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We determined Faraday rotation measures (RMs) towards 137 pulsars in the northern sky, using Low-Frequency Array (LOFAR) observations at 110-190 MHz. This low-frequency RM catalogue, the largest to date, improves the precision of existing…

Resolving the phase structure of neutral hydrogen (HI) is crucial for understanding the life cycle of the interstellar medium (ISM). However, accurate measurements of HI temperature and density are limited by the availability of background…

Astrophysics of Galaxies · Physics 2020-08-19 Claire E. Murray , J. E. G. Peek , Chang-Goo Kim

The new generation of broad-band radio continuum surveys will provide large data sets with polarization information. New algorithms need to be developed to extract reliable catalogs of linearly polarized sources that can be used to…

Using a combination of N-body simulations, semi-analytic models and radiative transfer calculations, we have estimated the theoretical cross power spectrum between galaxies and the 21cm emission from neutral hydrogen during the epoch of…

We present an original data analysis and a physical model that provide new insights into the origin of, and relationship between, two observables of the dusty, polarized Galaxy at intermediate and high latitudes: (i) the misalignment…

Astrophysics of Galaxies · Physics 2025-12-15 Andrea Bracco , Ari J. Cukierman , Raphael Skalidis , François Boulanger

Several different methods are regularly used to infer the properties of the neutral interstellar medium (ISM) using atomic hydrogen (H I) 21cm absorption and emission spectra. In this work, we study various techniques used for inferring ISM…

Astrophysics of Galaxies · Physics 2023-11-27 Soumyadeep Bhattacharjee , Nirupam Roy , Prateek Sharma , Amit Seta , Christoph Federrath

We present deep polarimetric observations at 154 MHz with the Murchison Widefield Array (MWA), covering 625 deg^2 centered on RA=0 h, Dec=-27 deg. The sensitivity available in our deep observations allows an in-band, frequency-dependent…

Utilizing Planck polarized dust emission maps at 353 GHz and new large-area maps of the neutral hydrogen (HI) cold neutral medium (CNM) fraction ($f_\mathrm{CNM}$), we investigate the relationship between dust polarization fraction…

Astrophysics of Galaxies · Physics 2025-01-07 Minjie Lei , S. E. Clark

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

Diffuse cluster radio sources, in the form of radio halos and relics, reveal the presence of cosmic rays and magnetic fields in the intracluster medium (ICM). These cosmic rays are thought to be (re-)accelerated through ICM turbulence and…

(abridged) Spectroscopic observations of high-redshift galaxies slowly reveal the same complexity of the interstellar medium (ISM) as expected from resolved observations in nearby galaxies. While providing a wealth of diagnostics, such…

Astrophysics of Galaxies · Physics 2022-11-09 Vianney Lebouteiller , Lise Ramambason

The Low Frequency Array (LOFAR) is the only existing radio interferometer able to observe at ultra-low frequencies (<100 MHz) with high resolution (<15") and high sensitivity (<1 mJy/beam). To exploit these capabilities, the LOFAR Surveys…

The aim of this study is to probe the sub-mJy polarized source population with LOFAR. We present the method used to stack LOFAR polarization datasets, the resulting catalog of polarized sources, and the derived polarized source counts. The…

We have used polarimetric imaging to study the magneto-ionic medium of the Galaxy, obtaining 1420 MHz images with an angular resolution of 1' over more than 40 square-degrees of sky around the W3/W4/W5/HB3 HII region/SNR complex in the…

Astrophysics · Physics 2009-10-31 A. D. Gray , T. L. Landecker , P. E. Dewdney , A. R. Taylor , A. G. Willis , M. Normandeau

We have observed a complex and continuous change in the integrated pulse profile of PSR B2217+47, manifested as additional components trailing the main peak. These transient components are detected over 6 years at $150$ MHz using the LOw…

We aim to study the polarization and magnetic field properties of the SNR HB 9 using new 21-cm continuum cube data from the Five-hundred-meter Aperture Spherical radio telescope (FAST). We computed the Faraday depth at 21 cm, and…

Astrophysics of Galaxies · Physics 2025-05-21 Li Xiao , Ming Zhu , Xiao-Hui Sun , Wolfgang Reich , Patricia Reich , Peng Jiang , Chun Sun

We investigate data from the Galactic Effelsberg--Bonn HI Survey (EBHIS), supplemented with data from the third release of the Galactic All Sky Survey (GASS III) observed at Parkes. We explore the all sky distribution of the local Galactic…

Astrophysics of Galaxies · Physics 2016-04-27 P. M. W. Kalberla , J. Kerp , U. Haud , B. Winkel , N. Ben Bekhti , L. Floeer , D. Lenz

The Low Frequency Array (LOFAR) is an ideal instrument to conduct deep extragalactic surveys. It has a large field of view and is sensitive to large scale and compact emission. It is, however, very challenging to synthesize thermal noise…

We investigate the properties of the Galactic ISM by applying Faraday tomography to a radio polarization data set in the direction of the Galactic anti-centre. We address the problem of missing large-scale structure in our data, and show…

Astrophysics · Physics 2015-05-13 D. H. F. M. Schnitzeler , P. Katgert , A. G. de Bruyn

The first generation of redshifted 21 cm detection experiments, carried out with arrays like LOFAR, MWA and GMRT, will have a very low signal-to-noise ratio per resolution element (\sim 0.2). In addition, whereas the variance of the…