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We present a differentiable, end-to-end Bayesian forward modeling framework for line intensity mapping cosmology experiments, with a specific focus on low-frequency radio telescopes targeting the redshifted 21 cm line from neutral hydrogen…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-15 Nicholas Kern

We report an improved technique for diffuse foreground minimization from Cosmic Microwave Background (CMB) maps using a new multi-phase iterative internal-linear-combination (ILC) approach in harmonic space. The new procedure consists of…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-18 Vipin Sudevan , Pavan K. Aluri , Sarvesh Kumar Yadav , Rajib Saha , Tarun Souradeep

We developed a Python package GEHONG to mock the three-dimensional spectral data cube under the observation of an ideal telescope for the Integral Field Spectrograph of the Chinese Space Station Telescope (CSST-IFS). This package can…

Instrumentation and Methods for Astrophysics · Physics 2026-02-17 Shuai Feng , Shiyin Shen , Wei Chen , Zhaojun Yan , Renhao Ye , Jianjun Chen , Xuejie Dai , Junqiang Ge , Lei Hao , Ran Li , Yu Liang , Lin Lin , Fengshan Liu , Jiafeng Lu , Zhengyi Shao , Maochun Wu , Yifei Xiong , Chun Xu , Yang Yang , Jun Yin

High-velocity clouds (HVCs) are neutral or ionised gas clouds in the vicinity of the Milky Way that are characterised by high radial velocities inconsistent with participation in the regular rotation of the Galactic disc. Previous attempts…

Astrophysics of Galaxies · Physics 2017-12-05 Tobias Westmeier

We present a fast algorithm for generating full sky, high resolution ($\sim 5'$) simulations of the CMB anisotropy pattern. We also discuss the inverse problem, that of evaluating from such a map the full set of $a_{\ell m}$'s and the…

Astrophysics · Physics 2014-10-13 Pio Francesco Muciaccia , Paolo Natoli , Nicola Vittorio

We constructed a far ultraviolet (FUV) all sky map based on observations from the Far Ultraviolet Imaging Spectrograph (FIMS) aboard the Korean microsatellite STSAT-1. For the ~20% of the sky not covered by FIMS observations, predictions…

Astrophysics of Galaxies · Physics 2021-01-20 Young-Soo Jo , Yeon-Ju Choi , Min-Gi Kim , Chang-Ho Woo , Kyoung-Wook Min , Kwang-Il Seon

We have developed an automated cross-correlation technique to detect 21cm emission in sample spectra obtained from the HI Parkes All Sky Survey. The initial sample selection was the nearest spectra to 2435 low surface brightness galaxies in…

We consider the evolution of the sky-averaged 21 cm background during the early phases of structure formation. Using simple analytic models, we calculate the thermal and ionization histories, assuming that stellar photons dominate the…

Astrophysics · Physics 2009-11-11 Steven Furlanetto

Observations of intergalactic neutral hydrogen can provide a wealth of information about structure and galaxy formation, potentially tracing accretion and feedback processes on Mpc scales. Below a column density of NHI ~ 10^19 cm-2, the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Attila Popping , Romeel Dave , Robert Braun , Benjamin D. Oppenheimer

In two-dimensional spectrographs, the optical distortions in the spatial and dispersion directions produce variations in the sub-pixel sampling of the background spectrum. Using knowledge of the camera distortions and the curvature of the…

Astrophysics · Physics 2009-12-08 Daniel D. Kelson

The early star-forming Universe is still poorly constrained, with the properties of high-redshift stars, the first heating sources, and reionization highly uncertain. This leaves observers planning 21-cm experiments with little theoretical…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-22 Aviad Cohen , Anastasia Fialkov , Rennan Barkana , Matan Lotem

Experiments designed to measure the redshifted 21~cm line from the Epoch of Reionization (EoR) are challenged by strong astrophysical foreground contamination, ionospheric distortions, complex instrumental response and other different types…

Foreground emission makes it difficult to detect the highly-redshifted cosmological 21 cm signal at any frequency. However, at low frequencies foregrounds are likely to become optically thick, which would make it completely impossible to…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-18 Daniya Seitova , Jonathan C. Pober

Extracting the multiphase structure of the neutral interstellar medium (ISM) is key to understand the star formation in galaxies. The radiative condensation of the diffuse warm neutral medium producing a thermally unstable lukewarm medium…

The reported detection of the global 21-cm signal by the EDGES collaboration is significantly stronger than standard astrophysical predictions. One possible explanation is an early radio excess above the cosmic microwave background. Such a…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-12 Sudipta Sikder , Rennan Barkana , Anastasia Fialkov , Itamar Reis

The redshifted 21 cm line is an emerging tool in cosmology, in principle permitting three-dimensional surveys of our Universe that reach unprecedentedly large volumes, previously inaccessible length scales, and hitherto unexplored epochs of…

Instrumentation and Methods for Astrophysics · Physics 2020-04-27 Adrian Liu , J. Richard Shaw

We present our new model for the description of the very high energy Galactic gamma-ray emission based on a discrete injection of cosmic rays by individual sources. We investigate the morphology of the very high energy gamma-ray sky, the…

High Energy Astrophysical Phenomena · Physics 2025-01-13 Samy Kaci , Gwenael Giacinti

State-of-the-art cosmological hydrodynamical simulations have star particles with typical mass between $\sim 10^8$ and $\sim 10^3$ M$_{\odot}$ according to resolution, and treat them as simple stellar populations. On the other hand,…

Astrophysics of Galaxies · Physics 2018-07-31 Milena Valentini , Alessandro Bressan , Stefano Borgani , Giuseppe Murante , Léo Girardi , Luca Tornatore

In the Halo21 absorption modeling challenge we generated synthetic absorption spectra of the circumgalactic medium (CGM), and attempted to estimate the metallicity, temperature, and density (Z, T, and nH) of the underlying gas using…

The 21 cm intensity mapping (IM) technique provides us with an efficient way to observe the cosmic large-scale structure (LSS). From the LSS data, one can use the baryon acoustic oscillation and redshift space distortion to trace the…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-07 Peng-Ju Wu , Yichao Li , Jing-Fei Zhang , Xin Zhang