Astrophotonics is the next-generation approach that provides the means to miniaturize near-infrared (NIR) spectrometers for upcoming large telescopes and make them more robust and inexpensive. The target requirements for our spectrograph are: a resolving power of ⇠3000, wide spectral range (J and H bands), free spectral range of about 30 nm, high on-chip throughput of about 80% (-1dB) and low c...

ABSTRACT We have observed the canonical gigahertz-peaked spectrum source 0108]388 with the Very Long Baseline Array at a range of frequencies above and below the spectral peak. The activity that dominates the radio emission from 0108]388, which is also classiÐed as a compact symmetric object, is thought to be less than 1000 years old. We present strong evidence that the spectral turnover in 010...

We prove new enclosures for the spectrum of non-selfadjoint operator matrices associated with second order linear differential equations z̈(t) +Dż(t) +A0z(t) = 0 in a Hilbert space. Our main tool is the quadratic numerical range for which we establish the spectral inclusion property under weak assumptions on the operators involved; in particular, the damping operator only needs to be accretive a...

Spectral subtraction has the drawback that it introduces an unpleasant residual noise. This noise is a result of under-subtraction which occurs due to high variance of noise magnitude spectrum estimates. In this study we investigate a number of smoothing techniques that can be employed to reduce this variability. We extend the scope of this paper by using the phase spectrum in a novel manner al...