The XMM-Newton slew survey in the 2-10 keV band

The XMM-Newton Slew Survey (XSS) covers a significant fraction of the sky in a broad X-ray bandpass. Although shallow by contemporary standards, in the `classical' 2-10 keV band of X-ray astronomy, the XSS provides significantly better sensitivity than any currently available all-sky survey. We investigate the source content of the XSS, focussing on detections in the 2-10 keV band down to a very low threshold (> 4 counts net of background). At the faint end, the survey reaches a flux sensitivity of roughly 3e-12 erg/cm2/s (2-10 keV). Our starting point was a sample of 487 sources detected in the XMMSL1d2 XSS at high galactic latitude in the hard band. Through cross-correlation with published source catalogues from surveys spanning the electromagnetic spectrum from radio to gamma-rays, we find that 45% of the sources have likely identifications with normal/active galaxies, 18% are associated with other classes of X-ray object (nearby coronally active stars, accreting binaries, clusters of galaxies), leaving 37% of the XSS sources with no current identification. We go on to define an XSS extragalactic hard band sample comprised of 219 galaxies and active galaxies. We investigate the properties of this extragalactic sample including its X-ray logN-logS distribution. We find that in the low-count limit, the XSS is strongly affected by Eddington bias. There is also a very strong bias in the XSS against the detection of extended sources, most notably clusters of galaxies. A significant fraction of the detections at and around the low-count limit may be spurious. Nevertheless, it is possible to use the XSS to extract a reasonably robust sample of extragalactic sources, excluding galaxy clusters. The differential logN-logS relation of these extragalactic sources matches very well to the HEAO-1 A2 all-sky survey measurements at bright fluxes and to the 2XMM source counts at the faint end.Comment: 16 pages, 13 figures, FITS table of XSS extragalactic sample available from http://www.star.le.ac.uk/~amr30/Slew

American Recovery and Reinvestment Act (ARRA) FEMP Technical Assistance U.S. Army Project 181 Implementation Challenges in Deployment of an Energy Security Microgrid for Army Reserve Facilities located on the Former Fort Devens Army Base

This documents reports on a request for technical assistance from Fort Devens to analyze procurement of energy from nearby renewable generating resources

Analysis of Hanford-based Options for Sustainable DOE Facilities on the West Coast

Large-scale conventional energy projects result in lower costs of energy (COE). This is true for most renewable energy projects as well. The Office of Science is interested in its facilities meeting the renewable energy mandates set by Congress and the Administration. Those facilities on the west coast include a cluster in the Bay Area of California and at Hanford in central Washington State. Land constraints at the California facilities do not permit large scale projects. The Hanford Reservation has land and solar insolation available for a large scale solar project as well as access to a regional transmission system that can provide power to facilities in California. The premise of this study is that a large-scale solar project at Hanford may be able to provide renewable energy sufficient to meet the needs of select Office of Science facilities on the west coast at a COE that is competitive with costs in California despite the lower solar insolation values at Hanford. The study concludes that although the cost of solar projects continues to decline, estimated costs for a large-scale project at Hanford are still not competitive with avoided power costs for Office of Science facilities on the west coast. Further, although it is possible to transmit power from a solar project at Hanford to California facilities, the costs of doing so add additional costs. Consequently, development of a large- scale solar project at Hanford to meet the renewable goals of Office of Science facilities on the west coast is currently uneconomic. This may change as solar costs decrease and California-based facilities face increasing costs for conventional and renewable energy produced in the state. PNNL should monitor those cost trends

The XMM-Newton Slew Survey: Towards The Whole X-ray Sky and the Rarest X-ray Events

The data collected by XMM-Newton as it slews between pointings currently cover almost half the entire sky, and many familiar features and new sources are visible. The soft-band sensitivity limit of the Slew is close to that of the RASS, and a large-area Slew-RASS comparison now provides the best opportunity for discovering extremely rare high-variability objects.Comment: To appear in Proceedings of "X-ray Astronomy 2009: Present Status, Multi-Wavelength Approach and Future Perspectives", Bologna, Italy, September 7-11, 2009, AIP, eds. A. Comastri, M. Cappi, and L. Angelin

A complete sample of Seyfert galaxies selected at 1/4 keV

We have used the ROSAT Bright Source Catalogue to extract a complete sample of sources selected in the band from 0.1-0.4 keV. This 1/4 keV-selected sample is comprised of 54 Seyfert galaxies, 25 BL Lacertae objects, 4 clusters and 27 Galactic stars or binaries. Seyfert-type galaxies with ``ultrasoft'' X-ray spectra can very often be classed optically as Narrow-line Seyfert 1s (NLS1s). Such objects are readily detected in 1/4 keV surveys; the sample reported here contains 20 NLS1s, corresponding to a 40% fraction of the Seyferts. Optical spectra of the Seyfert galaxies were gathered for correlative analysis, which confirmed the well-known relations between X-ray slope and optical spectral properties (e.g., [O III]/H-beta ratio; Fe II strength, H-beta width). The various intercorrelations are most likely driven, fundamentally, by the shape of the photoionising continuum in Seyfert nuclei. We argue that a steep X-ray spectrum is a better indicator of an ``extreme'' set of physical properties in Seyfert galaxies than is the narrowness of the optical H-beta line. (Abridged)Comment: 17 pages, 4 figures, accepted for publication in MNRA

Building health: an epidemiological study of "sick building syndrome" in the Whitehall II study

Objectives: Sick building syndrome (SBS) is described as a group of symptoms attributed to the physical environment of specific buildings. Isolating particular environmental features responsible for the symptoms has proved difficult. This study explores the role and significance of the physical and psychosocial work environment in explaining SBS. Methods: Cross sectional data on the physical environment of a selection of buildings were added to individual data from the Whitehall II study—an ongoing health survey of office based civil servants. A self-report questionnaire was used to capture 10 symptoms of the SBS and psychosocial work stress. In total, 4052 participants aged 42–62 years working in 44 buildings were included in this study. Results: No significant relation was found between most aspects of the physical work environment and symptom prevalence, adjusted for age, sex, and employment grade. Positive (non-significant) relations were found only with airborne bacteria, inhalable dust, dry bulb temperature, relative humidity, and having some control over the local physical environment. Greater effects were found with features of the psychosocial work environment including high job demands and low support. Only psychosocial work characteristics and control over the physical environment were independently associated with symptoms in the multivariate analysis. Conclusions: The physical environment of office buildings appears to be less important than features of the psychosocial work environment in explaining differences in the prevalence of symptoms