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Title: CORRELATIONS IN HORIZONTAL BRANCH OSCILLATIONS AND BREAK COMPONENTS IN XTE J1701-462 AND GX 17+2

We studied the horizontal branch oscillations (HBO) and the band-limited components observed in the power spectra of the transient neutron star low-mass X-ray binary XTE J1701-462 and the persistent ''Sco-like'' Z source GX 17+2. These two components were studied based on the state-resolved spectra. We found that the frequencies of XTE J1701-462 lie on the known correlations (WK and PBK), showing consistency with other types of X-ray binaries (black holes, atoll sources, and millisecond X-ray pulsars). However, GX 17+2 is shifted from the WK correlation like other typical Z sources. We suggest that the WK/PBK main track forms a boundary that separates persistent sources from transient sources. The characteristic frequencies of break and HBO are independent of accretion rate in both sources, though it depends on spectral models. We also report the energy dependence of the HBO and break frequencies in XTE J1701-462 and how the temporal properties change with spectral state in XTE J1701-462 and GX 17+2. We studied the correlation between rms at the break and the HBO frequency. We suggest that HBO and break components for both sources probably arise from a similar physical mechanism: Comptonization emission from the corona. These two components could be caused bymore » the same kind of oscillation in a corona with uneven density, and they could be generated from different areas of the corona. We further suggest that different proportions of the Comptonization component in the total flux cause the different distribution between GX 17+2 and XTE J1701-462 in the rms{sub break}-rms{sub HBO} diagram.« less
Authors:
; ;  [1] ;  [2] ;  [3] ;  [4]
  1. Department of Astronomy, Beijing Normal University, Beijing 100875 (China)
  2. School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)
  3. Laboratory for Particle Astrophysics, CAS, Beijing 100049 (China)
  4. INAF-Osservatorio Astronomico di Brera, Via E, Bianchi 46, I-23807 Merate (Italy)
Publication Date:
OSTI Identifier:
22364576
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 799; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BINARY STARS; BLACK HOLES; CORRELATIONS; DENSITY; DIAGRAMS; ENERGY DEPENDENCE; MASS; NEUTRON STARS; NEUTRONS; OSCILLATIONS; PULSARS; TRANSIENTS; X RADIATION