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We study the phenomenology of cosmic-rays (CRs) at the galactic/extragalactic transition, focusing on two opposite models for the composition of the extragalactic (EG) component. Model A assumes a mixed source composition, with nuclear…

Astrophysics · Physics 2011-05-12 D. Allard , E. Parizot , A. V. Olinto

Observations of the 21cm Epoch of Reionization (EoR) signal are dominated by Galactic and extragalactic foregrounds. The need for foreground removal has led to the development of two main techniques, often referred to as "foreground…

The large majority of EGRET point sources remain to this day without an identified low-energy counterpart. Whatever the nature of the EGRET unidentified sources, faint unresolved objects of the same class must have a contribution to the…

Astrophysics · Physics 2008-11-26 V. Pavlidou , J. M. Siegal-Gaskins , C. Brown , B. D. Fields , A. V. Olinto

Observation of clustering of ultra-high energy cosmic rays (UHECR) suggests that they are emitted by compact sources. Assuming small deflection of UHECR during the propagation, the statistical analysis of clustering allows to estimate the…

Astrophysics · Physics 2010-12-03 S. L. Dubovsky , P. G. Tinyakov , I. I. Tkachev

Foreground removal is one of the biggest challenges in the detection of the Cosmic Dawn (CD) and Epoch of Reionization (EoR). Various foreground subtraction techniques have been developed based on the spectral smoothness of foregrounds.…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-01 Mengfan He , Qian Zheng , Quan Guo , Huanyuan Shan , Zhenghao Zhu , Yushan Xie , Yan Huang , Feiyu Zhao

Numerous studies have established the theoretical potential of the 21cm bispectrum to boost our understanding of the Epoch of Reionization (EoR), and therefore early generation of stars and galaxies. In this paper we look at the impact of…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-09 Catherine A Watkinson , Cathryn M Trott , Ian Hothi

In the presence of strong clustering, low-resolution surveys measure the summed contributions of groups of sources within the beam. The counts of bright intensity peaks are therefore shifted to higher flux levels compared to the counts of…

Cluster-scale strong lensing is a powerful tool for exploring the properties of dark matter and constraining cosmological models. However, due to the complex parameter space, pixelized strong lens modeling in galaxy clusters is…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-07 Yushan Xie , Huanyuan Shan , Nan Li , Ran Li , Eric Jullo , Chen Su , Xiaoyue Cao , Jean-Paul Kneib , Ana Acebron , Mengfan He , Ji Yao , Chunxiang Wang , Jiadong Li , Yin Li

The 21cm signal from the Epoch of Reionization (EoR) is observed as a three-dimensional data set known as a lightcone, consisting of a redshift (frequency) axis and two spatial sky plane axes. When observed by radio interferometers, this…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-28 Ian Hothi , Erwan Allys , Benoit Semelin , Romain Meriot

We construct foreground simulations comprising spatially correlated extragalactic and diffuse Galactic emission components and calculate the `intrinsic' (instrument-free) two-dimensional spatial power spectrum and the cylindrically and…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-31 Peter H. Sims , Lindley Lentati , Paul Alexander , Chris L. Carilli

We use the GALPROP model for cosmic-ray (CR) propagation to obtain our best prediction of the Galactic component of gamma rays, and show that away from the Galactic plane it gives an accurate prediction of the observed EGRET intensities. On…

Astrophysics · Physics 2007-05-23 A. W. Strong , I. V. Moskalenko , O. Reimer

A critical challenge in the observation of the redshifted 21-cm line is its separation from bright Galactic and extragalactic foregrounds. In particular, the instrumental leakage of polarized foregrounds, which undergo significant Faraday…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-18 C. D. Nunhokee , G. Bernardi , S. A. Kohn , J. E. Aguirre , N. Thyagarajan , J. S. Dillon , G. Foster , T. L. Grobler , J. Z. E. Martinot , A. R. Parsons

The estimation of the polarization $P$ of extragalactic compact sources in Cosmic Microwave Background images is a very important task in order to clean these images for cosmological purposes -- as, for example, to constrain the…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-07 D. Herranz , F. Argüeso , L. Toffolatti , A. Manjón-García , M. López-Caniego

One of the key science goals for the most sensitive telescopes, both current and upcoming, is the detection of the redshifted 21-cm signal from the Cosmic Dawn and Epoch of Reionization. The success of detection relies on accurate…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-13 Aishrila Mazumder , Arnab Chakraborty , Abhirup Datta , Samir Choudhuri , Nirupam Roy , Yogesh Wadadekar , C. H. Ishwara-Chandra

We use high resolution hydrodynamical simulations to study the contribution to the X-ray background from high-$z$ energetic sources, such as X-ray binaries, accreting nuclear black holes and shock heated interstellar medium. Adopting the…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-25 Q. Ma , B. Ciardi , M. B. Eide , K. Helgason

Cosmic baryon evolution during the Cosmic Dawn and Reionization results in redshifted 21-cm spectral distortions in the cosmic microwave background (CMB). These encode information about the nature and timing of first sources over redshifts…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-04 Mayuri Sathyanarayana Rao , Ravi Subrahmanyan , N Udaya Shankar , Jens Chluba

The GMRT reionization effort aims to map out the large scale structure of the Universe during the epoch of reionization (EoR). Removal of polarized Galactic emission is a difficult part of any 21 cm EoR program, and we present new upper…

We present a multifrequency approach which optimizes the constraints on cosmological parameters with respect to extragalactic sources and secondary anisotropies contamination on small scales. We model with a minimal number of parameters the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 D. Paoletti , N. Aghanim , M. Douspis , F. Finelli , G. De Zotti , G. Lagache , Aurélie Pénin

Context. We use the Southern Photometric Local Universe Survey (S-PLUS) Fourth Data Release (DR4) to identify and classify H$\alpha$-excess point sources in the Southern Sky, combining photometric data from 12 S-PLUS filters with machine…