초기우주연구실은 재이온화 시기와 초기 은하의 형성과 진화를 중심으로, 우주의 첫 수억 년을 관측적으로 탐구한다. JWST를 비롯한 최신 우주·지상 망원경 자료를 활용하여 라이만-알파 방출, 은하의 물리적 성질, 그리고 재이온화 구조를 정밀 분석한다. 또한 머신러닝 및 데이터 과학 기법을 접목하여 대규모 관측 데이터를 해석하고, 초기우주의 공간적·물리적 진화를 이해하는 것을 목표로 한다.

1. 재이온화 시기
   우주 초기 중성수소가 이온화되는 재이온화 과정을 관측적으로 연구한다. 라이만-알파 방출선 관측 등을 활용해 은하 주변 이온화 버블의 특성을 분석하여 재이온화의 시간적·공간적 구조를 규명한다.
   
   
2. 초기은하의 형성과 진화
   초기 은하들을 대상으로 별 형성률, 금속함량, 이온화 광자 방출 등의 물리적 특성을 연구한다. JWST 및 차세대 관측 자료를 활용하여 초기 은하의 내부 특성과 진화를 이해하는 것을 목표로 한다.
   
   
3. 라이만-알파 및 방출선 은하 연구
   라이만-알파 방출은 초기우주 연구의 핵심 도구이다. 본 연구실은 라이만-알파 방출선의 세기, 분광 특성 및 공간적 분포를 분석하여 은하와 은하간 매질 간 상호작용을 연구한다.
   
   
4. 관측 데이터 분석 및 머신러닝 응용 대규모 우주망원경 및 지상망원경 자료를 체계적으로 분석하기 위해 통계적 모델링과 머신러닝 기법을 활용한다. 이를 통해 재이온화 구조의 지도화 및 은하 물리량 추정을 수행한다.

1. Donnan et al. (incl. I. Jung) 2025, ApJ, 993, 224, Very Bright, Very Blue, and Very Red: JWST CAPERS Analysis of Highly Luminous Galaxies with Extreme Ultraviolet Slopes at z = 10
2. Mascia et al. (incl. I. Jung) 2025, A&A, 701, A122, Little impact of mergers and galaxy morphology on the production and escape of ionizing photons in the early Universe
3. Le Reste et al. (incl. I. Jung) 2025, ApJS, 280, 27, The Lyα and Continuum Origins Survey. I. Survey Description and Lyα Imaging
4. Taylor et al. (incl. I. Jung) 2025, ApJL, 989, L7, CAPERS-LRD-z9: A Gas-enshrouded Little Red Dot Hosting a Broad-line Active Galactic Nucleus at z = 9.288
5. Jung et al. 2025, ApJ, 988, 4, Local Analogs of Potential Ionizers of the Intergalactic Medium: Compact Star-forming Galaxies with Intense C IV λ1550 Emission
6. Gazagnes et al. (incl. I. Jung) 2025, MNRAS, 540, 2331, A negligible contribution of two luminous z ~ 7.5 galaxies to the ionizing photon budget of reionization
7. Park et al. (incl. I. Jung) 2025, ApJ, 983, 91, Constraining Reionization with Lyα Damping-wing Absorption in Galaxy Spectra: A Machine Learning Model Based on Reionization Simulations
8. Finkelstein et al. (incl. I. Jung) 2025, ApJL, 983, L4, The Cosmic Evolution Early Release Science Survey (CEERS)
9. Shen et al. (incl. I. Jung) 2025, ApJL, 980, L45, NGDEEP: The Star Formation and Ionization Properties of Galaxies at 1.7 < z < 3.4
10. Zavala et al. (incl. I. Jung) 2025, NatAs, 9, 155, A luminous and young galaxy at z = 12.33 revealed by a JWST/MIRI detection of Hα and [O III]
11. Rahman et al. (incl. I. Jung) 2024, RNAAS, 8, 297, Spatially Resolved Stellar Populations of z = 3–6 Lyα-emitting Galaxies with CEERS JWST NIRCam Imaging
12. Hsiao et al. (incl. I. Jung) 2024, ApJ, 973, 81, JWST MIRI Detections of Hα and [O III] and a Direct Metallicity Measurement of the z = 10.17 Lensed Galaxy MACS0647‑JD
13. Abdurro'uf et al. (incl. I. Jung) 2024, ApJ, 973, 47, JWST NIRSpec High-resolution Spectroscopy of MACS0647–JD at z = 10.167: Resolved [O II] Doublet and Electron Density in an Early Galaxy
14. Hsiao et al. (incl. I. Jung) 2024, ApJ, 973, 8, JWST NIRSpec Spectroscopy of the Triply Lensed z = 10.17 Galaxy MACS0647–JD
15. Jung et al. 2024, ApJ, 971, 175, Constraints on the Lyman Continuum Escape from Low-mass Lensed Galaxies at 1.3 ≤ z ≤ 3.0
16. Napolitano et al. (incl. I. Jung) 2024, A&A, 688, A106, Peering into cosmic reionization: Lyα visibility evolution from galaxies at z = 4.5-8.5 with JWST
17. Hu et al. (incl. I. Jung) 2024, ApJ, 971, 21, Characterizing the Average Interstellar Medium Conditions of Galaxies at z ∼ 5.6–9 with Ultraviolet and Optical Nebular Lines
18. Finkelstein et al. (incl. I. Jung) 2024, ApJL, 969, L2, The Complete CEERS Early Universe Galaxy Sample: A Surprisingly Slow Evolution of the Space Density of Bright Galaxies at z ∼ 8.5–14.5
19. Pirzkal et al. (incl. I. Jung) 2024, ApJ, 969, 90, The Next Generation Deep Extragalactic Exploratory Public Near-infrared Slitless Survey Epoch 1 (NGDEEP-NISS1): Extragalactic Star-formation and Active Galactic Nuclei at 0.5 < z < 3.6
20. Cooper et al. (incl. I. Jung) 2024, ApJ, 970, 50, The Web Epoch of Reionization Lyα Survey (WERLS). I. MOSFIRE Spectroscopy of z ∼ 7–8 Lyα Emitters
21. Heintz et al. (incl. I. Jung) 2024, Sci, 384, 890, Strong damped Lyman-α absorption in young star-forming galaxies at redshifts 9 to 11
22. Jung et al. 2024, ApJ, 967, 73, CEERS: Diversity of Lyα Emitters during the Epoch of Reionization
23. Mascia et al. (incl. I. Jung) 2024, A&A, 685, A3, New insight on the nature of cosmic reionizers from the CEERS survey
24. Bagley et al. (incl. I. Jung) 2024, ApJL, 965, L6, The Next Generation Deep Extragalactic Exploratory Public (NGDEEP) Survey
25. Urbano Stawinski et al. (incl. I. Jung) 2024, MNRAS, 528, 5624, Deeper than DEEP: a spectroscopic survey of z > 3 Ly α emitters in the Extended Groth Strip
26. Shen et al. (incl. I. Jung) 2024, ApJL, 963, L49, NGDEEP Epoch 1: Spatially Resolved Hα Observations of Disk and Bulge Growth in Star-forming Galaxies at z ∼ 0.6–2.2 from JWST NIRISS Slitless Spectroscopy
27. Backhaus et al. (incl. I. Jung) 2024, ApJ, 962, 195, CEERS Key Paper. VIII. Emission-line Ratios from NIRSpec and NIRCam Wide-Field Slitless Spectroscopy at z > 2
28. Arrabal Haro et al. (incl. I. Jung) 2023, Natur, 622, 707, Confirmation and refutation of very luminous galaxies in the early Universe
29. Napolitano et al. (incl. I. Jung) 2023, A&A, 677, A138, Identifying Lyα emitter candidates with Random Forest: Learning from galaxies in the CANDELS survey
30. Leung et al. (incl. I. Jung) 2023, ApJL, 954, L46, NGDEEP Epoch 1: The Faint End of the Luminosity Function at z 9-12 from Ultradeep JWST Imaging
31. Bradley et al. (incl. I. Jung) 2023, ApJ, 955, 13, High-redshift Galaxy Candidates at z = 9-10 as Revealed by JWST Observations of WHL0137-08
32. Larson et al. (incl. I. Jung) 2023, ApJL, 953, L29, A CEERS Discovery of an Accreting Supermassive Black Hole 570 Myr after the Big Bang: Identifying a Progenitor of Massive z > 6 Quasars
33. Arrabal Haro et al. (incl. I. Jung) 2023, ApJL, 951, L22, Spectroscopic Confirmation of CEERS NIRCam-selected Galaxies at z ≃ 8-10
34. Fujimoto et al. (incl. I. Jung) 2023, ApJL, 949, L25, CEERS Spectroscopic Confirmation of NIRCam-selected z ≳ 8 Galaxy Candidates with JWST/NIRSpec: Initial Characterization of Their Properties
35. Yoon et al. (incl. I. Jung) 2023, ApJ, 950, 61, ALMA Observation of a z ≳ 10 Galaxy Candidate Discovered with JWST
36. Hsiao et al. (incl. I. Jung) 2023, ApJL, 949, L34, JWST Reveals a Possible z ∼ 11 Galaxy Merger in Triply Lensed MACS0647–JD
37. Simons et al. (incl. I. Jung) 2023, ApJS, 266, 13, CLEAR: Survey Overview, Data Analysis, and Products
38. Cleri et al. (incl. I. Jung) 2023, ApJ, 948, 112, CLEAR: High-ionization [Ne V] λ3426 Emission-line Galaxies at 1.4 < z < 2.3
39. Trump et al. (incl. I. Jung) 2023, ApJ, 945, 35, The Physical Conditions of Emission-line Galaxies at Cosmic Dawn from JWST/NIRSpec Spectroscopy in the SMACS 0723 Early Release Observations
40. Kartaltepe et al. (incl. I. Jung) 2023, ApJL, 946, L15, CEERS Key Paper. III. The Diversity of Galaxy Structure and Morphology at z = 3-9 with JWST
41. Abdurro'uf et al. (incl. I. Jung) 2023, ApJ, 945, 117, Spatially Resolved Stellar Populations of 0.3 < z < 6.0 Galaxies in WHL 0137-08 and MACS 0647+70 Clusters as Revealed by JWST: How Do Galaxies Grow and Quench over Cosmic Time?
42. Zavala et al. (incl. I. Jung) 2023, ApJL, 943, L9, Dusty Starbursts Masquerading as Ultra-high Redshift Galaxies in JWST CEERS Observations
43. Backhaus et al. (incl. I. Jung) 2023, ApJ, 943, 37, CLEAR: Spatially Resolved Emission Lines and Active Galactic Nuclei at 0.6 < z < 1.3