The results of the proposal to (1) carry out data analysis of some carefully selected Seyfert sources, and (2) construct physical models for radiation from these objects and carry out comparison with the observed data are reported

Tsuruta, Sachiko

English

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NOV-27-97 THU 11=44 PH BSU PHYSIOS FAX NO. 4069944452 P. E4
206338
FINAL TECHNICAL REPORT
SACHIKO TSURUTA
Physics Department, Montana State University
Bozeman, Montana 59717
Prelect Title: Temporal and Spectral Studies of Seyfert Nuclei
z.-
ContracJJ: NAG8-289
Period: 211193 - 1131195
Amount_ $18.501
Final Report:
In this pro_x)sal we proposed to (A) carry out data analysis of some carefully selected Seyfezt
sources; and OB) construct physics models for radiation from these object and carry out
comparison with the observed data. The results of our investigations az_ outlined below.
(A_ Dala Analysis:
With Tsuruta as PI, the data analysis of (D MCG-6-30-15, (i0 NGC 7469, and (iii) NGC 4593
were carried out by Tsuruta and her students. The results ate summarized below.
(i] MCG-6-30=15: This is one of the strongest, closest and most rapidly and violently variable
Seyfert 1 nucleus. The combined analysis of the data from multiple Ginga observations was the
major portion of the observation-reIated work of R. Sivron's Ph.D thesis, which was supervised
by S. Tsuruta and H. Kunieda, It was already published in (1) and (2). To improve the
statistics R. Sivton and A. LeRoux (both students of Tsuruta at MSU), H. gunieda and S.
Tsuruta have been carrying out combined analyses of these Ginga data together with even better
ASCA data now available. The work has been only recently completed, and we are now
submitting two papers on our results for publications in Ap.L (Astrophysical Journal)(3)(4). The
major findings arc: (a) the soft X-rays and hat_ reflection hump X-rays appear to be correlated;
Co) the careful combined analysis of O VII and O VIII absorptions point to the possibility that
both lines come from the same physical region.
(ii) NGC 7469: Our analysis showed that it exhibited interesting spectral variability, and the
results are publ!shed in (5). Our results for the combined analysis with the ROSAT data are to
be published in (6).
(iii) NGC 4594: We carried out combined analysis of our Ginga and ASCA data of this source
(to increase statistics). The work was a major portion of the observation part of M. Kcllen,
Tsuruta's student at MSU. We are now preparing our final results for publication('/). The
preliminary version was published in (8).
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This grant also supported the continuing work (from previous period) to complete our data
analysis of NGC 6814(9).
We also proposed, in thi-¢proposal, to construct promising physical models of the central engine,
which can be compared with the results from the data analysis. During the gr_. ts per/od, we
partially completed the construction of two promising physical models: O) disk-corona model,
and (ii) cloud model.
(i) Disk-Corona Model: This was the continuation of the work already started before the grant
period. The simplest model, where the reprocessing of softer photons from cold disk by hard
.radiation from the hot coronal plasmas was already published in (10)(11). During this grant
period Ke.llcn and Tsut_la improved on this model, by including the two-way interactions to
construct a more realistic se.lf-consistent model. Also input microphysics was significantly up-
dated and improved. The results showed that this model is consistent with all the observational
data currently available. The preliminary results a.re published in (8)(12). The more complete
results are to be published soon(13).
(ii) C,.,_I..M_: Another promising model for the spectra and dynamical behavior of Seyfert
I nuclei radiation is a cloud model. During this grant period Sivron, Caditz frsuruta's postdoc)
and Tsuruta constructed a cloud model, which showed that this model also explains all major
observed data of Seyfcrt I nuclei and is dynamical behavior. But we predicted that future better
observations should be able to distinguish between these two competing models. The results are
published in (1), (14), and (15).
PUBLICATIONS directly related to this grant:
(1) "Dynamical and Spectral Behavior of Seyfert Nuclei", 1995, Ph.D. Thesis, Montana State
University, by R.Sivron
(2) "Ginga Observation of MCG-6-15-30", 1994, B.A.A.S., R. Sivron, H. Kunieda and S.
Tsuruta
(3) "O VII and O VIII Lines of MCG-6-15-30", 1997, to be submittedfor Ap. J., by A,
LeRoux, R. Sivron, H. Kuni_a and S. Tsuruta
(4) Spectral Variability of MCG-6-15-30", 1997, to be submitted for Ap. $., by R. Sivron, H.
Kunieda and S. Tsuruta
(5) "Observations of NGC 7469 and Akn 120", 1993, M.N.R.A.S., Vol. 265, p. 996, by W.M.
Brandt, A. Fabian, N. Nandra, and S. Tsuruta
(6) "X-Ray Spectral Variability in NGC 7469", 1996, Ap. J., Vo]. 462, p. 158, by K. Leighly,
H. Kunieda, H. Awaid, P. Zycki, and S. Tsuruta
(7) "Spectral and TemporaL Variability of NGC 4594", 1997, Ap. $., to I>e submitted, by M.
Kellcn, H. Kunieda, A. LeRoux and S. Tsuruta
(8) "Temporal and Spectral Studies of Scyfert Nuclei", 199"7, Ph.D. Thesis, Montana State
University, by M. Kellen
NOV-27-97 THU 11:45 PM MSU PHYSICS FAX NO, 4069944452 P, 06
(9) Evide.ncc for X-Ray Flux and Spectral Modulation by Absorption in NGC 6814: The Nature
of the Fastest Variability', 1993, Ap. L, Vol. 421, p. 69, by K. ]__ighly, H. Kunioda,
Y. Tsusaka, H. Awaki, and S. Tsm'uta
(10) "Some Models of Active Galactic Nuclei', 1989, Ph.D. Thesis, Montana State University,
by B. Tritz
(11) '*Pair Plasmas in the Centra Engine of Active Galactic Nuclei", 1993, in Plasma Physics
and Controlled Nuclear Fusion (cds. T;D. Guycnne and J.L Hunt), ESA Pub. Div., p.
137, by S. Tsuruta and B. Tritz
(12) "Disk-Corona Model with Non-thermal Pair Production", 1995, Ap. J. Lett., Vol, 453, p,
L9, by S. Tsuruta and M. Kcllcn
(13) "Self-Consistent Disk-Corona Model of AGN", 1997, Ap. J., to be submitted, by S.
Tsuruta and M. KeUen
(14) "Dense Clouds near the Central Engine of AGN °°, 1993, Ap. J., Vol. 402, p. 420, by
R. Sivron and S. Tsuruta
(15) "Effects of Shocks on Emission from Central Engine ofAGN - I", 1996, Ap. J.,Vol. 469,
p. 542, by R. Sivron, D. Caditz and S. Tsuruta


Temporal and Spectral Studies of Seyfert Nuclei

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