Search Publications
Hubble Space Telescope Spectroscopic Observations of the Narrow-Line Region in Nearby Low-Luminosity Active Galactic Nuclei
Filippenko, Alexei V.; Ho, Luis C.; Shields, Joseph C. +5 more
We present Space Telescope Imaging Spectrograph observations of 14 nearby low-luminosity active galactic nuclei, including 13 LINERs and 1 Seyfert, taken at multiple parallel slit positions centered on the galaxy nuclei and covering the Hα spectral region. For each galaxy, we measure the emission-line velocities, line widths, and strengths to map …
Self-Regulated Fueling of Galaxy Centers: Evidence for Star Formation Feedback in IC 342's Nucleus
Meier, David S.; Böker, Torsten; Calzetti, Daniela +1 more
Using new, high-resolution interferometric observations of the CO and HCN molecules, we directly compare the molecular and ionized components of the interstellar medium in the center of the nearby spiral galaxy IC 342, on spatial scales of ≈10 pc. The morphology of the tracers suggests that the molecular gas flow caused by a large-scale stellar ba…
The Solar Magnetic Field and Coronal Dynamics of the Eruption on 2007 May 19
Luhmann, J. G.; Li, Y.; Lynch, B. J. +5 more
The solar eruption on 2007 May 19, from AR 10956 near solar disk center, consisted of a B9.5 flare (12:48 UT), a filament eruption, an EUV dimming, a coronal wave, and a multifront CME. The eruption was observed by the twin STEREO spacecraft at a separation angle of 8.5°. We report analysis of the source region photospheric magnetic field and its …
Topography of valley networks on Mars from Mars Express High Resolution Stereo Camera digital elevation models
Mangold, Nicolas; Neukum, Gerhard; Masson, Philippe +2 more
Martian valley networks have been identified mainly in the Noachian heavily cratered uplands. The geometry of valley networks can be studied using Mars Orbiter Laser Altimeter (MOLA) altimetry, which is sufficient to map large valleys without a detailed 3-D shape of valley networks. Imaging from the Mars Express High Resolution Stereo Camera (HRSC…
Time evolution of the line emission from the inner circumstellar ring of SN 1987A and its hot spots
Lundqvist, P.; Spyromilio, J.; Gröningsson, P. +4 more
We present seven epochs between October 1999 and November 2007 of high resolution VLT/UVES echelle spectra of the ejecta-ring collision of SN 1987A. The fluxes of most of the narrow lines from the unshocked gas decreased by a factor of 2-3 during this period, consistent with the decay from the initial ionization by the shock break-out. However, [O…
The broad-band XMM-Newton and INTEGRAL spectra of bright type 1 Seyfert galaxies
de Rosa, A.; Walter, R.; Bird, A. J. +7 more
Aims: The 0.5-150 keV broad-band spectra of a sample of nine bright type 1 Seyfert galaxies are analyzed here. These sources have been discovered/detected by INTEGRAL and subsequently observed with XMM-Newton for the first time with high sensitivity below 10 keV. The sample, although small, is representative of the population of type 1 AGN which a…
Ultraviolet observations of Phoebe from the Cassini UVIS
Hendrix, Amanda R.; Hansen, Candice J.
Observations of Saturn's distant moon Phoebe were made at far-ultraviolet (FUV) (1100-1900 Å) and extreme-ultraviolet (EUV) (600-1100 Å) wavelengths by the Cassini Ultraviolet Imaging Spectrograph (UVIS) during the Cassini spacecraft flyby on June 11, 2004. These are the first UV spectra of Phoebe and the first detection of water ice on a Solar Sy…
A Catalog of Bright Star Clusters in the Interacting Galaxy M51
Hwang, Narae; Lee, Myung Gyoon
We present a catalog of star clusters with V F555W < 23 mag detected in the interacting spiral galaxy M51 system based on mosaic images taken with the Hubble Space Telescope Advanced Camera for Surveys by the Hubble Heritage Team. We have selected about 3600 clusters based on their morphological information through visual inspection.…
INTEGRAL observations of Hercules X-1
Tsygankov, S.; Klochkov, D.; Santangelo, A. +6 more
Aims: We investigate the X-ray spectral and timing properties of the accreting X-ray pulsar Her X-1 observed with the INTEGRAL satellite in July-August 2005.
Methods: The data analyzed in this work cover a substantial part of one main-on state of the source. The short time scale pulse period development is measured. X-ray pulse profiles for di…
BAT X-Ray Survey. I. Methodology and X-Ray Identification
Greiner, J.; Strong, A. W.; Ajello, M. +3 more
We applied the maximum likelihood (ML) method, as an image reconstruction algorithm, to the BAT X-Ray Survey (BXS). This method was specifically designed to preserve the full statistical information in the data and to avoid mosaicking of many exposures with different pointing directions, thus reducing systematic errors when co-adding images. We re…