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Related papers: ROHSA: Regularized Optimization for Hyper-Spectral…

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We report the first results of a programme aimed at studying the properties of high redshift galaxies with on-going massive and dominant episodes of star formation (HII galaxies). We use the $L(\mathrm{H}\beta) - \sigma$ distance estimator…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Roberto Terlevich , Elena Terlevich , Jorge Melnick , Ricardo Chávez , Manolis Plionis , Fabio Bresolin , Spyros Basilakos

We detect the neutral hydrogen (HI) radial brightness temperature profile in large-scale haloes by stacking 48,430 galaxies selected from the 2dFGRS catalogue onto a set of 21-cm intensity maps obtained with the Parkes radio telescope,…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-14 Denis Tramonte , Yin-Zhe Ma

We present a study of the cold atomic hydrogen (HI) content of molecular clouds simulated within the SILCC-Zoom project. We produce synthetic observations of HI at 21 cm including HI self-absorption (HISA) and observational effects. We find…

Astrophysics of Galaxies · Physics 2022-03-14 D. Seifried , H. Beuther , S. Walch , J. Syed , J. D. Soler , P. Girichidis , R. Wünsch

We conducted a follow-up study on the analysis of the LOw Frequency ARray (LOFAR) Two-metre Sky Survey (LoTSS) mosaic in the high-latitude outer Galaxy presented in the first paper of this series. Here, we focus on the search for alignment…

Astrophysics of Galaxies · Physics 2024-07-10 Ana Erceg , Vibor Jelić , Marijke Haverkorn , Andrea Bracco , Lana Ceraj , Luka Turić , Juan D. Soler

We have mapped cold atomic gas in 21cm line HI self-absorption (HISA) at arcminute resolution over more than 90% of the Milky Way's disk. To probe the formation of H2 clouds, we have compared our HISA distribution with CO J=1-0 line…

HI self absorption (HISA) clouds are clumps of cold neutral hydrogen (HI) visible in front of warm background gas, which makes them ideal places to study the properties of the cold atomic component of the interstellar medium (ISM). The…

Astrophysics of Galaxies · Physics 2018-06-13 H. Denes , N. M. McClure-Griffiths , J. M. Dickey , J. R. Dawson , C. E. Murray

The spatial distribution of the gaseous components of the Milky Way is of great importance for a number of different fields, for example, Galactic structure, star formation, and cosmic rays. However, obtaining distance information to…

We introduce an adaptable kinematic modelling tool called ROHSA-SNAPD, "Spatially Non-parametric Approach to PSF Deconvolution using ROHSA". ROHSA-SNAPD utilises kinematic regularisation to forward model the intrinsic emission-line flux and…

Astrophysics of Galaxies · Physics 2025-09-22 Isaac Kanowski , Emily Wisnioski , J. Trevor Mendel , Antoine Marchal , Takafumi Tsukui

We develop and apply an enhanced regularization algorithm, used in RHESSI X-ray spectral analysis, to constrain the ill-posed inverse problem that is determining the DEM from solar observations. We demonstrate this computationally fast…

Solar and Stellar Astrophysics · Physics 2015-06-03 I. G. Hannah , E. P. Kontar

Observations of the EoR with the 21-cm hyperfine emission of neutral hydrogen (HI) promise to open an entirely new window onto the formation of the first stars, galaxies and accreting black holes. In order to characterize the weak 21-cm…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-06 Abhik Ghosh , L. V. E. Koopmans , Emma Chapman , Vibor Jelic

We use a large N-body simulation to examine the detectability of HI in emission at redshift z ~ 1, and the constraints imposed by current observations on the neutral hydrogen mass function of galaxies at this epoch. We consider three…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Nishikanta Khandai , Shiv K. Sethi , Tiziana Di Matteo , Rupert A. C. Croft , Volker Springel , Anirban Jana , Jeffrey P. Gardner

The sky-averaged (global) 21-cm signal is a powerful probe of the intergalactic medium (IGM) prior to the completion of reionization. However, it has so far been unclear that even in the best case scenario, in which the signal is accurately…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Jordan Mirocha , Geraint J. A. Harker , Jack O. Burns

We explore the possibility of retrieving cosmological information from 21-cm tomographic data at intermediate redshift. The first step in our approach consists of training an encoder, composed of several three dimensional convolutional…

Instrumentation and Methods for Astrophysics · Physics 2025-07-30 Sambatra Andrianomena

The availability of large datasets with stellar distance and polarization information will enable a tomographic reconstruction of the (plane-of-the-sky-projected) interstellar magnetic field in the near future. We demonstrate the…

We present a study of the ionization and thermal structure of neutral hydrogen clouds located in the Galactic halo, immersed in the extragalactic background radiation field, and supposed to be in pressure equilibrium with the surrounding…

Astrophysics · Physics 2009-10-22 Andrea Ferrara , George B. Field

Using a novel suite of cosmological simulations zooming in on a Mpc-scale intergalactic sheet or "pancake" at z~3-5, we conduct an in-depth study of the thermal properties and HI content of the warm-hot intergalactic medium (WHIM) at those…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-22 Nir Mandelker , Frank C. van den Bosch , Volker Springel , Freeke van de Voort , Joseph N. Burchett , Iryna S. Butsky , Daisuke Nagai , S. Peng Oh

We take advantage of the sensitivity and resolution of Herschel at 100 and 160 micron to directly image the thermal dust emission and investigate the infrared luminosities, L(IR), and dust obscuration of typical star-forming (L*) galaxies…

We have carried out a sensitive high-latitude (|b| > 15deg.) HI 21cm-line absorption survey towards 102 sources using the GMRT. With a 3-sigma detection limit in optical depth of ~0.01, this is the most sensitive HI absorption survey. We…

Astrophysics · Physics 2009-11-10 Rekhesh Mohan , K. S. Dwarakanath , G. Srinivasan

Hyperspectral (HS) unmixing is the process of decomposing an HS image into material-specific spectra (endmembers) and their spatial distributions (abundance maps). Existing unmixing methods have two limitations with respect to noise…

Image and Video Processing · Electrical Eng. & Systems 2024-03-20 Kazuki Naganuma , Shunsuke Ono

Automated sensing instruments on satellites and aircraft have enabled the collection of massive amounts of high-resolution observations of spatial fields over large spatial regions. If these datasets can be efficiently exploited, they can…

Methodology · Statistics 2015-12-08 Matthias Katzfuss