Archaeology and landscape features in Magnetometer Data

Geophysics, especially magnetometry, right now has become famous for detecting archeological features and mapping entire archaeological sites (Gaffney 2008). It allows to map pits, fortifications, buildings, post holes, graves etc. without excavation i. e. destruction. Nevertheless, since magnetometry plots any type of magnetic anomalies including modern disturbances and natural e. g. geological structures, it also maps the natural environment of the site. Geophysics allow to detect features ..

X-ray analysis of the proper motion and pulsar wind nebula for PSR J1741-2054

We obtained six observations of PSR J1741-2054 using the $Chandra$ ACIS-S detector totaling $\sim$300 ks. By registering this new epoch of observations to an archival observation taken 3.2 years earlier using X-ray point sources in the field of view, we have measured the pulsar proper motion at $\mu =109 \pm 10 {\rm mas\ yr}^{-1}$ in a direction consistent with the symmetry axis of the observed H$\alpha$ nebula. We investigated the inferred past trajectory of the pulsar but find no compelling association with OB associations in which the progenitor may have originated. We confirm previous measurements of the pulsar spectrum as an absorbed power law with photon index $\Gamma$=2.68$\pm$0.04, plus a blackbody with an emission radius of (4.5$^{+3.2}_{-2.5})d_{0.38}$ km, for a DM-estimated distance of $0.38d_{0.38}$ kpc and a temperature of $61.7\pm3.0$ eV. Emission from the compact nebula is well described by an absorbed power law model with a photon index of $\Gamma$ = 1.67$\pm$0.06, while the diffuse emission seen as a trail extending northeast of the pulsar shows no evidence of synchrotron cooling. We also applied image deconvolution techniques to search for small-scale structures in the immediate vicinity of the pulsar, but found no conclusive evidence for such structures.Comment: 7 pages, 8 figures, 4 Tables; Accepted by Ap

Chandra pulsar survey (ChaPS)

Taking advantage of the high sensitivity of the Chandra Advanced CCD Imaging Spectrometer, we have conducted a snap-shot survey of pulsars previously undetected in X-rays. We detected 12 pulsars and established deep flux limits for 11 pulsars. Using these new results, we revisit the relationship between the X-ray luminosity, L_psr_x, and spin-down power, Edot. We find that the obtained limits further increase the extremely large spread in the non-thermal X-ray efficiencies, eta_psr_x=L_psr_x/Edot, with some of them being now below 1e-5. Such a spread cannot be explained by poorly known distances or by beaming of pulsar radiation. We also find evidence of a break in the dependence of L_psr_x on Edot, such that pulsars become more X-ray efficient at Edot<~ 1e34-1e35 erg/s. We examine the relationship between the gamma-ray luminosity, L_psr_g, and Edot, which exhibits a smaller scatter compared to that in X-rays. This confirms that the very large spread in the X-ray efficiencies cannot be explained just by beaming because the gamma-ray emission is generally expected to be beamed stronger than the X-ray emission. Intriguingly, there is also an indication of a break in the L_psr_g(Edot) dependence at Edot~1e35 erg/s, with lower-Edot pulsars becoming less gamma-ray efficient. We also examine the distance-independent L_psr_f/L_psr_x ratio as a function of Edot for a sample of gamma-ray pulsars observed by Chandra and find that it peaks at Edot~1e35 erg/s, showing that the breaks cannot originate from poorly measured distances. We discuss the implications of our findings for existing models of magnetospheric emission and venues for further exploration.Comment: Submitted to Ap

Aerosol size-dependent below-cloud scavenging by rain and snow in the ECHAM5-HAM

Wet deposition processes are highly efficient in the removal of aerosols from the atmosphere, and thus strongly influence global aerosol concentrations, and clouds, and their respective radiative forcings. In this study, physically detailed size-dependent below-cloud scavenging parameterizations for rain and snow are implemented in the ECHAM5-HAM global aerosol-climate model. Previously, below-cloud scavenging by rain in the ECHAM5-HAM was simply a function of the aerosol mode, and then scaled by the rainfall rate. The below-cloud scavenging by snow was a function of the snowfall rate alone. The global mean aerosol optical depth, and sea salt burden are sensitive to the below-cloud scavenging coefficients, with reductions near to 15% when the more vigorous size-dependent below-cloud scavenging by rain and snow is implemented. The inclusion of a prognostic rain scheme significantly reduces the fractional importance of below-cloud scavenging since there is higher evaporation in the lower troposphere, increasing the global mean sea salt burden by almost 15%. Thermophoretic effects are shown to produce increases in the global and annual mean number removal of Aitken size particles of near to 10%, but very small increases (near 1%) in the global mean below-cloud mass scavenging of carbonaceous and sulfate aerosols. Changes in the assumptions about the below-cloud scavenging by rain of particles with radius smaller than 10 nm do not cause any significant changes to the global and annual mean aerosol mass or number burdens, despite a change in the below-cloud number removal rate for nucleation mode particles by near to five-fold. Annual and zonal mean nucleation mode number concentrations are enhanced by up to 30% in the lower troposphere with the more vigourous size-dependent below-cloud scavenging. Closer agreement with different observations is found when the more physically detailed below-cloud scavenging parameterization is employed in the ECHAM5-HAM model

The spectrum of the recycled PSR J0437-4715 and its white dwarf companion

We present extensive spectral and photometric observations of the recycled pulsar/white-dwarf binary containing PSR J0437-4715, which we analyzed together with archival X-ray and gamma-ray data, to obtain the complete mid-infrared to gamma-ray spectrum. We first fit each part of the spectrum separately, and then the whole multi-wavelength spectrum. We find that the optical-infrared part of the spectrum is well fit by a cool white dwarf atmosphere model with pure hydrogen composition. The model atmosphere (Teff = 3950pm150K, log g=6.98pm0.15, R_WD=(1.9pm0.2)e9 cm) fits our spectral data remarkably well for the known mass and distance (M=0.25pm0.02Msun, d=156.3pm1.3pc), yielding the white dwarf age (tau=6.0pm0.5Gyr). In the UV, we find a spectral shape consistent with thermal emission from the bulk of the neutron star surface, with surface temperature between 1.25e5 and 3.5e5K. The temperature of the thermal spectrum suggests that some heating mechanism operates throughout the life of the neutron star. The temperature distribution on the neutron star surface is non-uniform. In the X-rays, we confirm the presence of a high-energy tail which is consistent with a continuation of the cut-off power-law component (Gamma=1.56pm0.01, Ecut=1.1pm0.2GeV) that is seen in gamma-rays and perhaps even extends to the near-UV.Comment: 23 pages. To appear in Ap

Geoarchäologische Untersuchungen zu Hausbefunden einer ältestlinienband-keramischen Siedlung bei Salbitz (Kreis Nordsachsen)

Bisher sind in Sachsen vier Siedlungen der als Älteste Linienbandkeramik bezeichneten frühesten Ackerbaukultur bekannt. Um die Erhaltung einer dieser Fundstellen in der Nähe des mittelsächsischen Dorfes Salbitz abschätzen zu können, führte das LfA Sachsen im Frühjahr 2011 die Ausgrabung eines kleinen Siedlungsausschnittes durch. Erfasst wurde bei der Ausgrabung der durch den Sandlöss bis in die saalezeitlichen Schmelzwassersande gegrabene östliche Außengraben eines Hauses samt begleitender flachgründiger Längsgrube. Die dort angeschnittenen Archäosedimente wurden geochemisch und mikromorphologisch untersucht. Die Arbeiten konzentrierten sich auf die holozäne Bodenentwicklung sowie die Funktion und die Verfüllungsgeschichte der angetroffenen Gruben. Die Untersuchungen deuten darauf hin, dass bereits im Frühholozän eine Parabraunerde entwickelt gewesen ist, die später der Erosion zum Opfer fiel. Der eventuell im konstruktiven Zusammenhang mit der Hauswand stehende Außengraben ist wie auch die zur Lehmentnahme für den Wandverputz angelegte Längsgrube mit schluffigem Material mit Bt-Resten verfüllt

Removal of hydrogen from Ti VT 1-0 under action of accelerated electrons

The process of hydrogen removal from titanium of VT1-0 grade under the action of accelerated electrons has been studied experimentally. The irradiation was carried out by an electron beam with energies of 25-40 keV during 15-60 min. The information on the hydrogen content in samples from titanium of VT1-0 grade has been obtained both before and after irradiation with accelerated electrons. The activation energy of hydrogen desorption from titanium has been calculated. It was found that the increase of the time and the energy of an irradiation lead to the decrease of the residual hydrogen content in the titanium samples

Ungulates rely less on visual cues, but more on adapting movement behaviour, when searching for forage

© 2017 The Author(s). This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. Venter et al. (2017), Ungulates rely less on visual cues, but more on adapting movement behaviour, when searching for forage. PeerJ 5:e3178; DOI 10.7717/peerj.3178.Finding suitable forage patches in a heterogeneous landscape, where patches change dynamically both spatially and temporally could be challenging to large herbivores, especially if they have no a priori knowledge of the location of the patches. We tested whether three large grazing herbivores with a variety of different traits improve their efficiency when foraging at a heterogeneous habitat patch scale by using visual cues to gain a priori knowledge about potential higher value foraging patches. For each species (zebra (Equus burchelli), red hartebeest (Alcelaphus buselaphus subspecies camaa) and eland (Tragelaphus oryx)), we used step lengths and directionality of movement to infer whether they were using visual cues to find suitable forage patches at a habitat patch scale. Step lengths were significantly longer for all species when moving to nonvisible patches than to visible patches, but all movements showed little directionality. Of the three species, zebra movements were the most directional. Red hartebeest had the shortest step lengths and zebra the longest. We conclude that these large grazing herbivores may not exclusively use visual cues when foraging at a habitat patch scale, but would rather adapt their movement behaviour, mainly step length, to the heterogeneity of the specific landscape.Peer reviewedFinal Published versio

A JWST Survey of the Supernova Remnant Cassiopeia A

We present initial results from a James Webb Space Telescope (JWST) survey of the youngest Galactic core-collapse supernova remnant, Cassiopeia A (Cas A), made up of NIRCam and MIRI imaging mosaics that map emission from the main shell, interior, and surrounding circumstellar/interstellar material (CSM/ISM). We also present four exploratory positions of MIRI Medium Resolution Spectrograph integral field unit spectroscopy that sample ejecta, CSM, and associated dust from representative shocked and unshocked regions. Surprising discoveries include (1) a weblike network of unshocked ejecta filaments resolved to ∼0.01 pc scales exhibiting an overall morphology consistent with turbulent mixing of cool, low-entropy matter from the progenitor’s oxygen layer with hot, high-entropy matter heated by neutrino interactions and radioactivity; (2) a thick sheet of dust-dominated emission from shocked CSM seen in projection toward the remnant’s interior pockmarked with small (∼1″) round holes formed by ≲0.″1 knots of high-velocity ejecta that have pierced through the CSM and driven expanding tangential shocks; and (3) dozens of light echoes with angular sizes between ∼0.″1 and 1′ reflecting previously unseen fine-scale structure in the ISM. NIRCam observations place new upper limits on infrared emission (≲20 nJy at 3 μm) from the neutron star in Cas A’s center and tightly constrain scenarios involving a possible fallback disk. These JWST survey data and initial findings help address unresolved questions about massive star explosions that have broad implications for the formation and evolution of stellar populations, the metal and dust enrichment of galaxies, and the origin of compact remnant objects

Дослідження місцезнаходжень культури лінійно-стрічкової кераміки на Волині

Українсько-німецько-польська експедиція проводила дослідження пам’яток культури лінійно-стрічкової кераміки на Волині в межах підготовки проекту їх планового вивчення