Detector and Telescope Development for ProtoEXIST and Fine Beam Measurements of Spectral Response of CZT Detectors

We outline our plan to develop ProtoEXIST, a balloon-borne prototype experiment for the Energetic X-ray Imaging Survey Telescope (EXIST) for the Black Hole Finder Probe. EXIST will consist of multiple wide-field hard X-ray coded-aperture telescopes. The current design of the EXIST mission employs two types of telescope systems: high energy telescopes (HETs) using CZT detectors, and low energy telescopes (LETs) using Si detectors. With ProtoEXIST, we will develop and demonstrate the technologies required for the EXIST HETs. As part of our development efforts, we also present recent laboratory measurements of the spectral response and efficiency variation of imaging CZT detectors on a fine scale (~0.5 mm). The preliminary results confirm the need for multi-pixel readouts and small inter-pixel gaps to achieve uniform spectral response and high detection efficiency across detectors.Comment: 9 pages, 12 figures, 1 table, appears in SPIE 2005 proceedings (5898: UV, X-ray, and Gamma-ray Space Instrumentation for Astronomy XIV

Identification and characterization of laccase-type multicopper oxidases involved in dye-decolorization by the fungus Leptosphaerulina sp.

13 p.-4 fig.-4 tab.[Background] Fungal laccases are multicopper oxidases (MCOs) with high biotechnological potential due to their capability to oxidize a wide range of aromatic contaminants using oxygen from the air. Albeit the numerous laccase-like genes described in ascomycete fungi, ascomycete laccases have been less thoroughly studied than white-rot basidiomycetous laccases. A variety of MCO genes has recently been discovered in plant pathogenic ascomycete fungi, however little is known about the presence and function of laccases in these fungi or their potential use as biocatalysts. We aim here to identify the laccase-type oxidoreductases that might be involved in the decolorization of dyes by Leptosphaerulina sp. and to characterize them as potential biotechnological tools.[Results] A Leptosphaerulina fungal strain, isolated from lignocellulosic material in Colombia, produces laccase as the main ligninolytic oxidoreductase activity during decolorization of synthetic organic dyes. Four laccase-type MCO genes were partially amplified from the genomic DNA using degenerate primers based on laccase-specific signature sequences. The phylogenetic analysis showed the clustering of Lac1, Lac4 and Lac3 with ascomycete laccases, whereas Lac2 grouped with fungal ferroxidases (together with other hypothetical laccases). Lac3, the main laccase produced by Leptosphaerulina sp. in dye decolorizing and laccase-induced cultures (according to the shotgun analysis of both secretomes) was purified and characterized in this study. It is a sensu-stricto laccase able to decolorize synthetic organic dyes with high efficiency particularly in the presence of natural mediator compounds.[Conclusions] The searching for laccase-type MCOs in ascomycetous families where their presence is poorly known, might provide a source of biocatalysts with potential biotechnological interest and shed light on their role in the fungus. The information provided by the use of genomic and proteomic tools must be combined with the biochemical evaluation of the enzyme to prove its catalytic activity and applicability potential.This research was supported by the Program for Interuniversity Cooperation and Scientific Reasearch (PCI) from the Spanish Agency for International Cooperation and Development (AECID), Project AP/033932/11, and the Spanish Project NOESIS BIO2014-56388-R.Peer reviewe

Panchromatic Observations of SN 2011dh Point to a Compact Progenitor Star

We report the discovery and detailed monitoring of X-ray emission associated with the Type IIb SN 2011dh using data from the Swift and Chandra satellites, placing it among the best studied X-ray supernovae to date. We further present millimeter and radio data obtained with the SMA, CARMA, and EVLA during the first three weeks after explosion. Combining these observations with early optical photometry, we show that the panchromatic dataset is well-described by non-thermal synchrotron emission (radio/mm) with inverse Compton scattering (X-ray) of a thermal population of optical photons. In this scenario, the shock partition fractions deviate from equipartition by a factor, (e_e/e_B) ~ 30. We derive the properties of the shockwave and the circumstellar environment and find a shock velocity, v~0.1c, and a progenitor mass loss rate of ~6e-5 M_sun/yr. These properties are consistent with the sub-class of Type IIb SNe characterized by compact progenitors (Type cIIb) and dissimilar from those with extended progenitors (Type eIIb). Furthermore, we consider the early optical emission in the context of a cooling envelope model to estimate a progenitor radius of ~1e+11 cm, in line with the expectations for a Type cIIb SN. Together, these diagnostics are difficult to reconcile with the extended radius of the putative yellow supergiant progenitor star identified in archival HST observations, unless the stellar density profile is unusual. Finally, we searched for the high energy shock breakout pulse using X-ray and gamma-ray observations obtained during the purported explosion date range. Based on the compact radius of the progenitor, we estimate that the breakout pulse was detectable with current instruments but likely missed due to their limited temporal/spatial coverage. [Abridged]Comment: (27 pages, 5 figures, 2 tables, final version to appear in ApJ

A Relativistic Type Ibc Supernova Without a Detected Gamma-ray Burst

Long duration gamma-ray bursts (GRBs) mark the explosive death of some massive stars and are a rare sub-class of Type Ibc supernovae (SNe Ibc). They are distinguished by the production of an energetic and collimated relativistic outflow powered by a central engine (an accreting black hole or neutron star). Observationally, this outflow is manifested in the pulse of gamma-rays and a long-lived radio afterglow. To date, central engine-driven SNe have been discovered exclusively through their gamma-ray emission, yet it is expected that a larger population goes undetected due to limited satellite sensitivity or beaming of the collimated emission away from our line-of-sight. In this framework, the recovery of undetected GRBs may be possible through radio searches for SNe Ibc with relativistic outflows. Here we report the discovery of luminous radio emission from the seemingly ordinary Type Ibc SN 2009bb, which requires a substantial relativistic outflow powered by a central engine. The lack of a coincident GRB makes SN 2009bb the first engine-driven SN discovered without a detected gamma-ray signal. A comparison with our extensive radio survey of SNe Ibc reveals that the fraction harboring central engines is low, ~1 percent, measured independently from, but consistent with, the inferred rate of nearby GRBs. Our study demonstrates that upcoming optical and radio surveys will soon rival gamma-ray satellites in pinpointing the nearest engine-driven SNe. A similar result for a different supernova is reported independently.Comment: To appear in Nature on Jan 28 2010. Embargoed for discussion in the press until 13:00 US Eastern Time on Jan 27 (Accepted version, 27 pages, Manuscript and Suppl. Info.

Testing the Epeak - Eiso relation for GRBs detected by Swift and Suzaku-WAM

One of the most prominent, yet controversial associations derived from the ensemble of prompt-phase observations of gamma-ray bursts (GRBs) is the apparent correlation in the source frame between the peak energy Epeak) of the nu-F(nu) spectrum and the isotropic radiated energy, Eiso. Since most gamma-ray bursts (GRBs) have Epeak above the energy range (15-150 keV) of the Burst Alert Telescope (BAT) on Swift, determining accurate Epeak values for large numbers of Swift bursts has been difficult. However, by combining data from Swift/BAT and the Suzaku Wide-band All-Sky Monitor (WAM), which covers the energy range from 50-5000 keV, for bursts which are simultaneously detected, one can accurately fit Epeak and Eiso and test the relationship between them for the Swift sample. Between the launch of Suzaku in July 2005 and the end of April 2009, there were 48 gamma-ray bursts (GRBs) which triggered both Swift/BAT and WAM and an additional 48 bursts which triggered Swift and were detected by WAM, but did not trigger. A BAT-WAM team has cross-calibrated the two instruments using GRBs, and we are now able to perform joint fits on these bursts to determine their spectral parameters. For those bursts with spectroscopic redshifts, we can also calculate the isotropic energy. Here we present the results of joint Swift/BAT-Suzaku/WAM spectral fits for 91 of the bursts detected by the two instruments. We show that the distribution of spectral fit parameters is consistent with distributions from earlier missions and confirm that Swift bursts are consistent with earlier reported relationships between Epeak and isotropic energy. We show through time-resolved spectroscopy that individual burst pulses are also consistent with this relationship.Comment: Accepted for publication in the Astrophysical Journa

The Second Swift BAT Gamma-Ray Burst Catalog

We present the second Swift Burst Alert Telescope (BAT) catalog of gamma-ray bursts (GRBs), which contains 476 bursts detected by the BAT between 2004 December 19 and 2009 December 21. This catalog (hereafter the BAT2 catalog) presents burst trigger time, location, 90% error radius, duration, fluence, peak flux, time-averaged spectral parameters and time-resolved spectral parameters measured by the BAT. In the correlation study of various observed parameters extracted from the BAT prompt emission data, we distinguish among long-duration GRBs (L-GRBs), short-duration GRBs (S-GRBs), and short-duration GRBs with extended emission (S-GRBs with E.E.) to investigate differences in the prompt emission properties. The fraction of L-GRBs, S-GRBs and S-GRBs with E.E. in the catalog are 89%, 8% and 2% respectively. We compare the BAT prompt emission properties with the BATSE, BeppoSAX and HETE-2 GRB samples. We also correlate the observed prompt emission properties with the redshifts for the GRBs with known redshift. The BAT T90 and T50 durations peak at 70 s and 30 s, respectively. We confirm that the spectra of the BAT S-GRBs are generally harder than those of the L-GRBs. The time-averaged spectra of the BAT S-GRBs with E.E. are similar to those of the L-GRBs. Whereas, the spectra of the initial short spikes of the S-GRBs with E.E. are similar to those of the S-GRBs. We show that the BAT GRB samples are significantly softer than the BATSE bright GRBs, and that the time-averaged Epeak of the BAT GRBs peaks at 80 keV which is significantly lower energy than those of the BATSE sample which peak at 320 keV. The time-averaged spectral properties of the BAT GRB sample are similar to those of the HETE-2 GRB samples. By time-resolved spectral analysis, we find that only 10% of the BAT observed photon indices are outside the allowed region of the synchrotron shock model.Comment: 65 pages, 33 figures, 13 tables, Accepted in ApJS, Nine machine-readable tables are available at http://swift.gsfc.nasa.gov/docs/swift/results/bat2_catalog

GRB 071028B, a burst behind large amounts of dust in an unabsorbed galaxy

We report on the discovery and properties of the fading afterglow and underlying host galaxy of GRB 071028B, thereby facilitating a detailed comparison between these two. Observations were performed with the Gamma-ray Burst Optical and Near-infrared Detector at the 2.2 m telescope on the La Silla Paranal Observatory in Chile. We conducted five observations from 1.9 d to 227.2 d after the trigger and obtained deep images in the g'r'i'z' and JHKs bands. Based on accurate seven-channel photometry covering the optical to near-infrared wavelength range, we derive a photometric redshift of z = 0.94 +0.05 -0.10 for the unabsorbed host galaxy of GRB 071028B. In contrast, we show that the afterglow with an intrinsic extinction of AV(SB) = (0.70 +/- 0.11) mag is moderately absorbed and requires a relatively flat extinction curve. According to the reported Swift/BAT observations, the energetics yield an isotropic energy release of E(gamma,iso.,rest) = (1.4 +2.4 -0.7) x 10^51 erg.Comment: 8 pages, 5 figures, accepted for publication in A&

The High-Metallicity Explosion Environment of the Relativistic Supernova 2009bb

We investigate the environment of the nearby (d ~ 40Mpc) broad-lined Type Ic supernova SN 2009bb. This event was observed to produce a relativistic outflow likely powered by a central accreting compact object. While such a phenomenon was previously observed only in long-duration gamma-ray bursts (LGRBs), no LGRB was detected in association with SN 2009bb. Using an optical spectrum of the SN 2009bb explosion site, we determine a variety of ISM properties for the host environment, including metallicity, young stellar population age, and star formation rate. We compare the SN explosion site properties to observations of LGRB and broad-lined SN Ic host environments on optical emission line ratio diagnostic diagrams. Based on these analyses, we find that the SN 2009bb explosion site has a very high metallicity of ~2x solar, in agreement with other broad-lined SN Ic host environments and at odds with the low-redshift LGRB host environments and recently proposed maximum metallicity limits for relativistic explosions. We consider the implications of these findings and the impact that SN 2009bb's unusual explosive properties and environment have on our understanding of the key physical ingredient that enables some SNe to produce a relativistic outflow.Comment: 7 pages, 4 figures, 1 table; accepted for publication in ApJ Letters (replaced to include missing figure

Retinal and choroidal thickness measurements using spectral domain optical coherence tomography in anterior and intermediate uveitis.

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The TLR7/9 adaptors TASL and TASL2 mediate IRF5-dependent antiviral responses and autoimmunity in mouse.

Endosomal nucleic acid sensing by Toll-like receptors (TLRs) is central to antimicrobial immunity and several autoimmune conditions such as systemic lupus erythematosus (SLE). The innate immune adaptor TASL mediates, via the interaction with SLC15A4, the activation of IRF5 downstream of human TLR7, TLR8 and TLR9, but the pathophysiological functions of this axis remain unexplored. Here we show that SLC15A4 deficiency results in a selective block of TLR7/9-induced IRF5 activation, while loss of TASL leads to a strong but incomplete impairment, which depends on the cell type and TLR engaged. This residual IRF5 activity is ascribed to a previously uncharacterized paralogue, Gm6377, named here TASL2. Double knockout of TASL and TASL2 (TASL <sup>DKO</sup> ) phenocopies SLC15A4-deficient feeble mice showing comparable impairment of innate and humoral responses. Consequently, TASL <sup>DKO</sup> mice fail to control chronic LCMV infection, while being protected in a pristane-induced SLE disease model. Our study thus demonstrates the critical pathophysiological role of SLC15A4 and TASL/TASL2 for TLR7/9-driven inflammatory responses, further supporting the therapeutic potential of targeting this complex in SLE and related diseases