Search Publications
X-ray properties of active M dwarfs as observed by XMM-Newton
Schmitt, J. H. M. M.; Robrade, J.
We present a comparative study of X-ray emission from a sample of active M dwarfs with spectral types using XMM-Newton observations of two single stars, AD Leonis and EV Lacertae, and two unresolved binary systems, AT Microscopii and EQ Pegasi. The light curves reveal frequent flaring during all four observations. We perform a uniform spectral ana…
A search for changing-look AGN in the Grossan catalog
Maiolino, R.; Fiore, F.; Bianchi, S. +4 more
We observed with XMM-Newton 4 objects selected from the Grossan (1992, Ph.D. Thesis) catalog, with the aim to search for new "changing-look" AGN. The sample includes all the sources which showed in subsequent observations a flux much lower than the one measured with HEAO A-1: NGC 7674, NGC 4968, IRAS 13218+0552 and NGC 1667. None of the sources wa…
Submillimetre photometry of X-ray absorbed quasi-stellar objects: their formation and evolutionary status
Ivison, R. J.; Smail, Ian; Page, M. J. +4 more
We present an analysis of the submillimetre/X-ray properties of 19 X-ray absorbed, Compton-thin quasi-stellar objects (QSOs) selected to have luminosities and redshifts that represent the peak of cosmic QSO activity, i.e. ~L* objects at 1 < z < 3. Of these, we present new data for 11 objects not previously observed at submillimetre wavelengt…
A Wide-Field Hubble Space Telescope Survey of the Cluster Cl 0024+16 at z = 0.4. III. Spectroscopic Signatures of Environmental Evolution in Early-Type Galaxies
Smith, Graham P.; Treu, Tommaso; Smail, Ian +4 more
We report results from a panoramic spectroscopic survey of 955 objects in the field of the rich cluster Cl 0024+1654 (z~=0.4), complementing the HST imaging presented in the first paper in this series. Combining with previous work, we compile a catalog of 1394 unique redshifts in the field of this cluster, including 486 cluster members spread acro…
8-13 µm Spectroscopy of Young Stellar Objects: Evolution of the Silicate Feature
Meyer, Michael R.; Hillenbrand, Lynne A.; Blake, Geoffrey A. +1 more
Silicate features arising from material around pre-main-sequence stars are useful probes of the star and planet formation process. In order to investigate possible connections between dust processing and disk properties, 8-13 µm spectra of 34 young stars, exhibiting a range of circumstellar environments and including spectral types A-M, were…
Complex X-Ray Absorption and the Fe Kα Profile in NGC 3516
Turner, T. J.; Kraemer, S. B.; Reeves, J. N. +2 more
We present data from simultaneous Chandra, XMM-Newton, and BeppoSAX observations of the Seyfert 1 galaxy NGC 3516, taken during 2001 April and November. We have investigated the nature of the very flat observed X-ray spectrum. Chandra grating data show the presence of X-ray absorption lines, revealing two distinct components of the absorbing gas, …
Self-Consistent Magnetohydrodynamic Modeling of a Coronal Mass Ejection, Coronal Dimming, and a Giant Cusp-shaped Arcade Formation
Shibata, Kazunari; Chen, P. F.; Isobe, Hiroaki +3 more
We performed magnetohydrodynamic simulations of coronal mass ejections (CMEs) and associated giant arcade formations, and the results suggest new interpretations of observations of CMEs. We performed two cases of the simulation: with and without heat conduction. Comparing between the results of the two cases, we found that the reconnection rate in…
Multifractal Analysis Of Solar Magnetograms
Abramenko, Valentyna I.
As solar observational techniques improve, fine small-scale structures observed on the solar surface become more pronounced. Complex filigree structures of solar granulation, sunspots, photospheric magnetic and velocity fields cannot be described adequately by a single parameter (e.g., filling factor, fractal dimension, or power-law index). Method…
The WEBT campaign to observe AO 0235+16 in the 2003-2004 observing season. Results from radio-to-optical monitoring and XMM-Newton observations
Lähteenmäki, A.; Papadakis, I. E.; Smith, N. +64 more
A multiwavelength campaign to observe the BL Lac object
The NGC 5846 Group: Dynamics and the Luminosity Function to MR=-12
Mahdavi, Andisheh; Tully, R. Brent; Trentham, Neil
We conduct a photometric and spectroscopic survey of a 10 deg2 region surrounding the nearby NGC 5846 group of galaxies, using the Canada-France-Hawaii and Keck I telescopes to study the population of dwarf galaxies as faint as MR=-10. Candidates are identified on the basis of quantitative surface brightness and qualitative m…