Article
Astronomy & Astrophysics
Siddhartha Gurung-Lopez, Shun Saito, Carlton M. Baugh, Silvia Bonoli, Cedric G. Lacey, Alvaro A. Orsi
Summary: A novel approach using neural networks to measure the systemic redshift of Lyman alpha emitters (LAEs) is introduced in this study to mitigate clustering distortions caused by misidentification of Ly alpha wavelength in their Ly alpha line profiles. Training the neural network to predict Ly alpha wavelength improves accuracy significantly and works effectively even with decreased quality of Ly alpha line profiles. The methodology benefits LAE surveys like HETDEX in accurately determining systemic redshift of a subpopulation and estimating the systemic redshift of the rest of the galaxy sample.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Chris Byrohl, Dylan Nelson
Summary: We develop a comprehensive theoretical model for Lyman-alpha (Lyα) emission, from the scale of individual Lyα emitters (LAEs) to Lyα haloes (LAHs), Lyα blobs (LABs), and Lyα filaments (LAFs) of the diffuse cosmic web itself. By post-processing a cosmological magnetohydrodynamical simulation, we capture the resonant scattering process of Lyα photons and build an emission model incorporating recombinations and collisions in diffuse gas, radiative effects from nearby AGN, and emission sourced by stellar populations. Our model provides insights into the observability and physical origin of the Lyα cosmic web, revealing that diffuse Lyα filaments are illuminated by photons from the intergalactic medium, galaxies, and their gaseous haloes. We predict the abundance, area, linear size, and embedded halo/emitter populations within filaments and suggest that the Lyα cosmic web can be detected with modern integral field spectrographs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Raghunath Ghara, Sambit K. Giri, Benedetta Ciardi, Garrelt Mellema, Saleem Zaroubi
Summary: The MWA team obtained new upper limits on the power spectrum of the 21-cm signal at 6.5-8.7 redshifts and used Bayesian inference to constrain the ionization and thermal state of the IGM, revealing no constraints on IGM state above 7.8 redshift in the absence of an additional radio background. The results suggest that models with an IGM fraction of ionized regions below 0.6 and average gas temperature less than or equal to 10(3) h(-1) are disfavored, along with an exclusion of an additional radio background of at least 0.008% of the CMB at 1.42 GHz within the same credible interval limits.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
R. Thomas, L. Pentericci, O. Le Fevre, A. M. Koekemoer, M. Castellano, A. Cimatti, F. Fontanot, A. Gargiulo, B. Garilli, M. Talia, R. Amorin, S. Bardelli, S. Cristiani, G. Cresci, M. Franco, J. P. U. Fynbo, N. P. Hathi, P. Hibon, Y. Khusanova, V Le Brun, B. C. Lemaux, F. Mannucci, D. Schaerer, G. Zamorani, E. Zucca
Summary: The study aims to analyze the variance of intergalactic medium transmission by examining the parameter in rest-frame UV spectra of high-redshift galaxies. Utilizing VUDS and VANDELS data, the research divided galaxies into two sub-samples based on IGM transmission and created average spectra, showing the direct observation of IGM transmission variance in high-redshift galaxies.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Hidenobu Yajima, Makito Abe, Sadegh Khochfar, Kentaro Nagamine, Akio K. Inoue, Tadayuki Kodama, Shohei Arata, Claudio Dalla Vecchia, Hajime Fukushima, Takuya Hashimoto, Nobunari Kashikawa, Mariko Kubo, Yuexing Li, Yuichi Matsuda, Ken Mawatari, Masami Ouchi, Hideki Umehata
Summary: This study presents results from a new cosmological hydrodynamics simulation campaign of protocluster regions, showing the formation and evolution of galaxies in extremely overdense regions. The simulations reveal the presence of starburst galaxies and supermassive black holes in these regions, suggesting that protoclusters may kickstart cosmic reionization.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Jenny G. Sorce, Pierre Ocvirk, Dominique Aubert, Stefan Gottloeber, Paul R. Shapiro, Taha Dawoodbhoy, Gustavo Yepes, Kyungjin Ahn, Ilian T. Iliev, Joseph S. W. Lewis
Summary: This study investigates the reionization histories of paired haloes similar to the Milky Way and finds a wide diversity in their histories. It also reveals that halo pairs with smaller total energy tend to be reionized earlier. The study highlights the importance of considering the properties of halo pairs in understanding the effects of cosmic reionization.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Ikuru Iwata, Marcin Sawicki, Akio K. Inoue, Masayuki Akiyama, Genoveva Micheva, Toshihiro Kawaguchi, Nobunari Kashikawa, Stephen Gwyn, Stephane Arnouts, Jean Coupon, Guillaume Desprez
Summary: Using imaging data from the CFHT Large Area U-band Deep Survey (CLAUDS) and the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP), this study constrains the ionizing radiation escape fraction from active galactic nuclei (AGNs) at z similar to 3-4. The results show that the Lyman Continuum (LyC) escape fraction of AGNs at z > 3.3 is generally lower than unity, and the contribution of UV-selected AGNs to the LyC emissivity at that epoch is minor.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Sowgat Muzahid, Joop Schaye, Sebastiano Cantalupo, Raffaella Anna Marino, Nicolas F. Bouche, Sean Johnson, Michael Maseda, Martin Wendt, Lutz Wisotzki, Johannes Zabl
Summary: The first characterization of the circumgalactic medium of Ly alpha emitters (LAEs) reveals distinct features in terms of luminosity and interstellar material absorption, with no strong dependence of absorption on transverse distance, redshift, or Ly alpha emission line properties. However, a correlation is found between increased absorption near LAEs with higher star formation rates, suggesting a link between surrounding interstellar hydrogen and star formation in LAEs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Zhihui Li, Charles C. Steidel, Max Gronke, Yuguang Chen
Summary: Researchers observed Lyman-alpha Blob 1 in the SSA22 protocluster region using the Keck telescope, identifying key features and analyzing the spatial distributions of Ly alpha and H beta. Through detailed modeling, they successfully constrained parameters such as Hi density in the interclump medium, clump velocities, and systemic redshift, providing insights into the formation and characteristics of Ly alpha profiles.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Tiago Costa, Fabrizio Arrigoni Battaia, Emanuele P. Farina, Laura C. Keating, Joakim Rosdahl, Taysun Kimm
Summary: The detection of Ly alpha nebulae around z>6 quasars reveals extended gas reservoirs around rapidly growing supermassive black holes. Cosmological models can explain the observations of z>6 quasars, but it is uncertain whether they can also explain the observed extended Ly alpha emission. The study finds that a combination of recombination radiation and emission from collisionally excited gas can power Ly alpha nebulae in agreement with observations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Hakim Atek, Lukas J. Furtak, Pascal Oesch, Pieter van Dokkum, Naveen Reddy, Thierry Contini, Garth Illingworth, Stephen Wilkins
Summary: We investigate the burstiness of star formation and the ionizing efficiency of a large sample of galaxies at 0.7 < z < 1.5 using HST grism spectroscopy and deep ultraviolet (UV) imaging. Our findings suggest that the burstiness parameters of these strong emission-line galaxies may differ from previous observations and simulations. We also observe an increase of ionizing photon production efficiency with redshift, further confirming similar results at higher redshifts.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Jarred Gillette, Marie Wingyee Lau, Fred Hamann, Serena Perrotta, David S. N. Rupke, Dominika Wylezalek, Nadia L. Zakamska, Andrey Vayner
Summary: Red quasars may represent a young stage of galaxy evolution that provide important feedback to their host galaxies. A study on extremely red quasars reveals that their haloes are similar to blue quasars, but with more compact and circularly symmetric inner regions. There is no evidence of feedback on circumgalactic scales, possibly due to the short duration of quasar activity.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
T. Roy Choudhury, Aseem Paranjape, Sarah E. Bosman
Summary: A computationally efficient method is proposed in this study to simulate Lyman alpha absorption optical depth in the presence of neutral hydrogen "islands" leftover from reionization at redshifts between 5 and 6. By analyzing large-scale fluctuations in optical depth, it is confirmed at greater than or similar to 2 sigma confidence that reionization is not complete before around 5.6, with a possibility of completion as late as around 5.2.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Review
Astronomy & Astrophysics
Claude-Andre Faucher-Giguere, S. Peng Oh
Summary: The past decade has witnessed significant theoretical progress in our understanding of the circumgalactic medium (CGM) due to rich observations and advanced simulations. The properties of the CGM are determined by the competition between gravity-driven infall and gas cooling. The interaction between the hot and cold phases of the multiphase gas and the effect of CGM on galaxy evolution remain open questions.
ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Mengtao Tang, Daniel P. Stark, Richard S. Ellis
Summary: As the James Webb Space Telescope approaches scientific operation, there is much interest in exploring the redshift range beyond that accessible with Hubble Space Telescope imaging. Currently, the only means to gauge the presence of such early galaxies is to age-date the stellar population of systems in the reionisation era. However, a spectroscopic study reveals that the previously believed genuinely young systems may have higher dynamical masses than expected.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Ulrike Kuchner, Roan Haggar, Alfonso Aragon-Salamanca, Frazer R. Pearce, Meghan E. Gray, Agustin Rost, Weiguang Cui, Alexander Knebe, Gustavo Yepes
Summary: Galaxy clusters grow by accreting galaxies from the field and along cosmic filaments, with up to 45% of galaxies falling into clusters via filaments. Backsplash galaxies, comprising between 30-60% of filament galaxies at R-200, return to clusters after deflecting widely from their entry trajectory, especially in relaxed clusters. The study reveals that galaxies in clusters are influenced by their environment, with pristine galaxies being environmentally affected by cosmic filaments alone.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Laurent Legrand, Anne Hutter, Pratika Dayal, Graziano Ucci, Stefan Gottloeber, Gustavo Yepes
Summary: Using the ASTRAEUS framework, this study quantifies the star formation histories of galaxies in the first billion years by coupling an N-body simulation with semi-analytic and semi-numerical models. Key findings include the decrease in stellar mass formed in the stochastic phase with increasing stellar mass and redshift, the stability of mass assembly and time spent in the stochastic phase with different radiative feedback models, and the variation of alpha and beta parameters with stellar mass at all redshifts. The proposed fits can reliably recover stellar mass and mass-to-light ratios for galaxies at specific ranges of stellar mass and UV magnitude at redshifts between 5-9, making this physical model useful for deriving SFHs for galaxies observed by future instruments.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Yang Wang, Nicola R. Napolitano, Weiguang Cui, Xiao-Dong Li, Alexander Knebe, Chris Power, Frazer Pearce, Lin Tang, Gustavo Yepes, Xi Kang
Summary: This work presents a model to describe the star formation histories (SFHs) of individual galaxies from three simulations. The model divides SFHs into two components: the 'main sequence' and the 'variation', which are generated by tracing the history of the SFR-M-* main sequence and reproducing scatter around it using fractional Brownian motions. The study finds that the evolution of the main sequence varies between simulations, fractional Brownian motions can reproduce many features of SFHs but discrepancies still exist, and variations and mass-loss rate are crucial for reconstructing the SFHs of the simulations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Tony Zhang, Chia-Hsun Chuang, Risa H. Wechsler, Shadab Alam, Joseph DeRose, Yu Feng, Francisco-Shu Kitaura, Marcos Pellejero-Ibanez, Sergio Rodriguez-Torres, Chun-Hao To, Gustavo Yepes, Cheng Zhao
Summary: This study explores the method of reducing simulation variance by adopting fixed-amplitude initial conditions, finding that constructing covariance matrices for such simulations is not trivial but can be estimated reasonably using the ezmock method. The research further examines the dependence of variance suppression on three-point clustering, small-scale clustering, and galaxy bias, proposing intuitive explanations based on the ezmock bias model.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Tomas Hough, Sofia A. Cora, Roan Haggar, Cristian Vega-Martinez, Ulrike Kuchner, Frazer Pearce, Meghan Gray, Alexander Knebe, Gustavo Yepes
Summary: In this study, the semi-analytic model of galaxy formation and evolution SAG is combined with 102 simulated galaxy clusters from THE THREE HUNDRED project to investigate the relationship between star formation quenching and the dynamical history of galaxies in and around clusters. Galaxies are classified into four populations based on their orbital history, and it is found that the majority of quenched galaxies inside clusters are ancient infallers with low or no hot and cold gas content. The quenching of ancient infallers is mainly caused by ram-pressure stripping (RPS) between the first and second pericentric passages. Recent infallers make up a smaller fraction of quenched galaxies inside clusters, and they tend to have a higher proportion of hot and cold gas. Pre-processing effects contribute to the quenching of recent infallers before they enter the main cluster progenitor. Backsplash galaxies, which account for about 65% of quenched galaxies around clusters, require both pre-processing and in-cluster processes to suppress star formation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Laurent Legrand, Pratika Dayal, Anne Hutter, Stefan Gottloeber, Gustavo Yepes, Maxime Trebitsch
Summary: Using the ASTRAEUS framework, the impact of environmental density and radiative feedback on the assembly of galaxies and their host halos during the Epoch of Reionization is explored. It is found that there is a specific environment where galaxies are most efficient at accreting dark matter, minor mergers contribute more to dark matter assembly at z=5, and radiative feedback suppresses star formation in low-mass galaxies in over-dense environments.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Oliver Newton, Arianna Di Cintio, Salvador Cardona-Barrero, Noam I. Libeskind, Yehuda Hoffman, Alexander Knebe, Jenny G. Sorce, Matthias Steinmetz, Elmo Tempel
Summary: Ultradiffuse galaxies (UDGs) are difficult to detect due to their low surface brightness, but they are important for studying cosmological models and galaxy formation. Previous studies have found a small number of UDGs in the Local Group, but it is unclear if this is expected. Using hydrodynamic simulations, we predict that there are around 12 isolated UDGs in the Local Group, of which 2 are detectable in the Sloan Digital Sky Survey. Future all-sky surveys could potentially reveal a larger population of UDGs in the Local Group.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
Ana Contreras-Santos, Alexander Knebe, Weiguang Cui, Roan Haggar, Frazer Pearce, Meghan Gray, Marco De Petris, Gustavo Yepes
Summary: Using the data from THE THREE HUNDRED project, this study investigates galaxy pairs in high-density environments and explores the effectiveness of observational techniques and machine learning in identifying true pairs. The results show that the specific thresholds used to find pairs significantly affect the purity and completeness of the sample. By training a machine learning model, the study improves the accuracy and completeness of identifying true pairs and identifies important properties for distinguishing them.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Qingyang Li, Weiguang Cui, Xiaohu Yang, Romeel Dave, Elena Rasia, Stefano Borgani, Meneghetti Massimo, Alexander Knebe, Klaus Dolag, Jack Sayers
Summary: This paper presents theoretical studies on the scaled profiles of physical properties associated with the baryonic components in galaxy clusters, from z = 4 to z = 0. By comparing two simulations and observed profiles, it is found that the agreements between the simulations and observations are mostly at outer radii, with better agreement in gas profiles for Gadget-X compared to Gizmo-SIMBA in the central regions. The evolution trends are generally consistent between the two simulations, with less discrepancy in the gas density profile compared to temperature and entropy profiles at high redshift.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Massimo Meneghetti, Weiguang Cui, Elena Rasia, Gustavo Yepes, Ana Acebron, Giuseppe Angora, Pietro Bergamini, Stefano Borgani, Francesco Calura, Giulia Despali, Carlo Giocoli, Giovanni Granata, Claudio Grillo, Alexander Knebe, Andrea V. Maccio, Amata Mercurio, Lauro Moscardini, Priyamvada Natarajan, Antonio Ragagnin, Piero Rosati, Eros Vanzella
Summary: Previous studies have found an excess in the estimated probability of galaxy-galaxy strong lensing in observed galaxy clusters compared to the theoretical predictions. In this study, the researchers analyzed a larger set of simulated galaxy clusters and investigated how different implementations of star formation and feedback in simulations affect the theoretical expectations. The results show that the probability for galaxy-galaxy strong lensing is higher in simulations with denser stellar cores, but the discrepancy with observations still persists.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Daniel J. Cornwell, Alfonso Aragon-Salamanca, Ulrike Kuchner, Meghan E. Gray, Frazer R. Pearce, Alexander Knebe
Summary: This paper tests and quantifies the ability of upcoming wide-field spectroscopic surveys to identify the environment of individual galaxies in the vicinity of massive galaxy clusters. The study finds that associating galaxies with the correct cosmic web environment is highly uncertain in the infall regions surrounding galaxy clusters due to peculiar velocities and projection effects. However, with large enough spectroscopic samples and correct statistical treatment, robust conclusions on the relationship between galaxy properties and their environment can be extracted.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Krishna Naidoo, Wojciech A. Hellwing, Maciej Bilicki, Noam Libeskind, Simon Pfeifer, Yehuda Hoffman
Summary: This article presents a methodology for constructing modified gravity (MG) constrained simulations of the local Universe using positions and peculiar velocities from the CosmicFlows data set. The analysis focuses on the nDGP and Hu-Sawicki f(eth R) models. A model-independent methodology is developed for constructing constrained simulations with any given power spectra and numerically calculated linear growth functions. The importance of generating MG constrained initial conditions (ICs) to study the subtle effects of MG in the local Universe is highlighted.