scholarly journals Understanding the Long‐Term Spectral Variability of Cygnus X‐1 with Burst and Transient Source Experiment and All‐Sky Monitor Observations

2002 ◽  
Vol 578 (1) ◽  
pp. 357-373 ◽  
Author(s):  
Andrzej A. Zdziarski ◽  
Juri Poutanen ◽  
William S. Paciesas ◽  
Linqing Wen
Keyword(s):  
Spectral Variability ◽  
Transient Source ◽  
Sky Monitor ◽  
Burst And Transient Source

Results from the Ariel 5 All-Sky Monitor

1976 ◽  
Vol 350 (1663) ◽  
pp. 505-519 ◽  
Keyword(s):  
First Year ◽  
Temporal Effects ◽  
Transient Source ◽  
Second Year ◽  
Sky Monitor ◽  
Long Term Studies

A summary of results obtained from the first year of Ariel-5 All-Sky Monitor operation is presented. Transient source observations, as well as the results of long-term studies of Sco X-1, Cyg X-3 and Cyg X-1 are described. By example, the included results are indicative of the temporal effects to which the All-Sky Monitor remains sensitive as it begins its second year of observation.

scholarly journals Aperiodic Flux Variability in A 0535+262

1996 ◽  
Vol 165 ◽  
pp. 313-319
Author(s):  
Mark H. Finger ◽  
Robert B. Wilson ◽  
B. Alan Harmon ◽  
William S. Paciesas
Keyword(s):  
Neutron Star ◽  
Gamma Ray ◽  
Beat Frequency ◽  
Power Spectra ◽  
Center Frequency ◽  
X Ray ◽  
Binary Pulsar ◽  
Transient Source ◽  
Flux Variability ◽  
Burst And Transient Source

A “giant” outburst of A 0535+262, a transient X-ray binary pulsar, was observed in 1994 February and March with the Burst and Transient Source Experiment (BATSE) onboard the Compton Gamma-Ray Observatory. During the outburst power spectra of the hard X-ray flux contained a QPO-like component with a FWHM of approximately 50% of its center frequency. Over the course of the outburst the center frequency rose smoothly from 35 mHz to 70 mHz and then fell to below 40 mHz. We compare this QPO frequency with the neutron star spin-up rate, and discuss the observed correlation in terms of the beat frequency and Keplerian frequency QPO models in conjunction with the Ghosh-Lamb accretion torque model.

The burst and transient source experiment for the gamma-ray observatory

1982 ◽  
Author(s):  
G. J. Fishman ◽  
C. A. Meegan ◽  
T. A. Parnell ◽  
R. B. Wilson
Keyword(s):  
Gamma Ray ◽  
Transient Source ◽  
Burst And Transient Source

scholarly journals An X-Ray All Sky Monitor for a Japanese Experimental Module on the Space Station

1990 ◽  
Vol 123 ◽  
pp. 463-468
Author(s):  
M. Matsuoka ◽  
N. Kawai ◽  
T. Imai ◽  
M. Yamauchi ◽  
A. Yoshida ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Space Station ◽  
Transient Phenomena ◽  
X Ray ◽  
Sky Monitor ◽  
Image Position ◽  
Japanese Experimental Module

AbstractWe propose an X-ray all sky monitor for Japanese Experimental Module (JEM) on the space station. Considering practical circumstances, we show as a case study that the all sky monitor with slit hole cameras is most promising for monitoring the short-term and long-term X-ray transients. We call this all sky monitor as MAXI (Monitor of All-sky X-ray Image). Position determination of gamma-ray bursts could be achieved with accuracy less than one degree observing the X-ray component of the burst. Weak X-ray sources such as active galactic nuclei could be also monitored with time resolution less than one day. The X-ray all sky monitor will work to discover X-ray novae and transient phenomena and give us the alarm for further detailed observations. The obtained data will be also used for archival study.

scholarly journals GRS 1915+105: Flares, QPOs and Other Events at 15 GHz

1998 ◽  
Vol 164 ◽  
pp. 333-334
Author(s):  
G. G. Pooley ◽  
R. P. Fender
Keyword(s):  
X Ray ◽  
Transient Source ◽  
Sky Monitor ◽  
Quasiperiodic Oscillations

AbstractMonitoring with the Ryle Telescope at 15 GHz of the Galactic X-ray transient source GRS 1915+105 has revealed a remarkable range of rapid and extended flares which appear to be related to the X-ray emission as recorded by the RXTE all-sky monitor. Quasiperiodic oscillations in the range 20–40 min have been found and are probably related to oscillations in the soft X-ray flux.

Gamma-ray burst locations from the Burst and Transient Source Experiment

1991 ◽  
Author(s):  
M. N. Brock ◽  
C. A. Meegan ◽  
F. E. Roberts ◽  
G. J. Fishman ◽  
R. B. Wilson ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Burst ◽  
Transient Source ◽  
Burst And Transient Source

scholarly journals A short and sudden increase of the magnetic field strength and the accompanying spectral variability in the O9.7 V star HD 54879

2019 ◽  
Vol 484 (4) ◽  
pp. 4495-4506 ◽  
Author(s):  
S Hubrig ◽  
M Küker ◽  
S P Järvinen ◽  
A F Kholtygin ◽  
M Schöller ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Longitudinal Magnetic Field ◽  
Sudden Increase ◽  
Spectral Variability ◽  
Dipole Strength ◽  
Large Program ◽  
Short And Long Term ◽  
The Magnetic Field

Abstract Only 11 O-type stars have been confirmed to possess large-scale organized magnetic fields. The presence of a −600 G longitudinal magnetic field in the O9.7 V star HD 54879 with a lower limit of the dipole strength of ∼2 kG was discovered a few years ago in the framework of the ESO large program ‘B-fields in OB stars’. Our FORS 2 spectropolarimetric observations from 2017 October 4 to 2018 February 21 reveal the presence of short- and long-term spectral variability and a gradual magnetic field decrease from about −300 G down to about −90 G. Different scenarios are discussed in an attempt to interpret our observations. Our FORS 2 radial velocity measurements indicate that HD 54879 is a member of a long-period binary.

scholarly journals LONG-TERM X-RAY MONITORING OF LS I +61°303: ANALYSIS OF SPECTRAL VARIABILITY AND FLARES

2011 ◽  
Vol 733 (2) ◽  
pp. 89 ◽  
Author(s):  
Jian Li ◽  
Diego F. Torres ◽  
Shu Zhang ◽  
Yupeng Chen ◽  
Daniela Hadasch ◽  
...  
Keyword(s):  
Spectral Variability ◽  
X Ray

scholarly journals Long-term Spectral Variability of the Ultraluminous X-Ray Source Holmberg IX X–1

2017 ◽  
Vol 849 (2) ◽  
pp. 121 ◽  
Author(s):  
V. Jithesh ◽  
Ranjeev Misra ◽  
Zhongxiang Wang
Keyword(s):  
Spectral Variability ◽  
X Ray
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