1,120 research outputs found
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 to
) 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 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
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