5,489 research outputs found
Redshifts and Luminosities for 112 Gamma Ray Bursts
Two different luminosity indicators have recently been proposed for Gamma Ray
Bursts that use gamma-ray observations alone. They relate the burst luminosity
(L) with the time lag between peaks in hard and soft energies, and the
spikiness or variability of the burst's light curve (V). These relations are
currently justified and calibrated with only 6 or 7 bursts with known red
shifts. We have examined BATSE data for the lag and V for 112 bursts. (1) A
strong correlation between the lag and V exists, and it is exactly as predicted
from the two proposed relations. This is proof that both luminosity indicators
are reliable. (2) GRB830801 is the all-time brightest burst, yet with a small V
and a large lag, and hence is likely the closest known event being perhaps as
close as 3.2 Mpc. (3) We have combined the luminosities as derived from both
indicators as a means to improve the statistical and systematic accuracy when
compared with the accuracy from either method alone. The result is a list of
112 bursts with good luminosities and hence red shifts. (4) The burst averaged
hardness ratio rises strongly with the luminosity of the burst. (5) The burst
luminosity function is a broken power law, with the break at L = 2x10^{52}
erg/s. The luminosity function has power law indices of -2.8+-0.2 above the
break and -1.7+-0.1 below the break. (6) The number density of GRBs varies with
red shift roughly as (1+z)^(2.5+-0.3) between 0.2<z<5. Excitingly, this result
also provides a measure of the star formation rate out to z~5 with no effects
from reddening, and the rate is rising uniformly for red shifts above 2.Comment: 13 pages, 4 figures, submitted to ApJLet
On the reliability of the theoretical internal conversion coefficients
Possible sources of uncertainties in the calculations of the internal
conversion coefficients are studied. The uncertainties induced by them are
estimated.Comment: 16 pages (including 3 figures inserted by 'epsfig' macro
The Ouachita Jazz Band, Fall Concert
This is the program for the Ouachita Jazz Band fall concert, held on November 17, 1994, in the Mabee Fine Arts Center\u27s Recital Hall. Dr. Craig V. Hamilton was the director
The Ouachita Jazz Band, Spring Concert
This is the program for the spring concert of the Ouachita Jazz Band, directed by Dr. Craig V. Hamilton. The concert was held on March 16, 1995, in the Jones Performing Arts Center
Pauli problem for a spin of arbitrary length: A simple method to determine its wave function
The problem of determining a pure state vector from measurements is investigated for a quantum spin of arbitrary length. Generically, only a finite number of wave functions is compatible with the intensities of the spin components in two different spatial directions, measured by a Stern-Gerlach apparatus. The remaining ambiguity can be resolved by one additional well-defined measurement. This method combines efficiency with simplicity: only a small number of quantities have to be measured and the experimental setup is elementary. Other approaches to determine state vectors from measurements, also known as the ââPauli problem,ââ are reviewed for both spin and particle systems
Control of Ultra-cold Inelastic Collisions by Feshbash Resonances and Quasi-One-Dimensional Confinement
Cold inelastic collisions of atoms or molecules are analyzed using very
general arguments. In free space, the deactivation rate can be enhanced or
suppressed together with the scattering length of the corresponding elastic
collision via a Feshbach resonance, and by interference of deactivation of the
closed and open channels. In reduced dimensional geometries, the deactivation
rate decreases with decreasing collision energy and does not increase with
resonant elastic scattering length. This has broad implications; e.g.,
stabilization of molecules in a strongly confining two-dimensional optical
lattice, since collisional decay of the highly vibrationally excited states due
to inelastic collisions is suppressed. The relation of our results with those
based on the Lieb-Liniger model are addressed.Comment: 5 pages, 1 figur
The Ouachita Jazz Band in a Spring Concert
This is the program for The Ouachita Jazz Band spring concert directed by Dr. Craig V. Hamilton. The concert was held on April 23, 1990, in Mitchell Hall
Ouachita Baptist University Concert Band Spring Concert
This is the program for The Ouachita Baptist University Concert Band spring concert conducted by Dr. Craig V. Hamilton. The concert was held on March 29, 1990, in Verser Theatre
Ouachita Baptist University Concert Band in a Spring Concert
This is the program for The Ouachita Baptist University Concert Band spring concert conducted by Dr. Craig V. Hamilton. The concert was held on March 12, 1987, in Mitchell Auditorium
Ouachita Baptist University Concert Band in a Spring Concert
This is the program for The Ouachita Baptist University Concert Band spring concert conducted by Dr. Craig V. Hamilton. The concert was held on March 3, 1988, in Mitchell Auditorium
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