Was 49b: An Overmassive AGN in a Merging Dwarf Galaxy?

We present a combined morphological and X-ray analysis of Was 49, an isolated, dual AGN system notable for the presence of a dominant AGN Was 49b in the disk of the primary galaxy Was 49a, at a projected radial distance of 8 kpc from the nucleus. Using X-ray data from Chandra, NuSTAR, and Swift, we find that this AGN has a bolometric luminosity of L_bol ~ 2 x 10^45 erg/s, with a black hole mass of M_BH=1.3^{+2.9}_{-0.9} x 10^8 M_Sol. Despite its large mass, our analysis of optical data from the Discovery Channel Telescope shows that the supermassive black hole is hosted by a stellar counterpart with a mass of only 5.6^{+4.9}_{-2.6} x 10^9 M_Sol, making the SMBH potentially larger than expected from SMBH-galaxy scaling relations, and the stellar counterpart exhibits a morphology that is consistent with dwarf elliptical galaxies. Our analysis of the system in the r and K bands indicates that Was 49 is a minor merger, with a mass ratio of Was 49a to Was 49b between 1:7 and 1:15. This is in contrast with findings that the most luminous merger-triggered AGNs are found in major mergers, and that minor mergers predominantly enhance AGN activity in the primary galaxy.Comment: 11 pages, 6 figures, accepted for publication in Ap

Laser vibrometers and contacting transducers, target rotation and six degree-of-freedom vibration: what do we really measure?

This paper presents a comprehensive analysis of the velocity sensed by a single laser vibrometer beam incident in an arbitrary direction on a target that is of substantial interest in engineering - a rotating shaft requiring three translational and three rotational co-ordinates to describe its vibratory motion fully. Six separate "vibration sets", each a combination of motion parameters, appear in the full expression for vibration velocity sensitivity and it is shown not to be possible to resolve individual motion components within each set by arrangement, or even manipulation, of laser beams. To place this non-contact transducer velocity sensitivity model in its proper context, the velocity sensitivity of a contacting transducer under identical conditions is also derived and comparison is made between non-contacting and contacting transducer performance. Specific applications of the laser vibrometer theory to radial and axial vibration measurements are set out and it is shown how estimation of radial vibration components is only possible by post-processing, The theory is easily extended to include measurements made with multiple beams, underlining the model's versatility in enabling determination of the vibration component sensitivity of a measurement with any beam orientation or combination of beam orientations. This will prove beneficial in devising further optical configurations for the measurement of torsional, pitch and yaw vibrations

Rotational vibration measurements using laser doppler vibrometry: comprehensive theory and practical application

This paper builds on a previous study of the velocity sensed by a single laser vibrometer beam incident on a target in an arbitrary direction to predict the velocity sensed by multiple laser beams with arbitrary orientations. The usefulness of parallel beam arrangements is demonstrated and a concise new theory for the difference velocity sensitivity for two parallel beams is presented. Parallel beam arrangements for Virtually unambiguous measurement of torsional vibration are presented along with arrangements that allow measurement of the pitch and yaw vibration to be derived. Resolution of individual pitch and yaw motions is shown not to be possible by any geometrical arrangement of the beams but a post-processing technique that enables the genuine pitch and yaw vibrations to be estimated from the measurements of the pitch and yaw vibration sets is demonstrated and validated experimentally in the laboratory. Measurements of pitch and yaw vibration are, for the first time, obtained from the crank-shaft of a running diesel engine, enabling identification of the first natural frequency of the crank-shaft in bending

On the application of laser vibrometry to translational and rotational vibration measurements on rotating shafts

Laser Doppler vibrometry is now a well established experimental technique and commercially available instruments are gaining in popularity. This paper sets out a comprehensive model of the velocity sensed by both a single laser beam and by a pair of parallel beams incident on a rotating shaft requiring three translational and three rotational co-ordinates to describe its vibratory motion fully. While the intention is to measure the six vibration components, the model reveals how it is instead only possible to measure six vibration “sets”, each inseparable combinations of more than one of the vibration components. Arrangements for isolation of each “set” are detailed and an essential post-processing technique to resolve translational and rotational vibration components is demonstrated in a measurement of crankshaft bending vibration

The role of intermolecular coupling in the photophysics of disordered organic semiconductors: Aggregate emission in regioregular polythiophene

We address the role of excitonic coulping on the nature of photoexcitations in the conjugated polymer regioregular poly(3-hexylthiophene). By means of temperature-dependent absorption and photoluminescence spectroscopy, we show that optical emission is overwhelmingly dominated by weakly coupled H-aggregates. The relative absorbance of the 0-0 and 0-1 vibronic peaks provides a powerfully simple means to extract the magnitude of the intermolecular coupling energy, approximately 5 and 30 meV for films spun from isodurene and chloroform solutions respectively.Comment: 10 pages, 4 figures, published in Phys. Rev. Let

Polarization dependence of four-wave mixing in a degenerate two-level system

Nearly degenerate four-wave mixing (NDFWM) within a closed degenerate two-level atomic transition is theoretically and experimentally examined. Using the model presented by A. Lezama et al [Phys. Rev. A 61, 013801 (2000)] the NDFWM spectra corresponding to different pump and probe polarization cases are calculated and discussed. The calculated spectra are compared to the observation of NDFWM within the $6S_{1/2}(F=4)\to 6P_{3/2}(F=5)$ transition of cesium in a phase conjugation experiment using magneto optically cooled atomsComment: 10 pages, 13 figures; submitted to Phys. Rev.

The Correlation Between Galaxy HI Linewidths and K' Luminosities

The relationship between galaxy luminosities and rotation rates is studied with total luminosities in the K' band. Extinction problems are essentially eliminated at this band centered at 2.1 micron. A template luminosity-linewidth relation is derived based on 65 galaxies drawn from two magnitude-limited cluster samples. The zero-point is determined using 4 galaxies with accurately known distances. The calibration is applied to give the distance to the Pisces Cluster (60 Mpc) at a redshift in the CMB frame of 4771 km/s. The resultant value of the Hubble Constant is 81 km/s/Mpc. The largest sources of uncertainty arises from the small number of zero-point calibrators at this time at K' and present application to only one cluster.Comment: 13 pages including 5 figures and 2 tables. Accepted for publication in Astrophysical Journa

Measurement and analysis of grip force during a golf shot

In this study, grip force was measured during a standard golf tee shot using two different measurement techniques. The first utilized a matrix-type thin-film sensor applied to a golf grip, from which total grip force could be readily determined. The second method involved 31 individual thin-film force sensors strategically placed on two golf gloves, allowing the force output of specific regions of the hands to be measured. Twenty golfers of varying ability participated in each test. The discovery of a unique grip force ‘signature’ for each golfer emerged from these data. That is, each golfer had a very repeatable total grip force trace, but these traces varied considerably between golfers. High-speed video was also recorded for many of the golfers tested so that key phases in the swing could be identified on the force traces

Evaluation of thin, flexible sensors for time-resolved grip force measurement

Three types of thin, flexible force sensor were studied under a variety of loading conditions to determine their suitability for measuring grip force. Static accuracy, hysteresis, repeatability, and drift errors were established, the effects of shear force and surface curvature were considered, and dynamic accuracy and drift were measured. Novel tests were developed to consider dynamic accuracy and sensitivity to shear loadings. Additionally, three sensors were evaluated in a real-life gripping scenario, measuring grip force during a golf shot. Comments are made on sensor performance, ease of use, and durability