Long-lived planetesimal discs (2009)
We investigate the survival of planetesimal discs over Gyr timescales, using a unified approach that is applicable to all Keplerian discs of solid bodies -- dust grains, asteroids, planets, etc....
Balmer-Dominated Shocks: A Concise Review (2009)
A concise and critical review of Balmer-dominated shocks (BDSs) is presented, summarizing the state of theory and observations, including models with/without shock precursors and their synergy with...
Magnetohydrodynamic Shallow Water Waves: Linear Analysis (2009)
Heng, Kevin, Spitkovsky, Anatoly
We present a linear analysis of inviscid, incompressible, magnetohydrodynamic (MHD) shallow water systems. In spherical geometry, a generic property of such systems is the existence of five wave...
GEOMETRICAL PROOF OF ALBERTI’S AND THE DISTANCE POINT CONSTRUCTION (2009)
Kevin Heng, Ser Guan, Helmer Aslaksen
The philosophers of the Renaissance considered mathematical investigation integral to some of their theories. Such a combination of mathematics with natural philosophy was known as the “mixed...
Constraining the Porosities of Interstellar Dust Grains (2009)
We present theoretical calculations of the X-ray scattering properties of porous grain aggregates with olivine monomers. The small and large angle scattering properties of these aggregates are...
Planetesimal Disk Microlensing (2009)
Heng, Kevin, Keeton, Charles R.
Motivated by debris disk studies, we investigate the gravitational microlensing of background starlight by a planetesimal disk around a foreground star. We use dynamical survival models to construct...
A direct measurement of the dust extinction curve in an intermediate-redshift galaxy (2008)
Heng, Kevin, Lazzati, Davide, Perna, Rosalba, Garnavich, Peter, Noriega-Crespo, Alberto, Bersier, David, ...
We present a proof-of-concept study that dust extinction curves can be extracted from the infrared (IR), optical, ultraviolet (UV), and X-ray afterglow observations of GRBs without assuming known...
A Direct Measurement of the Dust Extinction Curve in an Intermediate-Redshift Galaxy (2008)
Heng, Kevin, Lazzati, Davide, Perna, Rosalba, Garnavich, Peter, Noriega-Crespo, Alberto, Bersier, David, ...
We present a proof-of-concept study that dust extinction curves can be extracted from the infrared (IR), optical, ultraviolet (UV) and X-ray afterglow observations of GRBs without assuming known...
Spatial Structure and Collisionless Electron Heating in Balmer-dominated Shocks (2008)
Van Adelsberg, Matthew, Heng, Kevin, McCray, Richard, Raymond, John C.
Balmer-dominated shocks in supernova remnants (SNRs) produce strong hydrogen lines with a two-component profile composed of a narrow contribution from cold upstream hydrogen atoms, and a broad...
Probing elemental abundances in SNR 1987A using XMM-Newton (2008)
Heng, Kevin, Haberl, Frank, Aschenbach, Bernd, Hasinger, Günther
Probing elemental abundances in SNR 1987A using XMM-Newton (2008)
Heng, Kevin, Haberl, Frank, Aschenbach, Bernd, Hasinger, Günther
Erratum: "Probing elemental abundances in SNR 1987A using XMM-Newton" (ApJ, 676, 361 [2008]) (2008)
Heng, Kevin, Haberl, Frank, Aschenbach, Bernd, Hasinger, Günther
Broad Lyman-Alpha Emission from Supernova Remnants in Young Galaxies (2007)
Charge transfer (or exchange) reactions between hydrogen atoms and protons in collisionless shocks of supernova remnants (SNRs) are a natural way of producing broad Balmer, Lyman and other lines of...
Probing Elemental Abundances in SNR 1987A Using XMM-Newton (2007)
Heng, Kevin, Haberl, Frank, Aschenbach, Bernd, Hasinger, Guenther
We report on the latest (2007 Jan) observations of supernova remnant (SNR) 1987A from the XMM-Newton mission. Since the 2003 May observations of Haberl et al. (2006), 11 emission lines have...
The Transition Zone in Balmer-Dominated Shocks (2007)
Heng, Kevin, Van Adelsberg, Matthew, McCray, Richard, Raymond, John C.
We examine the structure of the post-shock region in supernova remnants (SNRs). The ``shock transition zone'' is set up by charge transfer and ionization events between atoms and ions, and has a...
The Reverse Shock of SNR 1987A (2007)
The reverse shock of supernova remnant (SNR) 1987A emits in H-alpha and Ly-alpha, and comes in two flavors: surface and interior. The former is due to direct, impact excitation of hydrogen atoms...
Dust Echoes from the Ambient Medium of Gamma-Ray Bursts (2007)
Heng, Kevin, Lazzati, Davide, Perna, Rosalba
Long gamma-ray bursts (GRBs) are likely associated with the collapse of massive stars, which produce dust and are born in dusty environments. Absorption and scattering of ultraviolet/X-ray photons...
The transition zone in Balmer-dominated shocks (2007)
Heng, Kevin, Van Adelsberg, Matthew, McCray, Richard, Raymond, John C.
Balmer-Dominated Shocks Revisited (2006)
We present a new formalism to describe the ratios and profiles of emission lines from hydrogen in Balmer-dominated shocks. We use this model to interpret the measured widths and ratios of broad and...
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...
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...