Three wavelength image of the supernova remnant Cassiopeia A, the remains
of a star that exploded about 1680. The x-ray image (shown in green)
represents very hot gas at about 10 million Kelvin heated by the shock waves
accompanying the supersonic expansion of the exploding star moving out into
its surroundings at about 20 million miles per hour. The red represents
optical emission from cooler, denser clumps of gas at about 10 thousand Kelvin
immersed in the hotter gas under pressure balance. The blue is radio
synchrotron emission from relativistic electrons accelerated by the strong
magnetism of this supernova remnant. By studying all three together we can
learn in detail how the material expands and interacts with its surroundings.
John R. Dickel
Ph.D., University of Michigan, 1964
study supernova remnants both observationally and theoretically to detail the
interaction of the expanding blast with the surrounding interstellar medium.
By using radio, optical, infrared, and x-ray wavelengths, my colleagues and I
can investigate all the various components of the surroundings to see how
clumping and irregularities affect the expansion.
I am also participating in multiwavelength studies of the Magellanic
Clouds, satellite galaxies of the Milky Way, in order to elucidate the
physical properties of the many components of the interstellar medium in
I am part of the team building the Long Wavelength Array, an exciting
new radio telescope being constructed by University of New Mexico,
U.S. Naval Research Lab., Jet Propulsion Lab., Virginia Tech, Los
Alamos National Lab., Air Force Research Lab., Bruny Island Radio Spectrometer,
and University of Iowa.
Selected Recent Publications:
J. R. Dickel, R. A. Gruendl, V. McIntyre, S. Amy, & D. K. Milne,
2009, “Survey of the Magellanic Clouds at 4.8 and 8.6 GHz,” in J. van Loon
and J. Oliveira eds., The Magellanic System: Stars, Gas, and Galaxies (IAU
Symposium 256) 14.
F. D. Seward, R. M. Williams, Y.-H. Chu , R. A. Gruendl, & J. R.
Dickel 2010, “A Chandra Observation of the SNR 0540-697,” AJ, 140, 177.
J. R. Dickel, R. A. Gruendl, V. J. McIntyre, & S. W. Amy 2010, “A 4.8- and
8.6-GHz Survey of the Small Magellanic Cloud: The Images,” AJ, 140, 1511.
L. M. Bozzeto, M. D. Filipovic, E. J. Crawford, F. Haberl, M.
Sasaki, D.Urosevic, W. Peitsch, J. L. Payne, A. Y. De Horta , M. Stupar,
N. Tothill, J. Dickel, Y,-H. Chu, & R. Gruendl, 2012, “Multifrequency
Study of the large Magellanic Cloud Supernova Remnant J0529-6653 Near
Pulsar B0529-66” MNRAS, 420, 2588.
P. Maggi. F. Haberl, L. M. Bozzetto, M. D. Filipovic, S. Points,
Y.-H. Chu, M. Sasaki, W. Pietsch, R. A. Gruendl, J. Dickel, R. C. Smith,
R. Sturm, E. J. Crawford, & A. Y. deHorta, 2012, “Multi-frequency study
of supernova remnants in the Large Magellanic Cloud. Confirmation of the
supernova remnant status of DEM L205” A&A, 546, 109.
F. D. Seward, P. A. Charles, D. L. Foster, J. R. Dickel, P. S. Romero,
Z. I. Edwards, M. Perry, & R. M. Williams, 2012, “DEM L241, a
Supernova Remnant Containing a High-mass X-Ray Binary”, ApJ, 759, 123.
T. Temim, P. Slane, D. Castro, P. Plucinsky, J. Gelfand, & J. Dickel, 2013,
“High-energy Emission from the composite Supernova Remnant MSH 15-56” ApJ,
Magellanic Cloud images available: