Ho Seong Hwang

Seoul National University

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Myung Gyoon Lee

Jacobs (United Kingdom)

Margaret J. Geller

Smithsonian Astrophysical Observatory

Changbom Park

Korea Institute for Advanced Study

Hyunjin Shim

Kyungpook National University

Jong Chul Lee

Korea Astronomy and Space Science Institute

G. Magdis

Technical University of Denmark

D. Elbaz

Commissariat à l'Énergie Atomique et aux Énergies Alternatives

Hyunmi Song

Chungnam National University

D. Scott

University of British Columbia

Woong-Seob Jeong

Korea Astronomy and Space Science Institute

Cooperative Institutions

Centre National de la Recherche Scientifique

218

Max Planck Society

196

Max Planck Institute for Astronomy

166

Commissariat à l'Énergie Atomique et aux Énergies Alternatives

CEA Paris-Saclay

Max Planck Institute for Extraterrestrial Physics

Korea Astronomy and Space Science Institute

Université Paris Cité

Center for Astrophysics Harvard & Smithsonian

Seoul National University

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Galaxies flowing in the oriented saddle frame of the cosmic web

Monthly Notices of the Royal Astronomical Society (2018)

Katarina Kraljic Christophe Pichon Yohan Dubois Sandrine Codis Corentin Cadiou

The strikingly anisotropic large-scale distribution of matter made of an extended network of voids delimited by sheets, themselves segmented by filaments, within which matter flows towards compact nodes where they intersect, imprints its geometry on the dynamics of cosmic flows, ultimately shaping the distribution of galaxies and the redshift evolution of their properties. The (filament-type) saddle points of this cosmic web provide a local frame in which to quantify the induced physical and morphological evolution of galaxies on large scales. The properties of virtual galaxies within the Horizon-AGN simulation are stacked in such a frame. The iso-contours of the galactic number density, mass, specific star formation rate (sSFR), kinematics and age are clearly aligned with the filament axis with steep gradients perpendicular to the filaments. A comparison to a simulation without feedback from active galactic nuclei (AGN) illustrates its impact on quenching star formation of centrals away from the saddles. The redshift evolution of the properties of galaxies and their age distribution are consistent with the geometry of the bulk flow within that frame. They compare well with expectations from constrained Gaussian random fields and the scaling with the mass of non-linearity, modulo the redshift dependent impact of feedback processes. Physical properties such as sSFR and kinematics seem not to depend only on mean halo mass and density: the residuals trace the geometry of the saddle, which could point to other environment-sensitive physical processes, such as spin advection, and AGN feedback at high mass.

10.1093/mnras/sty3216

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Building Up a Cluster: The Case of A520

Boris Deshev C. Park Ho Seong Hwang B. Ziegler M. Verdugo

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The One-hundred-deg^2 DECam Imaging in Narrowbands (ODIN): Survey Design and Science Goals

arXiv (Cornell University) (2023)

Kyoung-Soo Lee Eric Gawiser Changbom Park Yujin Yang Francisco Valdés

We describe the survey design and science goals for ODIN (One-hundred-deg^2 DECam Imaging in Narrowbands), a NOIRLab survey using the Dark Energy Camera (DECam) to obtain deep (AB~25.7) narrow-band images over an unprecedented area of sky. The three custom-built narrow-band filters, N419, N501, and N673, have central wavelengths of 419, 501, and 673 nm and respective full-widthat-half-maxima of 7.2, 7.4, and 9.8 nm, corresponding to Lya 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 broad-band data from Hyper Suprime-Cam, DECam, and in the future, LSST, the ODIN narrow-band images will enable the selection of over 100,000 Lya-emitting (LAE) galaxies at these epochs. ODIN-selected LAEs will identify protoclusters as galaxy overdensities, and the deep narrow-band images enable detection of highly extended Lya 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 the redshift evolution of these properties to be determined during the period known as Cosmic Noon, where star formation was at its peak. The two narrow-band filter wavelengths are designed to enable interloper rejection and further scientific studies by revealing [O II] and [O III] at z=0.34, Lya and He II 1640 at z=3.1, and Lyman continuum plus Lya 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.

Large format

10.48550/arxiv.2309.10191

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The evolution of the star formation activity per halo mass up to redshift ~1.6 as seen byHerschel

Astronomy and Astrophysics (2011)

P. Popesso A. Biviano G. Rodighiero Ivano Baronchelli M. Salvato

Star formation in massive galaxies is quenched at some point during hierarchical mass assembly. To understand where and when the quenching processes takes place, we study the evolution of the total star formation rate per unit total halo mass (\Sigma(SFR/M)) in three different mass scales: low mass halos (field galaxies), groups, and clusters, up to a redshift ~1.6. We use deep far-infrared PACS data at 100 and 160 um to accurately estimate the total star formation rate of the Luminous Infrared Galaxy population of 9 clusters with mass ~10^{15} M_{\odot}, and 9 groups/poor clusters with mass ~ 5 x 10^{13} M_{\odot}. Estimates of the field \Sigma(SFR/M) are derived from the literature, by dividing the star formation rate density by the mean comoving matter density of the universe. The field \Sigma(SFR/M) increases with redshift up to z~1 and it is constant thereafter. The evolution of the \Sigma(SFR/M)-z relation in galaxy systems is much faster than in the field. Up to redshift z~0.2, the field has a higher \Sigma(SFR/M) than galaxy groups and galaxy clusters. At higher redshifts, galaxy groups and the field have similar \Sigma(SFR/M), while massive clusters have significantly lower \Sigma(SFR/M) than both groups and the field. There is a hint of a reversal of the SFR activity vs. environment at z~1.6, where the group \Sigma(SFR/M) lies above the field \Sigma(SFR/M)-z relation. We discuss possible interpretations of our results in terms of the processes of downsizing, and star-formation quenching.

Stellar mass

Field galaxy

10.1051/0004-6361/201117973

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Citations (54)

Star formation history of infrared luminous galaxies in the SDSS

한국천문학회보 (2011)

Jong Chul Lee Myung Gyoon Lee Ho Seong Hwang

Cosmic infrared background

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An Introduction to SDSS Data Products and Data Access

한국천문학회보 (2005)

Ho Seong Hwang Yun-Young Choi Taehyun Kim Myung Gyoon Lee Changbom Park

Data access

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BCG alignment with the locations of cluster members and the large-scale structure out to 10 R200

Monthly Notices of the Royal Astronomical Society (2023)

R. J. E. Smith Ho Seong Hwang Katarina Kraljic Paula Calderón-Castillo Thomas M Jackson

ABSTRACT Using a sample of >200 clusters, each with typically 100–200 spectroscopically confirmed cluster members, we search for a signal of alignment between the position angle (PA) of the Brightest Cluster Galaxy (BCG) and the distribution of cluster members on the sky about the cluster centre out to projected distances of 3 R200. The deep spectroscopy, combined with corrections for spectroscopic incompleteness, makes our sample ideal to determine alignment signal strengths. We also use an SDSS based skeleton of the filamentary large-scale structure (LSS), and measure BCG alignment with the location of the LSS skeleton segments on the sky out to projected distances of 10 R200. The alignment signal is measured using three separate statistical measures; Rao’s spacing test (U), Kuiper’s V parameter (V), and the Binomial probability test (P). The significance of the BCG alignment signal with both cluster members and LSS segments is extremely high (1 in a million chance or less to be drawn randomly from a uniform distribution). We investigate a wide set of parameters that may influence the strength of the alignment signal. Clusters with more elliptical-shaped BCGs show stronger alignment with both their cluster members and LSS segments. Also, selecting clusters with closely connected filaments, or using a luminosity-weighted LSS skeleton, increases the alignment signal significantly. Alignment strength decreases with increasing projected distance. Combined, these results provide strong evidence for the growth of clusters and their BCGs by preferential feeding along the direction of the filaments in which they are embedded.

Similarity (geometry)

SIGNAL (programming language)

10.1093/mnras/stad2535

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Citations (5)

Rotating Galaxy Clusters in SDSS and 2dFGRS

한국천문학회보 (2007)

Ho Seong Hwang Myung Gyoon Lee

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Beyond halo mass: the role of vorticity-rich filaments in quenching galaxy mass assembly

arXiv (Cornell University) (2020)

Hyunmi Song C. Laigle Ho Seong Hwang Julien Devriendt Yohan Dubois

We examine how the mass assembly of central galaxies depends on their location in the cosmic web. The HORIZON-AGN simulation is analysed at z~2 using the DISPERSE code to extract multi-scale cosmic filaments. We find that the dependency of galaxy properties on large-scale environment is mostly inherited from the (large-scale) environmental dependency of their host halo mass. When adopting a residual analysis that removes the host halo mass effect, we detect a direct and non-negligible influence of cosmic filaments. Proximity to filaments enhances the build-up of stellar mass, a result in agreement with previous studies. However, our multi-scale analysis also reveals that, at the edge of filaments, star formation is suppressed. In addition, we find clues for compaction of the stellar distribution at close proximity to filaments. We suggest that gas transfer from the outside to the inside of the haloes (where galaxies reside) becomes less efficient closer to filaments, due to high angular momentum supply at the vorticity-rich edge of filaments. This quenching mechanism may partly explain the larger fraction of passive galaxies in filaments, as inferred from observations at lower redshifts.

Mass distribution

Stellar mass

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REGULARITY UNDERLYING COMPLEXITY: A REDSHIFT-INDEPENDENT DESCRIPTION OF THE CONTINUOUS VARIATION OF GALAXY-SCALE MOLECULAR GAS PROPERTIES IN THE MASS-STAR FORMATION RATE PLANE

The Astrophysical Journal (2014)

M. Sargent E. Daddi M. Béthermin H. Aussel G. Magdis

Star-forming galaxies (SFGs) display a continuous distribution of specific star formation rates (sSFR) which can be approximated by the superposition of two log-normal distributions. The 1st of these encompasses the main sequence (MS) of SFGs, the 2nd one a rarer population of starbursts (SB). We show that the sSFR-distribution of SBs can be regarded as the result of a physical process (plausibly merging) taking the mathematical form of a log-normal boosting kernel and enhancing star formation activity. We explore the utility of splitting the star-forming population into MS and SB galaxies - an approach we term "2-Star Formation Mode" (2-SFM) framework - for understanding their molecular gas properties. Variations of star formation efficiency (SFE) and gas fractions among SFGs take a simple, redshift-independent form, once these quantities are normalized to the value of an average MS galaxy. The change in SFE for galaxies undergoing a starburst event scales supra-linearly with the SFR-increase, as expected for mergers. This implies a continuous distribution of galaxies in the Schmidt-Kennicutt plane that separates more clearly into loci for SBs and normal galaxies than observed in SFR vs. M* space. SBs with the largest deviations (>10-fold) from the MS, like many local ULIRGs, are not average SBs, but even rarer events with progenitors having larger gas fractions than typical MS galaxies. We statistically infer that the gas fractions of typical SBs decrease by a factor of 2 to 3 with respect to their direct MS progenitors, as expected to occur in short-term SFR-boosts during which internal gas reservoirs are drained more quickly than gas is accreted from the cosmic web. We predict variations of the CO-to-H2 conversion factor in the SFR-M* plane and provide evidence that the higher sSFR of distant galaxies is a direct consequence of larger gas fraction in these systems.

Stellar mass

10.1088/0004-637x/793/1/19

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Citations (305)