Search Publications

The Andromeda project. I. Deep HST-WFPC2 V, I photometry of 16 fields toward the disk and the halo of the M 31 galaxy. Probing the stellar content and metallicity distribution

Cacciari, C.; Bellazzini, M.; Federici, L. +2 more

We have obtained HST-WFPC2 F555W and F814W photometry for 16 fields in the vicinity of the luminous nearby spiral galaxy M 31, sampling the stellar content of the disk and the halo at different distances from the center, from ~ 20 to ~ 150 arcmin (i.e. ~ 4.5 to 35 kpc), down to limiting V and I magnitudes of ~ 27.

The Color-Magnitude Diagrams…

The Ibis-Picsit detector onboard Integral

Di Cocco, G.; Stephen, J. B.; Gianotti, F. +6 more

PICsIT is the high-energy detector layer of the IBIS Imager, composed of 4096 CsI(Tl) scintillator detectors 8.4 x 8.4x 300 mm in size with PhotoDiode readout. The detector operates in the 175 keV-20.4 MeV range and its data generation modes make it possible to collect information from single events and multiple coincident events. PICsIT is surrou…

XMM-Newton discovery of an X-ray filament in Coma

Finoguenov, A.; Briel, U. G.; Henry, J. P.

XMM-Newton observations of the outskirts of the Coma cluster of galaxies confirm the existence of a soft X-ray excess claimed previously and show it comes from warm thermal emission. Our data provide a robust estimate of its temperature ( ~ 0.2 keV) and oxygen abundance ( ~ 0.1 solar). Using a combination of XMM-Newton and ROSAT All-Sky Survey dat…

XMM observation of M 87. II. Abundance structure of the interstellar and intergalactic medium

Finoguenov, A.; Böhringer, H.; Matsushita, K.

Based on a detailed study of the temperature structure of the intracluster medium in the halo of M 87, abundance profiles of 7 elements, O, Mg, Si, S, Ar, Ca, and Fe are derived. In addition, abundance ratios are derived from the ratios of line strengths, whose temperature dependences are small within the temperature range of the ICM of M 87. The …

Multiwavelength studies of the Seyfert 1 galaxy NGC 7469 II. X-ray and UV observations with XMM-Newton

Kaastra, J. S.; Kriss, G. A.; Behar, E. +6 more

We present an XMM-Newton observation of NGC 7469, including studies of the X-ray and UV variability, 0.2-10 keV spectral continuum, Fe Kalpha emission line and the first-ever high-resolution X-ray spectrum of the soft X-ray warm absorber. We compare the properties of this X-ray warm absorber with the UV warm absorber as seen in a FUSE observation …

H₂ infrared line emission across the bright side of the rho Ophiuchi main cloud

Boulanger, F.; Abergel, A.; Falgarone, E. +3 more

We present imaging and spectroscopic observations of dust and gas (H₂) emission, obtained with ISO, from the western edge of the rho Ophiuchi molecular cloud illuminated by the B2 star HD147889 (chi ~ 400). This photodissociation region (PDR) is one of the nearest PDRs to the Sun (d = 135 +/- 15 pc from the stellar parallax) and the lay…

INTEGRAL Spectrometer SPI's GRB detection capabilities. GRBs detected inside SPI's FoV and with the anticoincidence system ACS

Hurley, K.; Hanlon, L.; McBreen, B. +16 more

The spectrometer SPI, one of the two main instruments of the INTEGRAL spacecraft, offers significant gamma-ray burst detection capabilities. In its 35^o (full width) field of view SPI is able to localise gamma-ray bursts at a mean rate of ~ 0.8/month. With its large anticoincidence shield of 512 kg of BGO crystals SPI is able to detect g…

Correlation between halo coronal mass ejections and solar surface activity

Wang, Jingxiu; Zhou, Guiping; Cao, Zhuoliang

We survey all the coronal mass ejections (CMEs) observed by the Large Angle and Spectrometric Coronagraph Experiment (LASCO) aboard the Solar Heliospheric Observatory (SOHO) in the interval from 1997 to 2001, and select 197 frontside halo CMEs whose associated near-surface activity could be clearly identified from SOHO EUV Imaging Telescope (EIT) …

The spiral galaxy M 33 mapped in the FIR by ISOPHOT. A spatially resolved study of the warm and cold dust

Lemke, D.; Völk, H. J.; Klaas, U. +4 more

The Sc galaxy M 33 has been mapped with ISOPHOT in the far-infrared, at 60, 100, and 170 mu m. The spatial resolution of these FIR maps allows the separation of spiral arms and interarm regions and the isolation of a large number of star-forming regions. The spectral energy distribution in the FIR indicates a superposition of two components, a war…

Rotation and magnetic field in the Be star omega Orionis

Frémat, Y.; Zorec, J.; Neiner, C. +5 more

omega Ori is a B2IIIe star for which rotational modulation and non-radial pulsations (NRP) have been recently investigated from two independent observational campaigns in 1998 and 1999. Putting the data of these 2 campaigns together, and adding data obtained in 2001, we search for multiperiodicity in the line profile variations …