Search Publications
Tentative detection of micron-sized forsterite grains in the proto-planetary disk surrounding HD 100453
Waters, L. B. F. M.; Dominik, C.; van Boekel, R. +4 more
We have re-analyzed the ISO-SWS spectrum of the intermediate mass pre-main-sequence star HD 100453. We confirm the weakness of the 10 µm amorphous silicate band. We have found strong indications of the presence of a crystalline silicate emission at 34 µm, which had escaped detection so far due to severe glitches in the data. The 23.5 a…
The double radio source 3C 343.1: A galaxy-QSO pair with very different redshifts
Burbidge, E. M.; Arp, H.; Burbidge, G.
The strong radio source 3C 343.1 consists of a galaxy and a QSO separated by no more than about 0.25''. The chance of this being an accidental superposition is conservatively ∼1×10-8. The z=0.344 galaxy is connected to the z=0.750 QSO by a radio bridge. The numerical relation between the two redshifts is that predicted from p…
Dark baryons not in ancient halo white dwarfs
McCracken, H. J.; Reylé, C.; Robin, A. C. +5 more
Having ruled out the possibility that stellar objects are the main contributor of the dark matter embedding galaxies, microlensing experiments cannot exclude the hypothesis that a significant fraction of the Milky Way dark halo might be made of MACHOs with masses in the range 0.5-0.8 M⊙. Ancient white dwarfs are generally considered the…
X-ray detections of two young bona-fide brown dwarfs
Bouy, H.
I report the detection of two bona-fide brown dwarfs by XMM-Newton:
Is T Leonis a superoutbursting intermediate polar?
Schmitt, J. H. M. M.; Ness, J. -U.; Vrielmann, S.
We present an XMM-Newton analysis of the cataclysmic variable T Leo. The X-ray light curve shows sinusoidal variation on a period Px equal to 0.89+0.14-0.10 times the previously spectroscopically determined orbital period. Furthermore, we find a signal in the power spectrum at 414 s that could be attributed to the …
Quantitative interpretation of the rotation curves of spiral galaxies at redshifts z ∼ 0.7 and z ∼ 1
Böhm, A.; Ziegler, B. L.; Möllenhoff, C. +1 more
We present decompositions of the rotation curves of three spiral galaxies at redshifts z ∼ 0.7 and 1 into contributions by their bulges, disks, and dark halos, respectively. In order to set constraints on the degeneracy of the decompositions we interpret the morphology of the spiral structures quantitatively in the framework of density wave theory…
Do X-ray plasma ejections accelerate Coronal Mass Ejections?
Tomczak, M.
The X1.2 flare occurred on 23 April 1998 approximately 13° behind the eastern solar limb. Its C2.0 precursor is identified as a rapidly expanding system of magnetic loops that was well-observed by Yohkoh. Basic parameters of this ejection are estimated based on images from the SXT telescope. The evolution of the X-ray ejection is compar…
Reconsidering the origin of the X-ray emission lines in GRB 011211
Ghisellini, G.; Tavecchio, F.; Lazzati, D.
We reanalyze the XMM-Newton data of GRB 011211 showing that the spectral features, interpreted by Reeves et al. (\cite{Ree02}, \cite{Ree03}) as due to thermal emission from a collisionally ionized plasma, can be also reproduced by a reflection model (with ionization parameter ξ∼ 102). We discuss the implications of this interpretation, …
Serpens X-1 observed by INTEGRAL
Palazzi, E.; Frontera, F.; Orlandini, M. +13 more
Here we report results of an INTEGRAL-AO1 observation of the X-ray burst and atoll source Ser X-1 performed in May 2003. The object was observed for a total on-source time of 400 ks but nearly 8° off-axis due to its amalgamation with an observation of SS 433, the pointing target source. Ser X-1 has been clearly detected up to 30 keV wit…
RX J0256.5+0006 : A merging cluster of galaxies at z = 0.36 observed with XMM-NEWTON
Nichol, R. C.; Romer, A. K.; Majerowicz, S. +3 more
We present here a study based on XMM-NEWTON data of