Search Publications
On the Formation of Filament Channels
Wang, Y. -M.; Muglach, K.
From the Hα archive of the Big Bear Solar Observatory (BBSO) we have selected three examples showing fibril structures that change their orientation, over 1 or 2 days, from nearly perpendicular to nearly parallel to the polarity inversion line (PIL). In one case, the filament channel forms within a single decaying bipole; in the other two cases, i…
The Black Hole Mass of NGC 4151: Comparison of Reverberation Mapping and Stellar Dynamical Measurements
Peterson, Bradley M.; Heckman, Timothy M.; Pogge, Richard W. +11 more
We present a stellar dynamical estimate of the black hole (BH) mass in the Seyfert 1 galaxy, NGC 4151. We analyze ground-based spectroscopy as well as imaging data from the ground and space, and we construct three-integral axisymmetric models in order to constrain the BH mass and mass-to-light ratio. The dynamical models depend on the assumed incl…
Structure and Dynamics of the Sun's Open Magnetic Field
Antiochos, S. K.; Mikić, Z.; DeVore, C. R. +1 more
The solar magnetic field is the primary agent that drives solar activity and couples the Sun to the heliosphere. Although the details of this coupling depend on the quantitative properties of the field, many important aspects of the corona-solar wind connection can be understood by considering only the general topological properties of those regio…
Resolving the Unresolved Cosmic X-Ray Background in the Chandra Deep Fields
Hickox, Ryan C.; Markevitch, Maxim
We present a measurement of the surface brightness of the cosmic X-ray background (CXB) in the Chandra Deep Fields, after excluding all detected X-ray, optical, and infrared sources. The work is motivated by a recent X-ray stacking analysis by Worsley and collaborators, which showed that galaxies detected by HST but not by Chandra may account for …
On the Putative Detection of z > 0 X-Ray Absorption Features in the Spectrum of Mrk 421
Rasmussen, Andrew P.; Kahn, Steven M.; Paerels, Frits +3 more
In a series of papers, Nicastro et al. have reported the detection of z>0 O VII absorption features in the spectrum of Mrk 421 obtained with the Chandra Low Energy Transmission Grating Spectrometer (LETGS). We evaluate this result in the context of a high-quality spectrum of the same source obtained with the Reflection Grating Spectrometer (RGS…
The Evolution of the Field and Cluster Morphology-Density Relation for Mass-Selected Samples of Galaxies
Kelson, D. D.; Wuyts, S.; Ford, H. C. +7 more
The Sloan Digital Sky Survey (SDSS) and photometric/spectroscopic surveys in the GOODS-South field (the Chandra Deep Field-South, CDF-S) are used to construct volume-limited, stellar-mass-selected samples of galaxies at redshifts 0<z<1. The CDF-S sample at 0.6<z<1.0 contains 207 galaxies complete down to M=4×1010 Msolar…
A Subaru Weak-Lensing Survey. I. Cluster Candidates and Spectroscopic Verification
Refregier, Alexandre; Ellis, Richard S.; Miyazaki, Satoshi +4 more
We present the results of an ongoing weak-lensing survey conducted with the Subaru Telescope whose initial goal is to locate and study the distribution of shear-selected structures, or halos. Using a Suprime-Cam imaging survey spanning 21.82 deg2, we present a catalog of 100 candidate halos located from lensing-convergence maps. Our sam…
The SSS Phase of RS Ophiuchi Observed with Chandra and XMM-Newton. I. Data and Preliminary Modeling
Ness, J. -U.; Gehrz, R. D.; Gonzalez-Riestra, R. +13 more
The phase of supersoft source (SSS) emission of the sixth recorded outburst of the recurrent nova RS Oph was observed on days 39.7 and 66.9 after outburst with Chandra and on day 54.0 with XMM-Newton. A ~35 s period on day 54.0 originates from the SSS emission and not from the shock. We discuss the bound-free absorption by neutral elements in the …
A Floor in the Solar Wind Magnetic Field
Cliver, E. W.; Svalgaard, L.
Long-term (~130 years) reconstruction of the interplanetary magnetic field (IMF) based on geomagnetic indices indicates that the solar wind magnetic field strength has a ``floor,'' a baseline value in annual averages that it approaches at each 11 yr solar minimum. In the ecliptic plane at 1 AU, the IMF floor is ~4.6 nT, a value substantiated by di…
On the Origin of Three Seismic Sources in the Proton-rich Flare of 2003 October 28
Zharkova, Valentina V.; Zharkov, Sergei I.
The three seismic sources, S1, S2, and S3, detected from MDI Dopplergrams using the time-distance (TD) diagram technique are presented with the locations, areas, and vertical and horizontal velocities of the visible wave displacements. Within the data cube of 120 Mm, the horizontal velocities and the wave propagation times vary slightly from sourc…