Search Publications
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
XMM-Newton observations of the dwarf elliptical galaxy NGC 3226
Gondoin, P.; Orr, A.; Siddiqui, H.
We report on an XMM-Newton observation of the dwarf elliptical galaxy NGC 3226 performed in November 2000. The analysis of the 0.4-10 keV spectrum of its nucleus is consistent with a power law continuum (Γ ≈ 1.96) absorbed at low energies by neutral gas (with a hydrogen column density NH ≈ 3-8× 1021 cm-2 and a cove…
A critical discussion on parametric and nonparametric regression methods applied to Hipparcos-FK5 residuals
Marco, F. J.; Martínez, M. J.; López, J. A.
In this paper we present an analysis of the differences between the Hipparcos and FK5 catalogues. We study parametric and nonparametric methods with two main objectives: first, to determine whether or not there is a pure rotation between the two catalogues, and to decide which model best represents the residuals; second, to give a practical formul…
A population of extreme mid-to-near-infrared sources: Obscured AGN and dusty starbursts
Vaccari, M.; Väisänen, P.; Johansson, P. H.
We present a sample of mid-infrared detected sources from the European Large Area ISO Survey (ELAIS) regions characterised by strong mid-IR radiation with faint near-IR and optical counterparts. These extreme mid-to-near-IR objects (EMNOs) are defined here by a flux ratio of fν (15 µm) / fν (2.2 µm) > 25. This …