Search Publications
2XMM J083026+524133: the most X-ray luminous cluster at redshift 1
Schwope, A.; Hoeft, M.; Lamer, G. +2 more
Aims: In the distant universe X-ray luminous clusters of galaxies are rare objects. Large area surveys are therefore needed to probe the high luminosity end of the cluster population at redshifts z ⪆ 1.
Methods: We correlated extended X-ray sources from the second XMM-Newton source catalogue (2XMM) with the SDSS in order to identify new cluste…
Zeeman-tomography of the solar photosphere. Three-dimensional surface structures retrieved from Hinode observations
Carroll, T. A.; Kopf, M.
Aims:The thermodynamic and magnetic field structure of the solar photosphere is analyzed by means of a novel 3-dimensional spectropolarimetric inversion and reconstruction technique.
Methods: On the basis of high-resolution, mixed-polarity magnetoconvection simulations, we used an artificial neural network (ANN) model to approximate the nonlin…
On the combination of ACE data with numerical simulations to determine the initial characteristics of a CME
Poedts, S.; Chané, E.; van der Holst, B.
Aims: Our goal is to combine the Advanced Composition Explorer (ACE) data with numerical simulations to determine the initial characteristics of the halo coronal mass ejection (CME), which was observed on April 4, 2000.
Methods: The evolution of a CME from the Sun to 1 AU is simulated in the framework of 2.5 D (axi-symmetric) ideal Magnetohydr…
Intensity oscillations and heating of the coronal X-ray bright points from Hinode/XRT
Kariyappa, R.; Varghese, B. A.
Aims: Our aim is to investigate the intensity oscillations in coronal X-ray Bright Points (XBPs).
Methods: We analysed a 7 h long time sequence of the soft X-ray images obtained on April 14, 2007 with a 2 min cadence using the X-Ray Telescope (XRT) on-board the Hinode mission. We use SSW in IDL to derive the time series of 14 XBPs and 2 backgr…
Morphology of galaxies in the Coma cluster region down to M_B = -14.25. I. A catalog of 473 members
Andreon, S.; Michard, R.
This paper presents morphological type, membership, and U{-}V color for a sample of galaxies in the Coma cluster direction, complete down to M_B=-15.00 mag and extending down to M_B=-14.25 mag. We have examined 1155 objects from the GMP 1983 catalog on B and V images of the CFH12K camera, and obtained the Hubble type in most cases. Coma cluster me…
NGC 300 X-1 and IC 10 X-1: a new breed of black hole binary?
Barnard, R.; Clark, J. S.; Kolb, U. C.
Context: IC 10 X-1 has recently been confirmed as a black hole (BH) + Wolf-Rayet (WR) X-ray binary, and NGC 300 X-1 is thought to be. The only other known BH+WR candidate is Cygnus X-3. IC 10 X-1 and NGC 300 X-1 have similar X-ray properties, with 0.3-10 keV luminosities ~1038 erg s-1, and their X-ray lightcurves exhibit orbi…
X-ray absorption in distant type II QSOs
Barcons, X.; Carrera, F. J.; Watson, M. G. +7 more
Aims: We present the results of the X-ray spectral analysis of an XMM-Newton-selected type II QSO sample with z ≥ 0.5 and 0.5-10 keV flux of 0.3-33×10-14 erg/s/cm^2. The distribution of absorbing column densities in type II QSOs is investigated and the dependence of absorption on X-ray luminosity and redshift is studied.
Methods: We…
A probable close brown dwarf companion to GJ 1046 (M 2.5V)
Kürster, M.; Reffert, S.; Endl, M.
Context: Brown dwarf companions to stars at separations of a few AU or less are rare objects, and none have been found so far around early-type M dwarfs (M 0V-M 5V). With GJ 1046 (M 2.5V), a strong candidate for such a system with a separation of 0.42 AU is presented.
Aims: We aim at constraining the mass of the companion in order to decide wh…
Suppression of convection around small magnetic concentrations
Ichimoto, K.; Katsukawa, Y.; Shimojo, M. +3 more
Aims: It is well known that convective motions in the photosphere are suppressed by magnetic fields. However, it has been difficult to study the interaction between convection and small magnetic features, such as G-band bright points (GBPs) or pores with polarimetric measurements, because of the available spatial resolution (~1´´). This situation …
High-redshift blazar identification for Swift J1656.3-3302
Palazzi, E.; Masetti, N.; Gehrels, N. +9 more
We report on the high-redshift blazar identification of a new gamma-ray source, Swift J1656.3-3302, detected with the BAT imager onboard the Swift satellite and the IBIS instrument on the INTEGRAL satellite. Follow-up optical spectroscopy has allowed us to identify the counterpart as an R∼ 19 mag source that shows broad Lyman-α, Si iv, He ii, C iv…