Search Publications
Low-resolution VLT spectroscopy of GRBs 991216, 011211 and 021211
Piro, L.; Pian, E.; Palazzi, E. +16 more
We present low-resolution VLT spectroscopy of the afterglow of the gamma-ray bursts (GRBs) 991216, 011211 and 021211. Our spectrum of GRB 991216 is the only optical spectrum for this afterglow. It shows two probable absorption systems at z=0.80 and z=1.02, where the highest redshift most likely reflects the distance to the host galaxy. A third sys…
Multi wavelength study of the gravitational lens system RXS J1131-1231. II. Lens model and source reconstruction
Surdej, J.; Riaud, P.; Sluse, D. +1 more
Aims.High angular resolution images of the complex gravitational lens system
…
IGR J16393-4643: a new heavily-obscured X-ray pulsar
Walter, R.; Bird, A. J.; Ubertini, P. +5 more
An analysis of the high-energy emission from IGR J16393-4643 (=AX J1639.0-4642) is presented using data from INTEGRAL and XMM-Newton. The source is persistent in the 20-40 keV band at an average flux of 5.1×10-11 erg cm-2 s-1, with variations in intensity by at least an order of magnitude. A pulse period of 912.0±0…
XMM-Newton observations of the σ Orionis cluster. II. Spatial and spectral analysis of the full EPIC field
Pallavicini, R.; Franciosini, E.; Sanz-Forcada, J.
We present the results of an XMM-Newton observation of the young (∼ 2{-}4 Myr) cluster around the hot star σ Orionis. In a previous paper we presented the analysis of the RGS spectrum of the central hot star; here we discuss the results of the analysis of the full EPIC field. We have detected 175 X-ray sources, 88 of which have been identified wit…
X-ray observations of RX J0822-4300 and Puppis-A
Hui, C. Y.; Becker, W.
Based on observations with the X-ray observatories Chandra and XMM-Newton we present results from a detailed spectro-imaging and timing analysis of the central compact X-ray source RX J0822-4300 in the supernova remnant Puppis-A. The superior angular resolution of Chandra allows for the first time to pinpoint the point source nature of this object…
An improved deprojection and PSF-deconvolution technique for galaxy-cluster X-ray surface-brightness profiles
Arnaud, M.; Pointecouteau, E.; Pratt, G. W. +1 more
We have developed a regularisation procedure for the direct deprojection and PSF-deconvolution of X-ray surface brightness profiles of clusters of galaxies. This procedure allows us to obtain accurate density profiles in a straightforward manner from X-ray observations (in particular data from XMM-Newton, where the PSF correction is important), wh…
The evolution of Lyman α absorbers in the redshift range 0.5 < z < 1.9
Reimers, D.; Janknecht, E.; Lopez, S. +1 more
We investigate the evolution and the statistical properties of the Ly α absorbers of the intergalactic medium (IGM) in the largely unexplored redshift range z=0.5-1.9. We use high-resolution (R ≥ 30 000) UV (STIS) and optical (VLT/UVES and Keck/HIRES) spectra of nine bright quasars with z_em < 1.94. The Ly α lines detected in the lines of sight…
XMM-Newton observations of a sample of γ-ray loud active galactic nuclei
Maraschi, L.; Tagliaferri, G.; Ghisellini, G. +7 more
Aims.To understand the nature of γ-ray loud active galactic nuclei (AGN) and the mechanisms for the generation of high-energy γ-rays.
Methods: .We performed a homogeneous and systematic analysis of simultaneous X-ray and optical/UV properties of a group of 15 γ-ray loud AGN, using observations performed with XMM-Newton. The sample is composed …
Ultraviolet-to-far infrared properties of Lyman break galaxies and luminous infrared galaxies at z ~ 1
Ilbert, O.; Buat, V.; Burgarella, D. +13 more
Aims.We present the first large, unbiased sample of Lyman Break Galaxies (LBGs) at z ∼ 1. Far ultraviolet-dropout (1530 Å) galaxies in the Chandra Deep Field South have been selected using GALEX data. This first large sample in the z ∼ 1 universe provides us with a high quality reference sample of LBGs.
Methods: .We analyzed the sample from t…
What is the spatial distribution of magnetic helicity injected in a solar active region?
Démoulin, P.; Pariat, E.; Nindos, A. +1 more
Context: .Magnetic helicity is suspected to play a key role in solar phenomena such as flares and coronal mass ejections. Several investigations have recently computed the photospheric flux of magnetic helicity in active regions. The derived spatial maps of the helicity flux density, called G_A, have an intrinsic mixed-sign patchy distribution.