Search Publications
HST/ACS imaging of a Balmer-dominated shock in Kepler’s supernova remnant
Blair, William P.; Rudnick, Lawrence; Harrus, Ilana M. +3 more
Optical images of Kepler’s supernova remnant obtained at two epochs, in 1987 at Las Campanas Observatory and in 2003 with the HST Advanced Camera for Surveys, show the motion of the Balmer-dominated forward shock. The measured proper motion, combined with estimates of the shock velocity, is used to derive a distance of 3.9-0.9+1.4 kpc to the remna…
To see or not to see a bow shock. Identifying bow shocks with Hα allsky surveys
Brown, D.; Bomans, D. J.
OB-stars have the highest luminosities and strongest stellar winds of all stars, which enables them to interact strongly with their surrounding ISM, thus creating bow shocks. These offer us an ideal opportunity to learn more about the ISM. They were first detected and analysed around runaway OB-stars using the IRAS allsky survey by van Buren et al…
Supernova Remnants in the Magellanic Clouds. V. The Complex Interior Structure of the N206 Supernova Remnant
Gruendl, R. A.; Chu, Y. -H.; Guerrero, M. A. +4 more
The N206 supernova remnant (SNR) in the Large Magellanic Cloud has long been considered a prototypical ``mixed morphology'' SNR. Recent observations, however, have added a new twist to this familiar plot: an elongated, radially oriented radio feature seen in projection against the SNR face. Utilizing the high resolution and sensitivity available w…
Major episodes of the hydrologic history in the region of Hesperia Planum, Mars
Neukum, G.; Marinangeli, L.; Ivanov, M. A. +5 more
The High Resolution Stereo Color camera (HRSC) data over Hesperia Planum and its surroundings reveal important details of geologic episodes and water-related processes in this region. (1) The Noachian fluvial events of Hesperia Planum depression included accumulation of water and formation of a water/ice reservoir there. Later, the reservoir was d…
A Simultaneous RXTE and XMM-Newton Observation of the Broad-Line Radio Galaxy 3C 111
Eracleous, Michael; Gliozzi, Mario; Mushotzky, Richard F. +2 more
We present the results of simultaneous XMM-Newton and RXTE observations of the broad-line radio galaxy 3C 111. We find that the Compton reflection bump is extremely weak; however, broad residuals are clearly present in the spectrum near the Fe Kα emission line region. When fitted with a Gaussian emission line, the feature has an equivalent width o…
The Vela Pulsar in the Ultraviolet
Pavlov, George G.; Kargaltsev, Oleg; Romani, Roger W.
We describe time-tagged observations of the Vela pulsar (PSR B0833-45) with the HST STIS MAMA UV detectors. Using an optimal extraction technique, we obtain an NUV light curve and crude FUV phase-resolved spectra. The pulse is dominated by complex nonthermal emission at all phases. We obtain approximate spectral indices for the brightest pulse com…
The Absorption Signature of Six Mg II-selected Systems over 0.5 <= z <= 0.9
Charlton, Jane C.; Churchill, Christopher W.; Ding, Jie
We present the results of photoionization modeling of six Mg II-selected absorption systems, at redshift 0.5<=z<=0.9, along lines of sight toward three quasars: PG 1241+176, PG 1248+401, and PG 1317+274. These are part of a larger sample of ~20 Mg II absorbers at intermediate redshift, which facilitates a survey of the properties of, and pro…
The XMM-Newton Needles in the Haystack Survey: the local X-ray luminosity function of `normal' galaxies
Georgakakis, A.; Georgantopoulos, I.; Koulouridis, E.
In this paper we estimate the local (z < 0.22) X-ray luminosity function of `normal' galaxies derived from the XMM-Newton Needles in the Haystack Survey. This is an on-going project that aims to identify X-ray-selected normal galaxies (i.e. non-AGN dominated) in the local Universe. We are using a total of 70 XMM-Newton fields covering an area o…
Large-Scale CO and [C I] Emission in the ρ Ophiuchi Molecular Cloud
Kulesa, Craig A.; Hungerford, Aimee L.; Walker, Christopher K. +2 more
We present a comprehensive study of the ρ Ophiuchi molecular cloud that addresses aspects of the physical structure and condition of the molecular cloud and its photodissociation region (PDR) by combining far-infrared and submillimeter-wave observations with a wide range of angular scale and resolution. We present 1600 arcmin2 maps (2.3…
X-Ray Luminosity and Absorption Column Fluctuations in the H2O Maser Galaxy NGC 4258 from Weeks to Years
Filippenko, Alexei V.; Greenhill, Lincoln J.; Fruscione, Antonella +3 more
We report monitoring of the 0.3-10 keV spectrum of NGC 4258 with the XMM-Newton Observatory at five epochs over 1.5 yr. We also report reprocessing of an overlapping four-epoch series of archival Chandra observations (0.5-10 keV). By including earlier ASCA and BeppoSAX observations, we present a new, 9 year time series of models fitted to the X-ra…