Search Publications

X-ray and optical substructures of the DAFT/FADA survey clusters

Adami, C.; Durret, F.; Lima Neto, G. B. +1 more

We have undertaken the DAFT/FADA survey with the double aim of setting constraints on dark energy based on weak lensing tomography and of obtaining homogeneous and high quality data for a sample of 91 massive clusters in the redshift range 0.4-0.9 for which there were HST archive data. We have analysed the XMM-Newton data available for 42 of these…

X-ray properties and scaling relations for {Planck} ESZ clusters

Vikhlinin, A.; Forman, W.; Murray, S. +2 more

Clusters of galaxies were first recognized through overdensities of galaxies. With the advent of X-ray telescopes, large numbers of clusters were by found by the spatially extended nature of their X-ray emission. Today with the availability of millimeter wave telescopes capable of finding clusters through the Sunyaev-Zeldovich effect, it is possib…

X-ray luminosity functions of different morphological and X-ray type AGN populations

Castañeda, H.; Cepa, J.; Bongiovanni, A. +12 more

Luminosity functions are one of the most important observational clues when studying galaxy evolution over cosmic time. In this paper we present the X-ray luminosity functions for X-ray detected AGN in the SXDS and GWS fields. The limiting fluxes of our samples are 9.0 ×10^-15 and 4.8 ×10^-16 erg cm^-2 s^-1 …

Relative astrometry and near-infrared differential photometry of nearby southern orbital binaries with adaptive optics

Cuypers, J.; Lampens, P.; Prieur, J. -L. +1 more

Observability of YSOs with the WISE and AKARI infrared space observatories

Tamura, M.; Marton, G.; Ueno, M. +4 more

Large area surveys allow us to identify young stellar objects and classify them based on their colours. The near-, mid- and far-infrared filters' sensitivities are different, therefore different proportions of young stars are observable. Evolutionary times for the different classes can be concluded from the popularity of the classes. Our aim was t…

Approximating the X-ray spectrum emitted from astrophysical charge exchange

Smith, R. K.; Foster, A. R.; Brickhouse, N. S.

Charge exchange (CX), both onto ions in the solar wind and potentially in other astrophysical contexts, can create X-ray emission lines largely indistinguishable from those created in collisional or photoionized plasmas. The prime distinguishing characteristic is in the distinctly different line ratios generated by the CX process. A complete astro…

Measuring the solar meridional flow from perturbations of eigenfunctions of global oscillations

Roth, M.; Schad, A.; Timmer, J.

We present a new concept to infer the meridional flow in the deep solar interior from global oscillation data. This concept is based on the estimation of the coupling strengths of p-mode eigenfunctions mediated by the meridional flow. We illustrate the performance of the method using simulations and present first inversion results of a large-scale…

A magnetic cycle of τ Bootis? The coronal and chromospheric view

Schmitt, J. H. M. M.; Günther, H. M.; Poppenhaeger, K.

τ Bootis is a late F-type main sequence star orbited by a Hot Jupiter. During the last years spectropolarimetric observations led to the hypothesis that this star may host a global magnetic field that switches its polarity once per year, indicating a very short activity cycle of only one year duration. In our ongoing observational campaign, we hav…

Preliminary results on γ Dor and δ Sct-γ Dor hybrid s in the CoRoT exo-field of LRa01

Hareter, M.

The 131 days long, high-precision light curves observed in the CoRoT exo-field during LRa01 were investigated for γ Dor and δ Sct-γ Dor hybrid stars. In total 418 γ Dor and 274 δ Sct-γ Dor hybrid candidates were identified. For a fraction of these candidates spectra are available obtained at the Anglo-Australian Observatory. Effective temperatures…

Spectroscopic evidence of charge exchange X-ray emission from galaxies

Wang, Q. D.; Liu, J.

What are the origins of the soft X-ray line emission from non-AGN galaxies? XMM-Newton RGS spectra of nearby non-AGN galaxies (including starforming ones: M82, NGC 253, M51, M83, M61, NGC 4631, M94, NGC 2903, and the Antennae galaxies, as well as the inner bulge of M31) have been analyzed. In particular, the K\alpha triplet of O VII shows that the…