Discovery of a new Galactic bona fide luminous blue variable with Spitzer

We report the discovery of a circular mid-infrared shell around the emission-line star Wray 16- 137 using archival data of the Spitzer Space Telescope. Follow-up optical spectroscopy of Wray 16-137 with the Southern African Large Telescope revealed a rich emission spectrum typical of the classical luminous blue variables (LBVs) like P Cygni. Subsequent spectroscopic and photometric observations showed drastic changes in the spectrum and brightness during the last three years, meaning that Wray 16-137 currently undergoes an S Dor-like outburst. Namely, we found that the star has brightened by ≈1 mag in the V and Ic bands, while its spectrum became dominated by Fe II lines. Taken together, our observations unambiguously show that Wray 16-137 is a new member of the family of Galactic bona fide LBVs

SALT observations of the supernova remnant MCSNR J0127−7332 and its associated Be X-ray binary SXP 1062 in the SMC

We report the results of optical spectroscopy of the Small Magellanic Cloud supernova remnant (SNR) MCSNR J0127−7332 and the mass donor Be star, 2dFS 3831, in its associated high-mass X-ray binary SXP 1062 carried out with the Southern African Large Telescope. Using high-resolution long-slit spectra, we measured the expansion velocity of the SNR shell of ≈140 km s−1, indicating that MCSNR J0127−7332 is in the radiative phase. We found that the observed line ratios in the SNR spectrum can be understood if the local interstellar medium is ionized by 2dFS 3831 and/or OB stars around the SNR. We propose that MCSNR J0127−7332 is the result of supernova explosion within a bubble produced by the stellar wind of the supernova progenitor and that the bubble was surrounded by a massive shell at the moment of supernova explosion. We estimated the age of MCSNR J0127−7332 to be ≲10 000 yr. We found that the spectrum of 2dFS 3831 changes with orbital phase. Namely, the equivalent width of the H α emission line decreased by ≈40 per cent in ≈130 d after periastron passage of the neutron star and then almost returned to its original value in the next ≈100 d. Also, the spectrum of 2dFS 3831 obtained closest to the periastron epoch (about 3 weeks after the periastron) shows a noticeable emission line of He II λ4686, which disappeared in the next 2 weeks. We interpret these changes as a result of the temporary perturbation and heating of the disc as the neutron star passes through it

Two-particle production in K+p interactions at 32 GeV/c

Results are presented on two-particle inclusive production in K+p interactions at 32 GeV/c. We study the x1,2=x1+x2 dependence of invariant structure functions of (ππ)-pairs and compare them to single particle inclusive distributions in the fragmentation regions. Distributions of particles observed at Feynman x2 in association with various "trigger" particles or systems at x1 in the same hemisphere are dicussed in terms of the reduced variable {Mathematical expression}. We further present absolute production rates and production ratios of π+'s and π-'s associated with π±, Ks0, Λ, {Mathematical expression}, K*+ (890), (Ks0π+), and (π+ π-)-triggers, and compare them with qualitative predictions of the quark recombination model. Forwardbackward correlations between (Ks0π±), (Ks0, p), (Λ, π-), {Mathematical expression}, and (p, π-) pairs are also discussed. © 1981 Springer-Verlag.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Non-diffractive two-body channels in reactions K+p→K0π+p and K+p→K+π-π+p at 32 GeV/c

We present results on a number of non-diffractive two-body channels contributing to reactions K+p→K0π+p and K+p→K+π-π+p. The data come from an exposure of the Mirabelle bubble chamber to an r.f. separated K+ beam of 32 GeV/c at the Serpukhov accelerator. Total cross sections are given for the final states K*+ (890)p, K*+ (1420)p, K0 Δ++ (1232), K*0 (890) Δ++ (1232), K*0 (1420) Δ++ (1232), K*0 (1780) Δ++ (1232) and K*0 (890) Δ++ (1950). The differential cross sections are given for all channels with sufficient statistics. The energy dependence of the total and differential cross sections is studied. © 1979.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Λ and Λ production in K+p interactions at 32 GeV/c

A study of the inclusive and semi-inclusive Λ and Λ production in K+p interactions at 32 GeV/c is presented. The inclusive cross sections for Λ and Λ amount to 0.78 ± 0.05 and 0.42 ± 0.04 mb thus showing a remarkable growth between 16 and 32 GeV/c with a factor of 1.7 for Λ and 2.8 for Λ. Target and beam fragmentation processes are found to be dominant for Λ and Λ production respectively with the following lower limits for the corresponding cross sections: σ(p → K+v{inverted}) > 0.5 mb and σ(K+ → pv{inverted}) > 0.3 mb. Although the early scaling conditions are fulfilled for the Λ production in the target fragmentation region, and Λ production in the beam fragmentation region, scaling is not observed between 16 and 32 GeV/c in the x and pT2 Feynman variables. The Λ production is found to be very similar in the K+p inclusive reaction at 32 GeV/c and in the semi-inclusive reaction K-p→ ΛKKX at the same energy. The ΛΛ pair production cross section increases significantly in K+p interactions from 16 to 32 GeV/c where it reaches the value σΛΛ = 47 ± 11 μb. The cross sections for Λ or Λ produced in association with an identified proton are also given and discussed. © 1977.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Observation in K+p interactions at 32 GeV/c of a narrow state at 2145 MeV/c2 decaying into øπ+

We present evidence for a new narrow state decaying into øπ+ with a mass of 2145 ± 10 MeV/c2 and an experimental width of 25 MeV/c2, produced in K+p interactions at 32 GeV/c. The production cross section σ · BR (→øπ+) is equal to 11 ± 3 μb. © 1980, All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe