The Unique Standing of Circinus X-1 Among LMXBs in Light of QPOs Observed by RXTE

Astronomy and Astrophysics – Astronomy

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

1

Scientific paper

We present analysis of two types of QPOs in Circinus X-1 observed by the Rossi X-ray Timing Explorer (RXTE) PCA instrument and discuss the impact of the results on the unique standing of Cir X-1 among low-mass x-ray binaries (LMXBs). It has been proposed that the atoll and Z classes of LMXBs differ in both magnetic field and accretion rate. Higher magnetic fields in Z sources could produce the magnetospheric horizontal-branch oscillations (HBOs, 13-55 Hz). Very high accretion rates in Z sources could result in the radiation-pressure driven normal/flaring branch oscillations (N/FBOs, 6-20 Hz). Based on EXOSAT observations, it has been suggested that Cir X-1 might be a unique atoll source that sometimes reaches high accretion rates. Thus Cir X-1 should sometimes show N/FBOs but never HBOs. The 5-20 Hz QPOs observed from Cir X-1 by EXOSAT are cited as the possible N/FBOs. PCA observations of Cir X-1 when the intensity is relatively high ( ~ 1.0 Crab, 2-30 keV) show the same evolving QPO at 1.3-35 Hz. During periods of flaring to higher intensity ( ~ 1.2-2 Crab), a broad constant-frequency 4 Hz peak is observed. In light of this 4 Hz QPO at high intensity and the expanded frequency range of the evolving QPO, the identification of the latter with N/FBOs is now in doubt. We discuss alternate interpretations for these two types of QPOs in Cir X-1.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

The Unique Standing of Circinus X-1 Among LMXBs in Light of QPOs Observed by RXTE does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The Unique Standing of Circinus X-1 Among LMXBs in Light of QPOs Observed by RXTE, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Unique Standing of Circinus X-1 Among LMXBs in Light of QPOs Observed by RXTE will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-1176896

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.