High-resolution X-ray Spectra Of The Symbiotic Star SS73 17

SS73 17 was an innocuous Mira-type symbiotic star until Integral and Swift discovered its bright hard X-ray emission, adding it to the small class of "hard X-ray emitting symbiotics." Suzaku observations in 2006 then showed it emits three bright iron lines as well, with little to no emission in the 0.3-2 keV bandpass. We present here followup observations with the Chandra HETG and Suzaku that confirm the earlier detection of strong emission lines of Fe Kalpha fluorescence, Fe XXV and Fe XXVI but also show significantly more soft X-ray emission. The high resolution spectrum also shows emission lines of other highly ionized ions as Si XIV and possibly S XVI. In addition, a reanalysis of the 2006 Suzaku data using the latest calibration shows that the hard (15-50 keV) X-ray emission is brighter than previously thought and remains constant in both the 2006 and 2008 data. The G ratio calculated from the Fe XXV lines shows that these lines are thermal, not photoionized, in origin. With the exception of the hard X-ray emission, the spectra from both epochs can be fit using thermal radiation assuming a differential emission measure based on a cooling flow model combined with a full and partial absorber. We show that acceptable fits can be obtained for all the data in the 1-10 keV band varying only the partial absorber. Based on the temperature and accretion rate, the thermal emission appears to be arising from the boundary layer between the accreting white dwarf and the accretion disk.Comment: 7 pages, 5 figures. Accepted by the Astrophysical Journa

MP3 - A meteorology and physical properties package to explore air-sea interaction on Titan

The exchange of mass, heat and momentum at the air:sea interface are profound influences on the terrestrial environment, affecting the intensity of hurricanes, the size of waves and lake-effect precipitation. Titan presents us with an opportunity to study these processes in a novel physical context, with a different sea, atmosphere and gravity. The MP3 instrument, under development for the proposed Discovery mission TiME (Titan Mare Explorer [1,2]) is an integrated suite of small, simple sensors that combines the function of traditional meteorology packages with liquid physical properties and depth-sounding : these latter functions follow the concept of - and indeed use spare elements from - the Huygens Surface Science Package (SSP,[3]). However, unlike Huygens’ brief and dynamic 3 hours of measurement, in TiME’s 6-Titan-day (96 Earth day) nominal mission enabled by radioisotope power, MP3 will have an unprecedented long-term measurement opportunity in one of the most evocative environments in the solar system, Titan’s sea Ligeia Mare

Granularity of the Diffuse Background Observed

First results are reported from a program for measuring the field-to-field fluctuation level of the cosmic diffuse background by using differences between the two background positions of each deep exposure with the High Energy X-ray Timing Experiment (HEXTE) instrument on the Remote X Ray Timing Explorer (RXTE). With 8 million live seconds accumulated to date a fluctuation level on the 15-25 keV band is observed which is consistent with extrapolations from the High Energy Astrophysical Observatory-1 (HEAO-1) measurements. Positive results are expected eventually at higher energies. Models of (active galactic nuclei) AGN origin will eventually be constrained by this program

Nearby quasar remnants and ultra-high energy cosmic rays

As recently suggested, nearby quasar remnants are plausible sites of black-hole based compact dynamos that could be capable of accelerating ultra-high energy cosmic rays (UHECRs). In such a model, UHECRs would originate at the nuclei of nearby dead quasars, those in which the putative underlying supermassive black holes are suitably spun-up. Based on galactic optical luminosity, morphological type, and redshift, we have compiled a small sample of nearby objects selected to be highly luminous, bulge-dominated galaxies, likely quasar remnants. The sky coordinates of these galaxies were then correlated with the arrival directions of cosmic rays detected at energies $> 40$ EeV. An apparently significant correlation appears in our data. This correlation appears at closer angular scales than those expected when taking into account the deflection caused by typically assumed IGM or galactic magnetic fields over a charged particle trajectory. Possible scenarios producing this effect are discussed, as is the astrophysics of the quasar remnant candidates. We suggest that quasar remnants be also taken into account in the forthcoming detailed search for correlations using data from the Auger Observatory.Comment: 2 figures, 4 tables, 11 pages. Final version to appear in Physical Review

The Carnegie Supernova Project I: photometry data release of low-redshift stripped-envelope supernovae

The first phase of the Carnegie Supernova Project (CSP-I) was a dedicated supernova follow-up program based at the Las Campanas Observatory that collected science data of young, low-redshift supernovae between 2004 and 2009. Presented in this paper is the CSP-I photometric data release of low-redshift stripped-envelope core-collapse supernovae. The data consist of optical (uBgVri) photometry of 34 objects, with a subset of 26 having near-infrared (YJH) photometry. Twenty objects have optical pre-maximum coverage with a subset of 12 beginning at least five days prior to the epoch of B-band maximum brightness. In the near-infrared, 17 objects have pre-maximum observations with a subset of 14 beginning at least five days prior to the epoch of J-band maximum brightness. Analysis of this photometric data release is presented in companion papers focusing on techniques to estimate host-galaxy extinction (Stritzinger et al., submitted) and the light-curve and progenitor star properties of the sample (Taddia et al., submitted). The analysis of an accompanying visual-wavelength spectroscopy sample of ~150 spectra will be the subject of a future paper.Comment: Updated a couple of small error

Playing God? Synthetic biology as a theological and ethical challenge

In the ethical debate over synthetic biology the formula “playing god” is widely used in order to attack this new branch of biotechnology. The article analyses, contextualizes and criticises this usage with respect to the theological concepts of creation, sin and humans as created in the image of God. Against the background of these theological understandings an ethical corridor of how to responsibly cope with the societal challenges of synthetic biology is presented

Small-Scale Fluctuations in Cosmic X-ray Background : A Power Spectrum Approach

Equations to investigate fluctuations in cosmic X-ray background radiation due to point-like sources at high-redshift are formulated in a systematic way. The angular power spectrum of X-ray background fluctuations is investigated from large-scales to small-scales in various cosmological models such as open universe models and models with the cosmological constant, assuming a simple evolution model of the sources. The effect of epoch-dependent bias is demonstrated for small-angle fluctuations. The contribution from shot noise fluctuations is also discussed.Comment: 12 pages, 4 figures, Phys.Rev.D in pres

Suzaku and SWIFT-BAT observations of a newly discovered Compton-thick AGN

Obscured AGN are fundamental to understand the history of Super Massive Black Hole growth and their influence on galaxy formation. However, the Compton-thick AGN (NH>1e24 cm^-2) population is basically unconstrained, with less than few dozen confirmed Compton-thick AGN found and studied so far. A way to select heavily obscured AGN is to compare the X-ray emission below 10 keV (which is strongly depressed) with the emission from other bands less affected by the absorption, i.e. the IR band. To this end, we have cross-correlated the 2XMM catalogue with the IRAS Point Source catalogue and, by using the X-ray to infrared flux ratio and X-ray colors, we selected a well defined sample of Compton-thick AGN candidates at z<0.1. The aim of this work is to confirm the nature and to study one of these local Compton-thick AGN candidates, the nearby (z=0.029) Seyfert 2 galaxy IRAS 04507+0358, by constraining the amount of intrinsic absorption (NH) and thus the intrinsic luminosity. To this end we obtained deep (100 ks) Suzaku observations (AO4 call) and performed a joint fit with SWIFT-BAT data. We analyzed XMM-Newton, Suzaku and SWIFT-BAT data and we present here the results of this broad-band (0.4-100 keV) spectral analysis. We found that the broad-band X-ray emission of IRAS 04507+0358 requires a large amount of absorption (larger than 1e24 cm^-2) to be well reproduced, thus confirming the Compton-thick nature of this source. In particular, the most probable scenario is that of a mildly (NH (1.3-1.5)x1e24 cm^-2, L(2-10 keV) (5-7)x1e43 erg s^-1) Compton-thick AGN.Comment: Accepted for publication in A&A; 8 pages, 7 figure

The Insulin-Like Growth Factor System in the Long-Lived Naked Mole-Rat.

Naked mole-rats (Heterocephalus glaber) (NMRs) are the longest living rodents known. They show negligible senescence, and are resistant to cancers and certain damaging effects associated with aging. The insulin-like growth factors (IGFs) have pluripotent actions, influencing growth processes in virtually every system of the body. They are established contributors to the aging process, confirmed by the demonstration that decreased IGF signaling results in life-extending effects in a variety of species. The IGFs are likewise involved in progression of cancers by mediating survival signals in malignant cells. This report presents a full characterization of the IGF system in the NMR: ligands, receptors, IGF binding proteins (IGFBPs), and IGFBP proteases. A particular emphasis was placed on the IGFBP protease, pregnancy-associated plasma protein-A (PAPP-A), shown to be an important lifespan modulator in mice. Comparisons of IGF-related genes in the NMR with human and murine sequences indicated no major differences in essential parts of the IGF system, including PAPP-A. The protease was shown to possess an intact active site despite the report of a contradictory genome sequence. Furthermore, PAPP-A was expressed and translated in NMRs cells and retained IGF-dependent proteolytic activity towards IGFBP-4 and IGF-independent activity towards IGFBP-5. However, experimental data suggest differential regulatory mechanisms for PAPP-A expression in NMRs than those described in humans and mice. This overall description of the IGF system in the NMR represents an initial step towards elucidating the complex molecular mechanisms underlying longevity, and how these animals have evolved to ensure a delayed and healthy aging process