Development of a nickel cadmium storage cell immune to damage from overdischarge and overcharge

Nickel-cadmium battery immune to damage from overcharge and overdischarg

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

The XMM-Newton Slew Survey

XMM-Newton, with the huge collecting area of its mirrors and the high quantum efficiency of its EPIC detectors, is the most sensitive X-ray observatory ever flown. This is strikingly evident during slew exposures, which, while yielding only at most 14 seconds of on-source exposure time, actually constitute a 2-10 keV survey ten times deeper than all other "all-sky" surveys. The current (April 2005) XMM archive contains 374 slew exposures which give a uniform coverage over around 10,000 square degrees (approx. 25% of the sky). Here we describe the results of pilot studies, the current status of the XMM-Newton Slew Survey, up-to-date results and our progress towards constructing a catalogue of slew detections in the full 0.2-12 keV energy band.Comment: 3 pages, 4 figures, XMM-Newton EPIC Consortium Meeting, Schloss Ringberg, Germany, April 2005, to appear in MPE Repor

The X-ray properties of the merging galaxy pair NGC 4038/9 - the Antennae

We report the results of an X-ray spectral imaging observation of the Antennae with the ROSAT PSPC. 55% of the soft X-ray flux from the system is resolved into discrete sources, including components identified with the galactic nuclei and large HII regions, whilst the remainder appears to be predominantly genuinely diffuse emission from gas at a temperature ~4x10^6 K. The morphology of the emission is unusual, combining a halo which envelopes the galactic discs, with what appears to be a distorted, but well-collimated bipolar outflow. We derive physical parameters for the hot gas in both diffuse components, which are of some interest, given that the Antennae probably represents an elliptical galaxy in the making.Comment: 15 pages plus 9 figures, uuencoded encapsulated postscript file. Accepted for publication in MNRA

The XMM-Newton Slew Survey: towards the XMMSL1 catalogue

The XMM-Newton satellite is the most sensitive X-ray observatory flown to date due to the great collecting area of its mirrors coupled with the high quantum efficiency of the EPIC detectors. It performs slewing manoeuvers between observation targets tracking almost circular orbits through the ecliptic poles due to the Sun constraint. Slews are made with the EPIC cameras open and the other instruments closed, operating with the observing mode set to the one of the previous pointed observation and the medium filter in place. Slew observations from the EPIC-pn camera in FF, eFF and LW modes provide data, resulting in a maximum of 15 seconds of on-source time. These data can be used to give a uniform survey of the X-ray sky, at great sensitivity in the hard band compared with other X-ray all-sky surveys.Comment: 2 pages, 2 figures, to appear in the proceedings of "The X-ray Universe 2005", San Lorenzo de El Escorial (Spain), 26-30 September 200

Report on a collecting trip of the British Myriapod Group to Hungary in 1994

During a collecting trip participated jointly by the members of the British Myriapod Group and by Hungarian experts in 1994, 34 species of millipedes, 14 of centipedes, 8 of woodlice and 73 of spiders were recorded from Hungary. Two records of the millipede species Boreoiulus tenuis (Bigler, 1913) and Styrioiulus styricus (Verhoeff, 1896) were new to the fauna of Hungary

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

Extended sources in the XMM-Newton slew survey

The low background, good spatial resolution and great sensitivity of the EPIC-pn camera on XMM-Newton give useful limits for the detection of extended sources even during the short exposures made during slewing maneouvers. In this paper we attempt to illustrate the potential of the XMM-Newton slew survey as a tool for analysing flux-limited samples of clusters of galaxies and other sources of spatially extended X-ray emission.Comment: 2 pages, 4 figures, to appear in the proceedings of "The X-ray Universe 2005", San Lorenzo de El Escorial (Spain), 26-30 September 200

Probing the Upper Scorpius mass function in the planetary-mass regime

We present the results of a deep ZYJ near-infrared survey of 13.5 square degrees in the Upper Scorpius (USco) OB association. We photometrically selected ~100 cluster member candidates with masses in the range 30-5 Jupiters, according to state-of-the-art evolutionary models. We identified 67 ZYJ candidates as bona-fide members, based on complementary photometry and astrometry. We also extracted five candidates detected with VISTA at YJ-only. One is excluded using deep optical z-band imaging, while two are likely non-members, and three remain as potential members. We conclude that the USco mass function is more likely decreasing in the planetary-mass regime (although a flat mass function cannot yet be discarded), consistent with surveys in other regions.Comment: Accepted by MNRAS, 10 pages, 4 figures, 4 tables (2 electronic tables). New version with updated figure3 where the (Z-J,Z) colour-magnitude diagram is include