scholarly journals EoR Foregrounds: the Faint Extragalactic Radio Sky

2017 ◽  
Vol 12 (S333) ◽  
pp. 175-182 ◽  
Author(s):  
Isabella Prandoni
Keyword(s):  
Observational Constraints ◽  
New Radio ◽  
Accurate Treatment ◽  
Galactic Radio

AbstractA wealth of new data from upgraded and new radio interferometers are rapidly improving and transforming our understanding of the faint extra-galactic radio sky. Indeed the mounting statistics at sub-mJy and μJy flux levels is finally allowing us to get stringent observational constraints on the faint radio population and on the modeling of its various components. In this paper I will provide a brief overview of the latest results in areas that are potentially important for an accurate treatment of extra-galactic foregrounds in experiments designed to probe the Epoch of Reionization.

scholarly journals G18.95-1.1, A Composite Supernova Remnant Interacting with the Ambient Interstellar Medium

1988 ◽  
Vol 101 ◽  
pp. 253-256
Author(s):  
E. Fürst ◽  
W. Reich ◽  
E. Hummel ◽  
Y. Sofue
Keyword(s):  
Spectral Line ◽  
Interstellar Medium ◽  
Radio Source ◽  
Supernova Remnant ◽  
Radio Continuum ◽  
New Radio ◽  
Galactic Radio

AbstractNew radio continuum and spectral line observations of the Galactic radio source G18.95-1.1 are reported. The distance to G18.95-1.1 is 2 kpc as derived from HI-21 cm spectral line observations. These data also indicate an interaction with the interstellar medium. The radio continuum observations classify G18.95-1.1 as a composite supernova remnant.

Observational Constraints on Models of the Solar Background Spectrum

1999 ◽  
Vol 516 (2) ◽  
pp. 939-945 ◽  
Author(s):  
Th. Straus ◽  
G. Severino ◽  
F.‐L. Deubner ◽  
B. Fleck ◽  
S. M. Jefferies ◽  
...  
Keyword(s):  
Observational Constraints ◽  
Background Spectrum

A Realistic Grid of Models for the Gravitationally Lensed Einstein Cross (Q2237+0305) and Its Relation to Observational Constraints

1998 ◽  
Vol 495 (2) ◽  
pp. 609-616 ◽  
Author(s):  
Kyu‐Hyun Chae ◽  
David A. Turnshek ◽  
Valery K. Khersonsky
Keyword(s):  
Observational Constraints

5G New Radio: Waveform, Frame Structure, Multiple Access, and Initial Access

2017 ◽  
Vol 55 (6) ◽  
pp. 64-71 ◽  
Author(s):  
Shao-Yu Lien ◽  
Shin-Lin Shieh ◽  
Yenming Huang ◽  
Borching Su ◽  
Yung-Lin Hsu ◽  
...  
Keyword(s):  
Multiple Access ◽  
Frame Structure ◽  
New Radio

scholarly journals Magnetospheric Structure of Rotation-Powered Neutron Stars

1992 ◽  
Vol 128 ◽  
pp. 56-77 ◽  
Author(s):  
Jonathan Arons
Keyword(s):  
Radio Emission ◽  
Gamma Radiation ◽  
Heavy Ions ◽  
Theoretical Work ◽  
Future Research ◽  
Observational Constraints ◽  
Polar Caps ◽  
Recent Theoretical Work ◽  
Density Flow ◽  
Promising Avenue

AbstractI survey recent theoretical work on the structure of the magnetospheres of rotation-powered pulsars, within the observational constraints set by their observed spindown, their ability to power synchrotron nebulae and their ability to produce beamed collective radio emission, while putting only a small fraction of their energy into incoherent X- and gamma radiation. I find no single theory has yet given a consistent description of the magnetosphere, but I conclude that models based on a dense outflow of pairs from the polar caps, permeated by a lower density flow of heavy ions, are the most promising avenue for future research.

scholarly journals Can the Local Bubble explain the radio background?

2021 ◽  
Vol 502 (2) ◽  
pp. 2807-2814
Author(s):  
Martin G H Krause ◽  
Martin J Hardcastle
Keyword(s):  
Magnetic Field ◽  
Energy Density ◽  
Radio Emission ◽  
Magnetic Energy ◽  
Cosmic Ray ◽  
Observational Constraints ◽  
Local Bubble ◽  
Magnetic Energy Density ◽  
Magnetic Field Model ◽  
Radio Background

ABSTRACT The ARCADE 2 balloon bolometer along with a number of other instruments have detected what appears to be a radio synchrotron background at frequencies below about 3 GHz. Neither extragalactic radio sources nor diffuse Galactic emission can currently account for this finding. We use the locally measured cosmic ray electron population, demodulated for effects of the Solar wind, and other observational constraints combined with a turbulent magnetic field model to predict the radio synchrotron emission for the Local Bubble. We find that the spectral index of the modelled radio emission is roughly consistent with the radio background. Our model can approximately reproduce the observed antenna temperatures for a mean magnetic field strength B between 3 and 5 nT. We argue that this would not violate observational constraints from pulsar measurements. However, the curvature in the predicted spectrum would mean that other, so far unknown sources would have to contribute below 100 MHz. Also, the magnetic energy density would then dominate over thermal and cosmic ray electron energy density, likely causing an inverse magnetic cascade with large variations of the radio emission in different sky directions as well as high polarization. We argue that this disagrees with several observations and thus that the magnetic field is probably much lower, quite possibly limited by equipartition with the energy density in relativistic or thermal particles (B = 0.2−0.6 nT). In the latter case, we predict a contribution of the Local Bubble to the unexplained radio background at most at the per cent level.

scholarly journals Flexible 5G New Radio LDPC Encoder Optimized for High Hardware Usage Efficiency

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1106
Author(s):  
Vladimir L. Petrović ◽  
Dragomir M. El Mezeni ◽  
Andreja Radošević
Keyword(s):  
Channel Coding ◽  
Parallel Architecture ◽  
Ldpc Codes ◽  
Parity Check ◽  
Case Scenario ◽  
New Radio ◽  
Physical Channel ◽  
Computationally Intensive ◽  
Hardware Processing ◽  
Usage Efficiency

Quasi-cyclic low-density parity-check (QC–LDPC) codes are introduced as a physical channel coding solution for data channels in 5G new radio (5G NR). Depending on the use case scenario, this standard proposes the usage of a wide variety of codes, which imposes the need for high encoder flexibility. LDPC codes from 5G NR have a convenient structure and can be efficiently encoded using forward substitution and without computationally intensive multiplications with dense matrices. However, the state-of-the-art solutions for encoder hardware implementation can be inefficient since many hardware processing units stay idle during the encoding process. This paper proposes a novel partially parallel architecture that can provide high hardware usage efficiency (HUE) while achieving encoder flexibility and support for all 5G NR codes. The proposed architecture includes a flexible circular shifting network, which is capable of shifting a single large bit vector or multiple smaller bit vectors depending on the code. The encoder architecture was built around the shifter in a way that multiple parity check matrix elements can be processed in parallel for short codes, thus providing almost the same level of parallelism as for long codes. The processing schedule was optimized for minimal encoding time using the genetic algorithm. The optimized encoder provided high throughputs, low latency, and up-to-date the best HUE.

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