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Coupling of the X-ray and radio emission in the black hole candidate and compact jet source GX 339-4

Astronomy and Astrophysics 359:1 (2000) 251-268

Authors:

S Corbel, RP Fender, AK Tzioumis, M Nowak, V McIntyre, P Durouchoux, R Sood

Abstract:

We report the results of a long-term campaign of radio, soft- and hard- X-ray observations of the galactic black hole candidate GX 339-4. In the Low-Hard X-ray state the system displays a strong 3-way linear correlation between soft-and hard-X-rays and radio emission, implying a coupling between the Comptonising corona and a radio-emitting compact jet. In this state the radio emission is linearly polarised at a level of around 2%, with an almost constant polarisation angle, indicative of a favored axis in this system probably related to the compact jet and/or black hole spin axis. In the Off X-ray state the radio emission declines with the X-ray emission to below detectable levels, suggesting that it is simply a lower-luminosity version of the Low-Hard state. In the High-Soft state both the hard-X-ray and radio emission are suppressed. We also note that the transitions from the Low-Hard state to the High-Soft state (and the reverse) are possibly associated with discrete ejection(s) of expanding relativistic plasma.

Disk mass accretion rate and infrared flares in GRS 1915+105

Astronomy and Astrophysics 358:2 (2000)

Authors:

T Belloni, S Migliari, RP Fender

Abstract:

We have analyzed in detail a set of Rossi X-ray Timing Explorer (RXTE) observations of the galactic microquasar GRS 1915+105 corresponding to times when quasi-periodic oscillations in the infrared have been reported. From time-resolved spectral analysis, we have estimated the mass accretion rate through the (variable) inner edge of the accretion disk. We compare this accretion rate to an estimate of the mass/energy outflow rate in the jet. We discuss the possible implications of these results in terms of disk-instability and jet ejection, and in particular note an apparent anti-correlation between the accretion and ejection rates, implying that the gas expelled in the jet must leave the accretion disk before reaching its innermost radius.

Measurement of B→Ds(*)+D*(*) branching fractions

Physical Review D American Physical Society (APS) 62:11 (2000) 112003

Authors:

S Ahmed, MS Alam, SB Athar, L Jian, L Ling, M Saleem, S Timm, F Wappler, A Anastassov, JE Duboscq, E Eckhart, KK Gan, C Gwon, T Hart, K Honscheid, D Hufnagel, H Kagan, R Kass, TK Pedlar, H Schwarthoff, JB Thayer, E von Toerne, MM Zoeller, SJ Richichi, H Severini, P Skubic, A Undrus, S Chen, J Fast, JW Hinson, J Lee, DH Miller, EI Shibata, IPJ Shipsey, V Pavlunin, D Cronin-Hennessy, AL Lyon, EH Thorndike, CP Jessop, H Marsiske, ML Perl, V Savinov, X Zhou, TE Coan, V Fadeyev, Y Maravin, I Narsky, R Stroynowski, J Ye, T Wlodek, M Artuso, R Ayad, C Boulahouache, K Bukin, E Dambasuren, S Karamov, G Majumder, GC Moneti, R Mountain, S Schuh, T Skwarnicki, S Stone, G Viehhauser, JC Wang, A Wolf, J Wu, S Kopp, AH Mahmood, SE Csorna, I Danko, KW McLean, Sz Márka, Z Xu, R Godang, K Kinoshita, IC Lai, S Schrenk, G Bonvicini, D Cinabro, S McGee, LP Perera, GJ Zhou, E Lipeles, SP Pappas, M Schmidtler, A Shapiro, WM Sun, AJ Weinstein, F Würthwein, DE Jaffe, G Masek, HP Paar, EM Potter, S Prell, V Sharma, DM Asner, A Eppich, TS Hill, RJ Morrison, HN Nelson, JD Richman, MS Witherell, RA Briere, GP Chen, BH Behrens, WT Ford, A Gritsan, J Roy, JG Smith, JP Alexander, R Baker, C Bebek, BE Berger, K Berkelman, F Blanc, V Boisvert, DG Cassel, M Dickson, PS Drell, KM Ecklund, R Ehrlich, AD Foland, P Gaidarev, L Gibbons, B Gittelman, SW Gray, DL Hartill, BK Heltsley, PI Hopman, CD Jones, DL Kreinick, M Lohner, A Magerkurth, TO Meyer, NB Mistry, E Nordberg, JR Patterson, D Peterson, D Riley, JG Thayer, D Urner, B Valant-Spaight, A Warburton, P Avery, C Prescott, AI Rubiera, J Yelton, J Zheng, G Brandenburg, A Ershov, YS Gao, DY-J Kim, R Wilson, TE Browder, Y Li, JL Rodriguez, H Yamamoto, T Bergfeld, BI Eisenstein, J Ernst, GE Gladding, GD Gollin, RM Hans, E Johnson, I Karliner, MA Marsh, M Palmer, C Plager, C Sedlack, M Selen, JJ Thaler, J Williams, KW Edwards, R Janicek, PM Patel, AJ Sadoff, R Ammar, A Bean, D Besson, R Davis, N Kwak, X Zhao, S Anderson, VV Frolov, Y Kubota, SJ Lee, R Mahapatra, JJ O’Neill, R Poling, T Riehle, A Smith, CJ Stepaniak, J Urheim
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Resolving the radio nebula around β Lyrae

Astronomy and Astrophysics 358:1 (2000) 229-232

Authors:

G Umana, PFL Maxted, C Trigilio, RP Fender, F Leone, SK Yerli

Abstract:

In this paper we present high spatial resolution radio images of the puzzling binary system β Lyrae obtained with MERLIN at 5 GHz. We find a nebula surrounding the binary with a brightness temperature of (11000 ± 700) K approximately 40 AU across. This definitively confirms the thermal origin of the radio emission, which is consistent with emission from the wind of the B6-8 II component (mass loss of order of 10-7 M⊙yr-1), ionized by the radiation field of the hotter companion. This nebula, surrounding the binary, is the proof that β Lyrae evolved in a non-conservative way, i. e. not all the mass lost by the primary is accretted by the secondary, and present measurements indicate that almost 0.015 M⊙ had been lost from the system since the onset of the Roche lobe overflow phase. Moreover, the nebula is aligned with the jet-like structures inferred from recent optical measurements, indicating a possible connection among them.

Resonant structure of τ→3 ππ 0 ν τ and τ→ωπν τ decays

Physical Review D 61:7 (2000)

Authors:

KW Edwards, R Janicek, PM Patel, AJ Sadoff, R Ammar, P Baringer, A Bean, D Besson, R Davis, S Kotov, I Kravchenko, N Kwak, X Zhao, S Anderson, VV Frolov, Y Kubota, SJ Lee, R Mahapatra, JJ O'Neill, R Poling, T Riehle, A Smith, S Ahmed, MS Alam, SB Athar, L Jian, L Ling, AH Mahmood, M Saleem, S Timm, F Wappler, A Anastassov, JE Duboscq, KK Gan, C Gwon, T Hart, K Honscheid, H Kagan, R Kass, J Lorenc, H Schwarthoff, E von Toerne, MM Zoeller, SJ Richichi, H Severini, P Skubic, A Undrus, M Bishai, S Chen, J Fast, JW Hinson, J Lee, N Menon, DH Miller, EI Shibata, IPJ Shipsey, Y Kwon, AL Lyon, EH Thorndike, CP Jessop, K Lingel, H Marsiske, ML Perl, V Savinov, D Ugolini, X Zhou, TE Coan, V Fadeyev, I Korolkov, Y Maravin, I Narsky, V Shelkov, R Stroynowski, J Ye, T Wlodek, M Artuso, R Ayad, E Dambasuren, S Kopp, G Majumder, GC Moneti, R Mountain, S Schuh, T Skwarnicki, S Stone, A Titov, G Viehhauser, JC Wang, A Wolf, J Wu, SE Csorna, KW McLean, S Marka, Z Xu, R Godang, K Kinoshita, IC Lai, P Pomianowski, S Schrenk, G Bonvicini

Abstract:

The resonant structure of the four pion final state in the decay τ→3 ππ 0 ν τ has been analyzed using 4.27 million τ + τ - pairs collected by the CLEO II experiment at the Cornell Electron Storage Ring. A partial wave analysis of the resonant structure of the τ→3 ππ 0 ν τ decay has been performed; the spectral decomposition of the four pion system is dominated by the ωπ and a 1 π final states. The mass and width of the ρ′ resonance have been extracted from a fit to the τ→ωπν τ spectral function. We have searched for second class currents in the decay τ→ωπν τ using spin-parity analysis and established an upper limit on the non-vector current contribution. © 2000 The American Physical Society.