The Circumstellar Medium of Cassiopeia A Inferred from the Outer Ejecta Knot Properties (2009)
We investigate the effect of the circumstellar medium density profile on the X-ray emission from outer ejecta knots in the Cassiopeia A supernova remnant using the 1 Ms Chandra observation. The...
Million Degree Plasmas in Extreme Ultraviolet (EUV) Astrophysics (2009)
Kowalski, Michael P., Barstow, Martin, Bruhweiler, Frederick, Cruddace, Raymond, Dupree, Andrea, Holberg, Jay, ...
Million degree plasmas are ubiquitous in the Universe, and examples include the atmospheres of white dwarfs; accretion phenomena in young stars, cataclysmic variables and active galactic nuclei; the...
We revisit in more detail a model for element abundance fractionation in the solar chromosphere, that gives rise to the "FIP Effect" in the solar corona and wind. Elements with first ionization...
Rakowski, Cara E., Laming, J. Martin, Ghavamian, Parviz
Understanding the heating of electrons to quasi-thermal energies at collisionless shocks has broad implications for plasma astrophysics. It directly impacts the interpretation of X-ray spectra from...
Ion Charge States in Halo CMEs: What can we Learn about the Explosion? (2007)
Rakowski, Cara E., Laming, J. Martin, Lepri, Susan T.
We describe a new modeling approach to develop a more quantitative understanding of the charge state distributions of the ions of various elements detected in situ during halo Coronal Mass Ejection...
Ion Charge States in the Fast Solar Wind: New Data Analysis and Theoretical Refinements (2007)
Laming, J. Martin, Lepri, Susan T.
We present a further investigation into the increased ionization observed in element charge states in the fast solar wind compared to its coronal hole source regions. Once ions begin to be...
We explore an analytic model of the accretion shock in the post bounce phase of a core-collapse supernova explosion. We find growing oscillations of the shock in the l=1 and l=2 modes, in agreement...
The Cassiopeia A Supernova Remnant in X-Rays (2007)
We review progress to date on analysis of the 1 million second Chandra Very Large Project (VLP)observation of the Cassiopeia A supernova remnant. We explore the possibility that Cas A exploded into a...
Ghavamian, Parviz, Laming, J. Martin, Rakowski, Cara E.
The analysis of Balmer-dominated optical spectra from non-radiative (adiabatic) SNRs has shown that the ratio of the electron to proton temperature temperature at the blast wave is close to unity at...
The Polar Regions of Cassiopeia A: The Aftermath of a Gamma Ray Burst? (2006)
Laming, J. Martin, Hwang, Una, Radics, Balint, Lekli, Gergely, Takacs, Endre
Probably not, but it is interesting nevertheless to investigate just how close Cas A might have come to generating such an event. Focusing on the northeast jet filaments, we analyze the polar regions...
Una Hwang, J. Martin Laming, Carles Badenes, Fred Berendse, John Blondin, Denis Cioffi, ...
We introduce a million-second observation of the supernova remnant Cassiopeia A with the Chandra X-ray Observatory. The bipolar structure of the Si-rich ejecta (NE jet and SW counterpart) is clearly...
Outflows Near An Accreting Black Hole: Ionization and Temperature Structure (2004)
Laming, J. Martin, Titarchuk, Lev
We calculate the temperature and ionization balance in an outflow from an accreting black hole under illumination by hard radiation from the central object. Electron scattering of the Fe K_alpha...
A Million-Second Chandra View of Cassiopeia A (2004)
Hwang, Una, Laming, J. Martin, Badenes, Carles, Berendse, Fred, Blondin, John, Cioffi, Denis, ...
We introduce a million-second observation of the supernova remnant Cassiopeia A with the Chandra X-ray Observatory. The bipolar structure of the Si-rich ejecta (NE jet and SW counterpart) is clearly...
A Unified Picture of the FIP and Inverse FIP Effects (2004)
We discuss models for coronal abundance anomalies observed in the coronae of the sun and other late-type stars following a scenario first introduced by Schwadron, Fisk & Zurbuchen of the interaction...
On Collisionless Electron-Ion Temperature Equilibration in the Fast Solar Wind (2003)
We explore a mechanism, entirely new to the fast solar wind, of electron heating by lower hybrid waves to explain the shift to higher charge states observed in various elements in the fast wind at 1...
Where was the Iron Synthesized in Cassiopeia A? (2003)
We investigate the properties of Fe-rich knots on the east limb of the Cassiopeia A supernova remnant using observations with Chandra/ACIS and analysis methods developed in a companion paper. We use...
We present a detailed analysis of Chandra X-ray spectra from individual ejecta knots in the supernova remnant Cassiopeia A. The spectra are fitted to give the electron temperature and (single)...
Slow Temperature Equilibration Behind the Shock Front of SN 1006 (2003)
Vink, Jacco, Laming, J. Martin, Gu, Ming Feng, Rasmussen, Andrew, Kaastra, Jelle S.
We report on the observation of OVII Doppler line broadening in a compact knot at the edge of SN 1006 detected with the Reflective Grating Spectrometer on board XMM-Newton. The observed line width of...
On the magnetic fields and particle acceleration in Cas A (2002)
Vink, Jacco, Laming, J. Martin
We investigate the non-thermal X-ray emission from Cas A. For the hard X-ray continuum we test the model proposed by Laming, which invokes bremsstrahlung from electrons accelerated by lower hybrid...
Laming, J. Martin, Grun, Jacob
Atomic physics calculations of radiative cooling are used to calculate criteria for the overstability of radiating shocks. Our calculations explain the measurement of shock overstability by Grun et...
The detection of the Sc-44 nuclear de-excitation lines and hard X-ray emission from Cas A (2002)
Vink, Jacco, Laming, J. Martin
We discuss the detection of Sc-44 (product of Ti-44) in the supernova remnant Cas A with the BeppoSAX-PDS instrument, and elaborate on the nature of the hard X-ray continuum, which is not only...
The Electron Temperature and 44Ti Decay Rate in Cassiopeia A (2001)
The effects of plasma elemental composition and ionization state on the effective decay rate of 44Ti are investigated. We essentially follow the methods of the first authors to treat this topic,...
Accelerated Electrons in Cassiopeia A: Thermal and Electromagnetic Effects (2001)
We consider in more detail a model previously proposed for the hard X-ray (>10 keV) emission observed from the supernova remnant Cas A, whereby electrons are accelerated by lower-hybrid waves and...
Savin, Daniel Wolf, Laming, J. Martin
We have investigated how the relative elemental abundances inferred from the solar upper atmosphere are affected by uncertainties in the dielectronic recombination (DR) rate coefficients used to...
Vink, Jacco, Laming, J. Martin, Kaastra, Jelle, Bleeker, Johan, Bloemen, Hans, Oberlack, Uwe
We report the detection of the Sc-44 nuclear decay lines at 67.9 keV and 78.4 keV associated with the nuclear decay of Ti-44 in Cassiopeia A. The line emission was observed by the PDS instrument on...
Accelerated Electrons in Cassiopeia A: An Explanation for the Hard X-ray Tail (2000)
We propose a model for the hard X-ray (> 10 keV) emission observed from the supernova remnant Cas A. Lower hybrid waves are generated in strong (mG) magnetic fields, generally believed to reside in...