The broad-band noise characteristics of selected cataclysmic variables (CVS), anomalous x-ray pulsars (AXPS) and soft gamma repeaters (SGRS)

Download

index.pdf

Date

2006

Author

Külebi, Baybars

Metadata

Show full item record

Item Usage Stats

173
views

55
downloads

In this work present the broad-band noise structure in the 2-60 keV data of Cataclysmic Variables (CVs) with Anomalous X-Ray Pulsars (AXPs) and Soft Gamma Repeaters (SGRs). We analyzed Rossi X-ray Timing Explorer (RXTE) PCA data and derived time series from 27 CVs, 4 AXPs and 1 SGR using the RXTE archive. In general, CVs of different types all show broad band noise which can be fitted with power laws, using exponentional cut-offs, and Lorentzians in a similar way to power spectral (noise) characteristics of X-ray Binaries (XRBs). In general terms the power spectra show a power law index of (-)1.2-2. A rather large scale flattening of the power spectra exits in nonmagnetic systems in the low to very low frequency range. We observe that in low and high states/outbursts the noise in the high frequency range and low frequency range is changed. CVs show considerably low frequency noise. In addition, we recovered several possible QPOs in the X-ray wavelengths from CVs mainly from Intermediate Polar systems. AXP and SGR sources which are thought to be powered by either magnetic decay or accretion show band limited noise in their low frequencies. We also correlated their equal time interval noise characteristic with their burst states and discovered that in the two AXPs (1E 2259+586, 1E 1048.1-5937) noise correlates with their bursts.

Subject Keywords

Stars.

URI

http://etd.lib.metu.edu.tr/upload/12608117/index.pdf
https://hdl.handle.net/11511/16577

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

The broad-band noise characteristics of selected AXPs and SGRs: Probing the magnetar coronae Kulebi, Baybars; Balman, Şölen (2007-08-17) We present the broad-band noise structure of Anomalous X-Ray Pulsars (AXPs) and Soft Gamma Repeaters (SGRs) in the 2-60 keV energy band which are thought to be powered by either magnetic decay(Thompson & Duncan 1995) or accretion (Alpar 2001). We have used Rossi X-ray Timing Explorer (R-XTE) PCA archival light curves and derived time series for 4 AXPs and 1 SGR. We detect that AXP and SGR sources show band limited noise at low frequencies in the range 0.005-0.05 Hz. We find that this noise level can be asso...
The torque and X-ray flux changes of OAO 1657-415 Baykal, Altan (1997-03-01) Combining previously published pulse frequencies and BATSE measurements, we estimate the noise strengths (or power density estimates) of angular accelerations by using the root mean square residuals of angular velocity time series of OAO 1657-415 and present the power spectra. The statistical interpretation of the angular velocity fluctuations is consistent with a random walk model. In order to investigate the short term angular velocity fluctuations in detail, a structure function analysis is applied for a...
On period and burst histories of AXPs and SGRs and the possible evolution of these objects on the P-P diagram Guseinov, OH; Yazgan, EFE; Ankay, A; Tagieva, S (World Scientific Pub Co Pte Lt, 2003-01-01) In this paper, timing data for anomalous X-ray pulsars and soft gamma repeaters are compiled. Timing properties of these objects are investigated. The effect of bursts of soft gamma repeaters on their period history is investigated. The P-P diagram for pulsars, X-ray binaries, anomalous X-ray pulsars, soft gamma repeaters and dim radio quiet neutron stars is constructed. The possible evolutionary tracks for anomalous X-ray pulsars, soft gamma repeaters and dim radio quiet neutron stars are examined.
THE NOISE IN THE 35-D CYCLE OF HER X-1 Baykal, Altan; DEETER, JE; SCOTT, DM (1993-11-15) We calculate the power density spectrum of fluctuations in the X-ray turn-on times of Her X-1, including new data which extend the X-ray and optical flux observations to a span of over 20 yr with 221 distinct 35-d high-low flux cycles. If we assume that turn-on times define the period of the 35-d clock, this statistical interpretation of turn-on behaviour is consistent with a white-noise process in the first derivative of the 35-d phase fluctuations (or a random walk in clock phase). We discuss the implicat...
The re-analysis of the ROSAT data of Nova Mus 1983 using white dwarf atmosphere emission models Balman, Şölen; Krautter, J (2001-10-01) The analyses of X-ray emission from classical novae during the outburst stage have shown that the soft X-ray emission below 1 keV, which is thought to originate from the photosphere of the white dwarf, is inconsistent with the simple blackbody model of emission. Thus, ROSAT Position Sensitive Proportional Counter (PSPC) archival data of the classical Nova Mus 1983 (GQ Mus) have been re-analysed in order to understand the spectral development in the X-ray wavelengths during the outburst stage. The X-ray spec...

Citation Formats

B. Külebi, “The broad-band noise characteristics of selected cataclysmic variables (CVS), anomalous x-ray pulsars (AXPS) and soft gamma repeaters (SGRS),” M.S. - Master of Science, Middle East Technical University, 2006.