed einstein ring at z ∼ 1 from the kilo degree survey dark matter fraction total and dark matter density slope and initial mass function |
| topic | Dark matter Gravitational lensing Galaxy dynamics Galaxy formation Galaxy evolution |
| url | https://doi.org/10.3847/2041-8213/ade680 |
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