Search Publications

The optical to γ-ray emission of the Crab pulsar: a multicomponent model

Cusumano, G.; Campana, R.; Mineo, T. +1 more

We present a multicomponent model to explain the features of the pulsed emission and spectrum of the Crab Pulsar, on the basis of X and γ-ray observations obtained with BeppoSAX, INTEGRAL and CGRO. This model explains the evolution of the pulse shape and of the phase-resolved spectra, ranging from the optical/UV to the GeV energy band, on the assu…

Estimated IR and phosphorescence emission fluxes for specific polycyclic aromatic hydrocarbons in the Red Rectangle

Joblin, C.; Toublanc, D.; Mulas, G. +1 more

Following tentative identification of the blue luminescence in the Red Rectangle by Vijh et al., we computed absolute fluxes for the vibrational IR emission and phosphorescence bands of three small polycyclic aromatic hydrocarbons. The calculated IR spectra were compared with available ISO observations. A subset of the emission …

The GLE on Oct. 28, 2003 - radio diagnostics of relativistic electron and proton injection

Mann, G.; Aurass, H.; Warmuth, A. +1 more

Timing discrepancies between signatures of accelerated particles at the sun and the arrival times of the particles at near-earth detectors are a matter of fundamental interest for space-weather applications. The solar injection times of various components of energetic particles were derived by Klassen et al. (2005, JGR, 110, A09S04) for the Octobe…

The globular cluster mass/low mass X-ray binary correlation: implications for kick velocity distributions from supernovae

Maccarone, T. J.; Kundu, A.; Zepf, S. E. +1 more

Optical and X-ray studies of six nearby galaxies show that the probability a globular cluster will be an X-ray source is consistent with being linearly proportional to its mass. We show that this result is consistent with some recent estimates of the velocity kick distributions for isolated radio pulsars - those which are the sum of two Maxwellian…

Two-phase X-ray burst from GX 3+1 observed by INTEGRAL

Frontera, F.; Lund, N.; in't Zand, J. J. M. +6 more

INTEGRAL detected on August 31, 2004, an unusual thermonuclear X-ray burst from the low-mass X-ray binary GX 3+1. Its duration was 30 min, which is between the normal burst durations for this source (⪉10 s) and the superburst observed in 1998 (several hours). We see emission up to 30 keV energy during the first few seconds of the burst where the b…

Improved oscillator strengths and wavelengths in Hf II, with applications to stellar elemental abundances

Nilsson, H.; Leckrone, D. S.; Lundberg, H. +4 more

Aims. We present new and improved radiative lifetimes for eight levels in Hf I and 18 levels in Hf II, along with oscillator strengths and wavelengths for 195 transitions in Hf II. With these data we determine the abundance of hafnium in two chemically peculiar stars: the hot-Am star HR 3383 and the HgMn star χ Lupi, and discuss the implications o…

Magnetic structure of the solar transition region as observed in various ultraviolet lines emitted at different temperatures

Tu, C. -Y.; Marsch, E.; He, J. -S. +1 more

Aims.The structure of the solar transition region (TR) in a polar coronal hole of the Sun is studied. In particular, the detailed association of the coronal magnetic field (carpet) with the radiance patterns of the TR, when seen in various far ultraviolet (FUV) emission lines, is investigated.
Methods: .A detailed comparison is made of the cor…

Near-infrared adaptive optics dissection of the core of NGC 1068 with NAOS-CONICA

Rouan, D.; Gendron, E.; Fusco, T. +4 more

We present an update analysis of recent near-infrared adaptive optics observations of NGC 1068 obtained with NAOS-CONICA at VLT/UT4. Ks, L' and M' bands images were deconvolved using MISTRAL, a regularized algorithm based on a maximum a posteriori estimation of the object. Two regularization methods, one including a new maximum …

A short hard X-ray flare from the blazar NRAO 530 observed by INTEGRAL

Maraschi, L.; Ghisellini, G.; Pian, E. +6 more

We report about a short flare from the blazar NRAO 530 occurred on 17 February 2004 and detected serendipitously by the IBIS/ISGRI detector on board INTEGRAL. In the 20-40 keV energy range, the source, that is otherwise below the detection limit, is detected at a level of ≈2 × 10^-10 erg cm^-2 s^-1 during a time inter…

Large-scale horizontal flows in the solar photosphere. I. Method and tests on synthetic data

Švanda, M.; Sobotka, M.; Klvaňa, M.

We propose a useful method for mapping large-scale velocity fields in the solar photosphere. It is based on the local

correlation tracking algorithm when tracing supergranules in full-disc dopplergrams. The method was developed using synthetic data.

The data are transformed during the data processing into a suitable coordinate system, th…