We identify a correlation space involving optical and UV emission-line parameters as well as the soft X-ray spectral index that provides optimal discrimination between all principal classes of active galactic nuclei (AGNs). Most of the sources in our three high-quality data samples show a strong intercorrelation with narrow-line Seyfert 1 (NLSy1) galaxies and steep-spectrum radio galaxies occup...

A resonant-cavity-enhanced photodiode with broad filter transmittance and high quantum efficiency was numerically designed and analyzed, fabricated, and validated experimentally. We show theoretically that the quantum-efficiency spectrum broadens because of anomalous dispersion of the reflection phase of a mirror in the device and describe conditions that allow maximal flatness of the transmitt...

Laser-driven, quasimonoenergetic electron beams of up to approximately 200 MeV in energy have been observed from steady-state-flow gas cells. These beams emitted within a low-divergence cone of 2.1+/-0.5 mrad FWHM display unprecedented shot-to-shot stability in energy (2.5% rms), pointing (1.4 mrad rms), and charge (16% rms) owing to a highly reproducible gas-density profile within the interact...

We constructed an ultrahigh-throughput, high-resolution ultraviolet (UV) Raman spectrograph that utilizes a high-efficiency filter-stage monochromator and a high-dispersion Echelle spectrograph. The spectrograph utilizes a total of six mirrors and two gratings, with an overall efficiency at 229 nm of ~18%. The limiting resolution of our spectrometer is 0.6 cm⁻¹ full width half-maximum (FWHM), a...

Here the high timing resolution positron detector designed to be used in the MEG experiment is described. Several technical challenges have been faced to obtain the unprecedented goal resolution of 100 ps FWHM for positrons to be detected in the MEG experiment. Also an overview on past experiments is proposed. The key role of the MEG experiment in unveiling New Physics phenomena is briefly stre...

We report on a dual output all-PM fiber laser system running at 100 MHz repetition rate offering coherent broadband and narrowband pulses centered at 2.05 µm with a spectral FWHM bandwidth of 60 nm and 1.5 nm at up to 360 mW and 500 mW, respectively. The broadband pulses are compressed down to 135 fs. The multi-stage double-clad amplifier based on Tm/Ho codoping is seeded by a supercontinuum li...

We review constraints on models of the broad line region that are imposed by observations of the emission lines in Active Galactic Nuclei. Comparison of high and low ionization lines in sources with FWHM Hβ ≤4000 km s points toward low ionization line emission produced in a flattened geometry (the accretion disk?) with an associated high ionization wind. It remains unclear whether these results...

This paper describes an opto-electronic cross-correlator designed for measurement of the temporal point spread function (TPSF) of light at the bedside. Ultra-short (< 2 ps) pulses of light from a mode-locked laser were used to illuminate a tissue phantom. The light exiting from the tissue phantom was coupled by an optical fibre to a small-area (200 microns diameter, Hamamatsu S2381) avalanche p...

Lasing in N(2) at 337 nm was achieved in a capacitively coupled discharge device having a cylindrical discharge volume with a length of 50 mm and a diameter of 3 mm. The cylindrical dielectric electrodes provide a nearly constant initial electric field throughout the discharge volume. Laser pulses with a width of 2.5 nsec (FWHM) and an energy of 8 microJ were obtained.

We report on single-dish monitoring as well as extremely high angular resolution observations of the flaring H2O maser in the Seyfert 2 galaxy Mrk 348. The H2O line is redshifted by ∼130 km s −1 with respect to the systemic velocity, is very broad, with a FWHM of 130 km s, and has no detectable high velocity components within 1500 km s on either side of the strong line. Monitoring observations ...