Discovery and Cosmological Implications of SPT-CL J2106-5844, the Most Massive Known Cluster at z>1

Using the South Pole Telescope (SPT), we have discovered the most massive known galaxy cluster at z>1, SPT-CL J2106-5844. In addition to producing a strong Sunyaev-Zel'dovich (SZ) effect signal, this system is a luminous X-ray source and its numerous constituent galaxies display spatial and color clustering, all indicating the presence of a massive galaxy cluster. Very Large Telescope and Magellan spectroscopy of 18 member galaxies shows that the cluster is at z = 1.132^(+0.002)_(–0.003). Chandra observations obtained through a combined HRC-ACIS GTO program reveal an X-ray spectrum with an Fe K line redshifted by z = 1.18 ± 0.03. These redshifts are consistent with the galaxy colors found in optical, near-infrared, and mid-infrared imaging. SPT-CL J2106-5844 displays extreme X-ray properties for a cluster having a core-excluded temperature of T_X = 11.0^(+2.6)_(–1.9) keV and a luminosity (within r _(500)) of LX (0.5-2.0 keV) = (13.9 ± 1.0) × 10_(44) erg s^(–1). The combined mass estimate from measurements of the SZ effect and X-ray data is M_(200) = (1.27 ± 0.21) × 10^(15) h ^(–1) _(70) M_⊙. The discovery of such a massive gravitationally collapsed system at high redshift provides an interesting laboratory for galaxy formation and evolution, and is a probe of extreme perturbations of the primordial matter density field. We discuss the latter, determining that, under the assumption of ΛCDM cosmology with only Gaussian perturbations, there is only a 7% chance of finding a galaxy cluster similar to SPT-CL J2106-5844 in the 2500 deg^2 SPT survey region and that only one such galaxy cluster is expected in the entire sky

Investigation of Electrochemistry of High Energy Compounds in Organic Electrolytes. Bibliography on Propylene Carbonate, Gamma- Butyrolactone, and Related Subjects Supplement to Third Progress Report

Bibliography on electrochemistry of high energy compounds in organic electrolyte

Efficient data representation for XML in peer-based systems

Purpose - New directions in the provision of end-user computing experiences mean that the best way to share data between small mobile computing devices needs to be determined. Partitioning large structures so that they can be shared efficiently provides a basis for data-intensive applications on such platforms. The partitioned structure can be compressed using dictionary-based approaches and then directly queried without firstly decompressing the whole structure. Design/methodology/approach - The paper describes an architecture for partitioning XML into structural and dictionary elements and the subsequent manipulation of the dictionary elements to make the best use of available space. Findings - The results indicate that considerable savings are available by removing duplicate dictionaries. The paper also identifies the most effective strategy for defining dictionary scope. Research limitations/implications - This evaluation is based on a range of benchmark XML structures and the approach to minimising dictionary size shows benefit in the majority of these. Where structures are small and regular, the benefits of efficient dictionary representation are lost. The authors' future research now focuses on heuristics for further partitioning of structural elements. Practical implications - Mobile applications that need access to large data collections will benefit from the findings of this research. Traditional client/server architectures are not suited to dealing with high volume demands from a multitude of small mobile devices. Peer data sharing provides a more scalable solution and the experiments that the paper describes demonstrate the most effective way of sharing data in this context. Social implications - Many services are available via smartphone devices but users are wary of exploiting the full potential because of the need to conserve battery power. The approach mitigates this challenge and consequently expands the potential for users to benefit from mobile information systems. This will have impact in areas such as advertising, entertainment and education but will depend on the acceptability of file sharing being extended from the desktop to the mobile environment. Originality/value - The original work characterises the most effective way of sharing large data sets between small mobile devices. This will save battery power on devices such as smartphones, thus providing benefits to users of such devices

Swift UVOT Grism Observations of Nearby Type Ia Supernovae - I. Observations and Data Reduction

Ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) are useful tools for understanding progenitor systems and explosion physics. In particular, UV spectra of SNe Ia, which probe the outermost layers, are strongly affected by the progenitor metallicity. In this work, we present 120 Neil Gehrels Swift Observatory UV spectra of 39 nearby SNe Ia. This sample is the largest UV (lambda < 2900 A) spectroscopic sample of SNe Ia to date, doubling the number of UV spectra and tripling the number of SNe with UV spectra. The sample spans nearly the full range of SN Ia light-curve shapes (delta m(B) ~ 0.6-1.8 mag). The fast turnaround of Swift allows us to obtain UV spectra at very early times, with 13 out of 39 SNe having their first spectra observed >~ 1 week before peak brightness and the earliest epoch being 16.5 days before peak brightness. The slitless design of the Swift UV grism complicates the data reduction, which requires separating SN light from underlying host-galaxy light and occasional overlapping stellar light. We present a new data-reduction procedure to mitigate these issues, producing spectra that are significantly improved over those of standard methods. For a subset of the spectra we have nearly simultaneous Hubble Space Telescope UV spectra; the Swift spectra are consistent with these comparison data.Comment: Accepted for publication in MNRA

Investigation of electrochemistry of high energy compounds in organic electrolytes, november 1, 1964 - april 30, 1965

Conversion by electrochemical process of chemical to electrical energy - high energy compounds in organic electrolytes and cathode material

No X-rays from the very nearby Type Ia SN2014J: constraints on its environment

Deep X-ray observations of the post-explosion environment around the very nearby Type Ia SN\,2014J (Dl=3.5 Mpc) reveal no X-ray emission down to a luminosity L<7x10^{36} erg/s (0.3-10 keV) at t~20 days after the explosion. We interpret this limit in the context of Inverse Compton emission from upscattered optical photons by the supernova shock and constrain the pre-explosion mass-loss rate of the stellar progenitor system to be <10^{-9} M_sun yr-1 (for wind velocity v_w=100 km/s). Alternatively, the SN shock might be expanding into a uniform medium with density $n_CSM<3 cm-3. These results rule out single-degenerate (SD) systems with steady mass-loss until the terminal explosion and constrain the fraction of transferred material lost at the outer Lagrangian point to be <1%. The allowed progenitors are (i) WD-WD progenitors, (ii) SD systems with unstable hydrogen burning experiencing recurrent nova eruptions with recurrence time t<300 yrs and (iii) stars where the mass loss ceases before the explosion.Comment: 9 pages, Submitted to Ap

CDS wide slit time-series of EUV coronal bright points

Wide slit (90" x 240" ) movies of four Extreme Ultraviolet coronal bright points (BPs) obtained with the Coronal Diagnostic Spectrometer (CDS) on board the Solar and Heliospheric Observatory (SoHO) have been inspected. The wavelet analysis of the He I 584.34 Å, O V 629.73 Å and Mg VII/IX 368 Å time-series confirms the oscillating nature of the BPs, with periods ranging between 600 and 1100 s. In one case we detect periods as short as 236 s. We suggest that these oscillations are the same as those seen in the chromospheric network and that a fraction of the network bright points are most likely the cool footpoints of the loops comprising coronal bright points. These oscillations are interpreted in terms of global acoustic modes of the closed magnetic structures associated with BPs

Rotational Dynamics of Organic Cations in CH3NH3PbI3 Perovskite

Methylammonium lead iodide (CH3NH3PbI3) based solar cells have shown impressive power conversion efficiencies of above 20%. However, the microscopic mechanism of the high photovoltaic performance is yet to be fully understood. Particularly, the dynamics of CH3NH3+ cations and their impact on relevant processes such as charge recombination and exciton dissociation are still poorly understood. Here, using elastic and quasi-elastic neutron scattering techniques and group theoretical analysis, we studied rotational modes of the CH3NH3+ cation in CH3NH3PbI3. Our results show that, in the cubic (T > 327K) and tetragonal (165K < T < 327K) phases, the CH3NH3+ ions exhibit four-fold rotational symmetry of the C-N axis (C4) along with three-fold rotation around the C-N axis (C3), while in orthorhombic phase (T < 165K) only C3 rotation is present. Around room temperature, the characteristic relaxation times for the C4 rotation is found to be ps while for the C3 rotation ps. The -dependent rotational relaxation times were fitted with Arrhenius equations to obtain activation energies. Our data show a close correlation between the C4 rotational mode and the temperature dependent dielectric permittivity. Our findings on the rotational dynamics of CH3NH3+ and the associated dipole have important implications on understanding the low exciton binding energy and slow charge recombination rate in CH3NH3PbI3 which are directly relevant for the high solar cell performance

NALNET book system: Cost benefit study

The goals of the NASA's library network system, NALNET, the functions of the current book system, the products and services of a book system required by NASA Center libraries, and the characteristics of a system that would best supply those products and services were assessed. Emphasis was placed on determining the most cost effective means of meeting NASA's requirements for an automated book system. Various operating modes were examined including the current STIMS file, the PUBFILE, developing software improvements for products as appropriate to the Center needs, and obtaining cataloging and products from the bibliographic utilities including at least OCLC, RLIN, BNA, and STIF. It is recommended that NALNET operate under the STIMS file mode and obtain cataloging and products from the bibliographic utilities. The recommendations are based on the premise that given the current state of the art in library automation it is not cost effective for NASA to maintain a full range of cataloging services on its own system. The bibliographic utilities can support higher quality systems with a greater range of services at a lower total cost