Search Publications
Proton and helium release times in SEP events observed with SOHO/ERNE
Laitinen, T.; Valtonen, E.; Huttunen-Heikinmaa, K.
We determine the proton and helium nuclei release times at the Sun for 25 SEP events within the time period May 8, 1996-June 20, 2001, and compare them to each other. The event onset times at 1 AU are determined with a Poisson-CUSUM method, and the solar release times are obtained by the velocity dispersion analysis. Velocity dispersions were deri…
XMM-Newton study of the two-dimensional structure of the REFLEX-DXL galaxy clusters
Zhang, Y. -Y.; Finoguenov, A.; Böhringer, H.
We carry out a two-dimensional study of temperature, entropy, and pressure distributions in a nearly volume-limited subsample of REFLEX clusters at redshift 0.3, the REFLEX-DXL. We use the observations gained by XMM-Newton, which cover the central 1{-}2× r500. We define the substructure in both entropy and pressure as a deviation from t…
Hubble Space Telescope imaging of globular cluster candidates in low surface brightness dwarf galaxies
Sharina, M. E.; Makarov, D. I.; Puzia, T. H.
Fifty-seven nearby low surface brightness dwarf galaxies (-10⪆ MV⪆ -16) were searched for globular cluster candidates (GCCs) using Hubble Space Telescope WFPC2 imaging in V and I. The sample consists of 18 dwarf spheroidal (dSph), 36 irregular (dIrr), and 3 "transition" type (dIrr/dSph) galaxies with angular sizes less than 3.7 kpc situ…
XMM-Newton X-ray spectroscopy of the high-mass X-ray binary 4U 1700-37 at low flux
Kaper, L.; van der Klis, M.; Barr, P. +4 more
We present results of a monitoring campaign of the high-mass X-ray binary system
Strong dust processing in circumstellar discs around 6 RV Tauri stars. Are dusty RV Tauri stars all binaries?
Waters, L. B. F. M.; Dominik, C.; Dejonghe, H. +2 more
We present extended Spectral Energy Distributions (SEDs) of seven classical RV Tauri stars, using newly obtained submillimetre continuum measurements and Geneva optical photometry supplemented with literature data. The broad-band SEDs show a large IR excess with a black-body slope at long wavelengths in six of the seven stars, R Sct being the noti…
The broad-band spectrum of the persistent emission from SGR 1806-20
Hurley, K.; Sunyaev, R.; Revnivtsev, M. +3 more
We present the results of an analysis of the quiescent X-ray emission from the Soft Gamma-Ray Repeater SGR 1806-20, taken during an INTEGRAL ultra-deep survey of the Galactic center region in Aug.-Sep. 2003. The total effective exposure time spent on the source by the IBIS telescope during these observations was 1.6 million seconds. Combining the …
Spherical harmonic decomposition of solar magnetic fields
Stenflo, J. O.; Knaack, R.
We have investigated the temporal evolution of large-scale magnetic fields in the solar photosphere during the time interval 1966-2004 by means of spherical harmonic decomposition and subsequent time series analysis. Two data sets of daily magnetograms recorded at the Mt. Wilson and Kitt Peak observatories were used to calculate the spherical harm…
Detailed comparison of downflows seen both in EIT 30.4 nm and Big Bear Hα movies
Berghmans, D.; Poedts, S.; de Groof, A. +2 more
An EIT shutterless campaign was conducted on 11 July 2001 and provided 120 high-cadence (68 s) 30.4 nm images of the north-eastern quarter of the Sun. Systematic intensity variations are seen which appear to propagate along an off-disk loop-like structure. In this paper we study the nature of these intensity variations by confronting the EIT obser…
Weak-line T Tauri stars: circumstellar disks and companions. I. Spectral energy distributions and infrared excesses
Ray, T. P.; Gras-Velázquez, À.
We have analysed new infrared photometric data taken by the Infrared Space Observatory, in combination with 2MASS data where available, of 12 weak-line T Tauri stars (WTTS), belonging to different molecular clouds. A control study of 6 classical T Tauri stars (CTTS) for comparison with IRAS data has also been made. WTTS traditionally are not expec…
Can surface magnetic fields reproduce solar irradiance variations in cycles 22 and 23?
Solanki, S. K.; Krivova, N. A.; Wenzler, T.
Total solar irradiance is reconstructed using data from the spectromagnetograph on Kitt Peak for 1992 2003 (covering parts of cycles 22 and 23) and compared with observational data. The model assumes that solar irradiance variations are caused by surface magnetism and its single free parameter is kept at the same value for both cycles. A good corr…