The four primary tasks of the Burst and Transient Source Experiment (BATSE) were completed. The Detector Response Matrices were maintained and some improvements implemented. The spectral analysis tasks based on the 4 channel lad data were accomplished. The BLOT team effort was completed and the SN1987A balloon flight data analysis paper was submitted

Pendleton, Geoffrey N.

English

NASA Technical Reports Server

"BATSE Data Analysis" 
FINAL REPORT 
Contract NAS8-38609 
Delivery Order Number 45 
July 8, 1992 - January 8, 1994 
Prepared by 
Dr. ~ e o f f r e i  N. Pendleton 
( N A S A - C R - / ~ ~ ? ~  BATSE D A T A  N94-26685 
A N A L Y S I S  F ina l  Report,  0 J u l .  1992 --THRU-- 
- 8 Jan. 1994 (Alabama U n i v , )  9 p N94-26690 
Uncl as 
Prepared for 
George C. Marshall Space flight Center 
National Aeronautics and Space Administration 
Marshall Space Flight Center, Alabama 35812 
Submitted by 
Department of Physics 
The University of Alabama in Huntsville 
Huntsville, Alabama 35899 
February 1994 
https://ntrs.nasa.gov/search.jsp?R=19940022182 2020-06-16T13:34:54+00:00Z
INTRODUCTION 
The four primary tasks of the delivery order have been completed. The Detector 
Response Matrices have been maintained and some improvements implemented. The 
spectral analysis tasks based on the 4 channel lad data have been accomplished. The 
BLOT team effort was completed and the SN1987A balloon flight data analysis paper 
was submitted. 
SOFTWARE SUPPORT & CALIBRATION 
The Burst Location Optimization Team effort succeeded in reducing the RMS sys- 
tematic error in the Gamma Ray Burst location errors from 7 degrees to 4 degrees. 
This particular calibration and software optimization effort was finished in November 
1992. As of October 1993 I have been assigned control of the burst location code and I 
am overseeing the production of burst locations for the 2B catalog using the code that 
produced the 1B catalog data. I am also installing a few final improvements in the 
code that slipped past the programmer previously in charge of the code and may be 
able to improve the locations a bit more. 
The fluxes and fluences were generated for the 1B catalog for 260 events. I then 
trained programmer Chris Chaganti to build an automated flux-fluence generator for 
use by the ops-team and the burst fluxes and fluences are now being generated in 
production mode. This code is also producing photon time histories in the four discla 
channels so we can make a burst movie for display to the general public using the lab's 
silicon graphics hardware. 
New drms have been generated for the LAD'S and SPEC detectors. Statistical 
fluctuations in the Monte Carlo data used to generate the matrices have been smoothed 
out to make the spectral reconstruction more accurate. More input energies have been 
added to the low energy end of the spec detectors to make them more accurate. 
A set of subroutines were constructed that combine detector response matrices and 
atmospheric scattering to produce detector response matrices for any condition for the 
batse detectors. This code is in the BDAS area under configuration control and is used 
by the UCSD co-Is, the MSFC occultation team, and the MSFC pulsar team. Richard 
Shwartz is using it to facilitate solar flare spectral analysis of BATSE data from GSFC 
for guest investigators. 
The Calibration of the 16 channel edges has been successful. The results were 
presented in a poster at the Second Compton Symposium and submitted in paper form 
for publication in the proceedings of the symposium (see attached abstract). 
SCIENTIFIC RESULTS 
I am on the author list of 19 refereed journal articles and 37 non refereed publications 
produced during this period. I list below my lead author work and work with graduate 
students in Huntsville during this interval. The supernova paper has been submitted to  
ApJ. The Gamma-Ray Burst Continuum Properties paper has been accepted by ApJ. 
for publication in the August 10, 1994 issue. The spectral analysis of bursts indicate 
that there are dips in the spectra that may represent the superposition of two spectral 
components simultaneously in Gamma-Ray bursts. I presented results on this at the 
Compton symposium in St. Louis (1992) and at the second Huntsville Burst Workshop 
(1993). The results are presented in the published proceedings of these conferences. 
I have worked with Bob Mallozzi to see what constraints the BATSE data can put 
on the low energy emission of the BLASAR's discovered by EGRET. These results 
are presented in the Compton symposium proceedings (1993). Bob and I have also 
looked at  the temporal evolution of the energy output of bursts and solar flare in order 
to compare and contrast their spectral properties. These results are presented in the 
second Huntsville gamma-ray burst workshop (1993). I have been working with Tom 
Koshut comparing the spectral parameters of short emission spikes in longer bursts 
with those of the short duration events. These results are presented in the second 
Huntsville gamma-ray burst workshop (1993). The abstracts of articles on which I am 
lead author produced during this contract interval are appended to this report. 
The Continuum Spectral Characteristics of 
Gamma-Ray Bursts Observed by BATSE 
Geoffrey N. Pendleton, William S. Paciesas, 
Michael S. Briggs, Robert S. Mallozzi, Tom M. Koshut 
Department of Physics, University of Alabama in Huntsville, Huntsville, AL 35899 
Gerald J. Fishman, Charles A. Meegan, Robert B. Wilson 
Alan B. Harmon 
NASA/MarshaEI Space Flight Center, Huntsville, A L  35812 
Chryssa Kouveliotou' 
Universities Space Research Association 
at NASA/Marshall Space Flight Center, Huntsville, AL 35812 
ABSTRACT 
Distributions of the continuum spectral characteristics of 260 bursts in 
the first BATSE catalog are presented. The data are derived from flux ratios 
calculated from the BATSE Large Area Detector (LAD) four channel discrim- 
inator data. The data are converted from counts to photons using a direct 
spectral inversion technique to remove the effects of atmospheric scattering 
and the energy dependence of the detector angular response. Although there 
are intriguing clusterings of bursts in the spectral hardness ratio distributions, 
no evidence for the presence of distinct burst classes based on spectral hardness 
ratios alone is found. All subsets of bursts selected for their spectral charac- 
teristics in this analysis exhibit spatial distributions consistent with isotropy. 
The spectral diversity of the burst population appears to be caused largely by 
the highly variable nature of the burst production mechanisms themselves. 
Continuum Spectral Characteristics of Bursts 
Measured with the BATSE Large Area Detectors 
G. N. Pendleton, W. S. Paciesas, M. S. Briggs 
R. S. Mallozzi, T. M. Koshut 
University of Alabama in Huntsville 
G. J. Fishman, R. B. Wilson, C. A. Meegan 
NASAIMarshall Space Flight Center 
C. Kouveliotou 
Universites Space Research Association 
The continuum spectra of bursts are studied with particular em- 
phasis placed on the search for spectral subcomponents. The spectra 
observed in individual bursts show significant evolution throughout their 
durations. This study addresses the degree to which hard and soft spec- 
tra are combined in bursts and the effect this has on the complexity of 
the observed spectra. In particular the presence of broad cusps in spec- 
tra in the 50-100 keV range are studied to determine both the degree to 
which these features are present in the LAD data and whether super- 
position of hard and soft spectra simultaneously can account for them. 
Also the time histories of the power output (ergs/sec) from bursts are 
studied to investigate the dynamic coupling between hard and soft spec- 
tra in bursts as a probe of the autonomy of the hard and soft emission 
mechanisms. 
A STUDY OF GAMMA-RAY BURST CONTINUUM PROPERTIES 
PRESENTING EVIDENCE FOR TWO SPECTRAL STATES IN BURSTS 
G. N. Pendleton, W. S. Paciesas, R. S. Mallozzi, T. M. Koshut 
University of Alabama in Huntsville, AL., 35899 
G. J. Fishman, C. A. Meegan, R. B. Wilson, B. A. Harmon 
Marshall Space Flight Center, AL., 35812 
J. P. Lestrade 
Mississippi State University, MISS., 39762 
ABSTRACT 
Evidence is presented for the existence of two spectral states contribut- 
ing simultaneously to the total spectrum observed in many gamma-ray bursts 
(GRB's). An ensemble of 120 GRB's measured by BATSE have been studied, 
using 4 channel spectral data, to determine in which bursts the spectral states 
can be most effectively resolved. The technique of summing the low intensity 
spectra together to get an average spectrum allows for precise characterization 
of the average low intensity spectral behavior. The 4 and 16 channel spectra 
obtained by the BATSE Large Area Detectors (LAD'S) are analyzed using a 
model-independent spectral inversion technique. The results of these analyses 
applied to an individual burst are discussed in detail. 
Balloon-Borne Measurements 
of the SNl987A Hard X-ray Continuum 
Geoffrey N. Pendleton, William S. Paciesas 
Department of Physics, University of Alabama in  HuntsviZle, Huntsville, AL 35899 
Gerald J. Fishman, Charles A. Meegan, Robert B. Wilson 
NASA/MarshaZl Space Flight Center, Huntsville, AL 35812 
SN1987A hard X-ray continuum spectra obtained on 1987 October 29, 
1988 April 9-10, and 1988 November 11, from balloon flight measurements are 
presented. The spectra ,spanning the energy range from 25 keV to 300 keV, 
have been analyzed using a detector response matrix inversion technique that 
converts the spectra from countslsec-cm2-kev to photons/sec-cm2-kev allowing 
direct comparison with theoretical models. The results indicate that the bulk 
of the 56Co is mixed moderately through the inner regions of the SN envelope 
but they do not preclude the mixing of a small amount of the 56Co further 
out into the envelope necessary to account for the observed 56Co line fluxes. 
The effect of the ratio of 57Co to 5 6 C ~  on the 1988 November 11, continuum 
spectrum is discussed.. 
CHANNEL TO ENERGY CALIBRATION RESULTS 
FOR THE BATSE LARGE AREA DETECTORS 
G. N. Pendleton, W. S. Paciesas, M. S. Briggs 
University of Alabama in Huntsville 
B.A. Harmon, C.A. Wilson 
G. J. Fishman, R. B. Wilson, C. A. Meegan 
NASAIMarshall Space Flight Center 
ABSTRACT 
Continuum 16 channel spectra obtained from in flight data are used to identify 
and correct for nonlinearities in the channel-to-energy conversion algorithm for the 
BATSE1 large area detectors. The Crab Nebula spectra obtained by the BATSE earth 
occultation technique2 are used to characterize any nonlinearities inherent in the low 
energy channel bin widths on a detector by detector basis. The bin widths are optimized 
to remove distortions from observed gamma ray spectra. The recalibrated bin edges are 
used in an analysis of Crab Pulsar data3 to verify the improvements in the calibration. 
1 
NASA 
wam-xrl Report Documentation Page Soace 
1. Reeon NO. 
I 
Final Report 
"BATSE Data Analysis" 
10. Work Unit No. 
2. Gowmment ~ c c e s a m  NO. 
5. Repon Date 
Feb 15, 1994 
6. Pertormtng Organruaon cod. 
1 
3. Rectpmnt's Catalog No. 
7. A u t W r l  / Geoffrey N. Pendleton 
1 Huntsville, AL 35899 
I 
8. Poffwmmg Organ~ution NO, 
9. Pedormcng Organrzatton Name and Address 
, The University of Alabama in 1 NAS8-38609, D.O. 45 1 1 1. Contmct or Grant NO. 
I George C. Marshall Space Flight Center 
National Aeronautics & Space Administration 
Farshall Space Flight Center, AL 35812 
1 12. Sponconng Agemv N a m  and Addnar 13. T m  of F1-n and Parioa Cowom 
I 
Final I 
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j 17 Kev Words (Suggesrttd bv Authorls)l 18. Distrtbutton Statement 
NASA FORM 1- OCT 86 
I Gamma-Ray Astronomy 
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/ 19. ~ecunry CW. (of thts repon1 / 20. Securtw Clawrf. lof tha -1 1 21. No. of pagn 22. P l i n  
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