Examinando por Autor "Lee, Kyoung-Soo"
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Ítem Discovering Large-scale Structure at 2 < z < 5 in the C3VO Survey(Institute of Physics, 2025-02) Hung, Denise; Lemaux, Brian C.; Cucciati, Olga; Forrest, Ben; Shah, Ekta A.; Gal, Roy R.; Giddings, Finn; Sikorski, Derek; Golden-Marx, Emmet; Lubin, Lori M.; Hathi, Nimish; Zamorani, Giovanni; Shen, Lu; Bardelli, Sandro; Cassarà, Letizia P.; De Lucia, Gabriella; Fontanot, Fabio; Garilli, Bianca; Guaita, Lucia; Hirschmann, Michaela Monika; Lee, Kyoung-Soo; Newman, Andrew B.; Ramakrishnan, Vandana; Vergani, Daniela; Xie, Lizhi; Zucca, ElenaThe Charting Cluster Construction with VUDS and ORELSE (C3VO) survey is an ongoing imaging and spectroscopic campaign aiming to map out the growth of structure up to z ∼ 5 and was born from the combination of the Visible Multi-Object Spectrograph Ultra Deep Survey and the Observations of Redshift Evolution in Large-Scale Environments (ORELSE) survey. As we previously accomplished with the ORELSE survey, we apply our technique known as Voronoi tessellation Monte Carlo (VMC) mapping to search for serendipitous galaxy overdensities at 2 < z < 5 in the three C3VO fields. We also apply the same technique to mock observations of simulated galaxies with properties derived from the GAlaxy Evolution and Assembly semianalytic model in order to judge the effectiveness of our search algorithm as a function of redshift, total mass, and fraction of spectroscopic redshifts. We find completeness and purity values of the order of 30%-50% for log ( M z = 0 / M ⊙ ) > 14 and 2 < z < 4, with a strong dependence on mass and redshift, with values as high as ∼80% and ∼70%, respectively, in the best-case scenario for log ( M z = 0 / M ⊙ ) > 14.5 . In the C3VO fields, we were able to recover many of the previously known structures in the literature as well as find hundreds of new overdensity candidates, once again demonstrating the powerful capabilities of VMC mapping when applied to wide-field optical and infrared galaxy evolution surveys at ever higher redshifts. © 2025. The Author(s). Published by the American Astronomical Society.Ítem ODIN: High Clustering Strength of Protoclusters at Cosmic Noon(Institute of Physics, 0025-04) Ramakrishnan, Vandana; Lee, Kyoung-Soo; Firestone, Nicole; Gawiser, Eric; Artale, Maria Celeste; Gronwall, Caryl; Guaita, Lucia; Hwang, Ho Seong; Im, Sang Hyeok; Jeong, Woong-Seob; Kim, Seongjae; Kumar, AnkitThe One-hundred-deg2 DECam Imaging in Narrowbands (ODIN) survey is carrying out a systematic search for protoclusters during Cosmic Noon, using Lyα-emitting galaxies (LAEs) as tracers. Once completed, ODIN aims to identify hundreds of protoclusters at redshifts of 2.4, 3.1, and 4.5 across seven extragalactic fields, covering a total area of up to 91 deg2. In this work, we report the high clustering strength of the ODIN protoclusters, determined via measurements of their cross-correlation with LAEs. Our sample consists of 150 protocluster candidates at z = 2.4 and 3.1, identified in two ODIN fields with a total area of 13.9 deg2. At z = 2.4 and 3.1, the inferred protocluster biases are 6 . 6 − 1.1 + 1.3 and 6 . 1 − 1.1 + 1.3 , corresponding to mean halo masses of log 〈 M / M ⊙ 〉 = 13.5 3 − 0.24 + 0.21 and 12.9 6 − 0.33 + 0.28 , respectively. By the present day, these protoclusters are expected to evolve into virialized galaxy clusters with a mean mass of ∼1014.5 M⊙. By comparing the observed number density of protoclusters to that of halos with the same measured clustering strength, we find that the completeness of our sample is of order unity. Finally, the similar descendant masses derived for our samples at z = 2.4 and 3.1, assuming that the halo number density remains constant, suggest that they represent similar structures observed at different cosmic epochs. As a consequence, any observed differences between the two samples can be understood as redshift evolution. The ODIN protocluster samples will thus provide valuable insights into the cosmic evolution of cluster galaxies. © 2025. The Author(s). Published by the American Astronomical Society.Ítem ODIN: Improved Narrowband Lyα Emitter Selection Techniques for z = 2.4, 3.1, and 4.5(Institute of Physics, 2024-10) Firestone, Nicole M.; Gawiser, Eric; Ramakrishnan, Vandana; Lee, Kyoung-Soo; Valdes, Francisco; Park, Changbom; Yang, Yujin; Ciardullo, Robin; Artale, María Celeste; Benda, Barbara; Broussard, Adam; Eid, Lana; Farooq, Rameen; Gronwall, Caryl; Guaita, Lucia; Gwyn, Stephen; Hwang, Ho Seong; Im, Sang Hyeok; Jeong, Woong-Seob; Karthikeyan, Shreya; Lang, Dustin; Moon, Byeongha; Padilla, Nelson; Sawicki, Marcin; Seo, Eunsuk; Singh, Akriti; Song, Hyunmi; Troncoso Iribarren, PaulinaLyman-alpha-emitting galaxies (LAEs) are typically young, low-mass, star-forming galaxies with little extinction from interstellar dust. Their low dust attenuation allows their Lyα emission to shine brightly in spectroscopic and photometric observations, providing an observational window into the high-redshift Universe. Narrowband surveys reveal large, uniform samples of LAEs at specific redshifts that probe large-scale structure and the temporal evolution of galaxy properties. The One-hundred-deg2 DECam Imaging in Narrowbands (ODIN) utilizes three custom-made narrowband filters on the Dark Energy Camera (DECam) to discover LAEs at three equally spaced periods in cosmological history. In this paper, we introduce the hybrid-weighted double-broadband continuum estimation technique, which yields improved estimation of Lyα equivalent widths. Using this method, we discover 6032, 5691, and 4066 LAE candidates at z = 2.4, 3.1, and 4.5 in the extended COSMOS field (∼9 deg2). We find that [O ii] emitters are a minimal contaminant in our LAE samples, but that interloping Green Pea-like [O iii] emitters are important for our redshift 4.5 sample. We introduce an innovative method for identifying [O ii] and [O iii] emitters via a combination of narrowband excess and galaxy colors, enabling their study as separate classes of objects. We present scaled median stacked spectral energy distributions for each galaxy sample, revealing the overall success of our selection methods. We also calculate rest-frame Lyα equivalent widths for our LAE samples and find that the EW distributions are best fit by exponential functions with scale lengths of w 0 = 53 ± 1, 65 ± 1, and 59 ± 1 Å, respectively.Ítem ODIN: Where Do Lyα Blobs Live? Contextualizing Blob Environments within Large-scale Structure(Institute of Physics, 2023-07) Ramakrishnan, Vandana; Moon, Byeongha; Im, Sang Hyeok; Farooq, Rameen; Lee, Kyoung-Soo; Gawiser, Eric; Yang, Yujin; Park, Changbom; Hwang, Ho Seong; Valdes, Francisco; Artale, Maria Celeste; Ciardullo, RobinWhile many Lyα blobs (LABs) are found in and around several well-known protoclusters at high redshift, how they trace the underlying large-scale structure is still poorly understood. In this work, we utilize 5352 Lyα emitters (LAEs) and 129 LABs at z = 3.1 identified over a ∼9.5 deg2 area in early data from the ongoing One-hundred-deg2 DECam Imaging in Narrowbands (ODIN) survey to investigate this question. Using LAEs as tracers of the underlying matter distribution, we identify overdense structures as galaxy groups, protoclusters, and filaments of the cosmic web. We find that LABs preferentially reside in regions of higher-than-average density and are located in closer proximity to overdense structures, which represent the sites of protoclusters and their substructures. Moreover, protoclusters hosting one or more LABs tend to have a higher descendant mass than those which do not. Blobs are also strongly associated with filaments of the cosmic web, with ∼70% of the population being within a projected distance of ∼2.4 pMpc from a filament. We show that the proximity of LABs to protoclusters is naturally explained by their association with filaments as large cosmic structures are where many filaments converge. The contiguous wide-field coverage of the ODIN survey allows us to establish firmly a connection between LABs as a population and filaments of the cosmic web for the first time.Ítem The One-hundred-deg2 DECam Imaging in Narrowbands (ODIN): Survey Design and Science Goals(Institute of Physics, 2024-02-11) Lee, Kyoung-Soo; Gawiser, Eric; Park, Changbom; Yang, Yujin; Valdes, Francisco; Lang, Dustin; Ramakrishnan, Vandana; Moon, Byeongha; Firestone, Nicole; Appleby, Stephen; Artale, Maria Celeste; Andrews, Moira; Bauer, Franz; Benda, Barbara; Broussard, Adam; Chiang, Yi-Kuan; Ciardullo, Robin; Dey, Arjun; Farooq, Rameen; Gronwall, Caryl; Guaita, Lucia; Huang, Yun; Hwang, Ho Seong; Sang Hyeok; Jeong, Woong-Seob; Karthikeyan, Shreya; Kim, Hwihyun; Kim, Seongjae; Kumar, Ankit; Nagaraj, Gautam R.; Nantais, Julie; Padilla, Nelson; Park, Jaehong; Pope, Alexandra; Popescu, Roxana; Schlegel, David; Seo, Eunsuk; Singh, Akriti; Song, Hyunmi; Troncoso, Paulina; Vivas, A. Katherina; Zabludoff, Ann; Zenteno, AlfredoWe describe the survey design and science goals for One-hundred-deg2 DECam Imaging in Narrowbands (ODIN), a NOIRLab survey using the Dark Energy Camera (DECam) to obtain deep (AB ∼ 25.7) narrowband images over an unprecedented area of sky. The three custom-built narrowband filters, N419, N501, and N673, have central wavelengths of 419, 501, and 673 nm and respective FWHM of 7.5, 7.6, and 10.0 nm, corresponding to Lyα at z = 2.4, 3.1, and 4.5 and cosmic times of 2.8, 2.1, and 1.4 Gyr, respectively. When combined with even deeper, public broadband data from the Hyper Suprime-Cam, DECam, and in the future, the Legacy Survey of Space and Time, the ODIN narrowband images will enable the selection of over 100,000 Lyα-emitting (LAE) galaxies at these epochs. ODIN-selected LAEs will identify protoclusters as galaxy overdensities, and the deep narrowband images enable detection of highly extended Lyα blobs (LABs). Primary science goals include measuring the clustering strength and dark matter halo connection of LAEs, LABs, and protoclusters, and their respective relationship to filaments in the cosmic web. The three epochs allow for the redshift evolution of these properties to be determined during the period known as Cosmic Noon, where star formation was at its peak. The narrowband filter wavelengths are designed to enable interloper rejection and further scientific studies by revealing [O ii] and [O iii] at z = 0.34, Lyα and He ii 1640 at z = 3.1, and Lyman continuum plus Lyα at z = 4.5. Ancillary science includes similar studies of the lower-redshift emission-line galaxy samples and investigations of nearby star-forming galaxies resolved into numerous [O iii] and [S ii] emitting regions.