Derivation of a Sample of Gamma-Ray Bursts from BATSE DISCLA Data

We have searched for gamma-ray bursts (GRBs) in the BATSE DISCLA data over a time period of 5.9 years. We employ a trigger requiring an excess of at least 5 sigma over background for at least two modules in the 50-300 keV range. After excluding certain geographic locations of the satellite, we are left with 4485 triggers. Based on sky positions, we exclude triggers close to the sun, to Cyg X-1, to Nova Persei 1992 and the repeater SGR 1806-20, while these sources were active. We accept 1013 triggers that correspond to GRBs in the BATSE catalog, and after visual inspection of the time profiles classify 378 triggers as cosmic GRBs. We denote the 1391 GRBs so selected as the "BD2 sample". The BD2 sample effectively represents 2.003 years of full sky coverage for a rate of 694 GRBs per year. Euclidean V/Vmax values have been derived through simulations in which each GRB is removed in distance until the detection algorithm does not produce a trigger. The BD2 sample produces a mean value = 0.334 +- 0.008.Comment: 5 pages, 3 figures, Latex with aipproc.sty, Proc. of the 5th Huntsville Gamma Ray Burst Symposium, Oct. 1999, ed. R.M. Kippen, AI

Chiral Perturbation Theory, Non-leptonic Kaon Decays, and the Lattice

In this talk, I first motivate the use of Chiral Perturbation Theory in the context of Lattice QCD. In particular, I explain how partially quenched QCD, which has, in general, unequal valence- and sea-quark masses, can be used to obtain real-world (i.e. unquenched) results for low-energy constants. In the second part, I review how Chiral Perturbation Theory may be used to overcome theoretical difficulties which afflict the computation of non-leptonic kaon decay rates from Lattice QCD. I argue that it should be possible to determine at least the O(p^2) weak low-energy constants reliably from numerical computations of the K to pi and K to vacuum matrix elements of the corresponding weak operators.Comment: 13 pages, invited plenary talk at Chiral 2000, Jefferson Lab., July 17-22, 200

The musealisation of the artist's house as architectural project

Artist’s houses that are opened to the public as museums shift from a private and everyday to a semi-public and institutional functioning. This transformation of an artist’s house into a house-museum might appear as a mere legal issue or as a matter of making previously secluded rooms and collections accessible to the public. But this musealisation of an artist’s house always involves a set of museological and architectural interventions as well. Not only need the house and its content to be displayed as historical documents through a careful mise-en-scène and through the addition of a sub-text of labels or explanatory panels that disclose the meaning of these historical documents; there is also a need for a logic and clear visitor’s route in a house that was not intended for this. Often this already demands architectural design decisions, but it is mainly in the introduction of the supporting museum functions like the necessary office spaces and an entrance hall with reception desk, cloakroom and bathrooms that the musealisation comes down to an architectural design challenge. The proposed paper wants to discuss the artist’s house museum from an architect’s point of view, on the basis of a selection of artist’s houses that were recently transformed into museums, such as the Atelier-Museum Luc Peire in Knokke (B) or the renovations of the Permeke and Rubens house museums. I want to propose the artist’s house museum as an architectural typology by mapping its various typical architectural and spatial characteristics. The first crucial point of interest here is how the spatial division is articulated between the historic interiors, the exhibition spaces and the museum’s service spaces outside of the visitor’s circuit. A second architectural question is how the museum as an active institution can be given an architectural ‘face’ while respecting and presenting the house and its collections as historical documents; how can both the ‘authentic’ private atmosphere and the contemporary public museum be given shape, and is there a place for authorial design in this mediating exercise

Grindbakken by Rotor. The Art and Architecture of Framing in Situ

In 2012 architectural design and research collective Rotor was invited to make the inaugural exhibition for a new open air cultural event space in a former part of Ghent’s sea harbour that is being redeveloped. Architect Sarah Melsens and visual artist Roberta Gigante had designed the conversion of the 200 m. long series of concrete gravel containers – grindbakken in Dutch. Their most striking intervention was to paint over the entire surface of the obsolete harbour infrastructure with white road paint. Rotor in turn produced a site-specific architectural exhibition by intervening during the painting works: they covered specific zones of interest to keep them from being overpainted. These zones were then exhibited as fragments inside the newly whitened spaces. The exhibition produced at once a powerful aesthetic valorisation and a careful archaeological analysis of an unassuming piece of infrastructure, as well as a conceptual critique of the architectural reconversion upon which Rotor’s exhibition nevertheless depended in many ways. This paper maps and interprets the important variety of shapes, positions and constellations that Rotor used to frame in ‘finds’, and compares Rotor’s framings to selected artistic and architectural reframing projects, from Le Corbusier to Lawrence Weiner

Luminosities, Space Densities and Redshift Distributions of Gamma-Ray Bursts

We use the BD2 sample of gamma-ray bursts (GRBs) based on 5.9 years of BATSE DISCLA data with a variety of models of the luminosity function to derive characteristic GRB luminosities, space densities and redshift distributions. Previously published results for an open universe and modest density evolution of the GRBs showed characteristic peak luminosities around 5x10**51 erg/s in the 50-300 keV band if the emission is isotropic, and local space densities around 0.2 Gpc**-3 yr**-1. In this paper, we illustrate for several luminosity function models the predicted distributions of peak flux, luminosity and redshifts. We use the luminosity function models also to address the connection between supernovae and GRB. If all supernovae of Type Ib/c harbor a GRB, the beaming fraction would have to be 10**-5 - 10**-3.5. We find that GRB 980425, if correctly identified with SN 1998bw, has to be part of a population different from that of the bulk of GRBs.Comment: 5 pages, 4 figures, Latex with aipproc.sty, Proc. of the 5th Huntsville Gamma Ray Burst Symposium, Oct. 1999, ed. R.M. Kippen, AI

The relentless retreat: Kelly James Clark's religion and the sciences of origins

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