




Gaussianity of cosmic velocity fields and linearity of the
velocitygravity relation
Ciecielag, P; Chodorowski, M J; Kiraga, M; Strauss, M A; Kudlicki, A;
Bouchet, F R Monthly Notices of the Royal Astronomical Society
(00358711), vol. 339, no. 3, 1 Mar. 2003, p. 641651 We present a
numerical study of the relation between the cosmic peculiar velocity field
and the gravitational acceleration field. We show that on mildly nonlinear
scales (410/h Mpc Gaussian smoothing), the distribution of the Cartesian
coordinates of each of these fields is well approximated by a Gaussian. In
particular, their kurtoses and negentropies are small compared to those of
the velocity divergence and density fields. We find that at these scales
the relation between the velocity and gravity field follows linear theory
to good accuracy. Specifically, the systematic errors in velocityvelocity
comparisons due to assuming the linear model do not exceed 6 percent in
beta. To correct for them, we test various nonlinear estimators of
velocity from density. We show that a slight modification of the coformula
proposed by Kudlicki et al. (1996, 2000) yields an estimator that is
essentially unbiased and has a small variance. (Author)

Selfgravity and quasistellar object discs
Goodman, J Monthly Notices of the Royal Astronomical Society (00358711),
vol. 339, no. 4, 11 Mar. 2003, p. 937948 The outer parts of standard
steadystate accretion disks around quasistellar objects (QSOs) are prone
to selfgravity, and they might be expected to fragment into stars rather
than feed the central black hole. Possible solutions to this wellknown
problem are examined with an emphasis on general dynamic constraints.
Irradiation by the QSO is insufficient for stability even if the outer disk
is strongly warped. Marginal local gravitational instability enhances
viscous transport but extends the stable regions only modestly. Compton
cooling in the observed QSO radiation field rules out hot thick disks
unless the local accretion rate is vastly superEddington. The formation of
stars or stellarmass black holes, and the release of energy in these
objects by fusion or accretion, may help to stabilize the remaining gas in
an otherwise standard disk. But at fixed mass accretion rate, the energy
inputs required for stability increase with radius; beyond a parsec, they
approach the total QSO luminosity and are probably unsustainable by stars.
Magnetic torques from a wind or corona, and gravitational torques from bars
or global spirals, may increase the accretion speed and reduce the density
of the disk. But dynamical arguments suggest that the accretion speed is at
most sonic, so that instability still sets in beyond about a parsec.
Alternatively, the QSO could be fed by stellar collisions in a very dense
stellar cluster, but the velocity dispersion would have to be much higher
than observed in nearby galactic nuclei containing quiescent black holes.
In view of these difficulties, we suggest that QSO disks do not extend
beyond a thousand Schwarzschild radii or so. Then they must be frequently
replenished with gas of small specific angular momentum. (Author)

Gravitational lens time delays for distant supernovae  Breaking the
degeneracy between radial mass profiles and the Hubble constant
Oguri, M; Kawano, Y Monthly Notices of the Royal Astronomical Society
(00358711), vol. 338, no. 4, 1 Feb. 2003, p. L25L29 Any attempt to
measure the Hubble constant with gravitational lens time delays is often
limited by the strong degeneracy between radial mass profiles of lens
galaxies and the Hubble constant. We show that strong gravitational lensing
of Type Ia supernovae breaks this degeneracy; the standard candle nature of
the Type Ia supernova luminosity function allows one to measure the
magnification factor directly, and this information is essential to
constrain radial mass profiles and the Hubble constant separately. Our
numerical simulation demonstrates that the Hubble constant can be
determined with approximately 5 percent accuracy from several lens events
only if magnification factors are used as constraints. Therefore, a distant
supernova survey is a promising way to measure the global Hubble constant
independently with the local estimates. (Author)

CLASS B0445+123  A new twoimage gravitational lens system
Argo, M K; Jackson, N J; Browne, I W A; York, T; McKean, J P; Biggs, A D;
Blandford, R D; de Bruyn, A G; Chae, K H; Fassnacht, C D Monthly Notices
of the Royal Astronomical Society (00358711), vol. 338, no. 4, 1 Feb.
2003, p. 957961 A new twoimage gravitational lens system has been
discovered as a result of the Cosmic Lens AllSky Survey. Radio
observations with the Very Large Array (VLA), the MultiElement Radio Linked
Interferometer Network and the Very Long Baseline Array at increasingly
higher resolutions all show two components with a flux density ratio of
about 7 : 1 and a separation of 1.34 arcsec. Both components are compact
and have the same spectral index. Followup observations made with the VLA
at 8.4 GHz show evidence of a feature to the southeast of the brighter
component and a corresponding extension of the weaker component to the
northwest. Optical observations with the William Herschel Telescope show
approximately 1.7arcsec extended emission aligned in approximately the
same direction as the separation between the radio components with an
Rband magnitude of 21.8 +/ 0.4. (Author)

B0850+054  a new gravitational lens system from CLASS
Biggs, A D; Rusin, D; Browne, I W A; de Bruyn, A G; Jackson, N J; Koopmans,
L V E; McKean, J P; Myers, S T; Blandford, R D; Chae, KH Monthly Notices
of the Royal Astronomical Society (00358711), vol. 338, no. 4, 1 Feb.
2003, p. 10841088 We report the discovery of a new gravitational lens
system from the CLASS survey. Radio observations with the VLA, WSRT and
MERLIN show that the radio source B0850+054 is composed of two compact
components with identical spectra, a separation of 0.7 arcsec and a flux
density ratio of 6:1. VLBA observations at 5 GHz reveal structures that are
consistent with the gravitational lens hypothesis. The brighter of the two
images is resolved into a linear string of at least six subcomponents,
while the weaker image is radially stretched towards the lens galaxy. UKIRT
Kband imaging detects an 18.7mag extended object, but the resolution of
the observations is not sufficient to resolve the lensed images and the
lens galaxy. Mass modeling has not been possible with the present data, and
the acquisition of highresolution optical data is a priority for this
system. (Author)

The cosmic gravityvelocity relation
Kudlicki, A; Chodorowski, M J; Strauss, M A; Ciecielag, P Small
Satellites for Astrophysical Research, the Copernican Principle and
Homogeneity of the Universe, Advances in Space Research (02731177), vol.
31, no. 2, Jan. 2003, p. 469474 We present a numerical study of the
relation between the cosmic peculiar velocity field and the gravitational
acceleration field. We show that on mildly nonlinear scales (310 Mpc
Gaussian smoothing), the distribution of the Cartesian coordinates of each
of these fields is very well approximated by a Gaussian. In particular,
their negentropies are small compared to those of the velocity divergence
and density fields. We find that at these scales the relation between the
velocity and acceleration fields follows linear theory to high accuracy.
The nonlinear correction of Kudlicki et al. (2000) works still better: its
reconstruction errors are several times smaller than those of the linear
theory approximation. (Author)

How fast is gravity?
Fomalont, E; Kopeikin, S New Scientist (02624079), vol. 177, no. 2377,
11 Jan. 2003, p. 3235 This article describes the efforts of National
Radio Astronomy Observatory (NRAO) scientist Ed Fomalont and University of
Missouri theoretical physics professor Sergei Kopeikin at measuring the
speed of gravity, one of the fundamental constants of nature. The problem
was to obtain information on the gravitational field of a moving body,
which is difficult information to obtain. An opportunity would come on
September 8, 2002, when the planet Jupiter would make a close passage to
the strong radio quasar J0842+1835. A gravitational lensing effect due to
Jupiter's moving gravitational field would then be measured. The lensing
effect that they were planning to measure would cause the apparent position
of the quasar to shift slightly. This would be measured by an array of
radio telescopes spaced as far apart as possible. The telescope used,
therefore, was the U.S. NRAO's Very Long Baseline Array. Although one of
the telescopes, the one at Saint Croix in the U.S. Virgin Islands,
malfunctioned on September 8, 2002, the data from the other telescopes was
able to compensate for the loss. Comparing the position of J0842+1835 on
September 8 with its average position on the offJupiter days preceeding
the September 8 passage, and plugging this into a formula by Kopeikin of
the gravitational field of the moving Jupiter, gave the answer. The result
was that gravity moves at the same speed as light. The actual figure was
1.06 times the speed of light, but the error was +/0.21. The results were
planned to be announced in January 2003 at the American Astronomical
Society's annual meeting in Seattle, Washington. (CSA)

Global 8.4GHz VLBI observations of JVAS B0218+357
Biggs, A D; Wucknitz, O; Porcas, R W; Browne, I W A; Jackson, N J; Mao, S;
Wilkinson, P N Monthly Notices of the Royal Astronomical Society
(00358711), vol. 338, no. 3, 21 Jan. 2003, p. 599608 In this paper we
present new observations of the gravitational lens system JVAS B0218+357
made with a global very long baseline interferometry (VLBI) network at a
frequency of 8.4 GHz. Our maps have an rms noise of 30 microJy/beam, and
with these we have been able to image much of the extended structure of the
radio jet in both the A and B images at high resolution (1 mas). The main
use of these maps will be to enable us to further constrain the lens model
for the purposes of H0 determination. We are able to identify several
subcomponents common to both images with the expected parity reversal,
including one which we identify as a counterjet. We have not been
successful in detecting either the core of the lensing galaxy or a third
image. Using a model of the lensing galaxy we have backprojected both of
the images to the source plane and find that they agree well. However,
there are small, but significant, differences which we suggest may arise
from multipath scattering in the interstellar medium (ISM) of the lensing
galaxy. We also find an exponent of the radial mass distribution of 1.04,
in agreement with lens modeling of published 15GHz VLBI data. Polarization
maps of each image are presented which show that the distributions of
polarization across images A and B are different. We suggest that this
results from Faraday rotation and associated depolarization in the lensing
galaxy. (Author)

Gravitational microlensing and blazar variability  The case of AO
0235+164
Webb, J R; Howard, E S Cosmology and Elementary Particle Physics; Coral
Gables Conference on Cosmology and Elementary Particle Physics, Fort
Lauderdale, FL, Dec. 1216, 2001, Melville, NY, American Institute of
Physics, 2002, p. 95102 We review the basics of gravitational lens
phenomena in astrophysics, concentrating on its applicability to Blazar
variability. A brief discussion of gravitational lenses in the context of
AGN is presented, followed by a more detailed model to explain the high
amplitude outburst observed in Blazar AO 0235+164. We find some preliminary
model parameters for the 199798 outburst of AO 0235+164. (Author)

Quantum discontinuity for massive gravity with a cosmological
term
Sati, H Cosmology and Elementary Particle Physics; Coral Gables
Conference on Cosmology and Elementary Particle Physics, Fort Lauderdale,
FL, Dec. 1216, 2001, Melville, NY, American Institute of Physics, 2002, p.
344347 The question of whether the graviton has a small nonzero mass or
exactly zero mass has been addressed by van Dam and Veltman, and Zkharov.
This paper reports on recent work on the van DamVeltmanZakharov
discontinuity for massive and partially massless gravitons in A(dS) space
at oneloop. (CSA)

Constructing spacetime  No strings attached
Cho, Adrian Science (00368075), vol. 298, no. 5596, 8 Nov. 2002, p.
1166, 1167 In the ongoing quest to meld quantum mechanics and gravity,
loop quantum gravity  an alternative theory to string theory  aims to
steal the stage. Whereas string theory begins by assuming how spacetime
stretches and twists, loop quantum gravity builds the "geometry of
spacetime" from scratch, a crucial feature of any fundamental theory of
quantum gravity. (CSA)

An investigation of gravitational lens determinations of H0 in
quintessence cosmologies
Lewis, G F; Ibata, R A Monthly Notices of the Royal Astronomical Society
(00358711), vol. 337, no. 1, 21 Nov. 2002, p. 2633 There is growing
evidence that the majority of the energy density of the universe is not
baryonic or dark matter, but rather it resides in an exotic component with
negative pressure. The nature of this 'quintessence' influences our view of
the universe, modifying angular diameter and luminosity distances. Here, we
examine the influence of a quintessence component upon gravitational lens
timedelays. As well as a static quintessence component, an evolving
equation of state is also considered. It is found that the equation of
state of the quintessence component and its evolution influence the value
of the Hubble constant derived from gravitational lenses. However, the
differences between evolving and nonevolving cosmologies are relatively
small. We undertake a suite of Monte Carlo simulations to examine the
potential constraints that can be placed on the universal equation of state
from the monitoring of gravitational lens systems, and demonstrate that at
least an order of magnitude more lenses than currently known will have to
be discovered and analyzed to accurately probe any quintessence component.
(Author)

Equipotential surface and normal gravity of the Galilean
satellites
Zhang, Hong; Zhang, Chengzhi Chinese Astronomy and Astrophysics
(02751062), vol. 26, no. 4, Oct. 2002, p. 481488 In this article,
expanded equations of normal gravity on the equipotential surface are
proposed for a natural satellite whose orbital plane is close to its
equatorial plane. Tidal effects on the normal gravity are also discussed.
The authors apply these to the Galilean satellites. Calculations suggest
that the tides raised by Jupiter weakly affect the Galilean satellites. The
radial displacements of the gravity due to the tides are in the range
between 10 exp 3 and 10 exp 5 m per sec per sec, which are similar to the
latitudinal and longitudinal displacements. The variations along the
latitude circle are larger than those along the longitude circle. We
conclude that the tidal effects on most of the Galilean satellites are
larger than those on the Moon. (Author)

Global lunar gravity mapping using SELENE subsatellites
Iwata, T; Hanada, H; Kawano, N; Takano, T; Namiki, N The Moon Beyond
2002: Next Steps in Lunar Science and Exploration, Taos, NM, Sept. 1214,
2002, Houston, TX, Lunar and Planetary Institute, 2002, p. 28 The SELENE
explorer is under development by NASDA of Japan and the Institute of Space
and Astronautical Science (ISAS) of Japan. SELENE will be launched in 2005
to elucidate lunar origin and evolution. SELENE is composed of a Main
Orbiter and two micro subsatellites: the Relay Satellite (Rstar) and the
VLBI Radio Satellite (Vstar), which will be used for selenodesy
experiments. These satellites will be used to obtain selenodetic data of
higher accuracy by fourway Doppler measurements and differential VLBI
observations. The Relay Satellite Transponder, RSAT1 on Rstar and RSAT2
on the Main Orbiter, will relay twoway ranging signals and fourway
carrier signals at S band or X band transmitted from a 64m antenna at the
Usada Deep Space Center (UDSC). The Doppler measurements will provide a
global gravity map of the moon. The differential VLBI observations for
determining Rstar and Vstar orbits are carried out by the differential VLBI
Radio Sources VRAD1 on Rstar and VRAD2 on Vstar. They transmit three
pairs of Sband and a pair of Xband carrier signals to a VLBI radio
telescope at seven ground stations. This paper describes the RSAT and the
VRAD. (CSA)

L2gain and stability analysis for a rigid spacecraft under
gravitygradient torque
Damaren, Christopher J AIAA Guidance, Navigation, and Control Conference
and Exhibit, Monterey, CA, Aug. 58, 2002 The nonlinear H(infinity) or
L2gain control methodology is applied to the disturbance attenuation
problem for a rigid spacecraft in a circular orbit which is subjected to a
gravitygradient torque. Simple rate feedback is shown to provide global
disturbance attenuation for the angular velocity relative to the orbital
frame. When a quaternion feedback term is added, local disturbance
attenuation of the attitude relative to the orbiting frame is also shown to
be possible, and a stability analysis shows that the (undisturbed) attitude
tends towards an arbitrarily small invariant set. (Author)

A near optimal midcourse guidance law based on spherical gravity
Deihoul, Ali; Massoumnia, Mohammad AIAA Guidance, Navigation, and Control
Conference and Exhibit, Monterey, CA, Aug. 58, 2002 In Massoumnia
(1995), an optimal midcourse guidance law for close distances where the
difference of gravity for interceptor and ballistic missile is negligible
was introduced. There, a closed form solution based on an optimization
problem was found with very good performance for close distances but
degraded performance in real problems with unequal gravity for missile and
interceptor. In this paper, we take into account the difference of gravity
by considering a spherical gravity model. A new equation to express the
relative motion between missile and interceptor is used to derive a "Near
Optimal Guidance Law". The results found using the new derivation are
similar to those in Massoumnia, but it results in a guidance law with
matrix coefficients. Next, we improve the performance of the guidance law
using Kepler's algorithm. This modified approach results in an almost
perfect intercept even for large distances between missile and interceptor.
(Author)

Design and optimization of lowthrust gravityassist trajectories to
selected planets
Debban, Theresa J; McConaghy, T T; Longuski, James M AIAA/AAS
Astrodynamics Specialist Conference and Exhibit, Monterey, CA, Aug. 58,
2002 Highly efficient lowthrust engines are providing new opportunities
in mission design. Applying gravity assists to lowthrust trajectories can
shorten mission durations and reduce propellant costs from conventional
methods. In this paper, an efficient approach is applied to the design and
optimization of lowthrust gravityassist trajectories to such challenging
targets as Mercury, Jupiter, and Pluto. Our results for the missions to
Mercury and Pluto compare favorably with similar trajectories in the
literature, while the mission to Jupiter yields a new option for solar
system exploration. (Author)

Spacetime foam  A groundstate candidate for quantum gravity
Garattini, R Journal of Optics B: Quantum and Semiclassical Optics
(14644266), vol. 4, no. 4, Aug. 2002, p. S285S288 A model of spacetime
foam made by N wormholes is considered. The Casimir energy leading to such
a model is computed by means of the phase shift method. The collection of
Schwarzschild and ReissnerNordstrom (RN) wormholes are separately
considered to represent the foam. The Casimir energy shows that the RN
wormholes cannot be used to represent the foam. (Author)

Reconstruction of the strip brightness distribution in a quasar
accretion disk from gravitational microlensing data
Bogdanov, M B; Cherepashchuk, A M Astronomicheskij Zhurnal (00046299),
vol. 79, no. 8, Aug. 2002, p. 693701 A technique is proposed for the
successive reconstruction of the branches of the strip brightness
distribution for a quasar accretion disk via the analysis of observations
of high magnification flux events in the multiple quasar images produced by
a gravitational lens. The distribution branches are searched for on compact
sets of nonnegative, monotonically nonincreasing, convex downward
functions. The results of numerical simulations and application of the
technique to real observations show that the solution obtained is stable
against random noise. Analysis of the light curve of a high magnification
event in image C of the gravitational lens QSO 2237+0305 observed by the
OGLE group in summer 1999 has yielded the form of the strip brightness
distribution in the accretion disk of the lensed quasar. The results are
consistent with the hypothesis that the quasar disk w s scanned by a fold
caustic. The form of the strip distribution is consistent with the expected
appearance of an accretion disk rotating around a supermassive black hole.
(Author)

Physical principles of advanced space propulsion based on Heims's field
theory
Droescher, Walter; Haeuser, Jochem 38th AIAA/ASME/SAE/ASEE Joint
Propulsion Conference and Exhibit, Indianapolis, IN, July 710, 2002 An
overview is given of the results of a completely geometrized unified field
theory that gives rise to a novel concept for an advanced space
transportation technology, permitting, in principle, superluminal travel.
This theory predicts the existence of a quasiantigravitational force, and
allows the design of an experiment for the verification of this theory.
This theory of quantum gravity, based on publications by Helm , introduces
new physics at the quantum scale, predicting that a transformation of
electromagnetic wave energy into gravitationallike energy that is
eventually transformed into gravitons at specific frequencies is possible,
thus reducing the inertial mass of a material (ponderable) test body. The
theory has been extended to eight dimensions. The predicted reduction of
inertia (mass) can be used as the design principle for an innovative space
transportation system. In this paper, Helm's field equations along with the
extensions mentioned above, are presented and discussed, and the magnitude
of the coupling constant between the conversion of electromagnetic energy
and gravitationallike energy is given. (Author)

Chaotic attitude tumbling of an asymmetric gyrostat in a gravitational
field
Kuang, J; Tan, S; Leung, A Y T Journal of Guidance, Control, and Dynamics
(07315090), vol. 25, no. 4, July 2002, p. 804814 The chaotic attitude
tumbling of an asymmetric gyrostat is investigated in detail. The gyrostat
has three symmetrical wheels along the principal axes rotating about a
fixed point under the influence of either the gravity torques or the
gravitygradient torques. Using the Deprit canonical variables, the Euler
attitude equations are transformed into Hamiltonian form. This makes the
PoincareArnoldMelnikov (PAM) function developed by Holmes and Marsden
applicable. The physical parameters triggering the chaotic attitude are
established. The analytical results are checked by using the fourthorder
RungeKutta simulation in terms of the Euler parameters (quaternions). The
relationships of the following physical parameters are established: moments
of inertia of carriers and wheels, positions of the mass center, kinetic
energy and moment of momentum of the torquefree gyrostat, and initial
attitude leading to chaotic motion. The results show that the PAM function
is a powerful analytical tool for the treatment of the dynamics of
nonlinear gyrostat orientations. (Author)

Reducing the Earth entry velocity for a comet nucleus sample return
mission
Sims, J A Astrodynamics 2001; AAS/AIAA Astrodynamics Conference;
Proceedings, Quebec, July 30Aug.2, 2001, San Diego, CA, Univelt,
Incorporated, 2002, p. 22552268 Direct return to Earth after
rendezvousing with a comet entails a very high entry velocity. Several
methods for reducing the entry velocity, including using additional
propellant on a direct return or using planetary gravity assists, are
presented. The entry velocity can be reduced to a regime commensurate with
current deep space sample return missions. The best method is a function of
the mission parameters and the target comet. (Author)

2016+112  A gravitationally lensed type II quasar
Koopmans, L V E; Garrett, M A; Blandford, R D; Lawrence, C R; Patnaik, A R;
Porcas, R W Monthly Notices of the Royal Astronomical Society
(00358711), vol. 334, no. 1, 21 July 2002, p. 3947 A singlescreen
model of the gravitational lens system 2016+112 is proposed, that explains
recent HST infrared (NICMOSF160W) observations and new highresolution
European VLBI Network (EVN) 5GHz radio observations, presented in this
paper. In particular, we find that a massive 'dark' structure at the lens
position, previously suggested by Xray, optical and spectroscopic
observations of the field around 2016+112, is not necessarily required to
accommodate the stronglensing constraints. A massive structure to the
northwest of the lens system, suggested from a weaklensing analysis of
the field, is included in the model. The lensed source is an Xray bright
active galaxy at z = 3.273 with a central bright optical continuum core and
strong narrow emission lines, suggestive of a type II quasar. The EVN 5GHz
radio maps show a radio jet structure with at least two compact
subcomponents. We propose that the diamond caustic crosses the counterjet
of the radio source, so that part of the counterjet, host galaxy and
narrowfine emission regions is quadruply imaged. The remainder of the
radio source, including the core, is doubly imaged. Our lens model predicts
a very high magnification (mu about 300) at the brightness peaks of the
inner two radio components of complex C. If the jet exhibits relativistic
velocities on microarsecond scales, it might result in apparent
hyperluminal motion. However, the lack of strong radio variability and the
peaked radio spectrum imply that these motions need not be present in the
source. Our model furthermore implies that the optical spectrum of Cprime
can only show features of the active galactic nuclei and its host galaxy.
(Author)

Operational cryogenic experience with the Gravity Probe B payload
Taber, M A; Murray, D O; Maddocks, J R; Burns, K M Advances in cryogenic
engineering. Volume 47B; Cryogenic engineering conference  CEC;
Proceedings, Madison, WI, Jul. 1620, 2001, Melville, NY, American
Institute of Physics, 2002, p. 12411248 The Gravity Probe B Relativity
Mission is a satellitebased experimental test of two predictions of
Einstein's General Theory of Relativity. The experimental design makes
substantial use of cryogenic technology. The flight payload, which includes
the dewar, the cryostat probe, and the science instrument, is now in final
test in preparation for integration with the spacecraft. We review the
unique aspects of the cryogenic subsystem and discuss the implications they
have for cryogenic operations. We also review cryogenic performance of the
payload and compare it to thermal model predictions. (Author)

Is There a Cosmological Constant?
Kochanek, Christopher RECON no. 20020061284. The grant contributed to
the publication of 18 refereed papers and 5 conference proceedings. The
primary uses of the funding have been for page charges, travel for invited
talks related to the grant research, and the support of a graduate student,
Charles Keeton. The refereed papers address four of the primary goals of
the proposal: (1) the statistics of radio lenses as a probe of the
cosmological model (#1), (2) the role of spiral galaxies as lenses (#3),
(3) the effects of dust on statistics of lenses (#7, #8), and (4) the role
of groups and clusters as lenses (#2, #6, #10, #13, #15, #16). Four papers
(#4, #5, #11, #12) address general issues of lens models, calibrations, and
the relationship between lens galaxies and nearby galaxies. One considered
cosmological effects in lensing Xray sources (#9), and two addressed
issues related to the overall power spectrum and theories of gravity (#17,
#18). Our theoretical studies combined with the explosion in the number of
lenses and the quality of the data obtained for them is greatly increasing
our ability to characterize and understand the lens population. We can now
firmly conclude both from our study of the statistics of radio lenses and
our survey of extinctions in individual lenses that the statistics of
optically selected quasars were significantly affected by extinction.
However, the limits on the cosmological constant remain at lambda < 0.65 at
a 2sigma confidence level, which is in mild conflict with the results of
the Type la supernova surveys. We continue to find that neither spiral
galaxies nor groups and clusters contribute significantly to the production
of gravitational lenses. The lack of group and cluster lenses is strong
evidence for the role of baryonic cooling in increasing the efficiency of
galaxies as lenses compared to groups and clusters of higher mass but lower
central density. Unfortunately for the ultimate objective of the proposal,
improved constraints on the cosmological constant, the next large survey
for gravitational lenses did not release its results during the term of the
proposal. The research supported the career development. of six graduate
students (polar, Fletcher, Herold, Keeton, Deng and Rusin) and two
postdocs (Labor and Munoz).

From the cosmological term to the Planck constant
Vargas, J G; Torr, D G Fundamental Theories of Physics. Volume 126,
Dordrecht, Netherlands, Kluwer Academic Publishers, Dordrecht, 2002, p.
110 This paper shows the potential of classical differential geometry to
unify gravity with the other interactions and, especially, quantum
mechanics. The topics addressed include the affine connection of spacetime,
the gravitational sector of teleparallelism, the completion of the
classical sector of teleparallelism, the quantum sector of teleparallelism,
and the relation between gravitation and quantum physics in
teleparallelism. Finally, the SakharovPuthoff conjecture as an integral
part of teleparallel physics is dealt with. (CSA)

Whitehead meets Feynman and the Big Bang
Chew, G F Fundamental Theories of Physics. Volume 126, Dordrecht,
Netherlands, Kluwer Academic Publishers, Dordrecht, 2002, p.
5158 Historical quantum cosmology (HQC) is based not on matter but on a
chain of local history, a chain lengthened by many local steps in each
global step that expands a doublecone spacetime. The universe's
forwardlight cone lower bound corresponds to the Big Bang, while its
backwardlight cone upper bound corresponds to the present. (All history
occurs after the Big Bang and before the present.) HQC adapts continuous
stringtheoretical and Feynmangraphical notions to a discrete Whiteheadian
process. While standard physicscosmology posits a spatially unbounded
universe of matter that (continuously) carries conserved energy, momentum,
angular momentum, and electric charge, in HQC only a tiny "rigid" component
("enduring process" in Whitehead's terminology) of a discrete and finite
history corresponds to matter. The huge majority of history is "nonrigidly
meandering" in time as well as in space and carries none of the above
conserved quantities. Dense "vacuonic" history, unobservable by the
scientific method, nevertheless carries conserved magnetic charge, contacts
material history, and participates in magnetodynamic action at a distance.
One outcome is zitterbewegung for most standardmodel elementary particles,
leading to rest mass and collapse of the material wave function. Another is
the probabilistic nature of predictions based solely on past material
history. There is the prospect of understanding gravity as the outcome of
the interplay between magnetically polarized vacuum and matter. The origin
of the standard model's three colors, three generations, and
(approximately) 30deg Weinberg angle are sketched and related to the
internal structure of the photon and other "elementary" particles. (Author)

Can one unify gravity and electromagnetic fields?
Vigier, JP; Amoroso, R L Fundamental Theories of Physics. Volume 126,
Dordrecht, Netherlands, Kluwer Academic Publishers, Dordrecht, 2002, p.
241258 This paper presents an attempt to unify gravity and
electromagnetism associated with "holes" and "bumps" in the covariant
density distribution of a real average covariant Dirac ether built with
extended random elements filling flat spacetime. Some possible
experimental tests are also discussed. (Author)

The dipolar zeromodes of Einstein action  An informal summary with
some new issues
Modanese, G Fundamental Theories of Physics. Volume 126, Dordrecht,
Netherlands, Kluwer Academic Publishers, Dordrecht, 2002, p. 259266 In
this note we describe a set of gravitational field configurations, called
"dipolar zero modes", which have not been considered earlier in the
literature. They give an exactly null contribution to the pure Einstein
action and can thus represent large vacuum fluctuations in the quantized
theory of gravity. The basic idea behind dipolar fluctuations was discussed
for the first time in our earlier work on stability of Euclidean quantum
gravity (Modanese, 1998); the Lorentzian case was treated in Modanese
(1999). In 2000 we made the first explicit computations, and we were able
to set some lower bounds on the strength of the fluctuations (Modanese,
2000). Also, we gave for the first time in Modanese (2000): (1) an estimate
of possible suppression effects by cosmological or R2terms, (2) a
computation of the total ADM energy of the zero modes, (3) a clarification
(in the Lorentzian case) of the influence of matter fields on the
fluctuations, with possible anomalous coupling. Here, after a few general
remarks about vacuum fluctuations and "spacetime foam" in quantum gravity,
we set out the general features of the dipolar fluctuations and give some
explicit order of magnitude calculations. Then, we show that a Lambdaterm
cuts, to some extent, the dipolar fluctuations; this can lead in certain
cases to an anomalous coupling to matter. In conclusion, we discuss a
number of new topics not addressed in Modanese (2000). (Author)

Theoretical and experimental progress on the GEM
(GravityElectroMagnetism) theory of field unification
Brandenburg, J E; Kline, J F; Dipietro, V Fundamental Theories of
Physics. Volume 126, Dordrecht, Netherlands, Kluwer Academic Publishers,
Dordrecht, 2002, p. 267278 Theoretical and experimental progress on the
GEM (GravityElectroMagnetism) theory is summarized. A portion of the
KaluzaKlein action is shown to form a "Vacuum Bernoulli Equation" showing
gravitational energy density to be equated to an electromagnetic (EM)
dynamic pressure that is quadratic in the local Poynting flux: g sq/(2piG)
S sq/(c sq x u(0)) = constant, where G and S are the local gravity and
Poynting vector magnitudes, respectively; G is the NewtonCavendish
constant, and u(0) is a local magnetic energy density. This relation
satisfies the Equivalence Principle. It is shown that this equation
predicts that gravity modification can occur through a Vacuum Bernoulli
Effect (VBE) by creating a perturbing Poynting flux by a rotating EM field,
a "Poynting Vortex", and that this effect can lead to a lifting force for
human flight applications. The theory is then applied to experiments
involving EMdriven gyroscopes with some success. Explorations of the
possibility of a GEMS theory, including the strong force, are briefly
discussed. (Author)

Can gravity be included in Grand Unification?
Rowlands, P; Cullerne, J P Fundamental Theories of Physics. Volume 126,
Dordrecht, Netherlands, Kluwer Academic Publishers, Dordrecht, 2002, p.
279286 Grand unification of the electromagnetic, weak, and strong
interactions is at present believed to occur at an energy of order 10 exp
15 GeV, about four orders below the Planck mass (M(P)), at which quantum
gravity becomes significant. However, there are serious problems with the
current minimal SU(5) model, which fails to predict a full convergence of
the three interactions. Also, the assumed electroweak mixing parameter, sin
squared theta(w) = 0.375, is at total variance with the experimental value
of 0.231. The problem, the authors of this paper believe, lies in the
current, rather "mechanistic", understanding of the fractional values
observed for quark charges. A model of quarks, based on integral charges,
suggests a value of sin squared theta(w) = 0.25, with a consequent
prediction of Grand Unification at the Planck mass, and a value of 1/alpha
= 118 at 14 TeV. (CSA)

Spinors in affine theory of gravity
Von Borzeszkowski, HH; Treder, HJ Fundamental Theories of Physics.
Volume 126, Dordrecht, Netherlands, Kluwer Academic Publishers, Dordrecht,
2002, p. 295302 We consider some mathematical aspects of purely affine
theories of gravity. In particular, we show that in affine spaces one can
establish a truncated spinor formalism reducing in metricaffine spaces to
the standard one. As a consequence, one can formulate gravitational
equations with matter sources to which there can exist solutions with a
RiemannCartan geometry. (Author)

A new approach to quantum gravity  An overview
Bell, S B M; Cullerne, J P; Diaz, B M Fundamental Theories of Physics.
Volume 126, Dordrecht, Netherlands, Kluwer Academic Publishers, Dordrecht,
2002, p. 303312 We quantize General Relativity for a class of
energymomentumstress tensors. One particular type of curved spacetime is
used as the building block for all the others. Its extrinsic description
and relationship to the versatile Dirac and photon equations are discussed.
An amended Dirac equation is formulated and solved for the spacetime of a
defined Medium observer to show the derivation of the Bohr atom as a
consequence of quantum electrodynamics (QED). The derivation of the Bohr
and Sommerfeld models of the atom is sketched from QED. Then, the inverse
is done, wherein the QED is derived from the Bohr and Sommerfeld models.
The application of the new method to gravity is then undertaken. Bohrs two
equations for quantum gravity are derived. Up to this point, the point of
view has been taken of the Thalesium atom or Geotron for the calculations
in this paper. The authors then next assume the point of view of the Small
observer for whom the circular loop is temporal. Applying the method of
quantization previously used, it is found that QED is the full quantum
theory. Moreover, the equivalent of the electromagnetic potential is found
from the Bohr equations. (CSA)

Gravity and cosmology and problems of G
Grebeniuk, M A; Melnikov, V N Fundamental Theories of Physics. Volume
126, Dordrecht, Netherlands, Kluwer Academic Publishers, Dordrecht, 2002,
p. 313320 Main trends in modern gravitation and cosmology and their
relation to unified models are analyzed. The role of multidimensional
gravitational models with different matter sources in solving the basic
problems of cosmology is stressed. Exact solutions in multidimensional
cosmology with pbranes for some special cases are considered. The Riemann
tensor squared is calculated in a general case and investigated for a
number of special solutions. Singularities of the Riemann tensor squared
are also discussed. Also the case of static internal spaces is considered.
It is shown that the external space for this case is a de Sitter or antide
Sitter one. The behavior of the cosmological constant and its generation by
pbranes is demonstrated. (Author)

Quantum gravity operators and nascent cosmologies
Crowell, L B Fundamental Theories of Physics. Volume 126, Dordrecht,
Netherlands, Kluwer Academic Publishers, Dordrecht, 2002, p. 321330 The
Planck length is a fundamental scale of physics. Suppose that we have a
black hole with a mass M whose Schwarzschild radius is known to be r =
2GM/c(2). Now, let this black hole have a de Broglie wavelength gamma =
h/p, where p = E/c = Mc, the spacetime momentum of the black hole. Assume
this wavelength is equal to its diameter defined by the Schwarzschild
radius; further, the mass of the black hole is M = h/(c x lambda). The
analyst finds that the de Broglie wavelength of this black hole is
lambda(P) = sq rt(G /(h(bar) x c cubed)) = 1.616 x 10 exp 33 cm. This
length converts into energy units, as the scale is 10 exp 19 GeV. (Author)

The Case for General Relativistic Effects in the Fe K(alpha) Profile of
an Active Galaxy
Turner, T J; Mushotzky, R; Yaqoob, T; George, I M; Snowden, S L; Netzer, H;
Kraemer, S B; Nandra, K; Chelouche, D RECON no. 20020070381. We present
results from a simultaneous Chandra HETG (High Energy Transmission Grating)
and XMM (Xray Multimirror Mission)Newton observation of NGC 3516. We
find evidence for several narrow components of Fe K(alpha) along with a
broad line. We consider the possibility that the lines arise in a blob of
material ejected from the nucleus with velocity of approximately 0.25c. We
also consider an origin in a neutral accretion disk, suffering enhanced
illumination at 35 and 175 R(sub g), perhaps due to magnetic reconnection.
The presence of these narrow features indicates there is no Comptonizing
region along the lineofsight to the nucleus. This in turn is compelling
support for the hypothesis that broad Fe K(alpha) components are, in
general, produced by strong gravity.

Ballistic JUPITER gravityassist, perihelionDeltaV trajectories for a
realistic interstellar explorer
McAdams, J V; McNutt Jr, R J Spaceflight Mechanics 2002; Proceedings of
the AAS/AIAA Space Flight Mechanics Meeting. Vol. 1, San Antonio, TX, Jan.
2730, 2002, San Diego, CA, Univelt, Incorporated, 2002, p. 725737 This
proposed interstellar precursor mission will penetrate into the nearby
interstellar medium by achieving 1000 AU from the sun within the working
lifetime (about 50 years) of the mission initiators. A variety of science
goals and orbital mechanics constraints contribute to the formulation of a
list of candidate stars for targeting the solar system escape trajectory
direction. An approach is developed that will minimize both launch energy
to Jupiter and a subsequent nearsun, highI(SP) highthrust maneuver in
order to attain a highspeed escape from the solar system towards a target
star. Detailed performance characteristics are given for selected reference
trajectories. (Author)

Blast from the vast (gravity wave detectors)
Battersby, S New Scientist (02624079), vol. 172, no. 2319, 1 Dec. 2001,
p. 2629 This article discusses two giant gravity wave detectors based on
laser interferometry, one located in the U.S. and the other in Germany,
which are being used to study some of the most violent events in the
universe. The development of a global interferometric network of gravity
wave detectors is addressed. (CSA)

The current state of string theory
Horowitz, G Relativistic astrophysics; 20th Texas Symposium; Proceedings,
Austin, TX, Dec. 1015, 2000, Melville, NY, American Institute of Physics,
2001, p. 310 String theory is a promising candidate for a quantum theory
of gravity and a unified theory of all forces and particles. I will briefly
summarize the current status of this theory and discuss some recent
results. The most important results involve describing quantum states of
black holes in terms of strings, which has provided a fundamental
explanation of black hole entropy and Hawking radiation. Further
investigation of this connection between black holes and strings has led to
a completely new nonperturbative formulation of string theory. (Author)

Braneworld astronomy
Hogan, C Relativistic astrophysics; 20th Texas Symposium; Proceedings,
Austin, TX, Dec. 1015, 2000, Melville, NY, American Institute of Physics,
2001, p. 1121 Unified theories suggest that space is intrinsically
10dimensional, even though everyday phenomena seem to take place in only
three large dimensions. In "Brane World" models, matter and radiation are
localized to a "brane" which has a thickness less than about. (TeV) exp 1
in all but the usual three dimensions, while gravity propagates in
additional dimensions, some of which may extend as far as submillimeter
scales. A brief review is presented of some of these models and their
astrophysical phenomenology. One distinctive possibility is a gravitational
wave background originating in the mesoscopic early universe, at
temperatures above about 1 TeV and on scales smaller than a millimeter,
during the formation of our 3dimensional brane within a 10dimensional
space. (Author)

A universe in a global monopole
Benson, K; Cho, I Relativistic astrophysics; 20th Texas Symposium;
Proceedings, Austin, TX, Dec. 1015, 2000, Melville, NY, American Institute
of Physics, 2001, p. 2833 We investigate brane physics in a universe
with an extradimensional global monopole and negative bulk cosmological
constant. To counter divergence of the graviton zero mode, we employ a
physical cutoff. This cutoff yields 4D gravity on a brane at the monopole
core; it also solves the hierarchy problem, by inducing the observed
hierarchy between particle and Planck scales in the effective 4D universe.
Our model has a discrete spectrum of massive Kaluza Klein modes, easily
made consistent with 4D gravity on the brane. Extradimensional matter
fields also induce 4D matter fields on the brane, with the same Kaluza
Klein spectrum of excited states. (Author)

Visualization of gravitational lenses
Alfaro, F Relativistic astrophysics; 20th Texas Symposium; Proceedings,
Austin, TX, Dec. 1015, 2000, Melville, NY, American Institute of Physics,
2001, p. 262264 Using C, Xforms, Mesa, and Imlib, a computer program has
been developed to visualize the gravitational lens phenomenon. The program
has been used to generate sequences of images of a source object and its
corresponding images. It has also been used to visually test different
models of gravitational lenses. (CSA)

Xrays and accretion discs as probes of the strong gravity of black
holes
Fabian, A Relativistic astrophysics; 20th Texas Symposium; Proceedings,
Austin, TX, Dec. 1015, 2000, Melville, NY, American Institute of Physics,
2001, p. 643655 The observations and interpretation of broad iron lines
in the Xray spectra of Seyfert 1 galaxies are reviewed. The line profiles
observed from MCG63015 and NGC 3516 show extended red wings to the line
explained by large gravitational redshifts. The results are consistent
with the emission expected from an Xray irradiated flat accretion disc
orbiting very close to a black hole. Results from XMMNewton and Chandra
are presented, and the possibility of broad oxygen lines is discussed.
(Author)

Estimation of postNewtonian approximation of gravity that affects
satellites of planet
Zhong, MQ Acta Physica Sinica (10003290), vol. 50, no. 12, Dec. 2001,
p. 24972500 The postNewtonian approximation in general relativity is
used to estimate the gravity for the Jovian system and the comet
ShoemakerLevy 9 that collided with Jupiter. We calculate and discuss the
postNewtonian corrections to the gravity of Jupiter and the precessions of
its satellites, which are compared with the Earthmoon system. (Author)

Microlensing by a noncompact spheroidal gravitational lens
Bogdanov, M B Astronomicheskij Zhurnal (00046299), vol. 78, no. 12, Dec.
2001, p. 10591065 In the process of their evolution, smallscale
clusters of weakly interacting massive particles (WIMPs) that formed in the
early Universe can acquire rotational momentum and spheroidal shape. Even
small oblateness of a cluster similar to that of the critical Roche surface
can lead to the appearance of caustics in the plane of a source lensed by
the object. The multiple source images that form in this case cannot be
resolved in modern observations, and the cluster behaves like a noncompact
spheroidal lens. The caustic crossing that occurs in the case of relative
motion of the observer, the cluster of particles, and the lensed star can
produce a large variety of flux curves, including those such as have been
observed during microlensing events and interpreted as manifestations of
binary gravitational lenses. Therefore, we cannot rule out the possibility
that at least some of these events might actually be associated with
clusters of WIMPs. (Author)

Gravity's kaleidoscope
Wambsganss, J Scientific American (08368733), vol. 285, no. 5, Nov.
2001, p. 6571 The astronomical uses of gravitational lenses are
examined. What such lenses can reveal about quasars, the cosmological
constant, dark matter, and extrasolar planets is discussed. (CSA)

Measurements of the gravity waves velocity
Dubrovskiy, V A; Smirnov, N N IAF, International Astronautical Congress,
52nd, Toulouse, France, Oct. 15, 2001 Results of studies on the Earth's
microseismic background are presented. It is assumed that background peaks
should correspond to the resonance gravitywave exchange in the system of
two gravityconnected bodies. The microseismic spectrum is compared with
the distribution of the gravity potential of the nearest stars. A close
peaktopeak correspondence is found. This correspondence and resonance
condition led to an evaluation of the gravitywave velocity. The resulting
value is nine orders of magnitude more than the velocity of light. Some
consequences of these results are discussed. (Author)

NASA's Cosmic Journeys  Space science missions to the limits of
gravity, space and time
Diaz, A V IAF, International Astronautical Congress, 52nd, Toulouse,
France, Oct. 15, 2001 I outline NASA's "Cosmic Journeys" roadmap 
designed to observe the extremes of gravity throughout the universe  and
explain how this roadmap's space science missions systematically build upon
the technological advances mastered in preceding science missions. Cosmic
Journeys will travel through the major epochs of the universe, from the era
of galaxy and black hole formation to the beginning of time. It will probe
the regions surrounding black holes, ultimately obtaining a direct image of
the event horizon. It will trace the history of the first crucial seconds
after the Big Bang in search for the highest energy processes, where
gravity may have been united with the other fundamental forces. The key
technologies needed for these fantastic endeavors are currently being
developed for space missions today. Cosmic Journeys missions include the
recently launched MAP, which will help determine the shape and density of
the universe. In development are Swift, which will detect gammaray bursts
and relay their location to other telescopes within seconds, and GLAST, a
nextgeneration gammaray observatory. Missions under formulation include
the Constellation Xray Observatory, which would map regions of dark matter
and measure the spin of black holes; LISA, which will measure gravity
waves; and a set of "vision missions" such as MAXIM, whose goal to image a
black hole event horizon further stretches the scientific imagination and
technology challenges for our field. (Author)

LISA  The technology challenge
Gianolio, A; Whitcomb, G IAF, International Astronautical Congress, 52nd,
Toulouse, France, Oct. 15, 2001 LISA is a mission configured to detect
and observe gravitational waves from massive black holes and galactic
binary stars with periods in the range of a few seconds to a few hours. To
do this, three spacecraft fly in an isosceles triangle formation of side 5
x 10 exp 6 km and with one spacecraft at each apex. In each spacecraft are
cubical proofmasses that are kept in a dragfree environment shielded from
all forces except that due to gravity. The mutual position of the
proofmasses is continuously measured by means of a laser interferometer.
The configuration thus forms a large Michelson type interferometer in which
the proof masses are effectively adjustable elements. Gravitational waves
differentially disturb the proofmasses, generating a measurable signal.
The real challenge will consist in the isolation and reduction of all the
noise sources which will limit the sensitivity of the measurement. (Author)

Testing the effective scale of quantum gravity with the next generation
of gamma ray telescopes
Blanch, O; Lopez, J; Martinez, M Astroparticle Physics (09276505), vol.
19, no. 2, May 2003, p. 245252 The actual potential of the next
generation of gamma ray telescopes in improving the existing tests of an
effective quantum gravity scale from the study of the propagation delay for
gamma rays of different energies coming from a distant astrophysical source
is discussed. It is shown that the existence of a cosmological gamma ray
horizon, will impose very demanding conditions on the observations of the
telescopes to try to test a quantum gravity scale close to the Planck mass.
(Author)






