79 research outputs found
« PÄknieta Struna » (« Le lien rompu »)
After World War II, the surviving Polish Jews helped to rebuild the destroyed country and restore whatever was left of the earlier so flowering Jewish culture in Poland, be it in Yiddish or Polish. Unfortunately, the motherland turned out to be a wicked stepmother and so waves of Jewish emigrants followed, mostly to Israel in the years 1945-1948, especially following the Kielce-pogrom of 1946, and in 1956-57 in the so-called Polish âThaw-weatherâ due to anti-Zionist campaign after the Suez War. This wave of emigration is unjustly forgotten, other than the final post-War wave of emigration after March events of 1968, which cleansed Poland of its Jewish inhabitants. The post-War emigrants were very closely attached to Poland and the Polish culture, but for them there was â at that time â no way back. Facing the hardships of exile, suffering of lost illusions and personal mortification, some of them, like Henryk Dankowicz and Aleksander Klugman whose texts will be discussed here, wrote their âJâaccuse !â but many of them felt that their âstringâ was suddenly âtornâ. How did they cope with the new situation and howÂ
Characterizing Exoplanets in the Visible and Infrared: A Spectrometer Concept for the EChO Space Mission
Transit-spectroscopy of exoplanets is one of the key observational techniques
to characterize the extrasolar planet and its atmosphere. The observational
challenges of these measurements require dedicated instrumentation and only the
space environment allows an undisturbed access to earth-like atmospheric
features such as water or carbon-dioxide. Therefore, several exoplanet-specific
space missions are currently being studied. One of them is EChO, the Exoplanet
Characterization Observatory, which is part of ESA's Cosmic Vision 2015-2025
program, and which is one of four candidates for the M3 launch slot in 2024. In
this paper we present the results of our assessment study of the EChO
spectrometer, the only science instrument onboard this spacecraft. The
instrument is a multi-channel all-reflective dispersive spectrometer, covering
the wavelength range from 400 nm to 16 microns simultaneously with a moderately
low spectral resolution. We illustrate how the key technical challenge of the
EChO mission - the high photometric stability - influences the choice of
spectrometer concept and drives fundamentally the instrument design. First
performance evaluations underline the fitness of the elaborated design solution
for the needs of the EChO mission.Comment: 20 pages, 8 figures, accepted for publication in the Journal of
Astronomical Instrumentatio
Measurement of the LT-asymmetry in \pi^0 electroproduction at the energy of the \Delta (1232) resonance
The reaction p(e,e'p)pi^0 has been studied at Q^2=0.2 (GeV/c)^2 in the region
of W=1232 MeV. From measurements left and right of q, cross section asymmetries
\rho_LT have been obtained in forward kinematics \rho_LT(\theta_\pi^0=20deg) =
(-11.68 +/- 2.36_stat +/- 2.36_sys)$ and backward kinematics
\rho_LT(\theta_\pi^0=160deg) =(12.18 +/- 0.27_stat +/- 0.82_sys). Multipole
ratios \Re(S_1+^* M_1+)/|M_1+|^2 and \Re(S_0+^* M_1+)/|M_1+|^2 were determined
in the framework of the MAID2003 model. The results are in agreement with older
data. The unusally strong negative \Re(S_0+^* M_1+)/|M_1+|^2 required to bring
also the result of Kalleicher et al. in accordance with the rest of the data is
almost excluded.Comment: 7 pages, 7 figures, 4 tables. Changed content. Accepted for
publication in EPJ
The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory
The Photodetector Array Camera and Spectrometer (PACS) is one of the three
science instruments on ESA's far infrared and submillimetre observatory. It
employs two Ge:Ga photoconductor arrays (stressed and unstressed) with 16x25
pixels, each, and two filled silicon bolometer arrays with 16x32 and 32x64
pixels, respectively, to perform integral-field spectroscopy and imaging
photometry in the 60-210\mu\ m wavelength regime. In photometry mode, it
simultaneously images two bands, 60-85\mu\ m or 85-125\mu\m and 125-210\mu\ m,
over a field of view of ~1.75'x3.5', with close to Nyquist beam sampling in
each band. In spectroscopy mode, it images a field of 47"x47", resolved into
5x5 pixels, with an instantaneous spectral coverage of ~1500km/s and a spectral
resolution of ~175km/s. We summarise the design of the instrument, describe
observing modes, calibration, and data analysis methods, and present our
current assessment of the in-orbit performance of the instrument based on the
Performance Verification tests. PACS is fully operational, and the achieved
performance is close to or better than the pre-launch predictions
4D treatment planning for scanned ion beams
At Gesellschaft fĂŒr Schwerionenforschung (GSI) more than 330 patients have been treated with scanned carbon ion beams in a pilot project. To date, only stationary tumors have been treated. In the presence of motion, scanned ion beam therapy is not yet possible because of interplay effects between scanned beam and target motion which can cause severe mis-dosage. We have started a project to treat tumors that are subject to respiratory motion. A prototype beam application system for target tracking with the scanned pencil beam has been developed and commissioned
Measurement of the beam-helicity asymmetry in the p(e_pol,e'p)pi_0 reaction at the energy of the Delta(1232) resonance
In a p(e_pol,e'p)pi_0 out-of-plane coincidence experiment at the
3-spectrometer setup of the Mainz Microtron MAMI, the beam-helicity asymmetry
has been precisely measured around the energy of the Delta(1232) resonance and
Q^2 = 0.2 (GeV/c)^2. The results are in disagreement with three up-to-date
model calculations. This is interpreted as lack of understanding of the
non-resonant background, which in dynamical models is related to the pion
cloud.Comment: 5 pages, 2 figures, 2 table
Multiple star systems in the Orion nebula
This is the author accepted manuscript. The final fersion is available from EDP Sciences via the DOI in this record.This work presents an interferometric study of the massive-binary fraction in the Orion Trapezium cluster with the recently comissioned GRAVITY instrument. We observed a total of 16 stars of mainly OB spectral type. We find three previously unknown companions for Ξ1 Ori B, Ξ2 Ori B, and Ξ2 Ori C. We determined a separation for the previously suspected companion of NU Ori. We confirm four companions for Ξ1 Ori A, Ξ1 Ori C, Ξ1 Ori D, and Ξ2 Ori A, all with substantially improved astrometry and photometric mass estimates. We refined the orbit of the eccentric high-mass binary Ξ1 Ori C and we are able to derive a new orbit for Ξ1 Ori D. We find a system mass of 21.7 Mâ and a period of 53 days. Together with other previously detected companions seen in spectroscopy or direct imaging, eleven of the 16 high-mass stars are multiple systems. We obtain a total number of 22 companions with separations up to 600 AU. The companion fraction of the early B and O stars in our sample is about two, significantly higher than in earlier studies of mostly OB associations. The separation distribution hints toward a bimodality. Such a bimodality has been previously found in A stars, but rarely in OB binaries, which up to this point have been assumed to be mostly compact with a tail of wider companions. We also do not find a substantial population of equal-mass binaries. The observed distribution of mass ratios declines steeply with mass, and like the direct star counts, indicates that our companions follow a standard power law initial mass function. Again, this is in contrast to earlier findings of flat mass ratio distributions in OB associations. We excluded collision as a dominant formation mechanism but find no clear preference for core accretion or competitive accretion.Marie SkĆodowska-Curie Grant AgreementFCT-PortugalERC Starting Gran
The CARMENES search for exoplanets around M dwarfs High-resolution optical and near-infrared spectroscopy of 324 survey stars
The CARMENES radial velocity (RV) survey is observing 324 M dwarfs to search for any orbiting planets. In this paper, we present the survey sample by publishing one CARMENES spectrum for each M dwarf. These spectra cover the wavelength range 520â1710 nm at a resolution of at least R >80 000, and we measure its RV, Hα emission, and projected rotation velocity. We present an atlas of high-resolution M-dwarf spectra and compare the spectra to atmospheric models. To quantify the RV precision that can be achieved in low-mass stars over the CARMENES wavelength range, we analyze our empirical information on the RV precision from more than 6500 observations. We compare our high-resolution M-dwarf spectra to atmospheric models where we determine the spectroscopic RV information content, Q, and signal-to-noise ratio. We find that for all M-type dwarfs, the highest RV precision can be reached in the wavelength range 700â900 nm. Observations at longer wavelengths are equally precise only at the very latest spectral types (M8 and M9). We demonstrate that in this spectroscopic range, the large amount of absorption features compensates for the intrinsic faintness of an M7 star. To reach an RV precision of 1 m sâ1 in very low mass M dwarfs at longer wavelengths likely requires the use of a 10 m class telescope. For spectral types M6 and earlier, the combination of a red visual and a near-infrared spectrograph is ideal to search for low-mass planets and to distinguish between planets and stellar variability. At a 4 m class telescope, an instrument like CARMENES has the potential to push the RV precision well below the typical jitter level of 3â4 m sâ1
The CARMENES search for exoplanets around M dwarfs HD147379 b: A nearby Neptune in the temperate zone of an early-M dwarf
We report on the first star discovered to host a planet detected by radial velocity (RV) observations obtained within the CARMENES survey for exoplanets around M dwarfs. HD 147379 (Vâ=â8.9 mag, Mâ=â0.58â±â0.08âMâ), a bright M0.0 V star at a distance of 10.7 pc, is found to undergo periodic RV variations with a semi-amplitude of Kâ=â5.1 ± 0.4 m sâ1 and a period of Pâ=â86.54 ± 0.06 d. The RV signal is found in our CARMENES data, which were taken between 2016 and 2017, and is supported by HIRES/Keck observations that were obtained since 2000. The RV variations are interpreted as resulting from a planet of minimum mass mPâsinâiâ=â25â±â2âMâ, 1.5 times the mass of Neptune, with an orbital semi-major axis aâ=â0.32 au and low eccentricity (e < 0.13). HD 147379 b is orbiting inside the temperate zone around the star, where water could exist in liquid form. The RV time-series and various spectroscopic indicators show additional hints of variations at an approximate period of 21.1 d (and its first harmonic), which we attribute to the rotation period of the star.FEDER/ERF FICTS-2011-02 fundsMajor Research Instrumentation Programme
and DFG Research Unit FOR2544 âBlue Planets around Red StarsEuropean Research Council (ERC-279347), Deutsche Forschungsgemeinschaft
(RE 1664/12-1, RE 2694/4-1), Bundesministerium fĂŒr Bildung
und Forschung (BMBF-05A14MG3, BMBF-05A17MG3), Spanish Ministry
of Economy and Competitiveness (MINECO, grants AYA2015-68012-C2-2-P,
AYA2016-79425-C3-1,2,3-P, AYA2015-69350-C3-2-P, AYA2014-54348-C03-
01, AYA2014-56359-P, AYA2014-54348-C3-2-R, AYA2016-79425-C3-3-P and
2013 RamĂČn y Cajal program RYC-2013-14875), Fondo Europeo de Desarrollo
Regional (FEDER, grant ESP2016-80435-C2-1-R, ESP2015-65712-C5-
5-R), Generalitat de Catalunya/CERCA programme, Spanish Ministerio de
EducaciĂłn, Cultura y Deporte, programa de FormaciĂłn de Profesorado Universitario
(grant FPU15/01476), Deutsches Zentrum fĂŒr Luft- und Raumfahrt
(grants 50OW0204 and 50OO1501), Office of Naval Research Global (award
no. N62909-15-1-2011), Mexican CONACyT grant CB-2012-183007
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