Search Publications
NGC 7679: an anomalous, composite Seyfert 1 galaxy whose X-ray luminous AGN vanishes at optical wavelengths
Held, E. V.; Lim, J.; Buson, L. M. +3 more
Morphological disturbances and gas kinematics of the SB0 galaxy NGC 7679 = Arp 216 are investigated to understand the history of this highly composite object, where AGN and starburst signatures dominate in the X-ray and optical/IR regime, respectively. Perturbations of the ionized gas velocity field appear quite mild within 15'' (~5 kpc) of the ce…
Multi-wavelength properties of the high-energy bright Seyfert 1 galaxy IGR J18027-1455
Chaty, S.; Combi, J. A.; Martí, J. +1 more
A new sample of hard X-ray sources in the Galactic Plane is being revealed by the regular observations performed by the INTEGRAL satellite. The full characterization of these sources is mandatory to understand the hard X-ray sky. Here we report new multifrequency radio, infrared and optical observations of the source
Probing the ionized ISM of the CSS quasar 3C 277.1. I. Observations
Fanti, R.; Cotton, W. D.; Fanti, C. +2 more
We present new multi-wavelength high resolution VLA polarimetric images of the CSS quasar 3C 277.1 and analyze them with older Merlin and HST [OIII] images. These observations were made to test the hypothesis that the [OIII] emission as well as the long wavelength radio opacity arise in shocks that the quasar jet induces in the ISM. The multi-wave…
An information-theoretical methodology for profile parameter estimation of solar coronal spectra
Nakagawa, A.
Aims.An attempt is made to establish an information-theoretical methodology for profile parameter estimation of the spectral lines of the solar corona.
Methods: .In this formalism, "description lengths" of a target line profile are defined for every possible profile model and are used to identify the optimal one among possible models. To prope…
Near-infrared observations of the carbon stars TU Geminorum and SS Virginis at milliarcsecond resolution
Chandrasekhar, T.; Richichi, A.
Aims.High-angular resolution investigations of carbon stars.
Methods. Milliarcsecond resolution observations in the near infrared K band by the method of lunar occultations are presented for the carbon stars
Results. Although a companion to
INTEGRAL and XMM-Newton observations towards the unidentified MeV source GRO J1411-64
Barcons, X.; Reimer, O.; Torres, D. F. +9 more
Aims.We investigate the nature of the COMPTEL unidentified source GRO J1411-64. Methods: The source was observed by INTEGRAL. Its central part was also observed by XMM-Newton. Results: The data analysis shows no hint for new detections at hard X-rays. The upper limits in flux herein presented constrain the energy spectrum of whatever was producing…
Discovery of a cluster of galaxies behind the Milky Way: X-ray and optical observations
Motch, C.; Mendes de Oliveira, C.; Janot-Pacheco, E. +2 more
We report the discovery of
The broad-band spectrum of Cyg X-2 with INTEGRAL
Stella, L.; van der Klis, M.; Lewin, W. H. G. +7 more
We study the broad band (3-100 keV) spectrum of Cygnus X-2 with INTEGRAL. We find that the spectrum is well fitted by a Comptonized component with a seed-photons temperature of ∼ 1 keV, an electron temperature of ∼ 3 keV and an optical depth τ ∼ 8. Assuming spherical geometry, the radius of the seed-photons emitting region is ∼ 17 km. The source s…
Luminosity-dependent evolution of soft X-ray selected AGN. New Chandra and XMM-Newton surveys
Hasinger, G.; Schmidt, M.; Miyaji, T.
We present new results on the cosmological evolution of unabsorbed (type-1) active galactic nuclei (AGN) selected in the soft (0.5-2 keV) X-ray band. From a variety of ROSAT, XMM-Newton and Chandra surveys we selected a total of ~1000 AGN with an unprecedented spectroscopic and photometric optical/NIR identification completeness. For the first tim…
Star counts in the Galaxy. Simulating from very deep to very shallow photometric surveys with the TRILEGAL code
Hatziminaoglou, E.; Girardi, L.; Groenewegen, M. A. T. +1 more
We describe TRILEGAL, a new populations synthesis code for simulating the stellar photometry of any Galaxy field. The code attempts to improve upon several technical aspects of star count models, by: dealing with very complete input libraries of evolutionary tracks; using a stellar spectral library to simulate the photometry in virtually any broad…