Search Publications
Observational signatures of the interaction between acoustic waves and the solar magnetic canopy
McIntosh, S. W.; Jefferies, S. M.; Armstrong, J. D. +1 more
Aims:We show that the spatial distribution (and its variation with frequency) of the power spectra of the velocity and intensity signals, in and around solar active regions, is a manifestation of the interaction of acoustic waves at the magnetic canopy.
Methods: We analysed 6 h of simultaneous, full-disk, velocity and intensity images obtained…
A refined analysis of the remarkable Bp star HR 6000
Hubrig, S.; Castelli, F.
Aims:UVES spectra of the very young (∼ 107 years) peculiar B-type star HR 6000 were analyzed in the near-UV and visual spectral regions (3050-9460 Å) with the aim of extending to other spectral ranges the study made previously in the UV using IUE spectra.
Methods: Stellar parameters T_eff = 12 850 K, log g = 4.10, and ξ=0 km s-…
Spectral properties of X-ray bright variable sources in the Taurus molecular cloud
Audard, M.; Güdel, M.; Briggs, K. R. +7 more
Aims:We analyze 19 bright variable X-ray sources detected in the XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST), to characterize the variations with time of their coronal properties and to derive information on the X-ray emitting structures.
Methods: We performed time-resolved spectroscopy of the EPIC PN and MOS spectra of the…
XMM-Newton observations of EF Eridani: the textbook example of low-accretion rate polars
Koester, D.; Schwope, A. D.; Vogel, J. +1 more
Archival X-ray observations of EF Eridani obtained in a low state revealed distinct X-ray detections at a luminosity LX ≃ 2 × 1029 erg s-1, three orders of magnitude below its high state value. The plasma temperature was found to be as low as kT loa 2 keV, a factor 10 below the high state. The X-ray/UV/IR spectral …
X-ray broad-band study of the symbiotic X-ray binary 4U 1954+31
Cusumano, G.; Palazzi, E.; Frontera, F. +5 more
We present results of several pointed X-ray broad band observations of the “symbiotic X-ray binary” 4U 1954+31 performed with the satellites BeppoSAX, EXOSAT, ROSAT, RXTE and Swift between October 1983 and April 2006. We also studied the RXTE ASM data over a period of more than 10 years, from January 1996 to October 2006. Light curves of all point…
A NICMOS search for obscured supernovae in starburst galaxies
Maiolino, R.; Della Valle, M.; Cresci, G. +1 more
The detection of obscured supernovae (SNe) in near-infrared monitoring campaigns of starburst galaxies has shown that a significant fraction of SNe is missed by optical surveys. However, the number of SNe detected in ground-based near-IR observations is still significantly lower than the number of SNe extrapolated from the FIR luminosity of the ho…
South-West extension of the hard X-ray emission from the Coma cluster
Eckert, D.; Produit, N.; Courvoisier, T. J. -L. +1 more
Aims:We explore the morphology of hard (18-30 keV) X-ray emission from the Coma cluster of galaxies.
Methods: We analyse a deep (1.1 Ms) observation of the Coma cluster with the ISGRI imager on board the INTEGRAL satellite.
Results: We show that the source extension in the North-East to South-West (SW) direction ( 17^prime) significantly e…
Search for tidal dwarf galaxy candidates in a sample of ultraluminous infrared galaxies
Colina, L.; Monreal-Ibero, A.; Arribas, S. +1 more
Context: Small star-forming galaxies made out of collisional debris have been found in a variety of merging systems. So far only a few of them are known in Ultraluminous Infrared Galaxies (ULIRGs) although they show clear signs of interactions. Whether external star formation may take place in such objects in an open question.
Aims: The aim of…
High-resolution X-ray spectroscopy and imaging of the nuclear outflow of the starburst galaxy NGC 253
Pietsch, W.; Ehle, M.; Bauer, M. +3 more
Aims:Using XMM-Newton data, we have studied the nuclear outflow of the nearby starburst galaxy NGC 253 in X-rays with respect to its morphology and to spectral variations along the outflow.
Methods: We analysed XMM-Newton RGS spectra, RGS brightness profiles in cross-dispersion direction, narrow-band RGS and EPIC images, and EPIC PN brightness…
Chandra and Spitzer observations of CDFS X-ray obscured QSOs
Georgakakis, A.; Georgantopoulos, I.; Akylas, A.
We present Chandra and Spitzer data for the 186, extragalactic, hard 2-10 keV X-ray selected sources, which lie in the central part of the Chandra Deep Field South (CDFS). For the vast majority of sources (99.5%), there is a spectroscopic or photometric redshift available. We classify 17 sources as X-ray obscured QSOs, strictly according to X-ray …