Search Publications
A Massive Bipolar Outflow and a Dusty Torus with Large Grains in the Preplanetary Nebula IRAS 22036+5306
Sahai, R.; Sánchez Contreras, C.; Patel, N. A. +2 more
We report high angular resolution (~1") CO J=3-2 interferometric mapping using the Submillimeter Array (SMA) of IRAS 22036+5306 (I22036), a bipolar preplanetary nebula (PPN) with knotty jets discovered in our HST snapshot survey of young PPNs. In addition, we have obtained supporting lower resolution (~10") CO and 13CO J=1-0 observation…
Flux Rope Model of the 2003 October 28-30 Coronal Mass Ejection and Interplanetary Coronal Mass Ejection
Chen, J.; Yurchyshyn, V. B.; Skoug, R. M. +2 more
A numerical model of an erupting solar flux rope is shown to reproduce both quantitative near-Sun properties of the 2003 October 28 coronal mass ejection and the timing, strength, and orientation of the fields measured in situ at 1 AU. Using a simple erupting flux rope model, we determine the best-fit parameters for this event. Our analysis shows …
Observed Frequency Variations of Solar p-Mode Travel Times as Evidence for Surface Effects in Sunspot Seismology
Birch, A. C.; Braun, D. C.
Using helioseismic holography, we measure acoustic (p-mode) travel-time perturbations, observed within solar active regions, as functions of frequency and phase speed. We find evidence for a frequency variation, at fixed phase speed, of the travel times that has not previously been reported. This variation is not expected from typical sound-speed …
The Two-dimensional XMM-Newton Group Survey: z < 0.012 Groups
Mulchaey, John S.; Finoguenov, Alexis; Davis, David S. +1 more
We present the results of the two-dimensional XMM-Newton Group Survey (2dXGS), an archival study of nearby galaxy groups. In this paper we consider 11 nearby systems (z<0.012) in Mulchaey et al., which span a broad range in X-ray luminosity from 1040 to 1043 ergs s-1. We measure the iron abundance and temperatur…
Ultraviolet Properties of Halo Coronal Mass Ejections: Doppler Shifts, Angles, Shocks, and Bulk Morphology
Raymond, J. C.; Ciaravella, A.; Kahler, S. W.
We present UV spectral information for 22 halo or partial halo CMEs observed by UVCS. The CME fronts show broad line profiles, while the line intensities are comparable to the background corona. The Doppler shifts of the front material are generally small, showing that the motion of gas in the fronts is mostly transverse to the line of sight. This…
E+A Galaxies with Blue Cores: Active Galaxies in Transition
Zabludoff, Ann I.; Zaritsky, Dennis; Yang, Yujin +1 more
Hubble Space Telescope (HST) ACS images reveal blue cores in four E+A, or post-starburst, galaxies. Follow-up spectroscopy shows that these cores have LINER spectra. The existence of LINERs, consistent with those in many elliptical galaxies, is yet one more piece of evidence that these postmerger, post-starburst, bulge-dominated galaxies will evol…
Near-Infrared and Optical Limits for the Central X-Ray Point Source in the Cassiopeia A Supernova Remnant
Pavlov, G. G.; Fesen, R. A.; Sanwal, D.
We set new near-infrared and optical magnitude limits for the central X-ray point source (XPS) in the Cassiopeia A supernova remnant based on HST images. Near-infrared images of the center of Cas A taken with the NICMOS 2 camera in combination with the F110W and F160W filters (~J and H bands) have magnitude limits >=26.2 and >=24.6, respecti…
The High-Velocity Outflow of PG 1211+143 May Not Be That Fast
Kaspi, Shai; Behar, Ehud
We analyze the X-ray spectrum of the quasar PG 1211+143 observed with the CCD and grating spectrometers on board XMM-Newton. Using an ion-by-ion fitting model, we find an outflow component of about 3000 km s-1, which includes absorption lines of K and L shell ions of the astrophysically abundant elements. We also identify and include in…
X-Ray-selected Intermediate-Redshift Groups of Galaxies
Mulchaey, John S.; Rosati, Piero; Lubin, Lori M. +2 more
We present spectroscopic confirmation of nine moderate-redshift galaxy groups and poor clusters selected from the ROSAT Deep Cluster Survey. The groups span the redshift range z~0.23-0.59 and have between 4 and 20 confirmed members. The velocity dispersions of these groups range from ~125 to 650 km s-1. Similar to X-ray groups at low re…
A Close Look at the Population of Supersoft and Quasi-soft X-Ray Sources Observed in M31 with XMM-Newton
Orio, Marina
The deepest X-ray images of M31, obtained with XMM-Newton, are examined to derive spectral and statistical properties of the population of the very soft X-ray sources. When classifying supersoft X-ray sources (SSSs) with criteria based on the same hardness ratios defined for recent Chandra observations, one-quarter of the selected SSSs turn out to…