SIMBAD references

2000A&A...361..121B - Astronomy and Astrophysics, volume 361, 121-138 (2000/9-1)

Low and high frequency quasi-periodic oscillations in 4U 1915-05.


Abstract (from CDS):

The X-ray burster and dipper 4U 1915-05 (also known as XB 1916-053) was observed 19 times for a total exposure of roughly 140 ks between 1996 February and October with the proportional counter array (PCA) aboard Rossi X-ray Timing Explorer (RXTE). We present here the detailed timing study of its X-ray emission. The source was observed in both a high intensity/soft spectral and a low intensity/hard spectral state. The 2-20keV luminosities are about 1.4x1037 and 3.2x1036erg/s in the two regimes respectively (assuming a source distance of 9.3kpc). We confirm that 4U 1915-05 is an atoll source based on its spectral behaviour and its aperiodic variability in the frequency range ∼4x10–3-128Hz. 4U 1915-05 displays red noise below ∼1Hz, but is especially remarkable for its quasi-periodic variability detected for the first time at several timescales. We detect low frequency quasi-periodic oscillations (LFQPOs) between ∼5 and 80Hz, as well as high frequency QPOs (HFQPOs) between ∼200 and 1300Hz. Both LFQPOs and HFQPOs frequencies positively correlate with the mass accretion rate inferred from the position of the source on the color-color diagram. In a narrow range of luminosity, we also detect twin simultaneous HFQPOs separated by 348±12Hz.

Abstract Copyright:

Journal keyword(s): stars: individual: 4U 1915-05 - stars: neutron - X-rays: stars

Simbad objects: 28

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