Search Publications

Imaging techniques for gamma-ray diffuse emission: application to INTEGRAL/SPI

Roques, J. -P.; Allain, M.

Diffuse imaging in the gamma-ray energy range is a challenging problem, since faint radiation is usually mixed with strong instrumental background components. This situation results in data sets that are not very informative, so they lead to non robust image reconstruction. In this paper, we used a Bayesian approach to produce sky-maps with high r…

From Hubble diagrams to scale factors

Tilquin, A.; Schücker, T.

Context: .
Aims: .We study the image of the transform from scale parameters to Hubble diagrams and present a lower bound on the radius of the universe today a₀ and a monotonicity constraint on the Hubble diagram.
Methods: .Our theoretical input is minimal: Einstein's kinematics and maximally symmetric universes.
Results: .Pr…

Non-radial pulsations in the γ Doradus star HD 195068

Mathias, P.; Jankov, S.; Chapellier, E. +2 more

We present high resolution spectroscopic observations of the γ Doradus star HD 195068. About 230 spectra were collected over 2 years. Time series analysis performed on radial velocity data shows a main peak at 1.61 d^-1 , a frequency not yet detected in photometry. The Hipparcos photometric 1.25 d^-1 frequenc…

The color signature of the transit of HD 209458: discrepancies between stellar atmospheric models and observations

Tingley, B.; Thurl, C.; Sackett, P.

Exoplanetary transits produce a double-horned color signature that is distinct from both binaries and blends and can thus be used to separate exoplanets from false positives in transit searches. Color photometry with precision sufficient to detect this signal in transits of HD 209458 is available in the literature. Analysis of these observations r…

A multi-wavelength study of the IRAS Deep Survey galaxy sample. I. Optical observations. The redshift distribution

Aussel, H.; de Zotti, G.; Mazzei, P. +2 more

Context: The IRAS Deep Survey (IDS) of the North Ecliptic Pole region remains one of the deepest complete far-infrared-selected galaxy samples available. ISOCAM observations in the LW3 filter (12-18 µm) of 3.2 arcmin × 3.2 arcmin fields centered on the nominal positions of 94 out of the 98 IDS sources yielding 116 ISOCAM detections. The resu…

A deep XMM-Newton serendipitous survey of a middle-latitude area

Caraveo, P. A.; Bignami, G. F.; de Luca, A. +4 more

The radio-quiet neutron star 1E1207.4-5209 was the target of a 260 ks XMM-Newton observation, that yielded, as a by product, a harvest of about 200 serendipitous X-ray sources above a limiting flux of 2 × 10^-15 erg cm^-2 s^-1 in the 0.3-8 keV energy range. In view of the intermediate latitude of our field (b≃ 10°), i…

Swift, RXTE, and INTEGRAL observation of Swift J1922.7-1716

Campana, S.; Belloni, T.; Falanga, M.

We report the results of analyzing Swift, RossiXTE, and INTEGRAL data of Swift J1922.7-1716, a likely transient X-ray source discovered by Swift/BAT. Both the fast variability measured by the RXTE/PCA and the combined Swift/XRT, RXTE/PCA, and INTEGRAL/ISGRI (0.5-100 keV) energy spectrum suggest that the system is a neutron-star low-mass X-ray bina…

On measuring the Tully-Fisher relation at z > 1. A case study using strong Hα emitting galaxies at z > 1.5

Yan, L.; van der Werf, P. P.; Moorwood, A. F. M. +1 more

The evolution of the line width - luminosity relation for spiral galaxies, the Tully-Fisher relation, strongly constrains galaxy formation and evolution models. At this moment, the kinematics of z>1 spiral galaxies can only be measured using rest frame optical emission lines associated with star formation, such as Hα and [O III]5007/4959 and [O…

Calibration of TRACE Lyman-α images using SOHO/SUMER observations

Kim, Sungsoo S.; Roh, Hee-Seon; Cho, Kyung-Seok +1 more

1216 Å channel images from the Transition Region and Coronal Explorer (TRACE) contain not only the desired HI Lyman-α (Lα) line emission from the Sun, but also some UV continuum around 1600 Å. By comparing TRACE data with Lα images from the Very High Angular Resolution Ultraviolet Telescope, Handy et al. proposed a simple procedure to remove the c…

High resolution spectroscopy of giant HII regions around young massive clusters

Maiolino, R.; Vanzi, L.; Scatarzi, A. +1 more

We present new high-resolution optical spectroscopy of giant HII regions around three young

massive clusters located in the blue dwarf galaxies NGC 5253 and He 2-10.

We used the observations to derive the mass of the clusters under the hypothesis of virialization. The virial masses exceed the optical ones. In one case, however, the viria…