Telescope of the week:
TrICE, the Track Imaging Cerenkov Experiment, tests a new camera design at Argonne National Laboratory.
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More about
Gamma Ray Telescopes on the Ground
Gamma Ray Telescopes in Space
High Energy Astrophysics
History of Physics
Astronomy
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The mystery of the brighest recorded supernova deepens
Supernova SN 2006gy. Optical telescopes and the Chandra X-ray satellite have announced an extreme supernova explosion that may have been helped along by gamma rays converting to electron-positron pairs.
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65th Compton Lecture Series, Spring 2007
The Quest for Gamma Rays: Exploring the Most Violent Places in the Universe
Gamma-ray astronomy has undergone a recent explosion in the discovery
of new sources at the highest energies. After decades of development,
we have sensitive telescopes that are mapping the gamma-ray sky and
making detailed observations of a rich variety of sources. Gamma-ray
emission requires a significant amount of energy, and as a result
shows us a view of the extreme universe including the sites of stellar
birth and death, supermassive black holes at the centers of galaxies,
and other powerful phenomena. As we continue to push the limits of the
available techniques for detecting gamma rays, we gain a deeper
insight into the properties of these violent environments, how they
form, the way they interact with their surroundings, and ultimately
what they can teach us about the fundamental properties of our
universe.
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NEW! Thanks to several of the attendees, audio files are available for most lectures.
Results for the "You be the TAC" poll.
Lecture Slides
"You Be the TAC" Handout and
Ballot
Results
Top two gamma-ray source classes:
- Blazar Galaxies
- Potential Sources of a Dark Matter Signal
Favorite Sources for VERITAS:
- Markarian 421 -- a well-known gamma-ray blazar galaxy that exhibits spectacular flares on occasion.
- TeV 2032 -- an unidentified gamma-ray source that is likely located within our own Galaxy.
- Draco Dwarf Galaxy -- this is a small, dim, nearby galaxy, where it might be possible to detect a gamma-ray signature from dark matter.
- W44 -- this is the site of a supernova remnant containing a pulsar with a wind nebula. This object has not yet been detected by gamma-ray telescopes, but if it is detected it will be an interesting remnant for studying how a pulsar forms a nebula.
The audience poll revealed that interest is spread across the range of
gamma-ray sources. In addition to an interest in blazars and
searching for dark matter, you showed a preference for gamma-ray
bursts, binary systems consisting of a pulsar or black hole and a
massive star, the center of our Galaxy, and supernova remnants.
Additionally, there was a show of support for unidentified gamma-ray
sources (those that do not yet have known radio, optical, or X-ray
counterparts.) Your responses mirror the opinions of scientists doing
gamma-ray astronomy, who also try to balance the study of a growing
catalog of sources that we know something about with the discovery of
new sources and new types of sources.
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The Adobe Reader for viewing pdf documents is available here. Contact Liz if you would like the power point versions
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The "You asked for it!" Section
Books
I've had several questions about books on gamma-ray astronomy.
There are two that I know that deal specifically with very high energy
gamma-ray instruments and their observations. They go beyond the level
of popular science books and are suitable for use with an astrophysics
course. Each takes a slightly different approach and provides
different levels of mathematical detail. Both were written before the
current generation of ground-based telescopes began operating. The
status of the field has changed since that time, but the
underlying physics and the fundamental astrophysical problems remain
the same.
I believe that both of these are available through several online
book sellers (At Amazon you can read a few pages to see what they are like.)
- Very High Energy Gamma-Ray Astronomy by T.C. Weekes -
This monograph gives a highly readable account of observational
gamma-ray astronomy from
the unique perspective of one of the founding fathers of the field.
- Very High Energy Cosmic Radiation by Felix. A. Aharonian
- This book is in the style of an astrophysics text book and
provides a rigorous study of the physical and astrophysical concepts relevant to gamma ray astronomy.
If you're looking for an introduction and overview or want an
update on the status of the field, then the best resources are online.
Goddard Space Flight Center's Imagine the Universe
site and the GLAST Overview website provide great general information about gamma-ray astrophysics. To
check up on what the current telescopes are doing, see the links in the lefthand column of this page. The
H.E.S.S. source of the month website includes information about many of the recently detected very high energy gamma-ray sources.
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