A balloon-borne 1 meter telescope for far-infrared astronomy

The flight of a balloon-borne one-meter telescope for infrared astronomy in the wavelength interval of 40 to 240 microns is discussed. The gyro-stabilized telescope mapped the intensity of the far infrared radiation from NGC 7538, Mars, the Orion Nebula, and W3 with a resolution of one minute and from selected regions of these sources with a resolution of 30 seconds. The infrared detection is described and its capabilities are analyzed. The instrumentation, orientation system, and modes of observation of the telescope are defined

Reacting to Perceived Overqualification: Uniting Strain-Based and Self-Regulatory Adjustment Reactions and the Moderating Role of Formal Work Arrangements

Thus far, research on perceived overqualification has focused on either maladaptive, strain-based versus more adaptive, self-regulatory reactions in isolation. Following person-environment fit theory, we seek to advance this one-sided focus by uniting both types of adjustment reactions and to consider their implications for perceived person-job fit, and performance and wellbeing outcomes. In line with theory, we also examine contextual boundary conditions in the form of indicators of formal work arrangements (i.e., permanent vs. temporary employment contract and job tenure). Utilizing three-wave data from 453 employees, we found that perceived overqualification indirectly and sequentially related to decreases in task performance, organizational citizenship behavior and job satisfaction via anger toward employment situation and lower levels of perceived person-job fit-thus reflecting the strain-based pathway. For the self-regulatory pathway, findings did not align with our initial proposition that the positive relationship between perceived overqualification and work organization (a form of structural job crafting whereby employees improve their work processes) would be weaker among temporary employees and those with longer tenure. Instead, having a temporary employment contract or having longer job tenure resulted in a negative relationship between perceived overqualification and work organization, which further contributed to a decrease in performance and satisfaction via lower levels of perceived person-job fit. Our study highlights the demotivating role of a temporary employment contract and long job tenure for overqualified employees to reorganize their work. In discussing our findings, we point to the importance of job stage and develop recommendations for managing overqualified employees

Typical local measurements in generalised probabilistic theories: emergence of quantum bipartite correlations

What singles out quantum mechanics as the fundamental theory of Nature? Here we study local measurements in generalised probabilistic theories (GPTs) and investigate how observational limitations affect the production of correlations. We find that if only a subset of typical local measurements can be made then all the bipartite correlations produced in a GPT can be simulated to a high degree of accuracy by quantum mechanics. Our result makes use of a generalisation of Dvoretzky's theorem for GPTs. The tripartite correlations can go beyond those exhibited by quantum mechanics, however.Comment: 5 pages, 1 figure v2: more details in the proof of the main resul

High-resolution infrared spectroscopy as a tool to detect false positives of transit search programs

Transit search programs such as CoRoT and Kepler now have the capability of detecting planets as small as the Earth. The detection of these planets however requires the removal of all false positives. Although many false positives can be identified by a detailed analysis of the LCs, the detections of others require additional observations. An important source of false positives are faint eclipsing binaries within the PSF of the target stars. We develop a new method that allows us to detect faint eclipsing binaries with a separation smaller than one arcsec from target stars. We thereby focus on binaries that mimic the transits of terrestrial planets. These binaries can be either at the same distance as the target star (triple stars), or at either larger, or smaller distances. A close inspection of the problem indicates that in all relevant cases the binaries are brighter in the infrared than in the optical regime. We show how high resolution IR spectroscopy can be used to remove these false positives. For the triple star case, we find that the brightness difference between a primary and an eclipsing secondary is about 9-10 mag in the visual but only about 4.5-5.9 magnitudes in the K-band. We demonstrate how the triple star hypothesis can be excluded by taking a high-resolution IR spectrum. Simulations of these systems show that the companions can be detected with a false-alarm probability of 2%, if the spectrum has a S/N-ratio > 100. We show that high-resolution IR spectra also allows to detect most of the false positives caused by foreground or background binaries. If high resolution IR spectroscopy is combined with photometric methods, virtually all false positives can be detected without RV measurements. It is thus possible to confirm transiting terrestrial planets with a modest investment of observing time.Comment: 6 pages, 7 figure

The Axial Charge Renormalization in a Relativistic Description of Finite Nuclei

Starting from a realistic One-Boson-Exchange model of the nucleon nucleon interaction the relativistic mean field for nucleons is determined within the Dirac Brueckner Hartree Fock approach for finite nuclei. The matrix elements of the axial charge operator evaluated for the solutions of the Dirac equation with this selfenergy are investigated. These matrix elements are enhanced with respect to the equivalent non relativistic ones obtained from the solutions of the Schr\'odinger equation with the non relativistic equivalent potential. The present results confirm at a qualitative level the results for the axial charge renormalization obtained with perturbative approaches. However, the results obtained differ in size from those of the perturbative approach and are nucleus and state dependent

Identification of the donor in GRS 1915+105

We report on the results of medium-resolution spectroscopy of GRS 1915+105 in the H and K band using the 8m VLT at ESO. We clearly identify absorption bandheads from CO12 and CO13. Together with other features this results in a classification of the donor as a K-M III star.Comment: 4 pages, Kluwer style, to appear in Astrophys. Space Sci. Rev, Proc. of 3rd Microquasar workshop, Granada, Sep. 2000, Eds. A.J. Castro-Tirado, J. Greiner, J.M. Paredes; all proceedings contr. available at http://www.aip.de/~jcg/granada.htm

K-band spectroscopy of IGR J16358-4726 and IGR J16393-4643: two new symbiotic X-ray binaries

Symbiotic X-ray Binaries (SyXBs) are a recently discovered subclass of Low Mass X-ray Binaries. Their growing number makes them an important evolutionary channel of X-ray Binaries. Our goal is to perform spectral analysis and classification of the proposed counterparts to IGR J16358-4726 and IGR J16393-4643 and to establish their nature as X-ray systems. We used the ESO/UT1 ISAAC spectrograph to observe the proposed counterparts to the two sources, obtaining K-band medium resolution spectra (R = 500) with a S/N > 140. Data reduction was performed with the standard procedure. We classified them by means of comparison with published atlases. We performed SED fitting in order to refine the spectral classification. The two counterparts clearly exhibit the typical features of late-type stars, notably strong CO absorption bands in the red part of the spectrum. With information from previous X-ray studies, we classify the two systems as two new members of the SyXB class. For IGR J16393-4643, we considered the most probable counterpart to the system, although three other objects cannot be completely discarded. For this system, we compared our findings with available orbital solutions, constraining the orbital parameters and the mass of the companion star. By including two more systems, we increased to eight the number of known SyXBs, which emerges as a non-negligible category of galactic X-ray binaries.Comment: 7 pages, 3 figures, 4 tables; this version includes referee's comments and language editing. Accepted for publication in Astronomy and Astrophysics

The XMM-Newton view of IRAS 09104+4109: evidence for a changing-look Type 2 quasar?

We analyzed the spectroscopic data from the PN and the MOS cameras in the 0.4-10 keV band. We also used an archival BeppoSAX 1-50 keV observation of IRAS 09104+4109 to investigate possible variations of the quasar emission. The X-ray emission in the EPIC band is dominated by the intra-cluster medium thermal emission. We found that the quasar contributes ~35% of the total flux in the 2-10 keV band. Both a transmission- (through a Compton-thin absorber with a Compton optical depth of \tau_C~0.3, i.e. Nh~5 x 10^{23} cm^-2) and a reflection-dominated (\tau_C>1) model provide an excellent fit to the quasar continuum emission. However, the value measured for the EW of Fe Kalpha emission line is only marginally consistent with the presence of a Compton-thick absorber in a reflection-dominated scenario, which had been suggested by a previous, marginal (i.e. 2.5\sigma) detection with the hard X-ray (15-50 keV), non-imaging BeppoSAX/PDS instrument. Moreover, the value of luminosity in the 2-10 keV band measured by the transmission-dominated model is fully consistent with that expected on the basis of the bolometric luminosity of IRAS 09104+4109. From the analysis of the XMM-Newton data we therefore suggest the possibility that the absorber along the line of sight to the nucleus of IRAS 09104+4109 is Compton-thin. Alternatively, the absorber column density could have changed from Compton-thick to -thin in the five years elapsed between the observations. If this is the case, then IRAS 09104+4109 is the first 'changing-look' quasar ever detected.Comment: Accepted by Astronomy and Astrophysic

K-band spectroscopy of pre-cataclysmic variables

Aims. There exists now substantial evidence for abundance anomalies in a number of cataclysmic variables (CVs), indicating that the photosphere of the secondary star incorporates thermonuclear processed material. However, the spectral energy distribution in CVs is usually dominated by the radiation produced by the accretion process, severely hindering an investigation of the stellar components. On the other hand, depending on how the secondary star has acquired such material, the above mentioned abundance anomalies could also be present in pre-CVs, i.e. detached white/red dwarf binaries that will eventually evolve into CVs, but have not yet started mass transfer, and therefore allow for an unobstructed view on the secondary star at infrared wavelengths. Methods. We have taken K-band spectroscopy of a sample of 13 pre-CVs in order to examine them for anomalous chemical abundances. In particular, we study the strength of the 12CO and 13CO absorption bands that have been found diminished and enhanced, respectively, in similar studies of CVs. Results. All our systems show CO abundances that are within the range observed for single stars. The weakest 12CO bands with respect to the spectral type are found in the pre-CV BPM 71214, although on a much smaller scale than observed in CVs. Furthermore there is no evidence for enhanced 13CO. Taking into account that our sample is subject to the present observational bias that favours the discovery of young pre-CVs with secondary stars of late spectral types, we can conclude the following: 1) our study provides observational proof that the CO anomalies discovered in certain CVs are not due to any material acquired during the common envelope phase, and 2) if the CO anomalies in certain CVs are not due to accretion of processed material during nova outburst, then the progenitors of these CVs are of a significantly different type than the currently known sample of pre-CVs

Quantum Optics and Photonics

Contains reports on nine research projects.National Science Foundation (Grant PHY82-10369)Joint Services Electronics Program (Contract DAAG29-83-K-0003)U.S. Air Force - Office of Scientific Research (Contract F49620-82-C-0091)Litton Guidance and Control SystemNational Science Foundation (Grant PHY82-10369