Search Publications
Off-Nuclear Star Formation and Obscured Activity in the Luminous Infrared Galaxy NGC 2623
Sanders, D. B.; Surace, J. A.; Armus, L. +13 more
New optical Hubble Space Telescope (HST), Spitzer Space Telescope, and XMM observations of the luminous infrared galaxy (LIRG) NGC 2623 are presented. This galaxy was observed as part of the Great Observatories All-sky LIRG Survey (GOALS). The prominent 3.2 kpc southern extension to the nucleus has been resolved by HST observations into ~100 star …
GRB 070610: A Curious Galactic Transient
Cenko, S. B.; Campana, S.; Price, P. A. +23 more
GRB 070610 is a typical high-energy event with a duration of 5 s. Yet within the burst localization we detect a highly unusual X-ray and optical transient, Swift J195509.6+261406. We see high-amplitude X-ray and optical variability on very short timescales even at late times. Using near-infrared imaging assisted by a laser guide star and adaptive …
The Structure of the Local Interstellar Medium. V. Electron Densities
Redfield, Seth; Falcon, Ross E.
We present a comprehensive survey of C II* absorption detections toward stars within 100 pc in order to measure the distribution of electron densities present in the local interstellar medium (LISM). Using high spectral resolution observations obtained by GHRS and STIS on board HST, we searched for all detections of LISM C II* absorption. We ident…
Coronal Rotation at Solar Minimum from UV Observations
Giordano, S.; Mancuso, S.
The observations of the UVCS SOHO instrument from 1996 May to 1997 May have been analyzed to reconstruct intensity time series of the O VI 1032 Å and H I Lyα 1216 Å spectral lines at different coronal heliolatitudes from 1.5 to 3.0 R⊙ from Sun center. At solar minimum, some features persist for several rotations, thus allowing analysis …
Spectral Hardening in Large Solar Flares
Benz, A. O.; Grigis, P. C.
Observations by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) are used to quantitatively study the hard X-ray evolution in five large solar flares selected for spectral hardening in the course of the event. The X-ray bremsstrahlung emission from nonthermal electrons is characterized by two spectroscopically distinct phases: impulsive …
Spatially Resolved Stellar Kinematics of Field Early-Type Galaxies at z = 1: Evolution of the Rotation Rate
van der Wel, Arjen; van der Marel, Roeland P.
We use the spatial information of our previously published VLT/FORS2 absorption-line spectroscopy to measure mean stellar velocity and velocity dispersion profiles of 25 field early-type galaxies at a median redshift z = 0.97 (full range 0.6 < z < 1.2). This provides the first detailed study of early-type galaxy rotation at these redshifts. …
Discovery of Fast-Moving X-Ray-Emitting Ejecta Knots in the Oxygen-Rich Supernova Remnant Puppis A
Burrows, D. N.; Mori, K.; Hughes, J. P. +5 more
We report on the discovery of fast-moving X-ray-emitting ejecta knots in the Galactic oxygen-rich supernova remnant Puppis A from XMM-Newton observations. We find an X-ray knotty feature positionally coincident with an O-rich fast-moving optical filament with blueshifted line emission located in the northeast of Puppis A. We extract spectra from n…
XMM-Newton Observations of CXOU J010043.1-721134: The First Deep Look at the Soft X-Ray Emission of a Magnetar
Tiengo, A.; Mereghetti, S.; Esposito, P.
We present the analysis of six XMM-Newton observations of the anomalous X-ray pulsar CXOU J010043.1-721134, the magnetar candidate characterized by the lowest interstellar absorption. In contrast with all the other magnetar candidates, its X-ray spectrum cannot be fitted by an absorbed power-law plus blackbody model. The sum of two (absorbed) blac…
Lens Galaxy Properties of SBS 1520+530: Insights from Keck Spectroscopy and AO Imaging
Auger, M. W.; Thompson, D.; Fassnacht, C. D. +3 more
We report on an investigation of the SBS 1520+530 gravitational lens system. We have used archival Hubble Space Telescope (HST) imaging, Keck spectroscopic data, and Keck adaptive optics (AO) imaging to study the lensing galaxy and its environment. The AO imaging has allowed us to fix the lens galaxy properties with a high degree of accuracy when …
NGC 346 in the Small Magellanic Cloud. IV. Triggered Star Formation in the H II Region N66
Henning, Thomas; Gouliermis, Dimitrios A.; Brandner, Wolfgang +4 more
Stellar feedback, expanding H II regions, wind-blown bubbles, and supernovae are thought to be important triggering mechanisms of star formation. Stellar associations, being hosts of significant numbers of early-type stars, are the loci where these mechanisms act. In this part of our photometric study of the star-forming region NGC 346/N66 in the …