Search Publications
Swift/XRT orbital monitoring of the candidate supergiant fast X-ray transient IGR J17354-3255
Esposito, P.; Ducci, L.; Romano, P. +5 more
We report on the Swift/X-ray Telescope (XRT) monitoring of the field of view around the candidate supergiant fast X-ray transient (SFXT) IGR J17354-3255, which is positionally associated with the AGILE/GRID gamma-ray transient AGL J1734-3310. Our observations, which cover 11 days for a total on-source exposure of ~24 ks, span 1.2 orbital periods (…
Long-term evolution of the neutron-star spin period of SXP 1062
Haberl, F.; Udalski, A.; Gallagher, J. S. +4 more
Context. The Be/X-ray binary SXP 1062 is of especial interest owing to the large spin period of the neutron star, its large spin-down rate, and the association with a supernova remnant constraining its age. This makes the source an important probe for accretion physics.
Aims: To investigate the long-term evolution of the spin period and assoc…
X-ray irradiation and mass-loss of the hot Jupiter WASP-43b
Schmitt, J. H. M. M.; Czesla, S.; Salz, M. +1 more
We report the X-ray detection of the low-mass K7V star WASP-43, which is orbited by a hot Jupiter in one of the closest exoplanet orbits known to date. The high mean density of the planet implies a massive core with ≈130 M⊕, yielding a heavy-element mass-fraction of 20%. From an 18 ks long XMM-Newton observation, we derive an X-ray lumi…
Coronal magnetic field strength from Type II radio emission: complementarity with Faraday rotation measurements
Mancuso, S.; Garzelli, M. V.
We analyzed the band splitting of a Type II radio burst observed on 1997 May 12 by ground- and space-based radio spectrometers. Type II radio emission is the most evident signature of coronal shock waves and the observed band splitting is generally interpreted as due to plasma emission from both upstream and downstream shock regions. From the infe…
New companions in the stellar systems of DI Cha, Sz 22, CHXR 32, and Cha Hα 5 in the Chamaeleon I star-forming region
Neuhäuser, R.; Schmidt, T. O. B.; Vogt, N. +2 more
Context. The star-forming regions in Chamaeleon (Cha) are among the nearest (distance ~165 pc) and youngest (age ~2 Myr) conglomerates of recently formed stars and among the ideal targets for studies of star formation.
Aims: We search for new, hitherto unknown binary or multiple-star components and investigate their membership in Cha and thei…
Probing the evolution of the substructure frequency in galaxy clusters up to z ~ 1
Böhringer, H.; Chon, G.; Weißmann, A.
Context. Galaxy clusters are the last and largest objects to form in the standard hierarchical structure formation scenario through merging of smaller systems. The substructure frequency in the past and present epoch provides excellent means for studying the underlying cosmological model.
Aims: Using X-ray observations, we study the substruct…
Observations of the magnetars 4U 0142+61 and 1E 2259+586 with the MAGIC telescopes
Maraschi, L.; Covino, S.; Antonelli, L. A. +154 more
Context. Magnetars are an extreme, highly magnetized class of isolated neutron stars whose large X-ray luminosity is believed to be driven by their high magnetic field.
Aims: We study for the first time the possible very high energy γ-ray emission above 100 GeV from magnetars, observing the sources 4U 0142+61 and 1E 2259+586.
Methods: We…
Temperature dependence of ultraviolet line parameters in network and internetwork regions of the quiet Sun and coronal holes
Peter, H.; Curdt, W.; Wang, X. +3 more
Aims: We study the temperature dependence of the average Doppler shift and the non-thermal line width in network and internetwork regions for both the quiet Sun (QS) and the coronal hole (CH), by using observations of the Solar Ultraviolet Measurements of Emitted Radiation instrument onboard the Solar and Heliospheric Observatory spacecraft. …
Helioseismology of sunspots: defocusing, folding, and healing of wavefronts
Gizon, L.; Schunker, H.; Liang, Z. -C. +1 more
We observe and characterize the scattering of acoustic wave packets by a sunspot in a regime where the wavelength is comparable to the size of the sunspot. Spatial maps of wave travel times and amplitudes are measured from the cross-covariance function of the random wave field observed by SOHO/MDI around the sunspot in active region NOAO 9787. We …
Spectral diagnostic of a microflare. Evidences of resonant scattering in C IV 1548 Å, 1550 Å lines
Gontikakis, C.; Patsourakos, S.; Winebarger, A. R.
Aims: We study a microflare, classified as a GOES-A1 after background subtraction, which was observed in active region NOAA 8541 on May 15, 1999.
Methods: We used TRACE filtergrams to study the morphology and time evolution. SUMER spectral lines were used to diagnose the chromospheric plasma (Si ii 1533 Å), transition region plasma (C iv…