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A radial mass profile analysis of the lensing cluster MS 2137.3-2353
Pelló, R.; Gavazzi, R.; Fort, B. +2 more
We reanalyze the strong lens modeling of the cluster of galaxies MS 2137.3-2353 using a new UBVRIJK data set obtained with the ESO Very Large Telescope. We infer the photometric redshifts of the two main arc systems which are both found to be at z=1.6+/- 0.1. After subtraction of the central cD star light in the previous F702/HST imaging we found …
On the Progenitor of the Type II-Plateau Supernova 2003gd in M74
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Li, Weidong
Hubble Space Telescope (HST) WFPC2 archival F606W and F300W images obtained within 1 year prior to the explosion of the nearby Type II supernova (SN) 2003gd in M74 (=NGC 628) have been analyzed to isolate the progenitor star. The SN site was located using precise astrometry applied to the HST images. Two plausible candidates are identified within …
Self-similar Models for the Mass Profiles of Early-Type Lens Galaxies
Keeton, C. R.; Kochanek, C. S.; Rusin, D.
We introduce a self-similar mass model for early-type galaxies and constrain it using the aperture mass-radius relations determined from the geometries of 22 gravitational lenses. The model consists of two components: a concentrated component, which traces the light distribution, and a more extended power-law component (ρ~r-n), which re…
Cluster observation of a bifurcated current sheet
Balogh, A.; Zhang, T. L.; Nakamura, R. +4 more
The current sheet structure and motion at XGSM = -19.5 RE, observed by Cluster/FGM during 1055-1107 UT on 29 August 2001, is examined. It is found that during the interval 1055-1102 UT the current sheet moves vertically up and down with a velocity of about 60 km/s. During this interval the current sheet has a bifurcated struc…
Elemental Abundances in the Solar Upper Atmosphere Derived by Spectroscopic Means
Feldman, U.; Widing, K. G.
The composition of the solar photosphere is believed to be uniform. Indeed a quantity that does not vary with solar surface location or with a particular solar feature, i.e., no observational evidence is available to indicate that the photospheric composition near the solar equator is different from the photospheric composition near the solar pole…
SPI/INTEGRAL in-flight performance
Boggs, S.; Knödlseder, J.; von Kienlin, A. +23 more
The SPI instrument has been launched on-board the INTEGRAL observatory on October 17, 2002. SPI is a spectrometer devoted to the sky observation in the 20 keV-8 MeV energy range using 19 germanium detectors. The performance of the cryogenic system is nominal and allows to cool the 19 kg of germanium down to 85 K with a comfortable margin. The ener…
Chandra X-Ray Observations of NGC 1316 (Fornax A)
Fabbiano, G.; Kim, Dong-Woo
We report the results of the Chandra ACIS subarcsecond resolution X-ray observation of the archetypal merger radio galaxy NGC 1316 (Fornax A). We confirm the presence of fine substructures in the hot interstellar medium (ISM). Some of these are likely to result from interaction with the radio jets, while others may be related to a complex intermin…
Internal structure of magnetic clouds: Plasma and composition
Lynch, B. J.; Antiochos, S. K.; Zurbuchen, T. H. +1 more
A comprehensive analysis of magnetic clouds observed by the Advanced Composition Explorer (ACE) spacecraft from February 1998 to July 2001 is presented. The magnetic field data from the MAG instrument is fit with the cylindrically symmetric, linear force-free model and the fit parameter distributions are examined. This magnetic field model enables…
A mid-infrared spectroscopic survey of starburst galaxies: Excitation and abundances
Lutz, D.; Genzel, R.; Sturm, E. +3 more
We present spectroscopy of mid-infrared emission lines in twelve starburst regions, located in eleven starburst galaxies, for which a significant number of lines between 2.38 and 45 mum were observed with the ISO Short Wavelength Spectrometer, with the intention of providing a reference resource for mid-infrared spectra of starburst galaxies. The …
The Circumstellar Disk of the Butterfly Star in Taurus
Stapelfeldt, Karl R.; Padgett, Deborah L.; Wolf, Sebastian
We present a model of the circumstellar environment of the so-called Butterfly star in Taurus (IRAS 04302+2247). The appearance of this young stellar object is dominated by a large circumstellar disk seen edge-on and the light-scattering lobes above the disk. Our model is based on multiwavelength continuum observations: (1) millimeter maps and (2)…