ANNUAL REPORT: 1997-1998
PARTICLE ASTROPHYSICS & COSMOLOGY
PRINCIPAL INVESTIGATOR: GEORGE F. SMOOT
Other Group Members:
Julian Borrill, Post Doctoral Fellow Physics
John Jacobsen, Post Doctoral Fellow Physics
Andrew Jaffe, Post Doctoral Fellow Physics
Jodi Lamoureux Post-Doctoral Fellow Physicist
Bruce Grossan, Assistant Research Physicist
- Eric Gawiser, Graduate Student, UCB Physics Department (shared with Joe
- Amedeo Balbi, Graduate Student, Physics Department, University of Roma
- Henrik Nordberg, Graduate Student, Physics Department, Lund University
- Bahman Rabii, Graduate Student, UCB Physics Department
- Mike Leung, undergraduate, Physics Department
- Asad Aboobaker, undergraduate, Physics Department
- KiWon Yoon, undergraduate, Physics Department
- Peter Curran, undergraduate, University College Cork
- Ian Ellwood, undergraduate
Abraham Harte, undergraduate, College of Marin
Jon Aymon, software/data analyst
John Gibson, electronic engineer
Vanessa Arce, Administrative Assistant
Willi Chinowsky, Research Physicist
1. COSMOLOGY with the Cosmic Background Radiation
Measurements of The Cosmic Background Radiation (CMB) provide important
information about physical processes in the Universe from soon after the
Big Bang until the present. In the Big Bang model, which has now become
the standard model of cosmology, the CMB last interacted significantly
with matter at a time roughly one third of million years after the start
of the universal expansion and about 10-15 billion years before the present
epoch. The CMB carries with it the information about that interaction and
to a lesser degree the effects occurring during its journey to us. Its
angular distribution is related to the distribution of matter and energy
in the early Universe; its spectrum provides information about processes
involving the release of energy.
During the past year we have continued our investigations using the
cosmic microwave background (CMB) radiation as a probe of cosmology.
Analysis of the COBE
satellite data sets continues to provide additional new results and
acts as a test bed for new techniques and algorithms in the 8th year past
its launch and 5 years since its discovery of CMB anisotropies. Its data
remain in many ways the best CMB anisotropy data. During 1998 the primary
new results were presented in papers about the discovery of the cosmic
infrared background radiation.
With COBE we have made major advances in measuring the large angular
scale distribution of the CMB. The major products from COBE include a series
of maps of the full sky in the 1 micrometer to 1 centimeter wavelength
range. COBE was operated for four years, providing high quality data from
about half its sensors. The other half of the sensors were turned off when
the liquid helium coolant was exhausted near the end of the first year.
The processing and analysis of the data from COBE has provided high
quality maps of the microwave and infrared sky, and their subsequent analysis
has yielded significant new cosmological and astrophysical information.
Of the three instruments aboard COBE, Dr. Smoot is principal investigator
of the Differential Microwave Radiometer (DMR) experiment. The announcement
of the detection of anisotropies by Dr. Smoot has been followed by numerous
interpretive papers by members of the COBE/DMR collaboration and by outside
The observed anisotropies have been a powerful cosmological tool providing
information on the initial conditions leading to the formation of large
scale structure such as galaxies and clusters of galaxies. It has also
let us determine important cosmological parameters such as the dynamics,
geometry and topology of the Universe.
Our group has continued the analysis of the old and new data. Public
release of the resulting skymaps occurred for the first year's observations
in June 1993. The first two years worth of data were released in June,
1994. The full four-year data and first results were made public in January
1996. The COBE project came to its official termination at the end of 1997;
however, we can anticipate that its data and experience will continue
to play an important role in cosmology for a few more years.
Figure 1. Full sky map of the CMB anisotropies from the COBE DMR.
Max Planck Surveyor
We, as part of a larger collaboration, have completed the Phase A study
of the third generation CMB anisotropy mission, the European Space Agency
(ESA) M3 mission: Max
Planck Surveyor satellite. Launch is anticipated circa 2007.
MAXIMA/BOOMERANG Balloon-borne Instruments
We - a collaboration with Professors Paul Richards at SSL, Andrew Lange
(CalTech), and Paola deBernardis (Rome) - have built and tested a pair
of new generation balloon-borne gondolas and instruments MAXIMA
& BOOMERANG . BOOMERANG had its first and successful flight in
early September 1997. MAXIMA had its first scientific utilizing an array
receiver in August 1998. A long-duration flight of BOOMERANG from Antarctica
is planned for in the coming season (mid-December to mid-January). We anticipate
flying MAXIMA again in the summer of 1999 and preparations are underway.
Data processing and analysis of these data is underway and we anticipate
first results being made public in early 1999 and much more later.
We have reached the point where the emission from the galaxy is beginning
to limit the interpretation of the data. Thus we have embarked on a program
to improve our understanding and modeling of this emission for both the
cosmological interpretations and the study of our galaxy. This involves
both a project to make low frequency radio maps of the sky dubbed the Galactic
Emission Mapping (GEM) project and an effort to model and find means
to remove Galactic and extragalactic foregrounds from the data. The GEM
instrument was shipped to Brazil from Tenerife. It has been refurbished
and is now operating and taking data.
2. Ultra-High Energy Neutrino Astronomy
In collaboration with Hank Crawford (SSL), Willi Chinowsky, Dave Nygren,
and Bob Stokstad we have been working on the development of a
km-scale ultra-high energy neutrino detector. This work has led us
to a collaboration with the AMANDA project. At this time we are deeply
involved in the analysis of the 1997 AMANDA data in which a number of very
high energy neutrino-induced muons have been detected. We are also busy
preparing for the arrival of the 1998 AMANDA data. Work is underway on
the development of a digital optical module technology and its deployment
in the Antarctic ice an the 1999-2000 season.
Completion of the Instrument Proposals and their Selection
for Planck Surveyor
Award of NERSC supercomputer time and resources
Award of NSF KDI grant to develop advanced data processing and analysis
7. Graduate Students Supported
- Bahman Rabii, Physics Department
- Henrik Nordberg, Physics Department, Lund University
- Amedeo Balbi, Physics Department, University of Roma
"The CMB Anisotropy Experiments: Cosmic Microwave Background," G.F. Smoot.
The Cosmic Microwave Background, edited by C.H. Lineweaver, J.G. Bartlett,
A. Blanchard, M. Signore, and J. Silk, 185-240, Kluwer Academic Publishers
- "The CMB Spectrum," G.F. Smoot. The Cosmic Microwave Background, edited
by C.H. Lineweaver, J.G. Bartlett, A. Blanchard, M. Signore, and J. Silk,
271-308, Kluwer Academic Publishers (1997).
- "Cosmology with the CMB," G.F. Smoot. International Journal of
Modern Physics D, 6, 4, 377-391, World Scientific Publishing Company
- "Diffraction Analysis of a Double-Shielded Antenna in the Fraunhofer
and Fresnel Regimes," C. Tello, T. Villela, C. A. Wuensche, N. Figueiredo,
S. Torres, M. Bersanelli, M. Bensadoun, G. DeAmici, and G.F. Smoot. Radio
- "The COBRAS/SAMBA Space Mission," N. Mandolesi, M. Bersanelli, C. Cesarsky,
L. Danese, G. Efstathiou, M. Griffin, J.M. Lamarre, H.U. Norgaard-Nielsen,
O. Pace, J.L. Puget, A. Raisanen, G.F. Smoot, and J. Tauber. Il Nuovo Cimento
20, 5 Sept.-Oct. (1997).
- "The COBE Diffuse Infrared Background Experiment Search for the Cosmic
Infrared Background: Limits and Detections," M.G. Hauser, R.G. Arendt,
T. Kelsall, E. Dwek, N. Odegard, J.L. Weiland, H.T. Freudenreich, W.T.
Reach, R.F. Silverberg, S.H. Moseley, Y.C. Pei, P. Lubin, J.C. Mather,
R.A. Shafer, G.F. Smoot, R. Weiss, D.T. Wilkinson, and E.L. Wright. December
The Astrophysical Journal (1997).
- "Observing the Early Universe," G.F. Smoot. Proceedings from presentation
at Ninth Partners in Science Conference. Posted on website. (1997).
- "Cosmic Background Radiation," G.F. Smoot and D. Scott. astro-ph/9711069.
Revision of original, Oct. (1997).
- "CMB Experiment Baseline Determination by Minimizing Pixel Observations
Dispersion," G.F. Smoot. astro-ph/9704193, COBE-5047-REV, The Astrophysical
Journal (1997) Submitted
- "A Determination of the Spectral Index of Galactic Synchrotron Emission
in the 1-10 GHz Range," P. Platania, M. Bensadoun, M. Bersanelli, G. De
Amici, A. Kogut, S. Levin, D. Maino, and G.F. Smoot . astro-ph/9707252,
The Astrophysical Journal (1997)
- "The Cosmic Microwave Background Spectrum: An Analysis of Observations,"
H.P. Nordberg, G.F. Smoot. astro-ph/9805123, The Astrophysical Journal
- "Galactic Free-Free and Ha Emission," G.F. Smoot. astro-ph/9801121 v.2
Jan. 14 The Astrophysical Journal (1998).
- "Cosmic Microwave Background Anisotropy Science," G.F. Smoot, Current
Topics in Astrofundamental Physics: Primordial Cosmology, edited by N.
Sanchez and A. Zichichi, Kluwer Academic Publishers (1998).
- `Matching Numerical Simulations To Continuum Field Theories: A Lattice
Renormalization Study', Julian Borrill and Marcelo Gleiser, Nuc Phys B483
416 (1997). hep-lat/9607026
- "Semilocal String Formation in Two Dimensions', Ana Achucarro, Julian
Borrill and Andrew R. Liddle, Phys Rev D57 3742 (1998). hep-ph/9702368
- `Power Spectrum Estimators For Large CMB Datasets', Julian Borrill (Submitted
to Phys Rev D) (1997). astro-ph/9712121
- `The Formation Rate Of Semilocal Strings', Ana Achucarro, Julian Borrill
and Andrew R. Liddle (Submitted to Phys Rev Lett) (1998). hep-ph/9802306
- `A Fast Method For Bounding The CMB Power Spectrum Likelihood Function',
Julian Borrill and Philip J. Stark, (Submitted to Phys Rev D) (1998).astro-ph/9803114
- `The Formation Of Non-Topological String Networks', Ana Achucarro, Julian
Borrill and Andrew R. Liddle (Physica B, in press) (1998). hep-ph/9810459
- `The Rate Of Formation Of Semilocal Strings', Julian Borrill, Ana Achucarro,
and Andrew R. Liddle in "Proceedings of PASCOS-98". (1998)
- "Limits to Radiative Neutrino Decay from SN1987a", A. Jaffe & M.S.
Turner, Phys. Rev. D55, 7951 (1997).
- "H0 and Odds on Cosmology", A. Jaffe, Ap. J., 471, 24, 1996.
- "Bending of Light by Gravity Waves", N. Kaiser & A. Jaffe, Ap. J.,
484, 545, 1997.
- "Cosmic Parameter Estimation Combining Sub-Degree CMB Experiments With
COBE", J.R. Bond & A. Jaffe, Proc. Moriond XVI, "Microwave Background
- "Estimating the Power Spectrum of the Cosmic Microwave Background",
J.R. Bond, A.H. Jaffe & L. Knox Phys. Rev. D, Submitted, 1997, CfPA/97-th-11