Ho Seong Hwang

Comparing the Nebular and Stellar Dust Attenuation Curves in Nearby Star-Forming Galaxies

Jong Chul Lee, Hyunjin Shim, Hyunmi Song +3

Differences in the spatial distributions of stars and ionized gas relative to dust in galaxies imply that stellar and nebular dust attenuation curves need not be identical. Althoug…

An Enhanced Catalog of Gaia DR3 Galaxy Candidates with Spectroscopic and Machine-Learning Photometric Redshifts

Junghyun Hwang, Ho Seong Hwang

We present an updated galaxy catalog based on the Gaia Data Release 3 (DR3) Galaxy Candidates table, augmented with both spectroscopic and machine-learning based photometric redshi…

HETDEX: Star Formation Stochasticity Diagram of Lyman Alpha Emitting Galaxies at Cosmic Noon Confirms Three Archetypes

Nicole Firestone, Eric Gawiser, Kartheik G. Iyer +14

In this work, we aim to measure the star formation stochasticity of Lyman Alpha Emitting Galaxies (LAEs) at Cosmic Noon. We identify 270 LAEs from the HETDEX Survey in the COSMOS f…

Dynamical Test of Cosmic Acceleration: $k$ -nearest Neighbor Cross Correlation of Cosmic Microwave Background and Cosmic Infrared Background

Dongkok Kim, Donghui Jeong, Yi-Kuan Chiang +1

The physical origin of cosmic acceleration remains one of the central questions in modern cosmology. The integrated Sachs-Wolfe (ISW) and Rees-Sciama (RS) effects, which arise from…

Ongoing Morphological Transformation from Elliptical to Spiral Galaxies Induced by Gas Accretion from Neighboring Galaxies

Gene Yun, Sang Hyeok Im, Ho Seong Hwang +2

We present results from spectroscopic observations of three interacting galaxy systems, each associated with a primary galaxy - VCC 1748, SDSS J1106, and 2MASX J0834 - which have b…

Constructing a Mock Galaxy Catalog for the All-sky SPECtroscopic Survey of Nearby Galaxies (A-SPEC) Using the Machine-assisted Semi-Simulation Model

Dongkok Kim, Yongseok Jo, Ho Seong Hwang +26

We present a methodology for constructing a mock galaxy catalog for the All-sky SPECtroscopic survey of nearby galaxies (A-SPEC) using the Machine-assisted Semi-Simulation Model. T…

The SPHEREx View of Galaxy Clusters: A Simulation-based Validation of the Forced Photometry Pipeline for Extended Sources

Hyeonguk Bahk, Ho Seong Hwang, Lindsey Bleem +12

We present a simulation-driven assessment of the performance of the SPHEREx pipeline for galaxy cluster science, focusing on photometry, source blending, survey depth, and photomet…

ODIN: Rest-frame Optical Morphologies and Star Formation Activity of Lyα Emitters at z=2.4, 3.1, and 4.5

Sang Hyeok Im, Ho Seong Hwang, Jeong Hwan Lee +19

We analyze the rest-frame optical (~8000 Å) morphologies and star formation activity of Lyα emitters (LAEs) at redshifts $2.4$ , $3.1$ , and $4.5$ , identified in the ODIN survey. To…

ODIN: Searching for LyC emission from Lyman- $α$ emitters at $z = 4.5$ in the E-COSMOS and XMM-LSS fields

Eunsuk Seo, Hyunmi Song, Lucia Guaita +18

We investigated Lyman-continuum (LyC) emission from Lyman- $α$ emitters (LAEs) at $z = 4.5$ , identified in the One-hundred-deg $^{2}$ DECam Imaging in Narrowbands (ODIN) survey. Of the 7…

ODIN: Spectroscopic Validation of Ly $α$ -Emitting Galaxy Samples with DESI

Ethan Pinarski, Govind Ramgopal, Nicole Firestone +65

The One-hundred-deg^2 DECam Imaging in Narrowbands (ODIN) survey is conducting the widest-field deep narrow-band imaging of the equatorial and southern skies. ODIN uses three custo…

ODIN: Confirmation and 3D Reconstruction of Six Massive Protoclusters at Cosmic Noon

Ashley Ortiz, Vandana Ramakrishnan, Kyoung-Soo Lee +64

Protoclusters represent sites of accelerated galaxy formation and extreme astrophysical activity characteristic of dense environments. Identifying massive protoclusters and mapping…

Evolution of submillimeter galaxies across cosmic-web environments

Ankit Kumar, M. Celeste Artale, Antonio D. Montero-Dorta +12

Submillimeter galaxies (SMGs) provide valuable insights into galaxy formation and evolution and are likely influenced by their cosmic environment. However, their rarity makes envir…

astro-ph.IM2026

A New Collision Avoidance Fiber Assignment Algorithm for Robotic Fiber Positioners in Multi-Object Spectroscopy

Minseong Kwon, Ho Seong Hwang, Jong Chul Lee +22

We present a new fiber assignment algorithm for a robotic fiber positioner system in multi-object spectroscopy. Modern fiber positioner systems typically have overlapping patrol re…

A redshift survey of the nearby galaxy cluster Abell 2199 : No upturn of the faint-end slope of galaxy luminosity function

Jong-In Park, Hyunmi Song, Ho Seong Hwang

We determine the galaxy luminosity function of cluster galaxies in the nearby galaxy cluster Abell 2199 (A2199), focusing on the faint-end slope down to $M_{r} \sim - 14.5$ . To achiev…

astro-ph.GA2026★ 1 cited

ODIN: Clustering Properties of Ly $α$ Blobs at $z$ $\sim$ 2.4 and 3.1

Byeongha Moon, Yujin Yang, Eric Gawiser +18

Spatially extended Ly $α$ nebulae, known as Ly $α$ blobs (LABs), are a rare population at $z > 2$ that are thought to trace proto-groups or the progenitors of massive galaxies in the…

Effect of local environment on Ly $α$ line profile in DESI/ODIN LAEs

Ana Sofía M. Uzsoy, Arjun Dey, Anand Raichoor +51

Lyman-Alpha Emitters (LAEs) are star-forming galaxies with significant Ly $α$ emission and are often used as tracers of large-scale structure at high redshift. We explore the relati…

astro-ph.GA2025★ 11 cited

ODIN: Characterizing the Three-dimensional Structure of Two Protocluster Complexes at $z = 3.1$

Vandana Ramakrishnan, Ashley Ortiz, Byeongha Moon +52

We present a detailed study of the 3D morphology of two extended associations of multiple protoclusters at $z = 3.1$ . These protocluster 'complexes', designated COSMOS-z3.1-A and COS…

astro-ph.GA2025★ 1 cited

Search for Slow Bars in Two Barred Galaxies with Nuclear Structures: NGC 6951 and NGC 7716

Yun Hee Lee, Ho Seong Hwang, Virginia Cuomo +9

We investigate two barred galaxies with nuclear structures, NGC 6951 and NGC 7716, to examine whether they host slow bars. Using Gemini/GMOS long-slit spectroscopy, we calculate th…

astro-ph.CO2025

RVSNUpy: A Python Package for Spectroscopic Redshift Measurement Based on Cross-Correlation

Taewan Kim, Jubee Sohn, Ho Seong Hwang

We introduce RVSNUpy, a new Python package designed to measure spectroscopic redshifts. Based on inverse-variance weighted cross-correlation, RVSNUpy determines the redshifts by co…

ODIN: Clustering Analysis of 14,000 Lyα Emitting Galaxies at z=2.4, 3.1, and 4.5

Danisbel Herrera, Eric Gawiser, Barbara Benda +15

Lyman Alpha Emitters (LAEs) are star-forming galaxies that efficiently probe the spatial distribution of galaxies in the high redshift universe. The spatial clustering of LAEs refl…

Resolved Stellar Mass Estimation of Nearby Late-type Galaxies for the SPHEREx Era: Dependence on Stellar Population Synthesis Models

Jeong Hwan Lee, Minjin Kim, Taehyun Kim +7

The upcoming all-sky infrared spectrophotometric SPHEREx mission is set to provide spatially resolved stellar mass maps of nearby galaxies, offering more detailed insights than int…

astro-ph.CO2025

Machine learning based Photometric Redshifts for Galaxies in the North Ecliptic Pole Wide field: catalogs of spectroscopic and photometric redshifts

Taewan Kim, Jubee Sohn, Ho Seong Hwang +13

We perform an MMT/Hectospec redshift survey of the North Ecliptic Pole Wide (NEPW) field covering 5.4 square degrees, and use it to estimate the photometric redshifts for the sourc…