ABSTRACT Magnetars are a promising candidate for the origin of fast radio bursts (FRBs). The detection an extremely luminous burst from Galactic magnetar SGR J1935+2154 on 2020 April 28 added credence to this hypothesis. We report simultaneous and non-simultaneous observing campaigns using Arecibo, Effelsberg, LOFAR, MeerKAT, MK2, Northern Cross telescopes MeerLICHT optical telescope in days mo...

Extragalactic foregrounds in cosmic microwave background (CMB) temperature maps lead to significant biases CMB lensing reconstruction if not properly accounted for. Combinations of multifrequency data have been used minimize the overall map variance (internal linear combination, or ILC), specifically null a given foreground, but these are tailored lensing. In this paper, we derive an optimal co...

We outline a new nonlinear multifrequency Traveling Wave Tube (TWT) model based on Eulerian electron beam equations. We identify and illustrate with preliminary examples types of problems the model may be applied to. In particular, the model is well suited to accommodate many closelyspaced frequencies in simulation and analysis.

In this article we consider the problem of matching time sequences in the MIMIC II[1] database. Unlike other time series similarity matching problems, our task is to match time sequences of observations made at different frequencies that have been obtained from the same subject. For each time series in high-frequency, our goal is to find its low-frequency counterpart. Heart rate of each patient...

lenses are often used to converge electromagnetic wave namely they convert incident phase front of feed antenna to a flat phase front. together, the lens and the feed create an electrically large aperture antenna. flat lenses provide the cost and weight benefits of the reflect-arrays, while maintaining the advantages of a lens antenna. these lenses use an array of unit-cells which are excited b...

the possibility of terahertz generation has been investigated from a photoconductive switch based on gaas, gated by a femtosecond laser. the emission properties of photoconductive antenna (pca) with low-temperature-grown (lt) gaas have been studied. in such gaas materials presence of the charged defects induces a redistribution of the electric field between the antenna electrodes. this effect h...

In this paper novel reflectarray antenna elements are proposed using aperture-coupled dielectric resonator antenna structures. Using these new structures, wide phase range and wide frequency bandwidth (up to 28.5%) with parallel and linear phase curves are obtained. In each case, an array consisting of 289 elements was simulated using the finite integration technique (FIT). The arrays exhibit 3...