Precision Photometry for Q0957+561 Images A and B

Since the persuasive determination of the time-delay in Q0957+561, much interest has centered around shifting and subtracting the A and B light-curves to look for residuals due to microlensing. Solar mass objects in the lens galaxy produce variations on timescales of decades, with amplitudes of a few tenths of a magnitude, but MACHO's (with masses of order $10^{-3}$ to $10^{-7}M_\odot$) produce variations at only the 5% level. To detect such small variations, highly precise photometry is required. To that end, we have used 200 observations over three nights to examine the effects of seeing on the light-curves. We have determined that seeing itself can be responsible for correlated 5% variations in the light-curves of A and B. We have found, however, that these effects can be accurately removed, by subtracting the light from the lens galaxy, and by correcting for cross contamination of light between the closely juxtaposed A and B images. We find that these corrections improve the variations due to seeing from 5% to a level only marginally detectable over photon shot noise (0.5%).Comment: 21 Pages with 9 PostScript figures, AASTeX 4 (preprint style

Rapid and flexible high-resolution scanning enabled by cycloidal computed tomography and convolutional neural network (CNN) based data recovery

We have combined a recently developed imaging concept (“cycloidal computed tomography”) with convolutional neural network (CNN) based data recovery. The imaging concept is enabled by exploiting, in synergy, the benefits of probing the sample with a structured x-ray beam and applying a cycloidal acquisition scheme by which the sample is simultaneously rotated and laterally translated. The beam structuring provides a means of increasing the in-slice spatial resolution in tomographic images irrespective of the blur imposed by the x-ray source and detector, while the “roto-translation” sampling allows for rapid scanning. Data recovery based on the recently proposed Mixed-Scale Dense (MSD) CNN architecture enables an efficient reconstruction of high-quality, high-resolution images despite the fact that cycloidal computed tomography data are highly incomplete. In the following, we review the basic principles underpinning cycloidal computed tomography, introduce the CNN based data recovery method and discuss the benefit of combining both

How Emotional Intelligence Might Get You the Job: The Relationship Between Trait Emotional Intelligence and Faking on Personality Tests

This study examined trait emotional intelligence (EI) in relation to the ability to fake on personality tests. Undergraduate students (N = 129) were first instructed to fill out a personality inventory honestly, and s

The motivation and opportunity for socially desirable responding does not alter the general factor of personality

Socially desirable responding may affect the factor structure of personality questionnaires and may be one of the reasons for the common variance among personality traits. In this study, we test this hypothesis by investigating the influence of the motivational test-taking context (development vs. selection) and the opportunity to distort responses (forced-choice vs. Likert response format) on personality questionnaire scores. Data from real selection and assessment candidates (total N = 3,980) matched on gender, age, and educational level were used. Mean score differences were found between the selection and development groups, with smaller differences for the FC version. Yet, exploratory structural equation models showed that the overall factor structures as well as the general factor were highly similar across the four groups. Thus, although socially desirable responding may affect mean scores on personality traits, it does not appear to affect factor st

The white dwarf in dwarf nova SDSS J080434.20+510349.2: Entering the instability strip?

SDSS J080434.20+510349.2 is the WZ type binary that displayed rare outburst in 2006 (Pavlenko et al., 2007). During the long-lasting tail of the late stage of the outburst binary shown the two-humped or four-humped profile of the orbital light modulation. The amplitude of orbital light curve decreased while the mean brightness decreased, more over that occurred $\sim$ 10 times faster during the fast outburst decline in respect to the late quiet state of slow outburst fading. There were no white dwarf pulsations detected neither 1 - 1.5 months prior to the outburst nor in 1.5 - 2 months after the 2006 outburst in this system. However the strong non-radial pulsations with period 12.6 minutes and mean amplitude of 0.05^m were first detected in V band with 2.6-m Shajn mirror telescope of the Crimean astrophysical observatory in ~ 8 months after the outburst. The evolution of pulsations over two years in 2006 - 2008 is considered. It is supposed that pulsations first appeared when the cooling white dwarf (after the outburst) entered the instability strip although the possibility of temporary lack of pulsations at some occasions also could not be excluded.Comment: Submitted to Proceedings of 16th European White Dwarf Workshop (EUROWD08

A Determination of H_0 with the CLASS Gravitational Lens B1608+656: III. A Significant Improvement in the Precision of the Time Delay Measurements

The gravitational lens CLASS B1608+656 is the only four-image lens system for which all three independent time delays have been measured. This makes the system an excellent candidate for a high-quality determination of H_0 at cosmological distances. However, the original measurements of the time delays had large (12-20%) uncertainties, due to the low level of variability of the background source during the monitoring campaign. In this paper, we present results from two additional VLA monitoring campaigns. In contrast to the ~5% variations seen during the first season of monitoring, the source flux density changed by 25-30% in each of the subsequent two seasons. We analyzed the combined data set from all three seasons of monitoring to improve significantly the precision of the time delay measurements; the delays are consistent with those found in the original measurements, but the uncertainties have decreased by factors of two to three. We combined the delays with revised isothermal mass models to derive a measurement of H_0. Depending on the positions of the galaxy centroids, which vary by up to 0.1 arcsec in HST images obtained with different filters, we obtain H_0 = 61-65 km/s/Mpc, for (Omega_M,Omega_L) = (0.3,0.7). The value of H_0 decreases by 6% if (Omega_M,Omega_L) = (1.0,0.0). The formal uncertainties on H_0 due to the time delay measurements are +/- 1 (+/- 2) km/s/Mpc for the 1-sigma (2-sigma) confidence limits. Thus, the systematic uncertainties due to the lens model, which are on the order of +/- 15 km/s/Mpc, now dominate the error budget for this system. In order to improve the measurement of H_0 with this lens, new models that incorporate the constraints provided by stellar dynamics and the optical/infrared Einstein ring seen in HST images must be developed.Comment: Accepted for publication in ApJ. 32 pages, 8 figures (3 in color

A Large Brightness Enhancement of the QSO 0957+561 A Component

We report an increase of more than 0.2 mag in the optical brightness of the leading image (A) of the gravitational lens Q0957+561, detected during the 09/2000 -- 06/2001 monitoring campaign (2001 observing season). The brightening is similar to or even greater than the largest change ever detected during the 20 years of monitoring of this system. We discuss two different provisional explanations to this event: intrinsic source variability or microlensing (either short timescale microlensing or cessation of the historical microlensing). An exhaustive photometric monitoring of Q0957+561 is needed until summer of 2002 and during 2003 to discriminate between these possibilities.Comment: 13 pages including 3 figures and 1 table. Accepted for publication in ApJ Let