6 research outputs found

    The Rapidly Flaring Afterglow of the Very Bright and Energetic GRB 070125

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    We report on multi-wavelength observations, ranging from the X-ray to radio wave bands, of the IPN-localized gamma-ray burst GRB 070125. Spectroscopic observations reveal the presence of absorption lines due to O I, Si II, and C IV, implying a likely redshift of z = 1.547. The well-sampled light curves, in particular from 0.5 to 4 days after the burst, suggest a jet break at 3.7 days, corresponding to a jet opening angle of ~7.0 degrees, and implying an intrinsic GRB energy in the 1 - 10,000 keV band of around E = (6.3 - 6.9)x 10^(51) erg (based on the fluences measured by the gamma-ray detectors of the IPN network). GRB 070125 is among the brightest afterglows observed to date. The spectral energy distribution implies a host extinction of Av < 0.9 mag. Two rebrightening episodes are observed, one with excellent time coverage, showing an increase in flux of 56% in ~8000 seconds. The evolution of the afterglow light curve is achromatic at all times. Late-time observations of the afterglow do not show evidence for emission from an underlying host galaxy or supernova. Any host galaxy would be subluminous, consistent with current GRB host-galaxy samples. Evidence for strong Mg II absorption features is not found, which is perhaps surprising in view of the relatively high redshift of this burst and the high likelihood for such features along GRB-selected lines of sight.Comment: 50 pages, 9 figures, 5 tables Accepted to the Astrophysical Journa

    The Dark Energy Survey : more than dark energy – an overview

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    This overview paper describes the legacy prospect and discovery potential of the Dark Energy Survey (DES) beyond cosmological studies, illustrating it with examples from the DES early data. DES is using a wide-field camera (DECam) on the 4 m Blanco Telescope in Chile to image 5000 sq deg of the sky in five filters (grizY). By its completion, the survey is expected to have generated a catalogue of 300 million galaxies with photometric redshifts and 100 million stars. In addition, a time-domain survey search over 27 sq deg is expected to yield a sample of thousands of Type Ia supernovae and other transients. The main goals of DES are to characterize dark energy and dark matter, and to test alternative models of gravity; these goals will be pursued by studying large-scale structure, cluster counts, weak gravitational lensing and Type Ia supernovae. However, DES also provides a rich data set which allows us to study many other aspects of astrophysics. In this paper, we focus on additional science with DES, emphasizing areas where the survey makes a difference with respect to other current surveys. The paper illustrates, using early data (from ‘Science Verification’, and from the first, second and third seasons of observations), what DES can tell us about the Solar system, the Milky Way, galaxy evolution, quasars and other topics. In addition, we show that if the cosmological model is assumed to be +cold dark matter, then important astrophysics can be deduced from the primary DES probes. Highlights from DES early data include the discovery of 34 trans-Neptunian objects, 17 dwarf satellites of the Milky Way, one published z > 6 quasar (and more confirmed) and two published superluminous supernovae (and more confirmed)

    Familial isolated primary hyperparathyroidism caused by mutations of the MEN1 gene.

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    BACKGROUND: Familial isolated primary hyperparathyroidism (FIHP) is an autosomal dominant disorder that can represent an early stage of either the multiple endocrine neoplasia type 1 (MEN1) or hyperparathyroidism-jaw tumor (HPT-JT) syndromes; alternatively, the condition can be caused by an allelic variant of MEN1 or HRPT2 (hyperparathyroidism 2 gene), or caused by a distinct entity involving another locus. We have explored these possibilities in a patient with primary hyperparathyroidism, whose mother had a history of renal calculi and primary hyperparathyroidism. INVESTIGATIONS: Serum biochemistry and radiological investigations for primary hyperparathyroidism, MEN1 and HPT-JT, and genetic testing for MEN1 and HRPT2 mutations were undertaken. DIAGNOSIS: FIHP with primary hyperparathyroidism as the sole endocrinopathy due to a previously unreported heterozygous missense germline MEN1 mutation, Tyr351Asn. In addition, another unreported heterozygous missense germline MEN1 mutation, Trp220Leu, was identified in an unrelated male patient with FIHP, whose mother and sister also had primary hyperparathyroidism. DNA from a parathyroid tumor from the sister revealed a loss of heterozygosity in which the mutant allele was retained. This is consistent with Knudson's 'two-hit' model of hereditary cancer and a tumor suppressor role for MEN1 in FIHP. MANAGEMENT: The patient underwent parathyroidectomy and has remained normocalcemic over a follow-up period of 6 years. The other four patients have remained normocalcemic for a follow-up period of 4-15 years following parathyroidectomy. None has developed abnormalities of the MEN1 syndrome, providing further support that FIHP is a distinct genetic variant of the MEN1 syndrome
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