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We explore spectroscopic and photometric methods for identifying high-redshift galaxies containing an Active Galactic Nucleus (AGN) with JWST observations. After demonstrating the limitations of standard optical methods, which appear…

We present a census of local active galactic nuclei (AGN) at a redshift of $z\leq0.025$ selected using the high-ionization [Ne v] $\lambda14.32\,\mu$m emission line from the Infrared Database of Extragalactic Observables from Spitzer…

Astrophysics of Galaxies · Physics 2026-03-16 S. Yassir , A. Annuar

We use data from the All Wavelength Extended Groth Strip International Survey to construct stacked X-ray maps of optically bright active galaxies (AGN) and an associated control sample of galaxies at high redshift (z less than 0.6). From…

Astrophysics of Galaxies · Physics 2019-02-11 Sagnick Mukherjee , Anirban Bhattacharjee , Suchetana Chatterjee , Jeffrey A. Newman , Renbin Yan

Observations of the redshifted 21-cm line during the Epoch of Reionization will open a new window to probe the intergalactic medium during the formation of the first stars, galaxies, and black holes. A particularly promising route to an…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-10 Kai-Feng Chen , Meredith Neyer , Jacqueline N. Hewitt , Aaron Smith , Mark Vogelsberger

We present two catalogues of active galactic nucleus (AGN) candidates selected from the latest data of two all-sky surveys -- Data Release 2 (DR2) of the \emph{Gaia} mission and the unWISE catalogue of the \emph{Wide-field Infrared Survey…

Based on the DUSTGRAIN-pathfinder suite of simulations, we investigate observational degeneracies between nine models of modified gravity and massive neutrinos. Three types of machine learning techniques are tested for their ability to…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-17 Julian Merten , Carlo Giocoli , Marco Baldi , Massimo Meneghetti , Austin Peel , Florian Lalande , Jean-Luc Starck , Valeria Pettorino

Machine-learning (ML) algorithms will play a crucial role in studying the large datasets delivered by new facilities over the next decade and beyond. Here, we investigate the capabilities and limits of such methods in finding galaxies with…

Instrumentation and Methods for Astrophysics · Physics 2019-08-22 Andreas L. Faisst , Abhishek Prakash , Peter L. Capak , Bomee Lee

Observations of the 21cm line of neutral hydrogen are poised to revolutionize our knowledge of cosmic reionization and the high-redshift population of galaxies. However, harnessing such information requires robust and comprehensive…

Astrophysics of Galaxies · Physics 2023-12-19 Joseph S. W. Lewis , Annalisa Pillepich , Dylan Nelson , Ralf S. Klessen , Simon C. O. Glover

The cosmic 21 cm signal is set to revolutionise our understanding of the early Universe, allowing us to probe the 3D temperature and ionisation structure of the intergalactic medium (IGM). It will open a window onto the unseen first…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-22 Bradley Greig , Andrei Mesinger

Initial density distribution provides a basis for understanding the complete evolution of cosmological density fluctuations. While reconstruction in our local Universe exploits the observations of galaxy surveys with large volumes,…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-28 Meng Zhou , Yi Mao

We present a set of low resolution empirical SED templates for AGNs and galaxies in the wavelength range from 0.03 to 30 microns based on the multi-wavelength photometric observations of the NOAO Deep-Wide Field Survey Bootes field and the…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 R. J. Assef , C. S. Kochanek , M. Brodwin , R. Cool , W. Forman , A. H. Gonzalez , R. C. Hickox , C. Jones , E. Le Floc'h , J. Moustakas , S. S. Murray , D. Stern

We consider the degree to which "21 cm tomography" of the high-redshift Universe can distinguish different ionization histories. Using a new analytic model for the size distribution of HII regions that associates these ionized bubbles with…

Astrophysics · Physics 2009-09-29 Steven Furlanetto , Matias Zaldarriaga , Lars Hernquist

We develop an effective perturbation theory (and, equivalently, a bias expansion) for the inhomogeneous 21cm radiation field from reionization. Using large-scale simulations of cosmological reionization, we find that this expansion…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-20 Matthew McQuinn , Anson D'Aloisio

Context. A defining characteristic of active galactic nuclei (AGN) that distinguishes them from other astronomical sources is their stochastic variability, which is observable across the entire electromagnetic spectrum. Upcoming optical…

The high-redshift 21-cm signal of neutral hydrogen is expected to be observed within the next decade and will reveal epochs of cosmic evolution that have been previously inaccessible. Due to the lack of observations, many of the…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-16 Aviad Cohen , Anastasia Fialkov , Rennan Barkana

The 21-cm forest signal is a promising probe of the Epoch of Reionization complementary to other 21-cm line observables and Ly$\alpha$ forest signal. Prospects of detecting it have significantly improved in the last decade thanks to the…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-20 Tomáš Šoltinský , Girish Kulkarni , Shriharsh P. Tendulkar , James S. Bolton

Point source detection techniques are used to identify and localise point sources in radio astronomical surveys. With the development of the Square Kilometre Array (SKA) telescope, survey images will see a massive increase in size from…

Computer Vision and Pattern Recognition · Computer Science 2022-02-09 Duncan Tilley , Christopher W. Cleghorn , Kshitij Thorat , Roger Deane

The [CII]$_{158\mu m}$ line has long been proposed as a promising line to spectroscopically confirm galaxies in the epoch of reionization. In this paper we present the results of new ALMA observations spectral scanning for [CII] in six…

Component separation is the process with which emission sources in astrophysical maps are generally extracted by taking multi-frequency information into account. It is crucial to develop more reliable methods for component separation for…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-19 J. M. Casas , L. Bonavera , J. González-Nuevo , C. Baccigalupi , M. M. Cueli , D. Crespo , E. Goitia , J. D. Santos , M. L. Sánchez , F. J. de Cos
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