Search Publications
The origin of the young stellar population in the solar neighborhood -- A link to the formation of the Local Bubble?
Breitschwerdt, D.; Berghöfer, T. W.
We have analyzed the trajectories of moving stellar groups in the solar neighborhood in an attempt to estimate the number of supernova explosions in our local environment during the past 20 million years. Using Hipparcos stellar distances and the results of kinematical analyses by Asiain et al. (\cite{Asiain1999a}a) on the Pleiades moving groups, …
An optical time-delay for the lensed BAL quasar HE 2149-2745
Kneib, J. -P.; Magain, P.; Lidman, C. +11 more
We present optical V and i-band light curves of the gravitationally lensed BAL quasar HE 2149-2745. The data, obtained with the 1.5 m Danish Telescope (ESO-La Silla) between October 1998 and December 2000, are the first from a long-term project aimed at monitoring selected lensed quasars in the Southern Hemisphere. A time delay of 103+/-12 days is…
Spatial Resolution of High-Velocity Filaments in the Narrow-Line Region of NGC 1068: Associated Absorbers Caught in Emission?
Ferruit, Pierre; Dopita, Michael A.; Groves, Brent +4 more
Using the STIS spectrograph on the Hubble Space Telescope, we have obtained a grid of [O III] λλ4959, 5007 and Hβ emission-line spectra at 0.05"×0.19"" and 60 km s-1 (FWHM) resolution that covers much of the narrow-line region (NLR) of NGC 1068. We find emitting knots that have blueshifted radial velocities up to 3200 km s-1 …
The magnetic nature of wide EUV filament channels and their role in the mass loading of CMEs
Aulanier, G.; Schmieder, B.
Previous works have shown that dark and wide EUV filament channels observed at lambda < 912 Å, are due to absorption of EUV lines in cool plasma condensations that are not observed in Hα . We extend this interpretation and we address the issue of the possible injection of their mass into CMEs, through the magneto-hydrostatic modeling in 3D of o…
The X-Ray-Radio Alignment in the z=2.2 Radio Galaxy PKS 1138-262
Pentericci, L.; Röttgering, H. J. A.; Miley, G. K. +4 more
We present high-resolution X-ray observations of the narrow-line radio galaxy PKS 1138-262 at z=2.156 with the ACIS-S detector on the Chandra X-Ray Observatory. These observations show that the X-ray emission from 1138-262 is dominated by emission from the active galactic nucleus (AGN) with a 2-10 keV luminosity of 4×1045 ergs s-1<…
Infrared Emission from Interstellar Dust. III. The Small Magellanic Cloud
Draine, B. T.; Li, Aigen
The infrared emission from interstellar dust in the Small Magellanic Cloud is modeled using a mixture of amorphous silicate and carbonaceous grains, including a population of polycyclic aromatic hydrocarbon (PAH) molecules. We show the following: (1) This dust model is able to reproduce the spectral energy distribution from near-IR to far-IR for t…
UVCS/SOHO observations of a CME-driven shock: Consequences on ion heating mechanisms behind a coronal shock
Raymond, J. C.; Wu, R.; Kohl, J. +3 more
We report the observation of a 1100 km s-1 CME-driven shock with the UltraViolet Coronagraph Spectrometer (UVCS) telescope operating on board SOHO on March 3, 2000. The shock speed was derived from the type II radio burst drift rate and from UVCS observations that can yield the density profile just before the passage of the shock. A CME…
Multi-wavelength study of the Seyfert 1 galaxy NGC 3783 with XMM-Newton
Kaastra, J. S.; Behar, E.; Sako, M. +5 more
We present the analysis of multi-wavelength XMM-Newton data from the Seyfert galaxy NGC 3783, including UV imaging, X-ray and UV lightcurves, the 0.2-10 keV X-ray continuum, the iron Kalpha emission line, and high-resolution spectroscopy and modelling of the soft X-ray warm absorber. The 0.2-10 keV spectral continuum can be well reproduced by a po…
Shock-excited radio burst from reconnection outflow jet?
Mann, G.; Vršnak, B.; Aurass, H.
Models of dynamic (two-ribbon-, arcade) flares involve the formation of a system of standing slow and possibly also fast mode shock waves associated with the fast reconnection process below the erupting filament. These shocks are anticipated theoretically, but are not unambiguously confirmed by observations. In this paper we identify for the first…
The Diversity of Extremely Red Objects
Ivison, R. J.; Smail, Ian; Morrison, G. E. +3 more
We present the results from a sensitive multiwavelength analysis of the properties of extremely red objects (EROs). Our analysis employs deep RIzJHK photometry of an 8.5‧×8.5‧ region to select a sample of 68 EROs with (R-K)>=5.3 and brighter than K=20.5 (5 σ). We combine this photometric data set with an extremely deep 1.4 GHz radio map of the …