Search Publications
The Energy-dependent X-Ray Timing Characteristics of the Narrow-Line Seyfert 1 Mrk 766
Turner, T. J.; Papadakis, I.; Reeves, J. N. +3 more
We present the energy-dependent power spectral density (PSD) and cross spectral properties of Mrk 766, obtained from combining data obtained during an XMM-Newton observation spanning six revolutions in 2005 with data obtained from an XMM-Newton long look in 2001. The PSD shapes and rms-flux relations are found to be consistent between the 2001 and…
Localized Enhancements of Fe+10 Density in the Corona as Observed in Fe XI 789.2 nm during the 2006 March 29 Total Solar Eclipse
Morgan, Huw; Habbal, Shadia Rifai; Jaeggli, Sarah +5 more
The first ever image of the full solar corona in the Fe XI 789.2 nm spectral line was acquired during the total solar eclipse of 2006 March 29. Several striking features stand out in the processed image: (1) The emission extended out to at least 3 Rsolar in streamers. (2) A bubble-like structure, occupying a cone of about 45° and reachi…
The Case for Optically Thick High-Velocity Broad-Line Region Gas in Active Galactic Nuclei
Gaskell, C. Martin; Snedden, Stephanie A.
A combined analysis of the profiles of the main broad quasar emission lines in both Hubble Space Telescope and optical spectra shows that while the profiles of the strong UV lines are quite similar, there is frequently a strong increase in the Lyα/Hα ratio in the high-velocity gas. We show that the suggestion that the high-velocity gas is opticall…
Global Coronal Mass Ejections
Zhukov, Andrei N.; Veselovsky, Igor S.
Observations of the low solar corona in the extreme ultraviolet and in soft X-rays evidence a close relationship of coronal dimmings and coronal mass ejections (CMEs). Dimmings are usually interpreted as places of plasma evacuation during a CME. We characterize a CME by the apparent angular extent of associated dimmings above the solar limb and de…
The Space Motion of the Globular Cluster NGC 6397
Anderson, Jay; Lépine, Sébastien; Rich, R. Michael +12 more
As a by-product of high-precision, ultradeep stellar photometry in the Galactic globular cluster NGC 6397 with the Hubble Space Telescope, we are able to measure a large population of background galaxies whose images are nearly pointlike. These provide an extragalactic reference frame of unprecedented accuracy, relative to which we measure the mos…
A Probabilistic Approach to Classifying Supernovae Using Photometric Information
Kuznetsova, Natalia V.; Connolly, Brian M.
This paper presents a novel method for determining the probability that a supernova candidate belongs to a known supernova type (such as Ia, Ibc, IIL, etc.) using its photometric information alone. It is validated with Monte Carlo simulations, and both space- and ground-based data. We examine the application of the method to well-sampled as well a…
Warm-Hot Intergalactic Medium Associated with the Coma Cluster
Finoguenov, A.; Mitsuda, K.; Tamura, T. +4 more
Hydrodynamic simulations predict that low-redshift baryons are predominantly in a warm-hot intergalactic medium (WHIM), which should exhibit absorption and emission lines in the soft X-ray region. The WHIM is predicted to be most dense around clusters of galaxies. We present our XMM-Newton RGS observations of X Comae, an active galactic nucleus be…
Chandra Observations of the Eagle Nebula. I. Embedded Young Stellar Objects near the Pillars of Creation
Linsky, Jeffrey L.; Andersen, Morten; Gagné, Marc +2 more
We present and analyze the first high-resolution X-ray images ever obtained of the Eagle Nebula star-forming region. On 2001 July 30 the Chandra X-Ray Observatory obtained a 78 ks image of the Eagle Nebula (M16) that includes the core of the young galactic cluster NGC 6611 and the dark columns of dust and cold molecular gas in M16 known as the ``P…
The Ultraluminous X-Ray Sources Near the Center of M82
Pun, C. S. J.; Kong, A. K. H.; Yang, Y. J. +2 more
We report the identification of a recurrent ultraluminous X-ray source (ULX), a highly absorbed X-ray source (possibly a background AGN), and a young supernova remnant near the center of the starburst galaxy M82. From a series of Chandra observations taken from 1999 to 2005, we found that the transient ULX first appeared in 1999 October. The sourc…
The Spectrum of the Black Hole X-Ray Nova V404 Cygni in Quiescence as Measured by XMM-Newton
Kong, Albert K. H.; Casares, J.; Haswell, C. A. +3 more
We present XMM-Newton observations of the black hole X-ray nova V404 Cyg in quiescence. Its quiescent spectrum can be best fitted by a simple power law with slope Γ~2. The spectra are consistent with that expected for the advection-dominated accretion flow (ADAF). V404 Cyg was roughly equal in luminosity compared to the previous observation of Cha…