Search Publications
The X-Ray Spectrum of the Seyfert I Galaxy Markarian 766: Dusty Warm Absorber or Relativistic Emission Lines?
Maraschi, L.; Behar, E.; Page, M. J. +10 more
Competing models for broad spectral features in the soft X-ray spectrum of the Seyfert I galaxy Mrk 766 are tested against data from a 130 ks XMM-Newton observation. A model including relativistically broadened Lyα emission lines of O VIII, N VII, and C VI is a better fit to 0.3-2 keV XMM RGS data than a dusty warm absorber. Moreover, the measured…
Soft X-Ray Excess Emission in Clusters of Galaxies Observed with XMM-Newton
Bonamente, M.; Lumb, D.; Nevalainen, J. +1 more
We present results on the spectroscopic analysis of XMM-Newton EPIC data of the central 0.5 h-150 Mpc regions of the clusters of galaxies Coma, A1795, and A3112. The temperature of the hot intracluster gas as determined by modeling the 2-7 keV PN and MOS data is consistent with that inferred from the Fe XXV/Fe XXVI line ratio…
Space Telescope Imaging Spectrograph Survey of Far-Ultraviolet Coronal Forbidden Lines in Late-Type Stars
Ayres, Thomas R.; Redfield, Seth; Harper, Graham M. +4 more
We describe an extensive search with the Space Telescope Imaging Spectrograph (STIS) for ultraviolet coronal (T>106 K) forbidden lines in a sample of 29 F-M dwarfs, giants, and supergiants. Measuring coronal lines in the 1150-1700 Å band with STIS has important advantages of superior velocity resolution and an absolute wavelength cal…
The Physical Parameters, Excitation, and Chemistry of the Rim, Jets, and Knots of the Planetary Nebula NGC 7009
Corradi, Romano L. M.; Gonçalves, Denise R.; Mampaso, Antonio +1 more
We present long-slit optical spectra along the major axis of the planetary nebula NGC 7009. These data allow us to discuss the physical, excitation, and chemical properties of all the morphological components of the nebula, including its remarkable systems of knots and jets. The main results of this analysis are the following: (1) the electron tem…
A SCUBA Galaxy in the Protocluster around 53W002 at z=2.4
Ivison, R. J.; Smail, Ian; Motohara, K. +4 more
We analyze an 850 µm Submillimetre Common-User Bolometer Array (SCUBA) map of the environment of the z=2.39 radio galaxy 53W002, which has been shown to reside in an overdensity of Lyα-detected galaxies. We identify four luminous submillimeter sources within a 2.3‧ (1.2 Mpc at z=2.39) diameter area around the radio galaxy (which itself is a …
Searching for z~=6 Objects with the Hubble Space Telescope Advanced Camera for Surveys: Preliminary Analysis of a Deep Parallel Field
Yan, Haojing; Windhorst, Rogier A.; Cohen, Seth H.
Recent results suggest that z~=6 marks the end of the reionization era. A large sample of objects at z~=6, therefore, will be of enormous importance, as it will enable us to observationally determine the exact epoch of the reionization and the sources that are responsible for it. With the Hubble Space Telescope Advanced Camera for Surveys (ACS) co…
Emission-Line Galaxies in the STIS Parallel Survey. II. Star Formation Density
Gardner, Jonathan P.; Teplitz, Harry I.; Rhodes, Jason +2 more
We present the luminosity function of [O II]-emitting galaxies at a median redshift of z=0.9, as measured in the deep spectroscopic data in the STIS Parallel Survey (SPS). The luminosity function shows strong evolution from the local value, as expected. By using random lines of sight, the SPS measurement complements previous deep single-field stud…
Abundances and Physical Conditions in the Interstellar Gas toward HD 185418
York, Donald G.; Welty, Daniel E.; Snow, Theodore P. +2 more
We present a study of the abundances and physical conditions in the interstellar gas toward the moderately reddened B0.5 V star HD 185418. This star is located at (l,b)=(53deg,-2.2d) and has an estimated distance of 790 pc and a reddening E(B-V)=0.50. This work is based on the analysis of Far Ultraviolet Spectroscopic Explore…
Chandra Observations of Low-Mass X-Ray Binaries and Diffuse Gas in the Early-Type Galaxies NGC 4365 and NGC 4382 (M85)
Sarazin, Craig L.; Sivakoff, Gregory R.; Irwin, Jimmy A.
We used the Chandra X-Ray Observatory ACIS-S3 to image the X-ray-faint elliptical galaxy NGC 4365 and lenticular galaxy NGC 4382. The observations resolve much of the X-ray emission into 99 and 58 sources, respectively, most of which are low-mass X-ray binaries (LMXBs) associated with each of the galaxies. Within one effective radius of NGC 4365, …
Signature of an Avalanche in Solar Flares as Measured by Photospheric Magnetic Fields
Wang, H.; Goode, P. R.; Abramenko, V. I. +2 more
We analyzed time variations of turbulent parameters of the photospheric magnetic field of four active regions obtained during the course of major solar flares using longitudinal magnetograms from the Big Bear Solar Observatory and from SOHO/MDI full-disk measurements. Analysis of the data indicated that, before each flare, the degree of intermitte…