The Interplanetary Network Supplement to the BeppoSAX Gamma-Ray Burst Catalogs

Between 1996 July and 2002 April, one or more spacecraft of the interplanetary network detected 787 cosmic gamma-ray bursts that were also detected by the Gamma-Ray Burst Monitor and/or Wide-Field X-Ray Camera experiments aboard the BeppoSAX spacecraft. During this period, the network consisted of up to six spacecraft, and using triangulation, the localizations of 475 bursts were obtained. We present the localization data for these events.Comment: 89 pages, 3 figures. Submitted to the Astrophysical Journal Supplement Serie

IPN localizations of Konus short gamma-ray bursts

Between the launch of the \textit{GGS Wind} spacecraft in 1994 November and the end of 2010, the Konus-\textit{Wind} experiment detected 296 short-duration gamma-ray bursts (including 23 bursts which can be classified as short bursts with extended emission). During this period, the IPN consisted of up to eleven spacecraft, and using triangulation, the localizations of 271 bursts were obtained. We present the most comprehensive IPN localization data on these events. The short burst detection rate, $\sim$18 per year, exceeds that of many individual experiments.Comment: Published versio

An exceptionally bright flare from SGR1806-20 and the origins of short-duration gamma-ray bursts

Soft-gamma-ray repeaters (SGRs) are galactic X-ray stars that emit numerous short-duration (about 0.1 s) bursts of hard X-rays during sporadic active periods. They are thought to be magnetars: strongly magnetized neutron stars with emissions powered by the dissipation of magnetic energy. Here we report the detection of a long (380 s) giant flare from SGR 1806-20, which was much more luminous than any previous transient event observed in our Galaxy. (In the first 0.2 s, the flare released as much energy as the Sun radiates in a quarter of a million years.) Its power can be explained by a catastrophic instability involving global crust failure and magnetic reconnection on a magnetar, with possible large-scale untwisting of magnetic field lines outside the star. From a great distance this event would appear to be a short-duration, hard-spectrum cosmic gamma-ray burst. At least a significant fraction of the mysterious short-duration gamma-ray bursts therefore may come from extragalactic magnetars.Comment: 21 pages, 5 figures. Published in Natur

Dynamic Cardiolipin Synthesis Is Required for CD8⁺ T Cell Immunity

Mitochondria constantly adapt to the metabolic needs of a cell. This mitochondrial plasticity is critical to T cells, which modulate metabolism depending on antigen-driven signals and environment. We show here that de novo synthesis of the mitochondrial membrane-specific lipid cardiolipin maintains CD8+ T cell function. T cells deficient for the cardiolipin-synthesizing enzyme PTPMT1 had reduced cardiolipin and responded poorly to antigen because basal cardiolipin levels were required for activation. However, neither de novo cardiolipin synthesis, nor its Tafazzin-dependent remodeling, was needed for T cell activation. In contrast, PTPMT1-dependent cardiolipin synthesis was vital when mitochondrial fitness was required, most notably during memory T cell differentiation or nutrient stress. We also found CD8+ T cell defects in a small cohort of patients with Barth syndrome, where TAFAZZIN is mutated, and in a Tafazzin-deficient mouse model. Thus, the dynamic regulation of a single mitochondrial lipid is crucial for CD8+ T cell immunity

Polyamines and eIF5A Hypusination Modulate Mitochondrial Respiration and Macrophage Activation

How cells adapt metabolism to meet demands is an active area of interest across biology. Among a broad range of functions, the polyamine spermidine is needed to hypusinate the translation factor eukaryotic initiation factor 5A (eIF5A). We show here that hypusinated eIF5A (eIF5AH) promotes the efficient expression of a subset of mitochondrial proteins involved in the TCA cycle and oxidative phosphorylation (OXPHOS). Several of these proteins have mitochondrial targeting sequences (MTSs) that in part confer an increased dependency on eIF5AH. In macrophages, metabolic switching between OXPHOS and glycolysis supports divergent functional fates stimulated by activation signals. In these cells, hypusination of eIF5A appears to be dynamically regulated after activation. Using in vivo and in vitro models, we show that acute inhibition of this pathway blunts OXPHOS-dependent alternative activation, while leaving aerobic glycolysis-dependent classical activation intact. These results might have implications for therapeutically controlling macrophage activation by targeting the polyamine-eIF5A-hypusine axis

Hydrogen and chlorine abundances in the Kimberley formation of Gale crater measured by the DAN instrument on board the Mars Science Laboratory Curiosity rover

The Dynamic Albedo of Neutron (DAN) instrument on board the Mars Science Laboratory Curiosity rover acquired a series of measurements as part of an observational campaign of the Kimberley area in Gale crater. These observations were planned to assess the variability of bulk hydrogen and neutron‐absorbing elements, characterized as chlorine‐equivalent concentration, in the geologic members of the Kimberley formation and in surface materials exposed throughout the area. During the traverse of the Kimberley area, Curiosity drove primarily over the “Smooth Hummocky” unit, a unit composed primarily of sand and loose rocks, with occasional stops at bedrock of the Kimberley formation. During the Kimberley campaign, DAN detected ranges of water equivalent hydrogen (WEH) and chlorine‐equivalent concentrations of 1.5–2.5 wt % and 0.6–2 wt %, respectively. Results show that as the traverse progressed, DAN observed an overall decrease in both WEH and chlorine‐equivalent concentration measured over the sand and loose rocks of the Smooth Hummocky unit. DAN measurements of WEH and chlorine‐equivalent concentrations in the well‐exposed sedimentary bedrock of the Kimberley formation show fluctuations with stratigraphic position. The Kimberley campaign also provided an opportunity to compare measurements from DAN with those from the Sample Analysis at Mars (SAM) and the Alpha‐Particle X‐ray Spectrometer (APXS) instruments. DAN measurements obtained near the Windjana drill location show a WEH concentration of ~1.5 wt %, consistent with the concentration of low‐temperature absorbed water measured by SAM for the Windjana drill sample. A comparison between DAN chlorine‐equivalent concentrations measured throughout the Kimberley area and APXS observations of corresponding local surface targets and drill fines shows general agreement between the two instruments

Hydrogen and chlorine abundances in the Kimberley formation of Gale crater measured by the DAN instrument on board the Mars Science Laboratory Curiosity rover

The Dynamic Albedo of Neutron (DAN) instrument on board the Mars Science Laboratory Curiosity rover acquired a series of measurements as part of an observational campaign of the Kimberley area in Gale crater. These observations were planned to assess the variability of bulk hydrogen and neutron‐absorbing elements, characterized as chlorine‐equivalent concentration, in the geologic members of the Kimberley formation and in surface materials exposed throughout the area. During the traverse of the Kimberley area, Curiosity drove primarily over the “Smooth Hummocky” unit, a unit composed primarily of sand and loose rocks, with occasional stops at bedrock of the Kimberley formation. During the Kimberley campaign, DAN detected ranges of water equivalent hydrogen (WEH) and chlorine‐equivalent concentrations of 1.5–2.5 wt % and 0.6–2 wt %, respectively. Results show that as the traverse progressed, DAN observed an overall decrease in both WEH and chlorine‐equivalent concentration measured over the sand and loose rocks of the Smooth Hummocky unit. DAN measurements of WEH and chlorine‐equivalent concentrations in the well‐exposed sedimentary bedrock of the Kimberley formation show fluctuations with stratigraphic position. The Kimberley campaign also provided an opportunity to compare measurements from DAN with those from the Sample Analysis at Mars (SAM) and the Alpha‐Particle X‐ray Spectrometer (APXS) instruments. DAN measurements obtained near the Windjana drill location show a WEH concentration of ~1.5 wt %, consistent with the concentration of low‐temperature absorbed water measured by SAM for the Windjana drill sample. A comparison between DAN chlorine‐equivalent concentrations measured throughout the Kimberley area and APXS observations of corresponding local surface targets and drill fines shows general agreement between the two instruments

Search for Gravitational Wave Bursts from Six Magnetars

Soft gamma repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are thought to be magnetars: neutron stars powered by extreme magnetic fields. These rare objects are characterized by repeated and sometimes spectacular gamma-ray bursts. The burst mechanism might involve crustal fractures and excitation of non-radial modes which would emit gravitational waves (GWs). We present the results of a search for GW bursts from six galactic magnetars that is sensitive to neutron star f-modes, thought to be the most efficient GW emitting oscillatory modes in compact stars. One of them, SGR 0501+4516, is likely similar to 1 kpc from Earth, an order of magnitude closer than magnetars targeted in previous GW searches. A second, AXP 1E 1547.0-5408, gave a burst with an estimated isotropic energy >10(44) erg which is comparable to the giant flares. We find no evidence of GWs associated with a sample of 1279 electromagnetic triggers from six magnetars occurring between 2006 November and 2009 June, in GW data from the LIGO, Virgo, and GEO600 detectors. Our lowest model-dependent GW emission energy upper limits for band-and time-limited white noise bursts in the detector sensitive band, and for f-mode ringdowns (at 1090 Hz), are 3.0 x 10(44)d(1)(2) erg and 1.4 x 10(47)d(1)(2) erg, respectively, where d(1) = d(0501)/1 kpc and d(0501) is the distance to SGR 0501+4516. These limits on GW emission from f-modes are an order of magnitude lower than any previous, and approach the range of electromagnetic energies seen in SGR giant flares for the first time.United States National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen/GermanyItalian Istituto Nazionale di Fisica NucleareFrench Centre National de la Recherche ScientifiqueAustralian Research CouncilCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Educacion y CienciaConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsFoundation for Fundamental Research on Matter supported by the Netherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFoundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space Administration NNH07ZDA001-GLASTCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationAlfred P. Sloan FoundationRussian Space AgencyRFBR 09-02-00166aIPN JPL Y503559 (Odyssey), NASA NNG06GH00G, NASA NNX07AM42G, NASA NNX08AC89G (INTEGRAL), NASA NNG06GI896, NASA NNX07AJ65G, NASA NNX08AN23G (Swift), NASA NNX07AR71G (MESSENGER), NASA NNX06AI36G, NASA NNX08AB84G, NASA NNX08AZ85G (Suzaku), NASA NNX09AU03G (Fermi)Astronom