High-Resolution X-ray Spectroscopy of SNR 1987A: Chandra LETG and HETG Observations in 2007 (2008)
Zhekov, Svetozar A., McCray, Richard, Dewey, Daniel, Canizares, Claude R., Borkowski, Kazimierz J., Burrows, David N., ...
We present an extended analysis of the deep Chandra LETG and HETG observations of the supernova remnant 1987A (SNR 1987A) carried out in 2007. The global fits to the grating spectra show that the...
Colliding Stellar Wind Models with Nonequilibrium Ionization: X-rays from WR 147 (2007)
The effects of nonequilibrium ionization are explicitly taken into account in a numerical model which describes colliding stellar winds (CSW) in massive binary sytems. This new model is used to...
X-Rays From Massive OB Stars: Thermal Emission From Radiative Shocks (2007)
Zhekov, Svetozar A., Palla, Francesco
Chandra gratings spectra of a sample of 15 massive OB stars were analyzed under the basic assumption that the X-ray emission is produced in an ensemble of shocks formed in the winds driven by these...
Chandra Observations of Supernova 1987A (2007)
Park, Sangwook, Burrows, David N., Garmire, Gordon P., McCray, Richard, Racusin, Judith L., Zhekov, Svetozar A.
We have been monitoring Supernova (SN) 1987A with {\it Chandra X-Ray Observatory} since 1999. We present a review of previous results from our {\it Chandra} observations, and some preliminary results...
Evolutionary Status of SNR 1987A at the Age of Eighteen (2006)
Park, Sangwook, Zhekov, Svetozar A., Burrows, David N., Garmire, Gordon P., Racusin, Judith L., McCray, Richard
$\sim$18 yr after the supernova explosion, the blast wave of SNR 1987A is entering the main body of the equatorial circumstellar material, which is causing a dramatic brightening of the remnant. We...
Chandra LETG Observations of Supernova Remnant 1987A (2006)
Zhekov, Svetozar A., McCray, Richard, Borkowski, Kazimierz J., Burrows, David N., Park, Sangwook
We discuss the results from deep Chandra LETG observations of the supernova remnant 1987A (SNR 1987A). We find that a distribution of shocks, spanning the same range of velocities (from 300 to 1700...
Evolution of the Reverse Shock Emission from SNR 1987A (2006)
Heng, Kevin, McCray, Richard, Zhekov, Svetozar A., Challis, Peter M., Chevalier, Roger A., Crotts, Arlin P. S., ...
We present new (2004 July) G750L and G140L Space Telescope Imaging Spectrograph (STIS) data of the H-alpha and Ly-alpha emission from supernova remnant (SNR) 1987A. With the aid of earlier data, from...
Iron depletion in the hot bubbles in planetary nebulae (2005)
Georgiev, Leonid N., Richer, Michael G., Arrieta, Anabel, Zhekov, Svetozar A.
We have searched for the emission from \fex and \fexiv that is expected from the gas emitting in diffuse X-rays in \bd, NGC 6543, NGC 7009, and NGC 7027. Neither line was detected in any object....
Supernova Remnant 1987A: High Resolution Images and Spectrum from Chandra Observations (2005)
Park, Sangwook, Zhekov, Svetozar A., Burrows, David N., Racusin, Judith L., McCray, Richard, Borkowski, Kazimierz J.
We report on the morphological and spectral evolution of SNR 1987A from the monitoring observations with the Chandra/ACIS. As of 2005, the X-ray-bright lobes are continuously brightening and...
The reverse shock of SNR1987A at 18 years after outburst (2005)
Smith, Nathan, Zhekov, Svetozar A., Heng, Kevin, McCray, Richard, Morse, Jon A., Gladders, Mike
We use low-dispersion spectra obtained at the Magellan Observatory to study the broad H-alpha emission from the reverse shock of the infant supernova remnant SNR1987A. These spectra demonstrate that...
Supernova Remnant 1987A: Opening the Future by Reaching the Past (2005)
Park, Sangwook, Zhekov, Svetozar A., Burrows, David N., McCray, Richard
We report an up-turn in the soft X-ray light curve of supernova remnant (SNR) 1987A in late 2003 (~6200 days after the explosion), as observed with the Chandra X-ray Observatory. Since early 2004,...
Supernova Remnant 1987A: The Latest Report from the Chandra X-Ray Observatory (2005)
Park, Sangwook, Zhekov, Svetozar A., Burrows, David N., Garmire, Gordon P., McCray, Dick
We continue monitoring supernova remnant (SNR) 1987A with the {\it Chandra X-ray Observatory}. As of 2004 January, bright X-ray spots in the northwest and the southwest are now evident in addition to...
A Chandra View of The Morphological And Spectral Evolution of Supernova Remnant 1987A (2004)
Park, Sangwook, Zhekov, Svetozar A., Burrows, David N., Garmire, Gordon P., McCray, Richard
We present an update on the results of our monitoring observations of the X-ray remnant of supernova (SN) 1987A with the {\it Chandra X-Ray Observatory}. As of 2002 December, we have performed a...
Monitoring The Evolution of SNR 1987A with Chandra (2003)
Park, Sangwook, Burrows, David N., Garmire, Gordon P., Zhekov, Svetozar A., McCray, Dick
We report on the results of our monitoring program of SNR 1987A with the Chandra X-Ray Observatory. The high resolution images and the spectra from the latest Chandra data suggest that the blast wave...
Pun, Chun S. J., Michael, Eli, Zhekov, Svetozar A., McCray, Richard, Garnavich, Peter M., Challis, Peter M., ...
We report and interpret HST/STIS long-slit observations of the optical and ultraviolet (1150 - 10270 Angstrom) emission-line spectra of the rapidly brightening Spot 1 on the equatorial ring of SN...