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Solar and interplanetary origins of the November 2004 superstorms
Tsurutani, Bruce T.; Echer, Ezequiel; Guarnieri, Fernando L.
During the first half of November 2004, many solar flares and coronal mass ejections (CMEs) were associated with solar active region (AR) 10696. This paper attempts to identify the solar and interplanetary origins of two superstorms which occurred on 8 and 10 November with peak intensities of Dst = -373 nT and -289 nT, respectively. Southward inte…
Radio Proper Motions of Wolf-Rayet Stars
Rodríguez, L. F.; Dzib, S.
We present the analysis of observations taken from the Very Large Array archive of six Wolf-Rayet stars with radio emission, with the purpose of determining their proper motions. Typically, these observations cover periods of 10 to 20 years. To verify the method, we included WR 140 in the sample, and found that the proper motions determined by us …
Characterization and selection of CZT detector modules for HEX experiment onboard Chandrayaan-1
Sreekumar, P.; Sudhakar, M.; Shanmugam, M. +4 more
We present the results of characterization of a large sample of Cadmium Zinc Telluride (CZT) detector modules planned to be used for the HEX (High Energy X-ray spectrometer) experiment onboard India's first mission to the Moon, Chandrayaan-1. We procured forty modules from Orbotech Medical Solutions Ltd. and carried out a detailed characterization…
Chandra and XMM-Newton observations of the low-luminosity X-ray pulsators SAX J1324.4-6200 and SAX J1452.8-5949
Paul, Biswajit; Wijnands, Rudy; Degenaar, Nathalie +5 more
We present results from our Chandra and XMM-Newton observations of two low-luminosity X-ray pulsators SAX J1324.4-6200 and SAX J1452.8-5949 which have spin periods of 172 and 437 s, respectively. The XMM-Newton spectra for both sources can be fitted well with a simple power-law model of photon index, Γ ~ 1.0. A blackbody model can equally well fit…
Jovian periodicities (∼10 h, ∼40 min) on Ulysses’ Distant Jupiter Encounter observations around the Halloween CIR events
Sarris, E. T.; Anagnostopoulos, G. C.; Louri, I. +1 more
We analyzed data from four different instruments (HI-SCALE, URAP, SWOOPS, VHM/FGM) onboard Ulysses spacecraft (s/c) and we searched for possible evidence of Jovian emissions when the s/c approached Jupiter during the times of Halloween events (closest time approach/position to Jupiter: February 5, 2004/ R = 1683 R J, θ = ∼49°). In parti…
Ellipsoidal Variable V1197 Orionis: Absolute Light-Velocity Analysis for Known Distance
Chochol, D.; Wilson, R. E.; Pribulla, T. +3 more
V1197 Orionis light curves from a long-term observing program for red giant binaries show ellipsoidal variation of small amplitude in the V and RC bands, although not clearly in U and B. Eclipses are not detected. All four bands show large irregular intrinsic variations, including fleeting quasi-periodicities identified by power spectra…
Renewed Activity from the X-Ray Transient SAXJ 1810.8-2609 with Integral
Fiocchi, M.; Ubertini, P.; Bazzano, A. +8 more
We report on the results of International Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of the neutron star low-mass X-ray binary SAX J1810.8-2609 during its latest active phase in 2007 August. The current outburst is the first one since 1998 and the derived luminosity is 1.1-2.6 ×1036 erg s-1 in the 20-100 keV en…
Formation Mechanism of Soft X-Ray Transient Trans-Equatorial Loop System
Masuda, Satoshi; Yokoyama, Masaki
The Soft X-ray Telescope (SXT) onboard Yohkoh often observed large-scale coronal loops connecting two active regions situated in opposite hemispheres. These are the trans-equatorial loop systems (TLSs). The formation mechanism of TLSs is not yet known. We analyzed a TLS observed simultaneously with Yohkoh/SXT and a coronagraph (SOHO/LASCO-C1). SOH…
Another Abundance Inhomogeneity in the South East Limb of the Cygnus Loop
Katsuda, Satoru; Uchida, Hiroyuki; Mori, Koji +2 more
We observed the south east (SE) limb of the Cygnus Loop with Suzaku. Our spatially-resolved spectroscopic study shows that a one-kTe non-equilibrium ionization model represents our spectra fairly well. We find that the metal abundances obtained are all depleted relative to the solar values with a positional dependence along the radial d…
Determining the fundamental parameters of F and G supergiants
Lyubimkov, L. S.; Rachkovskaya, T. M.; Poklad, D. B.
A technique for determining the effective temperature Teff and the acceleration of gravity log g of F and G supergiants is discussed using four bright stars as examples, specifically two F supergiants, α Lep(F0 Ib) and π Sgr (F2 II), and two G supergiants, β Aqr (G0 Ib) and α Aqr (G2 Ib). In all four cases the parameter log g was derive…