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We present spectral data cubes of the [CI] 809GHz, 12CO 115GHz, 13CO 110GHz and HI 1.4GHz line emission from an 1 square degree region along the l = 328{\deg} (G328) sightline in the Galactic Plane. Emission arises principally from gas in…

Interferometric measurements of the 21cm signal are a prime example of the data-driven era in astrophysics we are entering with current and upcoming experiments. We showcase the use of deep networks that are tailored for the structure of 3D…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-30 Caroline Heneka

The precise measurement of the sky-averaged HI absorption signal between 50 and 200 MHz is the primary goal of global 21-cm cosmology. This measurement has the potential to unravel the underlying physics of cosmic structure formation and…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-04 Emma Shen , Dominic Anstey , Marta Spinelli , Eloy de Lera Acedo , Anastasia Fialkov

We present a pilot study of extragalactic HI 21-cm absorption lines using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We observed 5 continuum sources with HI absorption features firstly identified in the 40% data…

Astrophysics of Galaxies · Physics 2021-03-31 Bo Zhang , Ming Zhu , Zhong-Zu Wu , Qing-Zheng Yu , Peng Jiang , You-Ling Yue , Meng-Lin Huang , Qiao-Li Hao

The 21-cm intensity mapping (IM) of neutral hydrogen (HI) is a promising tool to probe the large-scale structures. Sky maps of 21-cm intensities can be highly contaminated by different foregrounds, such as Galactic synchrotron radiation,…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-01 Elimboto Yohana , Yin-Zhe Ma , Di Li , Xuelei Chen , Wei-Ming Dai

In this second paper of the Hawaii SCUBA-2 Lensing Cluster Survey series, we cross-match SCUBA-2 maps with 3 and 6 GHz images from the Janksy-VLA Frontier Fields Legacy Survey for three cluster fields, MACS J0416.1--2403, MACS J0717.5+3745,…

Astrophysics of Galaxies · Physics 2017-05-10 Li-Yen Hsu , Vandana Desai , Eric Murphy , Lennox Cowie , Ian Heywood , Emmanuel Momjian , Amy Barger , Ian Smail

Observations of fluctuations in the redshifted 21 cm radiation from neautral hydrogen (HI) are perceived to be an important future probe of the universe at high redshifts. Under the assumption that at redshifts z less than 6…

Astrophysics · Physics 2009-11-13 Sk. Saiyad Ali , Somnath Bharadwaj , Sanjay K. Pandey

Neutral Hydrogen Intensity Mapping (HI IM) surveys will be a powerful new probe of cosmology. However, strong astrophysical foregrounds contaminate the signal and their coupling with instrumental systematics further increases the data…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-03 Marta Spinelli , Isabella P. Carucci , Steven Cunnington , Stuart E. Harper , Melis O. Irfan , José Fonseca , Alkistis Pourtsidou , Laura Wolz

State-of-the-art techniques to identify H\alpha emission line sources in narrow-band photometric surveys consist of searching for H\alpha excess with reference to nearby objects in the sky (position-based selection). However, while this…

Astrophysics of Galaxies · Physics 2022-11-16 M. Fratta , S. Scaringi , M. Monguió , A. F. Pala , J. E. Drew , C. Knigge , K. A. Iłkiewicz , P. Gandhi

The ability to subtract foreground contamination from low-frequency observations is crucial to reveal the underlying 21 cm signal. The traditional line-of-sight methods can deal with the removal of diffuse emission and unresolved point…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Xiao-Chun Mao

The introduction of low-frequency radio arrays over the coming decade is expected to revolutionize the study of the reionization epoch. Observation of the contrast in redshifted 21cm emission between a large HII region and the surrounding…

Astrophysics · Physics 2009-11-11 Stuart Wyithe , Abraham Loeb , David Barnes

$\mbox{H}$ $\mbox{I}$ 21-cm absorption, an extremely useful tool to study the cold atomic hydrogen gas, can arise either from the intervening galaxies along the line-of-sight towards the background radio source or from the radio source…

Astrophysics of Galaxies · Physics 2025-11-10 Debasish Mondal , Anirudh S. Nemmani , Arunima Banerjee

The ALMA SPECtroscopic Survey in the {\it Hubble} Ultra Deep Field is an ALMA large program that obtained a frequency scan in the 3\,mm band to detect emission lines from the molecular gas in distant galaxies. We here present our search…

Detecting neutral hydrogen structures in the intergalactic medium (IGM) during cosmic reionization via absorption (21 cm forest) against a background radiation is considered independent and complementary to the three-dimensional tomography…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-10 Nithyanandan Thyagarajan

Radio continuum surveys of the Galactic plane can find and characterize HII regions, supernova remnants (SNRs), planetary nebulae (PNe), and extragalactic sources. A number of surveys at high angular resolution (<25") at different…

We present radio and infrared observations of 4 hyper-compact HII regions and 4 ultra-compact HII regions in the southern Galactic plane. These objects were selected from a blind survey for UCHII regions using data from two new radio…

Astrophysics of Galaxies · Physics 2015-05-18 Tara Murphy , Martin Cohen , Ronald D. Ekers , Anne J. Green , Robin Wark , Vanessa Moss

The epoch of reionization is one of the least known chapters in the evolutionary history of the Universe. This thesis investigates two major approaches to unveil the reionization history of the Universe using HI 21-cm maps.The most…

Cosmology and Nongalactic Astrophysics · Physics 2009-06-04 Kanan K. Datta

Vision Transformers are used via a customized TransUNet architecture, which is a hybrid model combining Transformers into a U-Net backbone, to achieve precise, automated, and fast segmentation of radio astronomy data affected by calibration…

Instrumentation and Methods for Astrophysics · Physics 2025-08-14 Nicoletta Sanvitale , Claudio Gheller , Franco Vazza , Annalisa Bonafede , Virginia Cuciti , Emanuele De Rubeis , Federica Govoni , Matteo Murgia , Valentina Vacca

Observations of neutral hydrogen can provide a wealth of information about the distribution and kinematics of galaxies. To detect HI beyond the ionisation edge of galaxy disks, column density sensitivities have to be achieved that probe the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 A. Popping , R. Braun