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We model a 21 cm intensity mapping survey in the redshift range 0.01<z<1.5 designed to simulate the skies as seen by future radio telescopes such as the Square Kilometre Array (SKA), including instrumental noise and Galactic foregrounds. In…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-27 L. Wolz , F. B. Abdalla , C. Blake , J. R. Shaw , E. Chapman , S. Rawlings

Cross-correlations between 21cm observations and galaxy surveys provide a powerful probe of reionization by reducing foreground sensitivity while linking ionization morphology to galaxies. We quantify the constraining power of 21cm-Galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-27 Yannic Pietschke , Anne Hutter , Caroline Heneka

Millimetre-wave observations represent an important tool for Cosmology studies. The Line Intensity Mapping (LIM) technique has been proposed to map in three dimensions the specific intensity due to line (e.g. [CII], CO) emission, for…

Instrumentation and Methods for Astrophysics · Physics 2023-08-29 Usasi Chowdhury , Florence Levy-Bertrand , Martino Calvo , Johannes Goupy , Alessandro Monfardini

The large-scale structure growth index $\gamma$ provides a consistency test of the standard cosmology and is a potential indicator of modified gravity. We investigate the constraints on $\gamma$ from next-generation spectroscopic surveys,…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-12 José Fonseca , Jan-Albert Viljoen , Roy Maartens

The redshifted 1420 MHz emission from the HI in unresolved damped Lyman-\alpha clouds at high z will appear as a background radiation in low frequency radio observations. This holds the possibility of a new tool for studying the universe at…

Astrophysics · Physics 2009-10-31 Somnath Bharadwaj , Biman B. Nath , Shiv K. Sethi

Line Intensity Mapping (LIM) is a new observational technique that uses low-resolution observations of line emission to efficiently trace the large-scale structure of the Universe out to high redshift. Common mm/sub-mm emission lines are…

Observations of redshifted 21cm radiation from HI at high redshifts is an important future probe of reionization. We consider the Multi-frequency Angular Power Spectrum (MAPS) to quantify the statistics of the HI signal as a joint function…

Astrophysics · Physics 2008-11-26 Kanan K. Datta , T. Roy Choudhury , Somnath Bharadwaj

We investigate the possibility of utilising 21cm intensity mapping, optical galaxy, and Cosmic Microwave Background (CMB) surveys to constrain the power spectrum of primordial fluctuations predicted by single-field slow-roll inflation…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-09 Alkistis Pourtsidou

Detecting neutral Hydrogen (H\,{\sc i}) via the 21~cm line emission from the intergalactic medium at $z\gtrsim 6$ has been identified as one of the most promising probes of the epoch of cosmic reionization -- a major phase transition of the…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-04 Nithyanandan Thyagarajan , Chris Carilli , Bojan Nikolic

We propose the HI 21-cm power spectrum from the post-reionization epoch as a probe of a cosmological model with decaying dark matter particles. The unstable particles are assumed to undergo a 2-body decay into a massless and massive…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-12 Mohit Yadav , Tapomoy Guha Sarkar

Interstellar turbulence shapes the HI distribution in the Milky Way (MW). How this affects large-scale statistical properties of HI column density across the MW remains largely unconstrained. We use approx 13,000 square-degree GALFA-HI…

Astrophysics of Galaxies · Physics 2023-10-24 Amit K. Mittal , Brian L Babler , Snezana Stanimirovic , Nickolas Pingel

Mapping the distribution of neutral atomic hydrogen (HI) in the Universe through its 21 cm emission line provides a powerful cosmological probe to map the large-scale structures and shed light on various cosmological phenomena. The Baryon…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-20 Albin Joseph , Rajib Saha

Primordial non-Gaussianity is an invaluable window into the physical processes that gave rise to the cosmological structure. The presence of local shape PNG imprints a distinct scale-dependent correction to the bias of dark matter tracers…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-15 Azadeh Moradinezhad Dizgah , Garrett K. Keating , Anastasia Fialkov

The neutral hydrogen (HI) signal is a crucial probe for astrophysics and cosmology, but it is quite challenging to measure from raw data because of bright foreground contaminants at radio wavelengths. Cross-correlating the radio…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-27 Alessandro Marins , Chang Feng , Filipe B. Abdalla

We introduce the Galaxy Intensity Mapping cross-COrrelation estimator (GIMCO), which is a new tomographic estimator for the gravitational lensing potential, based on a combination of intensity mapping (IM) and galaxy number counts. The…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-25 Mona Jalilvand , Elisabetta Majerotto , Camille Bonvin , Fabien Lacasa , Martin Kunz , Warren Naidoo , Kavilan Moodley

Line intensity mapping using atomic hydrogen (HI) has the potential to efficiently map large volumes of the universe if the signal can be successfully separated from overwhelmingly bright radio foreground emission. This motivates…

ALMA observations have detected extended ($\simeq 10$ kpc) [C II] halos around high-redshift ($z \gtrsim 5$) star-forming galaxies. If such extended structures are common, they may have an impact on the line intensity mapping (LIM) signal.…

Astrophysics of Galaxies · Physics 2023-09-28 Meng Zhang , Andrea Ferrara , Bin Yue

Next-generation tests of fundamental physics and cosmology using large scale structure require measurements over large volumes of the Universe, including high redshifts inaccessible to present-day surveys. Line intensity mapping, an…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-15 Kirit S. Karkare , Azadeh Moradinezhad Dizgah , Garrett K. Keating , Patrick Breysse , Dongwoo T. Chung

We present a simulation experiment of a pipeline based on machine learning algorithms for neutral hydrogen (HI) intensity mapping (IM) surveys with different telescopes. The simulation is conducted on HI signals, foreground emission,…

Instrumentation and Methods for Astrophysics · Physics 2022-09-14 Lin-Cheng Li , Yuan-Gen Wang

We use full sky simulations, including the effects of foreground contamination and removal, to explore multi-tracer synergies between a SKA-like 21cm intensity mapping survey and a LSST-like photometric galaxy redshift survey. In particular…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-27 Amadeus Witzemann , David Alonso , José Fonseca , Mario G. Santos