Pawan Kumar

Department of Astronomy

Gamma-Ray Bursts, Helioseismology, Tidal Interaction, Accretion Disks, Cosmology


Phone: 512-471-3412

Office Location
RLM 17.204

Postal Address
The University of Texas at Austin
Department of Astronomy, College of Natural Sciences
2515 Speedway, Stop C1400
Austin, TX 78712

Ph.D., California Institute of Technology, Pasadena (1988)

Research Interests

Gamma-ray bursts; helioseismology; binary stars; tidal interaction; accretion disks; cosmology.

Group Areas
Gamma-ray Bursts, Asteroseismology

(Updated July 2008)

"Properties of Gamma-ray Burst Progenitor Stars", Kumar, P., Narayan, R. and Johnson, J., Science, vol. 321, 376, July 2008

"Mass Fall-back and Accretion in the Central Engine of Gamma-Ray Bursts", Kumar, P., Narayan, R. and Johnson, J., 2008, MNRAS 388, 1729

"A general scheme for modeling gamma-ray burst prompt emission", Kumar, P. and McMahon, E., 2008, MNRAS 384, 33

"Scattered emission from a relativistic outflow and its application to gamma-ray bursts", Shen, R.-F., Duran, R. Barniol, and Kumar, P., 2008, MNRAS 384, 1129

"A unified picture for the gamma-ray and prompt optical emissions of GRB 990123", Panaitescu, A., and Kumar, P., 2007, MNRAS 376, 1065

"The nature of the outflow in gamma-ray bursts", Kumar, P., McMahon, E., et al., 2007, MNRAS 376, 57

"GRB 060313: A New Paradigm for Short-hard Bursts?", Roming, Peter, et al., 2006, ApJ, 651, 985

"No universality for the electron power-law index (p) in gamma-ray bursts and other relativistic sources", Shen, Rongfeng, Kumar, P., and Robinson, Edward, L., 2006, MNRAS 371, 1441

"Swift observations of the prompt X-ray emission and afterglow from GRB050126 and GRB050219A", Goad, M.R., et al., 2006, A&A 449, 89

"A unified picture for gamma-ray burst prompt and X-ray afterglow emissions", Kumar, P., McMahon, E., et al., 2006, MNRAS 367, 52

"Distribution of gamma-ray burst ejecta energy with Lorentz factor", Granot, Jonathan and Kumar, P., 2006, MNRAS 366, 13

"Reverse shock emission as a probe of gamma-ray burst ejecta", McMahon, E., Kumar, P., and Piran, T., 2006, MNRAS 366, 575

"Swift Observations of the X-Ray Bright GRB 050315", Vaughan, S., et al., 2006, ApJ 638, 920

"Swift Panchromatic Observations of the Bright Gamma-Ray Burst GRB 050525a", Blustin, A.J., et al., 2006, ApJ 637, 901

"Discovery of an Afterglow Extension of the Prompt Phase of Two Gamma-Ray Bursts Observed by Swift", Barthelmy, S.D., et al., 2005, ApJ 635, 133

"The afterglow of GRB 050709 and the nature of the short-hard gamma-ray bursts", Fox, D.B., et al., 2005, Nature 437, 845

"An unexpectedly rapid decline in the X-ray afterglow emission of long Gamma-ray bursts", Tagliaferri, G., et al. 2005, Nature 436, 985

"An HST Search for Supernovae Accompanying X-Ray Flashes", Soderberg, A., et al, 2005, ApJ 627, 877

"Swift Observations of GRB 050128: The Early X-Ray Afterglow", Campana, S., et al., 2005, ApJ 625, 23

"The Swift Gamma-ray Burst Mission", Gehrels, N. et al., 2004, ApJ 611, 1005

"Prompt Gamma-ray and Early Afterglow Emission in the External Shock Model", McMahon, E., Kumar, P., and Panaitescu, A., 2004, MNRAS 354, 915

"Creation of Electron-Positron Pair Wind in Gamma-Ray Bursts and its Effect on the Early Afterglow Emission", Kumar, P., and Panaitescu, A., 2004, MNRAS 354, 252

"The Swift Gamma-Ray Burst Mission", Gehrels, N., et al., 2004, ApJ 611, 1005.

"Prompt Gamma-Ray and Early Afterglow Emission in the External Shock Model", McMahon, E., Kumar, P., and Panaitescu, A., 2004, to appear in MNRAS.

"Analysis of Two Scenarios for the Early Optical Emission of the GRB Afterglows 990123 and 021211", Panaitescu, A., and Kumar, P., 2004, MNRAS 353, 511.

"The Slow Decay of Some Radio Afterglows - A puzzle for the Simplest Gamma-Ray Burst Fireball Model", Panaitescu, A., and Kumar, P., 2004, MNRAS 350, 213.

"A Unified Treatment of the Gamma-Ray Burst 021211 and its Afterglow", Kumar, P., and Panaitescu, A.,2003, MNRAS 346, 905.

"The Effect of Angular Structure of Gamma-Ray burst Outflows on the Afterglow Emission", Panaitescu, A., and Kumar, P.,2003, ApJ 592, 390.

"Constraining the Structure of GRB Jets Through the Afterglow Light Curves", Kumar, P., and Granot, J., 2003, ApJ 591, 1086.

"The Evolution of a Structured Relativistic Jet and GRB Afterglow Light-curves", Kumar, P., and Granot, J., 2003, ApJ 591, 1075.

"GRB021004: A Massive Progenitor Star Surrounded by Shells", Shaefer, B.E., et.al,2003, ApJ 588, 387.

"X-ray Lines from Gamma-ray Bursts", Kumar, P., and Narayan, R., 2003, ApJ 584, 895.

"Angular Momentum Extraction by Gravity Waves in the Sun", Talon, S., Kumar, P., and Zahn, J-P., 2002, ApJ Lett. 574, L175.

"Off-Axis Afterglow Emition from Jetted Gamma-Ray Bursts", Granot, J., Panaitescu, A., Kumar, P., and Woosley, S.E., 2002,
ApJ Lett. 570, L61.

"Properties of Relavistic Jets in Gamma-Ray Burst Afterglows", Panaitescu, A., and Kumar, P., 2002, ApJ 571, 779.

"Fundamental Physical Parameters of Collimated Gamma-ray Burst Afterglows," Panaitescu, A., and Kumar, P., 2001, ApJ 560, L49

"Observational Prospects for Afterglows of Short-Duration Gamma-ray Bursts", Panaitescu, A., Kumar, P., and Narayan, R., 2001, ApJ Lett. 561, L171

"The energy of Long-duration Gamma-ray Bursts", Piran, T., Kumar, P., Panaitescu, A., and Piro, L., 2001, ApJ Lett. 560, L167

"Accretion Models of Gamma-ray Bursts", Narayan, R., Piran, T., and Kumar, P., 2001, ApJ 557, 949

"Jet Energy and other Parameters for the Afterglows of Gamma-Ray Bursts 980703, 990123, 990510, and 991216 Determined from Modeling of Multi-Frequency Data", Panaitescu, A., and Kumar, P., 2001, ApJ 554, 667

"BeppoSAX confirmation of beamed afterglow emission from GRB 990510", Pian, E., Soffitta, P., Aslessi, A., Amati, L., Costa, E., Frontera, F., Fruchter, A., Masetti, N., Palazzi, E., Paniaitescu, A., and Kumar, P., A&A 372, 456

"Energy distribution of Solar oscillation Modes inferred from Space-Based measurements", Wooddard, M.F., Korzennik, S.G., Rabello-Soars, M.C., Kumar, P., Tarbell, T.D., and Acton, S., 2001 ApJ Lett. 548, L103

"Tidal spin-up of stars in dense stellar cusps around massive black holes", Alexander, T., and Kumar, P., 2001, ApJ 549, 948

"Afterglow Emission from Naked Gamma-ray Bursts", Kumar, P. and Panaitescu, A., 2000, ApJ Lett. 541, L51

"Steepening of Afterglow Decay for Jets Interacting with Stratified Media", Kumar, P., and Panaitescu, A., 2000, ApJ Lett. 541, L9

"Analytic Light-Curves of Gamma-ray Burst Afterglows: Homogeneous versus Wind External Media", Panaitescu, A., and Kumar, P., 2000, ApJ 543, 66

"The Distribution of Burst Energy and Shock Parameters for Gamma-ray Bursts", Kumar, P., 2000, ApJ Lett. 538, L125

"Some Observational Consequences of GRB Shock Models", Kumar, P., and Piran, T., 2000, ApJ 532, 286

"Energetics and Luminosity Function of Gamma-ray Bursts", Kumar, P., and Piran, T., 2000, ApJ 535, 152

"Source depth for solar p-modes", Kumar, P., and Basu, S., 2000, ApJ Lett. 545, L65

"Gamma-Ray Burst Energetics", Kumar, P., 1999, ApJ Lett. 523, L113

"Line assymmetry of solar p-modes: Properties of acoustic sources", Kumar, P., and Basu, S., 1999, ApJ 519, 396

"Line asymmetry of solar p-modes: Reversal of asymmetry in intensity power spectra", Kumar, P., and Basu, S., 1999, ApJ 519, 389

"Angular momentum redistribution by waves in the Sun", Kumar, P., Suzanne, T., and Zahn, J-P, 1999, ApJ 520, 859

"The structure of the central disk of NGC 1068: a clumpy disk model", Kumar, P., 1998, ApJ 519, 599

"Dissipation of a tide in a differentially rotating star", Talon, S., and Kumar, P., 1998, ApJ 503, 387

"Possible explanations for some unusually large velocity dispersion molecular clouds near the Galactic centre", Kumar, P., and Riffert, H., 1997, MNRAS 292, 871

"Localized Helioseismic Constraints on Solar Structure", Bahcall, J.N., Basu, S., and Kumar, P., 1997, ApJ Lett. 485, L91

"Excitation of Solar Oscillations", Kumar, P., 1997, invited review, IAU symposium 181 "Sounding Solar and Stellar Interiors", eds. F.X. Schmider & J. Provost

"On the orbital decay of the PSR J0045-7319 Binary", Kumar, P. and Quataert, E., 1998, ApJ 493, 412

"Differential rotation enhanced dissipation of tides in the PSR Joo45-7319 Binary", Kumar, P. and Quataert, E., 1997, ApJ Lett. 479. L51

"Excitation and Damping of Solar Acoustic Oscillations", Kumar, P., invited review, in "Solar Convection and Oscillations and their relationship", eds. F.P. Pijpers, J. Christensen-Dalsgaard & C. Rosentha, (Kluwer, Dordrecht)

"Angular momentum transport by gravity waves and its effect on the rotation of the solar interior", Kumar, P., and Quataert, E.J., 1997, ApJ Lett. 475, L143

"HI Observations of two Molecular Clouds with Extremely Large Velocity Dispersions", Riffert, H., Kumar, P., and Huchtmeier, W.K., 1997, MNRAS 284, 749

"Asymmetries of Solar p-mode Line Profiles", Abrams, D., and Kumar, P., 1996, ApJ 472, 882

"Observational Search for Solar g-modes: Some Theoretical Considerations", Kumar, P., Quataert, E.J., and Bahcall, J.N., 1996, ApJ Lett. 458, L83

"Nonlinear Damping of Oscillations in Tidal-Capture Binaries", Kumar, P., and Goodman, G., 1996, ApJ 466, 946

"On the validity of the classical apsidal motion formula for tidal distortion", Quataert, E.J., Kumar, P. and Ao, C.O., 1996, ApJ 463, 284

"On the Interaction of Convection and Rotation in Stars", Kumar, P., Narayan, R. and Loeb, A.,1995, ApJ 453, 480

"Tidal Excitation of Modes in Binary Systems with Applications to Binary Pulsars", Kumar, P., Ao, C.O., and Quataert, E.J., 1995, ApJ 449, 294

"Causality in Strong Shear Flows", Narayan, R., Loeb, A., and Kumar, P., 1994, ApJ 431,359

"Properties of Acoustic Sources in the Sun", Kumar, P., 1994, ApJ 428, 827

"Limits on Coronal Reflection Using High-Frequency Solar Oscillations", Kumar, P., Fardal, M.A., Jefferies, S.M., Duvall, T.L. Jr., Harvey, J.W., and Pomerantz, M.A., 1994, ApJ Lett. 422, L29

"Excitation of Solar p-modes", Goldreich, P., Murray, N., and Kumar, P., 1994, ApJ 424, 466

"Effect of Nonlinear Interactions Among Solar acoustic Modes on p-mode Frequencies", Kumar, P., Goldreich, P., and Kerswell, R., 1994, ApJ 427, 483

"g-modes and The Solar Neutrino Problem", Bahcall J.N., and Kumar, P., 1993, ApJ Lett. 409, L73

"Solar Oscillations with Frequencies above the Acoustic Cutoff Frequency", Kumar, P., 1992, invited review, Proc. of GONG Meeting, ed. T.Brown

"Reconstructing the Primordial Spectrum of Fluctuations of the Universe from the Observed Nonlinear Clustering of Galaxies", Hamilton, A.J.S., Kumar, P., Lu, E., and Matthews, A., 1991,ApJ Lett. 374, L1

"The Location of the Source of High Frequency Solar Acoustic Oscillations", Kumar, P., and Lu, E., 1991, ApJ Lett. 375, L35

"Implications of Solar P-Mode Frequency Shifts", Goldreich, P., Murray, N., Willette, G., and Kumar, P., 1991, ApJ 370, 752

"Thermal and Mechanical Damping of Solar p-Modes", Goldreich, P., Kumar, P., 1991, ApJ 374, 366

"What are the Observed High Frequency Solar Acoustic Modes?", Kumar, P., Duvall, .L., Harvey, J.W., Jefferies, S.M., Pomerantz, M.A., and Thompson, M.J., 1990, Proc. Oji International Seminar, eds. Osaki, Y. and Shibahashi, H.

"Wave Generation By Turbulent Convection", Goldreich, P. and Kumar, P., 1990, ApJ 363, 694

"Excitation of Solar and Stellar Oscillations", Cox, A.N., Chitre, S.M., and Frandsen, S. and Kumar, P., 1990, invited review in Solar Interior and Atmosphere, eds. Cox, A.N., Livingston, W.C., and Matthews, M.

"Nonlinear Interactions Among Solar Acoustic Modes", Kumar, P. and Goldreich, P., 1989, ApJ 342, 558

"Distribution Functions for the Time Averaged Energies of Stochastically Excited Solar p-modes", Kumar, P., Franklin, J. and Goldreich, P., 1988, ApJ 328, 879

"The Interaction of Acoustic Radiation with Turbulence", Goldreich, P., and Kumar, P., 1988, ApJ 326, 462