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Multiwavelength Observations of GX 339-4 in 1996. I. Daily Light Curves and X-ray and Gamma-Ray Spectroscopy

(1998)

Authors:

IA Smith, EP Liang, D Lin, M Moss, A Crider, RP Fender, Ph Durouchoux, S Corbel, R Sood
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Observations of GX 339-4 in 1996

(1998)

Authors:

IA Smith, EP Liang, D Lin, M Bottcher, M Moss, A Crider, AV Filippenko, DC Leonard, RP Fender, Ph Durouchoux, S Corbel, R Sood
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MERLIN observations of superluminal motions in GRS 1915+105

Astrophysical Letters and Communications 38:1-6 (1998) 229-232

Authors:

RP Fender, ST Garrington, DJ McKay, TWB Muxlow, GG Pooley, RE Spencer, AM Stirling, EB Waltman

Abstract:

We present a brief discussion of high resolution observations of relativistic ejections from GRS 1915+103 with MERLIN. We have imaged superluminal motions in the inner 300 milliarcsec of several ejections from the system, with significantly higher proper motions than previously observed on arcsecond scales with the VLA. Under standard assumptions of an intrinsically symmetric jet, we derive a velocity for the ejecta which is higher then the previously accepted value of 0.92c, although the angle to the line of sight is comparable. © 1999 OPA (Overseas Publishers Association) N.V Published by license under the Gordon and Breach Science Publishers imprint.

Observation of Bc mesons in pp̄ collisions at √s = 1.8 TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 58:11 (1998)

Authors:

F Abe, H Akimoto, A Akopian, MG Albrow, A Amadon, SR Amendolia, D Amidei, J Antos, S Aota, G Apollinari, T Arisawa, T Asakawa, W Ashmanskas, M Atac, P Azzi-Bacchetta, N Bacchetta, S Bagdasarov, MW Bailey, P de Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, M Barone, G Bauer, T Baumann, F Bedeschi, S Behrends, S Belforte, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, S Bertolucci, S Bettelli, B Bevensee, A Bhatti, K Biery, C Bigongiari, M Binkley, D Bisello, RE Blair, C Blocker, S Blusk, A Bodek, W Bokhari, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, L Breccia, C Bromberg, N Bruner, R Brunetti, E Buckley-Geer, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, M Campbell, A Caner, W Carithers, D Carlsmith, J Cassada, A Castro, D Cauz, A Cerri, PS Chang, PT Chang, HY Chao, J Chapman, MT Cheng, M Chertok, G Chiarelli, CN Chiou, F Chlebana, L Christofek, ML Chu, S Cihangir, AG Clark, M Cobal, E Cocca, M Contreras, J Conway, J Cooper, M Cordelli, D Costanzo, C Couyoumtzelis, D Cronin-Hennessy, R Culbertson, D Dagenhart, T Daniels, F de Jongh, S dell'Agnello, M dell'Orso, R Demina, L Demortier

Abstract:

We report the observation of bottom-charmed mesons Bc ni 1.8 TeV pp̄ collisions using the CDF detector at the Fermilab Tevatron. The Bc mesons were found through their semileptonic decays, B±c → J/ψl± X. A fit to the J/ψl mass distribution yielded 20.4+6.2-5.5 events from Bc mesons. A test of the null hypothesis, i.e., an attempt to fit the data with background alone, was rejected at the level of 4.8 standard deviations. By studying the quality of the fit as a function of the assumed Bc mass, we determined M(Bc) = 6.40 ±0.39 (stat.)±0.13 (syst) GeV/c2. From the distribution of trilepton intersection points in the plane transverse to the beam direction we measure the Bc lifetime to be τ(Bc) = 0.46+0.18-0.16 (stat)±0.03 (syst) ps. We also measured the ratio of production cross section times branching fraction for B+c → J/ψl+ v relative to that for B+ → J/ψK+ to be σ(Bc)×B(B c→J/ψlv)/σ(B)×B(B→J/ψK) = 0.132+0.041-0.037 (stat)±0.031 (syst)+0.032-0.020(lifetime).
More details from the publisher

Observations of GX 339-4 in 1996

Astrophysical Letters and Communications 38:1-6 (1998) 265-268

Authors:

IA Smith, EP Liang, D Lin, M Böttcher, M Moss, A Crider, AV Filippenko, DC Leonard, RP Fender, P Durouchoux, S Corbel, R Sood

Abstract:

GX 339-4 is an unusual black hole candidate in that it is a persistent source, being detected by X-ray telescopes most of the time, but it also has nova-like flaring states. In 1996 we performed radio, optical, X-ray, and gamma-ray observations of GX 339-4 when it was in a hard state (= soft X-ray low state). Here we present a brief summary of some of the results. © 1999 OPA (Overseas Publishers Association) N.V. Published by license under the Gordon and Breach Science Publishers imprint.