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Space Telescope Imaging Spectrograph Echelle Observations of the Seyfert Galaxy NGC 4151: Physical Conditions in the Ultraviolet Absorbers
Gull, T. R.; Kraemer, S. B.; Crenshaw, D. M. +7 more
We have examined the physical conditions in intrinsic UV-absorbing gas in the Seyfert galaxy NGC 4151, using echelle spectra obtained with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope on 1999 July 19. We confirm the presence of the kinematic components detected in earlier Goddard High Resolution Spectrograph (GHRS)…
Speckle Interferometry of New and Problem Hipparcos Binaries. II. Observations Obtained in 1998-1999 from McDonald Observatory
Mason, Brian D.; Hartkopf, William I.; Holdenried, Ellis R. +1 more
The Hipparcos satellite made measurements of over 9734 known double stars, 3406 new double stars, and 11,687 unresolved but possible double stars. The high angular resolution afforded by speckle interferometry makes it an efficient means to confirm these systems from the ground, which were first discovered from space. Because of its coverage of a …
Homogenization of the Stellar Population along Late-Type Spiral Galaxies
dos Anjos, S.; Gadotti, D. A.
We present a study of the broadband UBV color profiles for 257 Sbc barred and nonbarred galaxies, using photoelectric aperture photometry data from the literature. Using robust statistical methods, we have estimated the color gradients of the galaxies, as well as the total and bulge mean colors. A comparative photometric study using CCD images was…
The central region of M 31 observed with XMM-Newton. II. Variability of the individual sources
Pietsch, W.; Read, A. M.; Tiengo, A. +13 more
We present the results of a study of the variability of X-ray sources in the central 30 arcmin of the nearby Andromeda Galaxy (M 31) based on XMM-Newton Performance Verification observations. Two observations of this field, with a total exposure time of about 50 ks, were performed in June and December of 2000. We found 116 sources brighter than a …
The central region of M 31 observed with XMM-Newton. I. Group properties and diffuse emission
Pietsch, W.; Read, A. M.; Tiengo, A. +13 more
We present the results of a study based on an XMM-Newton Performance Verification observation of the central 30' of the nearby spiral galaxy M 31. In the 34-ks European Photon Imaging Camera (EPIC) exposure, we detect 116 sources down to a limiting luminosity of 6 x 1035 erg s-1 (0.3-12 keV, d=760 kpc). The luminosity distrib…
The Southern Crab from a New Perspective
Livio, Mario; Corradi, Romano L. M.; Munari, Ulisse +2 more
New Hubble Space Telescope images and Cerro Tololo Inter-American Observatory echelle spectra of the nebula around the symbiotic Mira Henize 2-104 are presented. The nebula consists of two nested hourglass-shaped structures and a collimated polar jet. Spatiokinematical modeling shows that all three outflows were ejected during approximately the sa…
Coronal Mass Ejection of 2000 July 14 Flare Event: Imaging from Near-Sun to Earth Environment
Pick, M.; Kaiser, M. L.; Ipavich, F. M. +6 more
We report the results of our investigation of interplanetary effects caused by the large solar flare (X5.7/3B) that occurred on 2000 July 14. In association with this event a bright, fast, halo coronal mass ejection (CME) was observed. The analysis of multiwavelength, high-cadence images obtained from the Nançay Radioheliograph shows the on-disk s…
Temporal Variations of the Solar Rotation Rate at High Latitudes
Basu, Sarbani; Antia, H. M.
Frequency splitting coefficients from Global Oscillation Network Group and Michelson Doppler Imager observations covering the period 1995-2001 are used to study temporal variations in the solar rotation rate at high latitudes. The torsional oscillation pattern in the Sun is known to penetrate to a depth of about 0.1 Rsolar with alternat…
The plerion nebula in IC 443: The XMM-Newton view
Bocchino, F.; Bykov, A. M.
XMM-Newton observations of the X-ray feature 1SAX J0617.1+2221 in the IC 443 supernova remnant are reported. We resolve the structure of the nebula into a compact core with a hard spectrum of photon index gamma = 1.63+0.11-0.10 in the 2-10 keV energy range. The nebula also has an extended ({ ~ } 8hbox {^\prime}times 5arcmin )…
Physical Parameters of Erupting Luminous Blue Variables: NGC 2363-V1 Caught in the Act
Drissen, Laurent; Robert, Carmelle; Smith, Linda J. +3 more
A quantitative study of the luminous blue variable NGC 2363-V1 in the Magellanic galaxy NGC 2366 (D=3.44 Mpc) is presented, based on ultraviolet and optical Hubble Space Telescope STIS spectroscopy. Contemporary WFPC2 and William Herschel Telescope imaging reveals a modest V-band brightness increase of ~0.2 mag per year between 1996 January-1997 N…