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Related papers: 21cm Forest with the SKA

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The 21cm forest -- HI absorption features in the spectra of high-redshift radio sources -- can potentially provide a unique probe of the largely neutral intergalactic medium (IGM) during the epoch of reionization. We present simulations of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Katherine J. Mack , J. Stuart B. Wyithe

We describe a new technique for constraining the radio loud population of active galactic nuclei at high redshift by measuring the imprint of 21 cm spectral absorption features (the 21 cm forest) on the 21 cm power spectrum. Using…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-03 Aaron Ewall-Wice , Joshua S. Dillon , Andrei Mesinger , Jacqueline Hewitt

The 21-cm forest is a promising probe of the Epoch of Reionization. The local state of the intergalactic medium (IGM) is encoded in the spectrum of a background source (radio-loud quasars or gamma ray burst afterglow) by absorption at the…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Benoit Semelin

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

We investigate the feasibility of detecting 21cm absorption features in the afterglow spectra of high redshift long Gamma Ray Bursts (GRBs). This is done employing simulations of cosmic reionization, together with the instrumental…

We study the absorption along lines of sight toward high-z radio sources caused by the 21 cm transition of neutral hydrogen in the intergalactic medium (IGM) before reionization. Using semi-analytic methods, we compute the number density of…

Astrophysics · Physics 2009-11-07 Steven Furlanetto , Abraham Loeb

The absorption features in spectra of high-redshift background radio sources, caused by hyperfine structure lines of hydrogen atoms in the intervening structures, are known collectively as the 21-cm forest. They provide a unique probe of…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-21 Yue Shao , Yidong Xu , Yougang Wang , Wenxiu Yang , Ran Li , Xin Zhang , Xuelei Chen

HI 21~cm absorption spectroscopy provides an excellent probe of the neutral gas content of absorbing galaxies, yielding information on their kinematics, mass, physical size and ISM conditions. The high sensitivity, unrivaled frequency…

Astrophysics · Physics 2009-11-10 N. Kanekar , F. H. Briggs

Understanding the nature of dark matter (DM) particles remains a pivotal challenge in modern cosmology. Current cosmological research on these phenomena primarily utilizes cosmic microwave background (CMB) observations and other late-time…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-24 Meng-Lin Zhao , Yue Shao , Sai Wang , Xin Zhang

We explore the possibility of detecting HI 21cm absorption by the neutral intergalactic medium (IGM) toward very high redshift radio sources. The epoch considered is between the time when the first ionizing sources form and when the bulk of…

Astrophysics · Physics 2016-08-30 C. Carilli , N. Y. Gnedin , F. Owen

We explore the possibility of detecting HI 21cm absorption by the neutral intergalactic medium (IGM) toward very high redshift radio sources, and by gas associated with the first collapsed structures, using the Square Kilometer Array at low…

Astrophysics · Physics 2009-11-10 C. L. Carilli , N. Gnedin , S. Furlanetto , F. Owen

Using high redshift radio sources as background, the 21cm forest observations probe the neutral hydrogen absorption signatures of early structures along the lines of sight. Directly sensitive to the spin temperature, it complements the 21cm…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-18 Yidong Xu , Xuelei Chen , Zuhui Fan , Hy Trac , Renyue Cen

Understanding properties of the first sources in the Universe using the redshifted \HI ~21-cm signal is one of the major aims of present and upcoming low-frequency experiments. We investigate the possibility of imaging the redshifted 21-cm…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-15 Raghunath Ghara , T. Roy Choudhury , Kanan K. Datta , Samir Choudhuri

The 21cm forest, narrow absorption features in the spectra of high redshift radio sources caused by intervening neutral hydrogen, offers a unique probe of the intergalactic medium and small-scale structures during reionization. While…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-30 Hayato Shimabukuro , Yidong Xu , Yue Shao

We have undertaken a survey for HI 21-cm absorption within the host galaxies of z ~ 1.2 - 1.5 radio sources, in the search of the cool neutral gas currently "missing" at z > 1. This deficit is believed to be due to the optical selection of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 S. J. Curran , M. T. Whiting , A. Tanna , E. M. Sadler , M. B. Pracy , R. Athreya

The hyperfine structure absorption lines of neutral hydrogen in spectra of high-redshift radio sources, known collectively as the 21-cm forest, have been demonstrated as a sensitive probe to the small-scale structures governed by the dark…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-03 Tian-Yang Sun , Yue Shao , Yichao Li , Yidong Xu , He Wang , Xin Zhang

Absorption or emission against the cosmic microwave background radiation (CMB) may be observed in the redshifted 21cm line if the spin temperature of the neutral intergalactic medium prior to reionization differs from the CMB temperature.…

Astrophysics · Physics 2009-12-10 Tiziana Di Matteo , Rosalba Perna , Tom Abel , Martin J. Rees

We discuss the feasibility of the detection of the 21cm forest in the diffuse IGM with the radio telescope LOFAR. The optical depth to the 21cm line has been derived using simulations of reionization which include detailed radiative…

The 21-cm forest is a sensitive probe for the early heating process and small-scale structures during the epoch of reionization (EoR), to be realized with the upcoming Square Kilometre Array (SKA). Its detection relies on the availability…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-09 Qi Niu , Yichao Li , Yidong Xu , Hong Guo , Xin Zhang

21cm intensity mapping experiments aim to observe the diffuse neutral hydrogen (HI) distribution on large scales which traces the Cosmic structure. The Square Kilometre Array (SKA) will have the capacity to measure the 21cm signal over a…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-19 Laura Wolz , Filipe B. Abdalla , David Alonso , Chris Blake , Philip Bull , Tzu-Ching Chang , Pedro G. Ferreira , Cheng-Yu Kuo , Marios G. Santos , Richard Shaw
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