A characterization of the brightness oscillations during thermonuclear bursts from 4U 1636-536

被引:20
作者
Miller, MC [1 ]
机构
[1] Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA
关键词
stars : neutron; X-rays : bursts;
D O I
10.1086/308438
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
The discovery of nearly coherent brightness oscillations during thermonuclear X-ray bursts from six neutron star low-mass X-ray binaries has opened up a new way to study the propagation of thermonuclear burning and may ultimately lead to greater understanding of thermonuclear propagation in other astrophysical contexts, such as in Type Ia supernovae. Here, we report detailed analyses of the similar to 580 Hz brightness oscillations during bursts from 4U 1636-536. We investigate the bursts as a whole and, in more detail, the initial portions of the bursts. We analyze the similar to 580 Hz oscillations in the initial 0.75 s of the five bursts that were used in a previous search for a brightness oscillation at the expected similar to 290 Hz spin frequency. We find that, although it is appropriate to use an arbitrarily complicated model of the similar to 580 Hz oscillations to generate a candidate waveform for the similar to 290 Hz oscillations, models with more than two parameters are not required by the data. For the bursts as a whole, we show that the characteristics of the brightness oscillations vary greatly from burst to burst. We find, however, that in at least one of the bursts, and possibly in three of the four that have strong brightness oscillations throughout the burst, the oscillation frequency decreases well after the peak of the burst. This behavior poses a challenge to the standard burning layer expansion explanation for the frequency changes.
引用
收藏
页码:458 / 466
页数:9
相关论文
共 25 条
[1]   PROPAGATION OF NUCLEAR BURNING FRONTS ON ACCRETING NEUTRON-STARS - X-RAY-BURSTS AND SUB-HERTZ NOISE [J].
BILDSTEN, L .
ASTROPHYSICAL JOURNAL, 1995, 438 (02) :852-875
[2]   The ocean and crust of a rapidly accreting neutron star: Implications for magnetic field evolution and thermonuclear flashes [J].
Brown, EF ;
Bildsten, L .
ASTROPHYSICAL JOURNAL, 1998, 496 (02) :915-933
[3]  
BUCCHERI R, 1983, ASTRON ASTROPHYS, V128, P245
[4]  
EADIE WT, 1971, STAT METHODS EXPT PH
[5]  
FOX DW, 1999, 7081 IAU
[6]  
FRYXELL BA, 1982, APJ, V258, P773
[7]   NEW INSIGHTS FROM A GLOBAL VIEW OF X-RAY-BURSTS [J].
FUSHIKI, I ;
LAMB, DQ .
ASTROPHYSICAL JOURNAL, 1987, 323 (01) :L55-L60
[8]  
Helstrom C.W., 1960, STAT THEORY SIGNAL D
[9]   HELIUM-BURNING FLASHES ON AN ACCRETING NEUTRON STAR - A MODEL FOR X-RAY BURST SOURCES [J].
JOSS, PC .
ASTROPHYSICAL JOURNAL, 1978, 225 (03) :L123-L127
[10]   SYNCHRONIZATION-INDUCED PERIOD GAPS AND ULTRA-SHORT PERIODS IN MAGNETIC CATACLYSMIC BINARIES [J].
LAMB, DQ ;
MELIA, F .
ASTROPHYSICAL JOURNAL, 1987, 321 (02) :L133-L137