Search Publications
Evidence for a Photoevaporated Circumbinary Disk in Orion
Robberto, M.; Da Rio, N.; Ricci, L. +1 more
We have found a photoevaporated disk in the Orion Nebula that includes a wide binary. HST ACS observations of the proplyd 124-132 show two pointlike sources separated by 0.15'', or about 60 AU at the distance of Orion. The two sources have nearly identical I and z magnitudes. We analyze the brightest component, source N, comparing the observed mag…
The Radio Signature of Magnetic Reconnection for the M-Class Flare of 2004 November 1
Ji, Haisheng; Huang, Guangli; Wu, Guiping
In this Letter, we present radio diagnostics for the magnetic field and the density distribution of nonthermal electrons in the microwave source of the M1.1 flare of 2004 November 1. We calculate the nonthermal gyrosynchrotron radiation using observations made at the Nobeyama Radio Observatory to get the longitudinal magnetic field and the magnitu…
Puzzling X-rays from the new colliding wind binary Wolf-Rayet 65 (WC9d)
Hamann, W. -R.; Oskinova, L. M.
We report the discovery of variability in the X-ray emission from the Wolf-Rayet type star WR65. Using archival Chandra data spanning over 5yr, we detect changes of the X-ray flux by a factor of 3 accompanied by changes in the X-ray spectra. We believe that this X-ray emission originates from wind-wind collision in a massive binary system. The obs…
Cluster observations of particle acceleration up to supra-thermal energies in the cusp region related to low-frequency wave activity - possible implications for the substorm initiation process
Dandouras, I.; Zhang, H.; Zong, Q. -G. +6 more
The purpose of our study is to investigate the way particles are accelerated up to supra-thermal energies in the cusp diamagnetic cavities. For this reason we have examined a number of Cluster cusp crossings, originally identified by Zhang et al. (2005), for the years 2001 and 2002 using data from RAPID, STAFF, EFW, CIS, PEACE, and FGM experiments…
The Absolute Flux Distribution of LDS749B
Koester, D.; Bohlin, R. C.
Observations from the Space Telescope Imaging Spectrograph (STIS) define the flux of the DBQ4 star LDS749B from 0.12 to 1.0 µm with an uncertainty of ~1% relative to the three pure hydrogen white dwarf primary Hubble Space Telescope standards. With T eff = 13,575 K, log g = 8.05, and a trace of carbon at 1 × 10-6 of sol…
On the Formation of Perseus OB1 at High Galactic Latitudes
Lim, Jeremy; Lee, Hsu-Tai
The Per OB1 association, which contains the remarkable double cluster h and χ Per, is unusual in not having a giant molecular cloud in its vicinity. We show from Hipparcos data that the luminous members of this association exhibit a bulk motion away from the Galactic plane, such that their average velocity increases with height above the Galactic …
HST spectral imaging of Titan's haze and methane profile between 0.6 and 1 µm during the 2000 opposition
Young, E. F.; Anderson, C. M.; McKay, C. P. +1 more
We report on the analysis of high spatial resolution visible to near-infrared spectral images of Titan at L=240° in November 2000, obtained with the Space Telescope Imaging Spectrograph instrument on board the Hubble Space Telescope as part of program GO-8580. We employ a radiative transfer fractal particle aerosol model with a Bayesian parameter …
SUMER observations of the inverse Evershed effect in the transition region above a sunspot
Solanki, S. K.; Curdt, W.; Teriaca, L.
Aims: We analyse SUMER spectral scans of a large sunspot within active region NOAA 10923, obtained on 14-15 November 2006, to determine the morphology and dynamics of the sunspot atmosphere at different heights/temperatures.
Methods: The data analysed here consist of spectroheliograms in the continuum around 142.0 nm and in the Si iv 140.2 nm,…
Different triggering mechanisms for solar flares and coronal mass ejections
Lippiello, E.; de Arcangelis, L.; Godano, C.
Context: Experimental observations indicate that flares and CMEs are often associated, even if the precise relationship between the two phenomena is a still hot and open question.
Aims: We present a study of the statistical properties of solar flare and CME temporal organisation, in order to enlighten differences in the mechanisms at the basis…
Obscured Sources and Supergiant Fast X-ray Transients: New Classes of High Mass X-ray Binaries
Chaty, S.
A new type of high-energy binary systems has been revealed by the INTEGRAL satellite. These sources are in the course of being unveiled by means of multi-wavelength optical, near-and mid-infrared observations. Among these sources, two distinct classes are appearing: the first one is constituted of intrinsically obscured high-energy sources, of whi…