Search Publications
Mapping ices in protostellar environments on 1000 AU scales. Methanol-rich ice in the envelope of Serpens SMM 4
van Dishoeck, E. F.; Pontoppidan, K. M.; Dartois, E.
We present VLT-ISAAC L-band spectroscopy toward 10 stars in SVS 4, a 30 arcsec×45 arcsec dense cluster of pre-main sequence stars deeply embedded in the Serpens star forming cloud. The ISAAC spectra are combined with archival imaging from UKIRT and ISOCAM to derive accurate extinctions toward the SVS 4 stars. The data are then used to construct a …
A multiwavelength study of solar flare waves. II. Perturbation characteristics and physical interpretation
Magdalenić, J.; Vršnak, B.; Hanslmeier, A. +2 more
The study of solar flare waves - globally propagating wave-like disturbances usually observed in Hα as Moreton waves - has recently come back into focus prompted by the observation of coronal waves in the EUV with the SOHO/EIT instrument (``EIT waves"), and in several additional wavelength channels. We study 12 flare wave events in order to determ…
Solar magnetic elements at 0.1 arcsec resolution. General appearance and magnetic structure
Hansteen, V. H.; Carlsson, M.; Berger, T. E. +6 more
New observations of solar magnetic elements in a remnant active region plage near disk center are presented. The observations were obtained at the recently commissioned Swedish 1-m Solar Telescope on La Palma. We examine a single 430.5 nm G-band filtergram that resolves ∼70 km (0.1 arcsec) structures and find new forms of magnetic structures in th…
Kinematics of coronal mass ejections between 2 and 30 solar radii. What can be learned about forces governing the eruption?
Vršnak, B.; Gopalswamy, N.; Sudar, D. +1 more
Kinematics of more than 5000 coronal mass ejections (CMEs) measured in the distance range 2-30 solar radii is investigated. A distinct anticorrelation between the acceleration, a, and the velocity, v, is found. In the linear form, it can be represented as a=-k1(v-v0), where v0=400 km s-1, i.e., most of C…
The distance to the giant elliptical galaxy NGC 5128
Rejkuba, M.
The distance to NGC 5128, the central galaxy of the Centaurus group and the nearest giant elliptical to us, has been determined using two independent distance indicators: the Mira period-luminosity (PL) relation and the luminosity of the tip of the red giant branch (RGB). The data were taken at two different locations in the halo of NGC 5128 with …
XMM-Newton observations of the supernova remnant RX J1713.7-3946 and its central source
Ballet, J.; Decourchelle, A.; Giacani, E. +3 more
We present new results from the observations of the supernova remnant (SNR)
Dynamics of solar coronal loops. II. Catastrophic cooling and high-speed downflows
Peter, H.; Hansteen, V. H.; Müller, D. A. N.
This work addresses the problem of plasma condensation and ``catastrophic cooling'' in solar coronal loops. We have carried out numerical calculations of coronal loops and find several classes of time-dependent solutions (static, periodic, irregular), depending on the spatial distribution of a temporally constant energy deposition in the loop. Dyn…
The nature of the Galactic Center source IRS 13 revealed by high spatial resolution in the infrared
Rigaut, F.; Paumard, T.; Stolovy, S. R. +1 more
High spatial resolution observations in the 1 to 3.5 µm/ region of the Galactic Center source known historically as
Abundances of Na, Mg and Al in nearby metal-poor stars
Zhao, G.; Liang, Y. C.; Shi, J. R. +2 more
To determine the population membership of nearby stars we explore abundance results obtained for the light neutron-rich elements 23Na and 27 Al in a small sample of moderately metal-poor stars. Spectroscopic observations are limited to the solar neighbourhood so that gravities can be determined from HIPPARCOS parallaxes, and …
Band-splitting of coronal and interplanetary type II bursts. III. Physical conditions in the upper corona and interplanetary space
Magdalenić, J.; Vršnak, B.; Zlobec, P.
We analyse properties of 58 type II radio bursts recorded in the meter-to-kilometer wavelength range, focusing on episodes of band-split emission. The basic two parameters utilized are the frequency drift Df=df/dt and the relative band-split BDW=Δ f/f of type II burst emission lanes. On average, in the meter-to-kilometer wavelength rang…