Search Publications
XMM-Newton Detection of X-Ray Emission from the Compact Steep-Spectrum Radio Galaxy 3C 303.1
O'Dea, Christopher P.; Baum, Stefi; Worrall, D. M. +3 more
Using XMM-Newton we detect faint unresolved X-ray emission from the compact steep-spectrum radio galaxy 3C 303.1. We detect a thermal component at kT~=0.8 keV, which seems likely to be produced in the interstellar medium (ISM) of the host galaxy. There is evidence for a second component in the spectrum whose nature is currently ambiguous. Plausibl…
A Genuine Intermediate-Age Globular Cluster in M33
Chandar, Rupali; Sarajedini, Ata; Goudfrooij, Paul +1 more
We present deep integrated-light spectroscopy of nine M33 globular clusters taken with the Hectospec instrument at the MMT Observatory. Based on our spectroscopy and previous deep color-magnitude diagrams obtained with HST WFPC2, we present evidence for the presence of a genuine intermediate-age globular cluster in M33. The analysis of Lick line i…
The Interstellar N/O Abundance Ratio: Evidence for Local Infall?
Meyer, David M.; Lauroesch, James T.; Knauth, David C.
Sensitive measurements of the interstellar gas-phase oxygen abundance have revealed a slight oxygen deficiency (~15%) toward stars within 500 pc of the Sun as compared to more distant sight lines. Recent FUSE observations of the interstellar gas-phase nitrogen abundance indicate larger variations, but no trends with distance were reported due to t…
The Blue Straggler Population of the Globular Cluster M5: Comparison with M3
Warren, Steven R.; Bolte, Michael; Sandquist, Eric L.
We have surveyed the blue straggler star population of the Galactic globular cluster M5 using high-resolution images of the core along with wide-field ground-based images reaching to more than 19 core radii. To gauge M5's relative efficiency of producing stragglers, we compared our sample to five studies of other globular clusters. Using a ``brigh…
Temporal and Spatial Relationships between Ultraviolet and Hard X-Ray Emission in Solar Flares
Alexander, David; Coyner, Aaron J.
Hard X-ray and ultraviolet emissions in solar flares provide evidence for the interaction of particles accelerated in the solar corona with the ambient plasma in the chromosphere. Previous studies have shown that these emissions are temporally correlated indicating a common source, presumably magnetic reconnection, governing the flare energy relea…
The Narrow-Line Region of the Seyfert 2 Galaxy Mrk 78: An Infrared View
Pérez García, A. M.; Acosta-Pulido, J. A.; Ramos Almeida, C. +3 more
We report near-infrared spectroscopic data for the Seyfert 2 galaxy Mrk 78, taken with the LIRIS near-infrared camera/spectrometer at the William Herschel Telescope (WHT). The long-slit spectra clearly show extended emission. The resolution and depth of the near-infrared spectra allow the examination of its morphology and ionization regions, and a…
Spitzer Observations of V838 Monocerotis: Detection of a Rare Infrared Light Echo
Banerjee, D. P. K.; Misselt, K. A.; Su, K. Y. L. +1 more
We present Spitzer observations of the unusual variable V838 Monocerotis. Extended emission is detected around the object at 24, 70, and 160 µm. The extended infrared emission is strongly correlated spatially with the HST optical light echo images taken at a similar epoch. We attribute this diffuse nebulosity to an infrared light echo caused…
Multiwavelength Observations of the BL Lacertae Object PKS 2155-304 with XMM-Newton
Maraschi, L.; Treves, A.; Celotti, A. +3 more
The optical/UV and X-ray instruments on board XMM-Newton provide an excellent opportunity to perform simultaneous observations of violently variable objects over a broad wavelength range. The UV- and X-ray-bright BL Lac object PKS 2155-304 has been observed repeatedly with XMM-Newton about twice per year. In this paper, we present a detailed analy…
The Formation Epoch of Early-Type Galaxies in the z ~ 0.9 Cl 1604 Supercluster
Ford, H. C.; Demarco, R.; Menanteau, F. +12 more
We analyze the cluster color-magnitude relation (CMR) for early-type galaxies in two of the richer clusters in the z~0.9 supercluster system to derive average ages and formation redshifts for the early-type galaxy population. Both clusters were observed with the Advanced Camera for Surveys on board the Hubble Space Telescope through the F606W and …
Evidence of a High Carbon Abundance in the Local Interstellar Cloud
Slavin, Jonathan D.; Frisch, Priscilla C.
The nature of the local interstellar cloud (LIC) is highly constrained by the combination of in situ heliospheric and line-of-sight data toward nearby stars. We present a new interpretation of the LIC components of the absorption-line data toward ɛ CMa, based on recent atomic data that include new rates for the Mg+ to Mg0 die…