Low Mass X-ray Binaries Low Mass X-ray Binaries and Accreting and Accreting Millisecond Pulsars Millisecond Pulsars A. Patruno A. Patruno R. Wijnands R. Wijnands M. van der Klis M. van der Klis P. Casella P. Casella D. Altamirano D. Altamirano N. Danegaar N. Danegaar ASTRONOMICAL INSTITUTE A. PANNEKOEK ASTRONOMICAL INSTITUTE A. PANNEKOEK UNIVERSITY OF AMSTERDAM UNIVERSITY OF AMSTERDAM
15
Embed
Low Mass X-ray Binaries and Accreting Millisecond Pulsars
Low Mass X-ray Binaries and Accreting Millisecond Pulsars. A. Patruno R. Wijnands M. van der Klis P. Casella D. Altamirano N. Danegaar. ASTRONOMICAL INSTITUTE A. PANNEKOEK UNIVERSITY OF AMSTERDAM. Low Mass X-ray Binaries & Accreting Millisecond Pulsars. - PowerPoint PPT Presentation
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Low Mass X-ray BinariesLow Mass X-ray Binariesand Accreting and Accreting Millisecond PulsarsMillisecond Pulsars
A. Patruno A. Patruno R. Wijnands R. Wijnands
M. van der Klis M. van der Klis P. CasellaP. Casella
D. Altamirano D. Altamirano N. DanegaarN. Danegaar
ASTRONOMICAL INSTITUTE A. PANNEKOEK ASTRONOMICAL INSTITUTE A. PANNEKOEK UNIVERSITY OF AMSTERDAMUNIVERSITY OF AMSTERDAM
Low Mass X-ray Binaries & Accreting Low Mass X-ray Binaries & Accreting Millisecond PulsarsMillisecond Pulsars
Projects in AmsterdamProjects in Amsterdam
Accreting Millisecond Pulsars (AMPs)
Periodic Timing
Intermittent pulsars Cooling of LMXBs (cooling curves, EOS) MagnetarsMagnetars QPOs QPOs Radio Pulsars (timing, glitches)Radio Pulsars (timing, glitches) Neutron Star oscillations Neutron Star oscillations Thermonuclear bursts Thermonuclear bursts
Periodic Timing 1: the pulse Periodic Timing 1: the pulse profilesprofiles1. Fold pulse profiles
(extreme variability)
2. Track the phase of each folded profile, i.e., determine the Time Of Arrivals of the pulsations (TOAs)
3. Fit a model to the TOAs: for example a binary circular orbit + a spin frequency
4. Look at the residuals !
Fig. from Hartman et al. 2008Fig. from Hartman et al. 2008
Periodic Timing 2: the Periodic Timing 2: the Timing NoiseTiming Noise
XTE J1807-294
SAX J1808.4-3685
XTE J1814-338
Hartman, Patruno et al. 2008Hartman, Patruno et al. 2008
Patruno Hartman et al. in prep.Patruno Hartman et al. in prep.
Periodic Timing 3: the enigmatic Periodic Timing 3: the enigmatic FAR relationsFAR relations
XTE J1814-338 XTE J1807-294
The fractional amplitude of the pulsations is anticorrelated with the time of arrival of the pulsations
(i.e. when the fractional amplitude is larger the pulses arrive earlier than predicted by the model)
HETE J1900.1-2455 only first 2 monthsHETE J1900.1-2455 only first 2 months
SAX J1748.8-2021 intermittent, hundreds of SAX J1748.8-2021 intermittent, hundreds of secondsseconds
Aql X-1 only for 150 secondsAql X-1 only for 150 seconds
Intermittent pulsar 3: current Intermittent pulsar 3: current situationsituation
7 AMPs with pulsations throughout the 7 AMPs with pulsations throughout the outburstoutburst
Is magnetic screening ruled out ?
Cooling of accreting Cooling of accreting Neutron StarsNeutron Stars
Quasi persistent sources: very long outbursts (KS 1731-260: 12.5 years, MXB 1659-29: 2.5 years) compared to “normal” X-Ray Binaries
Cooling of accreting Cooling of accreting Neutron StarsNeutron Stars
KS 1731-260 MXB 1659-29
Flux and Temperature well fitted by an exponential decay plus a constant offset (core temperature)
y(t)=y(t)=aa exp[-(t-t0)/ exp[-(t-t0)/bb] + ] + cc
a = normalization constant
b = e-folding time
c = constant offset (core temperature)
Cooling of accreting Neutron Cooling of accreting Neutron Stars: physical interpretationStars: physical interpretation
Rutledge et al 2002, Wijnands 2005, Cackett et al. 2006
Rutledge et al. 2002 calculated detailed cooling curves for KS 1731-260 using the mass accretion history of the source.
High crust thermal conductivity
Enhanced cooling
Open issuesOpen issues
What is the origin of the timing noise in AMPs ?What is the origin of the timing noise in AMPs ? Why pulse shape changes ? (motion of the hot spot, Why pulse shape changes ? (motion of the hot spot,
magnetic field instabilities)magnetic field instabilities) Why we see intermittent pulsations ? (magnetic field Why we see intermittent pulsations ? (magnetic field
burial, smearing of pulsation, crustal cracks)burial, smearing of pulsation, crustal cracks) Cooling: are the cooling curves suggesting an Cooling: are the cooling curves suggesting an
enhanced neutrino emission and high crustal enhanced neutrino emission and high crustal thermal conductivity ? thermal conductivity ?