Search Publications
XMM Follow-up Observations of Three Swift BAT-selected Active Galactic Nuclei
Reynolds, C. S.; Mushotzky, R. F.; Koss, M. +2 more
We present XMM-Newton observations of three active galactic nuclei (AGNs) taken as part of a hunt to find very heavily obscured Compton-thick AGNs. For obscuring columns greater than 1025 cm-2, AGNs are only visible at energies below 10 keV via reflected/scattered radiation, characterized by a flat power law. We therefore sel…
Long-term X-ray Variability Study of IC342 from XMM-Newton Observations
Mak, Daisy S. Y.; Pun, Chun S. J.; Kong, Albert K. H.
We presented the results of an analysis of four XMM-Newton observations of the starburst galaxy IC342 taken over a four-year span from 2001 to 2005, with an emphasis on investigating the long-term flux and spectral variability of the X-ray point sources. We detected a total of 61 X-ray sources within 35' × 30' of the galaxy down to a luminosity of…
On the Inversion of Stokes Profiles with Local Stray-light Contamination
Asensio Ramos, A.; Manso Sainz, R.
Obtaining the magnetic properties of non-resolved structures in the solar photosphere is always challenging and problems arise because the inversion is carried out through the numerical minimization of a merit function that depends on the proposed model. We investigate the reliability of inversions in which the stray-light contamination is obtaine…
A Census of Mid-infrared-selected Active Galactic Nuclei in Massive Galaxy Clusters at 0 <~ z <~ 1.3
Saintonge, Amélie; Tran, Kim-Vy H.; Tomczak, Adam R.
We conduct a deep mid-infrared (mid-IR) census of nine massive galaxy clusters at (0 < z < 1.3) with a total of ~1500 spectroscopically confirmed member galaxies using Spitzer/IRAC photometry and established mid-IR color selection techniques. Of the 949 cluster galaxies that are detected in at least three of the four IRAC channels at the >…
Chandra and HST Studies of the X-Ray Sources in Galactic Globular Cluster M92
Anderson, Scott F.; Kong, Albert K. H.; Verbunt, Frank +3 more
We present the analysis of two observations of M92 taken with the Chandra X-Ray Observatory. We combined the two data sets with a total exposure of ~52 ks. With the combined observation, we detected 10 X-ray sources inside the half-mass radius (1farcm02), five of which are inside the core radius (0farcm26) of M92. The luminosities of the 10 source…
A Detection of an X-ray Wind and an Ionized Disk in the Chandra HETGS Observation of the Seyfert 2 Galaxy IRAS 18325-5926
Lee, Julia C.; Canizares, Claude R.; Iwasawa, Kazushi +1 more
We analyze the Chandra High Energy Transmission Grating Spectrometer observation of the Seyfert 2 AGN IRAS 18325-5926. We detect a v = -360+41 -66 km s-1 blueshifted ionized absorber in the X-ray spectrum, with photoionization parameter log ξ = 2.0+0.1 -0.1 and hydrogen column density N H…
Hubble Space Telescope Pixel Analysis of the Interacting Face-on Spiral Galaxy NGC 5194 (M51A)
Lee, Joon Hyeop; Kyeong, Jaemann; Kim, Sang Chul +3 more
A pixel analysis is carried out on the interacting face-on spiral galaxy NGC 5194 (M51A), using the Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) images in the F435W, F555W, and F814W (BVI) bands. After 4 × 4 binning of the HST/ACS images to secure a sufficient signal-to-noise ratio for each pixel, we derive several quantities des…
Transition Region Emission from Solar Flares during the Impulsive Phase
Raymond, J. C.; Ciaravella, A.; Giordano, S. +4 more
There are relatively few observations of UV emission during the impulsive phases of solar flares, so the nature of that emission is poorly known. Photons produced by solar flares can resonantly scatter off atoms and ions in the corona. Based on off-limb measurements by the Solar and Heliospheric Observatory/Ultraviolet Coronagraph Spectrometer, we…
Suzaku Observation of a New Merging Group of Galaxies at a Filamentary Junction
Yoshitake, Hiroshi; Kawahara, Hajime; Nishimichi, Takahiro +1 more
We report on a new merging group of galaxies, Suzaku J1552+2739, at z ~ 0.08 revealed by a Suzaku observation. The group was found by observing a junction of galaxy filaments optically identified in the Sloan Digital Sky Survey spectroscopic data. Suzaku J1552+2739 exhibits an irregular morphology and presents several peaks in its X-ray image. A b…
Measurement of Intermittency of Anisotropic Magnetohydrodynamic Turbulence in High-speed Solar Wind
Wu, D. J.; Yang, L.; Luo, Q. Y.
We investigate the intermittency of anisotropic magnetohydrodynamic (MHD) turbulence in high-speed solar wind. Using the data recorded by the Ulysses spacecraft, we apply the Castaing function to model the probability density functions of the fluctuating magnetic field and calculate the magnetic structure functions (SFs) Sp of the order…