Search Publications
Global characteristics of GRBs observed with INTEGRAL and the inferred large population of low-luminosity GRBs
McGlynn, S.; McBreen, S.; Foley, S. +2 more
Context: INTEGRAL has two sensitive gamma-ray instruments that have detected and localised 47 gamma-ray bursts (GRBs) from its launch in October 2002 up to July 2007.
Aims: We present the spectral, spatial, and temporal properties of the bursts in the INTEGRAL GRB catalogue using data from the imager, IBIS, and spectrometer, SPI.
Methods: …
A Hubble Space Telescope transit light curve for GJ 436b
Reiners, A.; Dreizler, S.; Benedict, G. F. +6 more
We present time series photometry for six partial transits of GJ 436b obtained with the Fine Guidance Sensor instrument on the Hubble Space Telescope (HST). Our analysis of these data yields independent estimates of the host star's radius Rstar = 0.505+0.029-0.020 R⊙, and the planet's orbital period P = …
Cumulative hard X-ray spectrum of local AGN: a link to the cosmic X-ray background
Sunyaev, R.; Krivonos, R.; Revnivtsev, M. +2 more
Aims: We determine the cumulative spectral energy distribution (SED) of local active galactic nuclei (AGN) in the 3-300 keV band and compare it with the spectrum of the cosmic X-ray background (CXB) in order to test the widely accepted paradigm that the CXB is a superposition of AGN and to place constraints on AGN evolution.
Methods: We perfor…
Star formation efficiency in galaxy clusters
Andrade-Santos, F.; Cypriano, E. S.; Laganá, T. F. +1 more
Context: The luminous material in clusters of galaxies exists in two forms: the visible galaxies and the X-ray emitting intra-cluster medium. The hot intra-cluster gas is the major observed baryonic component of clusters, about six times more massive than the stellar component. The mass contained within visible galaxies is approximately 3% of the …
Line ratios from shocked cloudlets in planetary nebulae
Velázquez, P. F.; Raga, A. C.; Esquivel, A. +2 more
Context: Some PNe and PPNe show compact knots, travelling at high velocities away from the central sources.
Aims: We compute a number of models from which we obtain predictions of the emission-line spectrum, which can be compared with the spectra of the observed knots.
Methods: We completed a series of 11 axisymmetric simulations of an ini…
The XMM-Newton bright serendipitous survey. Identification and optical spectral properties
Sbarufatti, B.; Pietsch, W.; Page, M. J. +12 more
Aims:We present the optical classification and redshift of 348 X-ray selected sources from the XMM-Newton Bright Serendipitous Survey (XBS), which contains a total of 400 objects (identification level = 87%). About 240 are new identifications. In particular, we discuss in detail the classification criteria adopted for the active galactic nuclei (A…
Integral field near-infrared spectroscopy of II Zw 40
Cresci, G.; Vanzi, L.; Melnick, J. +1 more
We present integral field spectroscopy in the near-infrared of the nearby starburst galaxy II Zw 40. Our new observations provide an unprecedented detailed view of the interstellar medium and star formation of this galaxy. The radiation emitted by the galaxy is dominated by a giant HII region, which extends over an area of more than 400 pc in size…
Spectral irradiance variations: comparison between observations and the SATIRE model on solar rotation time scales
Solanki, S. K.; Krivova, N. A.; Kopp, G. +2 more
Aims: We test the reliability of the observed and calculated spectral irradiance variations between 200 and 1600 nm over a time span of three solar rotations in 2004.
Methods: We compare our model calculations to spectral irradiance observations taken with SORCE/SIM, SoHO/VIRGO, and UARS/SUSIM. The calculations assume LTE and are based on the …
Evidence of magnetic field wrapping around penumbral filaments
Solanki, S. K.; Lites, B. W.; Borrero, J. M.
We employ high-spatial resolution spectropolarimetric observations from the Solar Optical Telescope on-board the Hinode spacecraft to investigate the fine structure of the penumbral magnetic fields. The Stokes vector of two neutral iron lines at 630 nm is inverted at every spatial pixel to retrieve the depth-dependence of the magnetic field vector…
The X-ray cycle in the solar-type star HD 81809. XMM-Newton observations and implications for the coronal structure
Schmitt, J. H. M. M.; Orlando, S.; Hall, J. +3 more
Context: The 11-yr cycle is the best known manifestation of the Sun's activity. While chromospheric cycles have been studied in a number of solar-like stars, very little is known about how these are reflected in the cyclical behavior of the coronal X-ray emission in stars other than the Sun.
Aims: Our long-term XMM-Newton program of long-term …