266 research outputs found
POLOCAM: a millimeter wavelength cryogenic polarimeter prototype for MUSIC-POL
As a proof-of-concept, we have constructed and tested a cryogenic polarimeter in the laboratory as a prototype for the MUSIC instrument (Multiwavelength Sub/millimeter Kinetic Inductance Camera). The POLOCAM instrument consists of a rotating cryogenic polarization modulator (sapphire half-waveplate) and polarization analyzer (lithographed copper polarizers deposited on a thin film) placed into the optical path at the Lyot stop (4K cold pupil stop) in a cryogenic dewar. We present an overview of the project, design and performance results of the POLOCAM instrument (including polarization efficiencies and instrumental polarization), as well as future application to the MUSIC-POL instrument
Evidence for a companion to BM Gem, a silicate carbon star
Balmer and Paschen continuum emission as well as Balmer series lines of P
Cygni-type profile from H_gamma through H_23 are revealed in the violet spectra
of BM Gem, a carbon star associated with an oxygen-rich circumstellar shell
(`silicate carbon star') observed with the high dispersion spectrograph (HDS)
on the Subaru telescope. The blue-shifted absorption in the Balmer lines
indicates the presence of an outflow, the line of sight velocity of which is at
least 400 km s^-1, which is the highest outflow velocity observed to date in a
carbon star. We argue that the observed unusual features in BM Gem are strong
evidence for the presence of a companion, which should form an accretion disk
that gives rise to both an ionized gas region and a high velocity, variable
outflow. The estimated luminosity of ~0.2 (0.03-0.6) L_sun for the ionized gas
can be maintained by a mass accretion rate to a dwarf companion of ~10^-8 M_sun
yr^-1, while ~10^-10 M_sun yr^-1 is sufficient for accretion to a white dwarf
companion. These accretion rates are feasible for some detached binary
configurations on the basis of the Bond-Hoyle type accretion process. We
concluded that the carbon star BM Gem is in a detached binary system with a
companion of low mass and low luminosity. However, we are unable to determine
whether this companion object is a dwarf or a white dwarf. The upper limits for
binary separation are 210 AU and 930 AU for a dwarf and a white dwarf,
respectively. We also note that the observed features of BM Gem mimic those of
Mira (omi Cet), which may suggest actual similarities in their binary
configurations and circumstellar structures.Comment: 11 pages, 2 figures, 1 table, accepted for publication in Ap
POLOCAM: a millimeter wavelength cryogenic polarimeter prototype for MUSIC-POL
As a proof-of-concept, we have constructed and tested a cryogenic polarimeter in the laboratory as a prototype for the MUSIC instrument (Multiwavelength Sub/millimeter Kinetic Inductance Camera). The POLOCAM instrument consists of a rotating cryogenic polarization modulator (sapphire half-waveplate) and polarization analyzer (lithographed copper polarizers deposited on a thin film) placed into the optical path at the Lyot stop (4K cold pupil stop) in a cryogenic dewar. We present an overview of the project, design and performance results of the POLOCAM instrument (including polarization efficiencies and instrumental polarization), as well as future application to the MUSIC-POL instrument
Deviations from the Local Hubble Flow. I. The Tip of the Red Giant Branch as a Distance Indicator
The properties of the velocity field in the local volume (cz < 550 km/s) have
been difficult to constrain due to a lack of a consistent set of galaxy
distances. The sparse observations available to date suggest a remarkably quiet
flow, with little deviation from a pure Hubble law. However, velocity field
models based on the distribution of galaxies in the 1.2 Jy IRAS redshift
survey, predict a quadrupolar flow pattern locally with strong infall at the
poles of the local Supergalactic plane. We probe this velocity field and begin
to establish a consistent set of galactic distances. We have obtained images of
nearby galaxies in the I and V band from the W.M. Keck Observatory and in F814W
and F555W filters from the Hubble Space Telescope. Where these galaxies are
well resolved into stars we may use the Tip of the Red Giant Branch (TRGB) as a
distance indicator. Using a maximum likelihood analysis to quantitatively
measure the I magnitude of the TRGB we determine precise distances to seven
nearby galaxies: Leo I, Sextans B, NGC 1313, NGC 3109, UGC 03755, UGC 06456,
and UGC 07577.Comment: AJ in Press, 54 pages, 30 figures, typos corrected, references added,
postscript version with high resolution figures available at
ftp://deep.berkeley.edu/pub/trgb/trgb.p
Introduction:strategy in EU foreign policy
The point of departure for the special collection is provided by the observation that the growing complexity of the crises in the neighbourhood and the internal ones faced by the Union provides a sense of urgency to any type of strategic thinking that the EU might embrace. Against this backdrop, the recent shift towards geopolitics and strategic thinking is contextualized and the understanding of key aspects of ways in which the shift is translated into strategies by EU actors is put forward. The analysis recognizes the recent developments within the institutional dimension of EUâs foreign and security policy, yet it confirms the fundamental meaning of the member statesâ willingness to invest resources and harmonize their foreign policy strategies at the EU level
THE DATA REDUCTION PIPELINE FOR THE APACHE POINT OBSERVATORY GALACTIC EVOLUTION EXPERIMENT
The Apache Point Observatory Galactic Evolution Experiment (APOGEE), part of the Sloan Digital Sky Survey III, explores the stellar populations of the Milky Way using the Sloan 2.5-m telescope linked to a high resolution (R ~ 22,500), near-infrared (1.51â1.70 ”m) spectrograph with 300 optical fibers. For over 150,000 predominantly red giant branch stars that APOGEE targeted across the Galactic bulge, disks and halo, the collected high signal-to-noise ratio (>100 per half-resolution element) spectra provide accurate (~0.1 km s-1) RVs, stellar atmospheric parameters, and precise (lesssim0.1 dex) chemical abundances for about 15 chemical species. Here we describe the basic APOGEE data reduction software that reduces multiple 3D raw data cubes into calibrated, well-sampled, combined 1D spectra, as implemented for the SDSS-III/APOGEE data releases (DR10, DR11 and DR12). The processing of the near-IR spectral data of APOGEE presents some challenges for reduction, including automated sky subtraction and telluric correction over a 3°-diameter field and the combination of spectrally dithered spectra. We also discuss areas for future improvement
Smoking, drinking and body weight after re-employment: does unemployment experience and compensation make a difference?
<p>Abstract</p> <p>Background</p> <p>The impact of unemployment on behaviours such as smoking, drinking and body weight has been extensively researched. However, little is known about the possible protective effects of social assistance programs on these behavioural changes. This study examines the impact of unemployment periods on smoking, drinking and body weight changes among re-employed individuals and investigates whether the receipt of unemployment benefits influences these behaviours.</p> <p>Methods</p> <p>This study used panel data provided by the Panel Study of Income Dynamics. Logistic regression models were used to analyze whether a period of unemployment in 2000 resulted in an increase in smoking and drinking or fluctuations in body weight among 2001 re-employed individuals in comparison with 1999 baseline levels. A total of 3,451 respondents who had been initially healthy and who had been continuously employed between 1998 and 1999 were included in the analysis.</p> <p>Results</p> <p>Compared to stably employed respondents, those who had experienced periods of unemployment in 2000 and did not receive unemployment benefits were more likely than continuously employed individuals to report an increase in alcohol consumption (OR 1.8, 95% CI 1.0â3.1) and a decrease in body weight (OR 1.7, 95% CI 1.1â2.8) when they were already re-employed in 2001.</p> <p>Conclusion</p> <p>Our findings suggest that the receipt of unemployment benefits confers a protective effect on health behavioural changes following periods of unemployment. These findings underscore the need to monitor the impact of unemployment assistance programs on health, particularly in light of the rapidly changing structure of employment and unemployment benefits.</p
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