Search Publications
Detection of Supersonic Horizontal Flows in the Solar Granulation
Bellot Rubio, L. R.
Hydrodynamic simulations of granular convection predict the existence of supersonic flows covering ~3%-4% of the solar surface at any time, but these flows have not been detected unambiguously as yet. Using data from the spectropolarimeter aboard the Hinode satellite, I present direct evidence of fast horizontal plasma motions in quiet-Sun granule…
Dust Distribution in the β Pictoris Circumstellar Disks
Artymowicz, Pawel; Croll, Bryce; Ahmic, Mirza
We present three-dimensional models of dust distribution around β Pictoris that produce the best fits to the Hubble Space Telescope/Advanced Camera for Surveys' images obtained by Golimowski and coworkers. We allow for the presence of either one or two separate axisymmetric dust disks. The density models are analytical, radial two power laws joine…
Are Coronal Loops Isothermal or Multithermal?
Mason, H. E.; Schmelz, J. T.; DeLuca, E. E. +5 more
Surprisingly few solar coronal loops have been observed simultaneously with TRACE and SOHO/Coronal Diagnostics Spectrometer (CDS), and even fewer analyses of these loops have been conducted and published. The SOHO Joint Observing Program 146 was designed in part to provide the simultaneous observations required for in-depth temperature analysis of…
Spectral Analysis of the Accretion Flow in NGC 1052 with Suzaku
Kadler, M.; Kerp, J.; Ros, E. +10 more
We present an analysis of the 101 ks, 2007 Suzaku spectrum of the low ionization nuclear emission region galaxy NGC 1052. The 0.5-10 keV continuum is well modeled by a power-law continuum modified by Galactic and intrinsic absorption, and it exhibits a soft, thermal emission component below 1 keV. Both a narrow core and a broader component of Fe K…
XMM-Newton View of the Multiphase Warm Absorber in Seyfert 1 Galaxy NGC 985
Elvis, Martin; Nicastro, Fabrizio; Mathur, Smita +6 more
We present an analysis of a new XMM-Newton observation of the Seyfert 1 galaxy NGC 985. The European Photon Imaging Camera (EPIC) spectra present strong residuals to a single power-law model, indicating the presence of ionized absorbing gas and a soft excess. A broadband fit to the EPIC and RGS spectra shows that the continuum can be well fitted w…
An Absence of X-ray Accretion Shock Instability Signatures in TW Hydrae
Drake, Jeremy J.; Raymond, John; Laming, J. Martin +1 more
Gas accreting onto T Tauri stars should form shocks that are susceptible to the classical radiative shock instability. The instability should give rise to strong periodic modulation in the X-ray emission from the shock-heated plasma. Time series analysis of soft X-rays thought to arise predominantly in an accretion shock on the classical T Tauri s…
A Narrow Streamer-Puff Coronal Mass Ejection from the Nonradial Eruption of an Active-Region Filament
Yang, Jiayan; Bi, Yi; Zheng, Ruisheng +2 more
So-called streamer-puff coronal mass ejections (CMEs) were recently identified by Bemporad et al. as a new variety of CME. They originate from nonradial ejecta from compact ejective flares occurring in the outskirts of the base of a streamer and travel out along it, during which the streamer is transiently inflated by the puff but is not disrupted…
Properties of Galaxies Hosting X-ray-selected Active Galactic Nuclei in the CL1604 Supercluster at z = 0.9
Kocevski, Dale D.; Fassnacht, Christopher D.; Lubin, Lori M. +4 more
Recent galaxy evolution models suggest that feedback from active galactic nuclei (AGNs) may be responsible for suppressing star formation in their host galaxies and the subsequent migration of these systems onto the red sequence. To investigate the role of AGNs in driving the evolution of their hosts, we have carried out a study of the environment…
Efficient Pseudo-Global Fitting for Helioseismic Data
Chaplin, W. J.; Elsworth, Y.; Fletcher, S. T. +1 more
Mode fitting or "peak bagging" is an important procedure in helioseismology allowing one to determine the various mode parameters of solar oscillations. Here we describe a way of reducing the systematic bias in the fits of certain mode parameters that are seen when using "local" fitting techniques to analyze the Sun-as-a-star p-mode power spectrum…
Physical Conditions in the Narrow-Line Region of Markarian 3. II. Photoionization Modeling Results
Kraemer, S. B.; Crenshaw, D. M.; Bruhweiler, F. C. +2 more
We have examined the physical conditions in the narrow-line region (NLR) of the Seyfert 2 galaxy Markarian 3, using long-slit spectra obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph, and photoionization models. We find three components of photoionized gas in the NLR. Two of these components, characterized by emission …