Solar plasma experiment

Solar plasma experiment by Mariner IV space prob

Manor Farm Barn, Kingston Deverill, Wiltshire; tree-ring analysis of timbers

Dendrochronological analysis was undertaken on 16 samples from the barn at Manor Farm. This resulted in the production of two site sequences, KDMBSQ01 and KDMBSQ02. The former comprises eight samples with an overall length of 150 rings and the latter two samples with an overall length of 81 rings. Site sequence KDMBSQ01 is dated as spanning the years AD 1260–1409. Site sequence KDMBSQ02 is undated. A single sample, KDM-B09, with an overall length of 113 rings is dated as spanning the years AD 1371–1483. Five samples remain ungrouped and undated. The results indicate that the timbers used in the primary construction of the barn were probably all felled in the last few years of the first decade of the fifteenth century. A single dated arcade post from the southernmost truss indicates that the building underwent repairs or modifications just under a century later, in the last few years of the fifteenth century or, the first few years of the sixteenth century

HerMES: The Rest-Frame UV Emission and A Lensing Model for the z=6.34 Luminous Dusty Starburst Galaxy HFLS3

We discuss the rest-frame ultraviolet emission from the starbursting galaxy HFLS3 at a redshift of 6.34. The galaxy was discovered in Herschel/SPIRE data due to its red color in the submillimeter wavelengths from 250 to 500 μm. Keck/NIRC2 K s -band adaptive optics imaging data showed two potential near-IR counterparts near HFLS3. Previously, the northern galaxy was taken to be in the foreground at z = 2.1, while the southern galaxy was assumed to be HFLS3's near-IR counterpart. The recently acquired Hubble/WFC3 and Advanced Camera for Surveys (ACS) imaging data show conclusively that both optically bright galaxies are in the foreground at z < 6. A new lensing model based on the Hubble imaging data and the millimeter-wave continuum emission yields a magnification factor of 2.2 ± 0.3, with a 95% confidence upper limit on the magnification of 3.5. When corrected for lensing, the instantaneous star formation rate is 1320 M_☉ yr^(–1), with the 95% confidence lower limit around 830 M_☉ yr^(–1). The dust and stellar masses of HFLS3 from the same spectral energy distribution (SED) models are at the level of 3 × 10^8 M_☉ and ~5 × 10^(10) M_☉, respectively, with large systematic uncertainties on assumptions related to the SED model. With Hubble/WFC3 images, we also find diffuse near-IR emission about 0.5 arcsec (~3 kpc) to the southwest of HFLS3 that remains undetected in the ACS imaging data. The emission has a photometric redshift consistent with either z ~ 6 or a dusty galaxy template at z ~ 2

Survey of the plasma electron environment of Jupiter: A view from Voyager

The plasma environment within Jupiter's bow shock is considered in terms of the in situ, calibrated electron plasma measurements made between 10 eV and 5.95 keV by the Voyager plasma science experiment (PLS). Measurements were analyzed and corrected for spacecraft potential variations; the data were reduced to nearly model independent macroscopic parameters of the local electron density and temperature. It is tentatively concluded that the radial temperature profile within the plasma sheet is caused by the intermixing of two different electron populations that probably have different temporal histories and spatial paths to their local observation. The cool plasma source of the plasma sheet and spikes is probably the Io plasma torus and arrives in the plasma sheet as a result of flux tube interchange motions or other generalized transport which can be accomplished without diverting the plasma from the centrifugal equator. The hot suprathermal populations in the plasma sheet have most recently come from the sparse, hot mid-latitude "bath" of electrons which were directly observed juxtaposed to the plasma sheet

Wick Farm Cottage, Heddington Wick Common, Heddington, Wiltshire: tree-ring analysis of timbers

Dendrochronological analysis was undertaken on all seven of the timbers sampled from two medieval phases at Wick Farm Cottage. This resulted in the production of two site chronologies, HWWFSQ01 and HWWFSQ02. These comprise three and two samples with overall lengths of 178 years and 67 years respectively. The first site chronology dates to AD 1158–1335, whilst the second chronology is undated. The dated samples, thought to be associated with the earliest medieval phase, indicate a programme of felling, and hence likely construction, in the mid-AD 1330s

Temperature determination via STJ optical spectroscopy

ESA's Superconducting Tunnel Junction (STJ) optical photon-counting camera (S-Cam2) incorporates an array of pixels with intrinsic energy sensitivity. Using the spectral fitting technique common in X-ray astronomy, we fit black bodies to nine stellar spectra, ranging from cool flare stars to hot white dwarfs. The measured temperatures are consistent with literature values at the expected level of accuracy based on the predicted gain stability of the instrument. Having also demonstrated that systematic effects due to count rate are likely to be small, we then proceed to apply the temperature determination method to four cataclysmic variable (CV) binary systems. In three cases we measure the temperature of the accretion stream, while in the fourth we measure the temperature of the white dwarf. The results are discussed in the context of existing CV results. We conclude by outlining the prospects for future versions of S-Cam.Comment: 9 pages, 9 figures (11 files); uses aa.cls; accepted for publication in A&

The Herschel Lensing Survey (HLS): Overview

The Herschel Lensing Survey (HLS) will conduct deep PACS and SPIRE imaging of ∼40 massive clusters of galaxies. The strong gravitational lensing power of these clusters will enable us to penetrate through the confusion noise, which sets the ultimate limit on our ability to probe the Universe with Herschel. Here we present an overview of our survey and a summary of the major results from our science demonstration phase (SDP) observations of the Bullet cluster (z = 0.297). The SDP data are rich and allow us to study not only the background high-redshift galaxies (e.g., strongly lensed and distorted galaxies at z = 2.8 and 3.2) but also the properties of cluster-member galaxies. Our preliminary analysis shows a great diversity of far-infrared/submillimeter spectral energy distributions (SEDs), indicating that we have much to learn with Herschel about the properties of galaxy SEDs. We have also detected the Sunyaev-Zel’dovich (SZ) effect increment with the SPIRE data. The success of this SDP program demonstrates the great potential of the Herschel Lensing Survey to produce exciting results in a variety of science areas

Variability of the Accretion Stream in the Eclipsing Polar EP Dra

We present the first high time resolution light curves for six eclipses of the magnetic cataclysmic variable EP Dra, taken using the superconducting tunnel junction imager S-Cam2. The system shows a varying eclipse profile between consecutive eclipses over the two nights of observation. We attribute the variable stream eclipse after accretion region ingress to a variation in the amount and location of bright material in the accretion stream. This material creates an accretion curtain as it is threaded by many field lines along the accretion stream trajectory. We identify this as the cause of absorption evident in the light curves when the system is in a high accretion state. We do not see direct evidence in the light curves for an accretion spot on the white dwarf; however, the variation of the stream brightness with the brightness of the rapid decline in flux at eclipse ingress indicates the presence of some form of accretion region. This accretion region is most likely located at high colatitude on the white dwarf surface, forming an arc shape at the foot points of the many field lines channeling the accretion curtain.Comment: Accepted for publication in MNRAS (7 pages