the nature of the doppler lines in the ultra-compact binary
DESCRIPTION
The Nature of the Doppler Lines in the Ultra-compact Binary 4U1626-67. Doppler Lines and Fe Fluorescence in the Ultra-compact Binary 4U1626-67. Previous HETG GTO observations: - PowerPoint PPT PresentationTRANSCRIPT
The Nature of the Doppler Lines in the Ultra-compact Binary 4U1626-67
Doppler Lines and Fe Fluorescence in the Ultra-compact Binary 4U1626-67
Previous HETG GTO observations: - Schulz et al. 2001: Double Peaked X-ray Lines from the O/Ne-rich Accretion Disk in 4U 1626-67: OBSIDs 104, 39 ksec - Krauss et al. 2007: High Resolution X-ray Spectroscopy of the Ultra-compact LMXB Pulsar 4U 1626-67: OBSIDs 104, 39 ksec 3504, 97 ksec
Doppler Lines and Fe Fluorescence in the Ultra-compact Binary 4U1626-67
New HETG GTO observations:-Chakrabarty & Schulz 2009 Cycle 11 GO time: OBSIDs 11058, 80 ksec, Jan 14. 2010
Doppler Lines and Fe Fluorescence in the Ultra-compact Binary 4U1626-67
Tbnew (Powerlaw + Bbodyrad):NH = 1.2x1021 cm-1 A = 0.0084 ph cm-2 s-1
= 0.80Abb = 593 (R2
km / D2kpc)
kTbb = 0.20 keV
Tbnew (Powerlaw + Bbodyrad):NH = 1.2x1021 cm-1 A = 0.0384 ph cm-2 s-1
= 1.19Abb = 83 (R2
km / D2kpc)
kTbb = 0.48 keV
Flares and Dips in the New Light Curve of 4U1626-67
Obsid 11058:
Obsid 3504:
Doppler Lines in the Ultra-compact Binary 4U1626-67
Doppler Lines in the Ultra-compact Binary 4U1626-67
Ionization Model Fits to the X-ray Spectrum of 4U1626-67
Photo-ionized modeling:
Collisional-ionized modeling:
Aped_density = 13:
Collisional Ionization Model Fits to the X-ray Spectrum of 4U1626-67
Pure C/O/Ne disk?:
1) Cannot maintain C I/Ne I/O I : log > 2 @ r~109 cm
2) Pure C/O disk model predicts T = 28000 K @ 20000 km (Werner et al. 2006)
Doppler Lines and Fe Fluorescence in the Ultra-compact Binary 4U1626-67
Magnetospheric Accretion Shocks in the Ultra-compact Binary 4U1626-67
Emission Volumes:
In conclusion we propose the following:
Doppler Lines in the Ultra-compact Binary 4U1626-67
Magnetospheric Accretion Shocks
Rco = 8.5x108 cm
Rco = Rmag
Vshift ~ 2000 km/s
~ Vco
Vco ~ Vshock
Tjump < 60 MK
CO plasma< 20 deg impact
Vshift = Vion
Tshock < 10 K
In conclusion we propose the following:
Doppler Lines in the Ultra-compact Binary 4U1626-67
• The light curve before torque reversal is featureless. The light curve after torque reversal shows enhance variability which includes type II flaring, intensity dips, and periods of quiescence.
• The X-ray flux at the time of the observation in 2009 is at about the same level as it was in 1994.
• The X-ray continuum after torque reversal is fit by the same spectrum as before, however with a higher blackbody temperature and a smaller emission radius.• The spectrum shows a narrow Fe K fluorescence line, which was not observed before torque reversal.
• A photo-ionized plasma cannot fit the Ne and O Doppler line emissions.
• The large ratio between the Ne X Lα line and the upper limit to the Ne X Lβ line rules out significant contributions due to resonance scattering.• A collisions ionized plasma fits both Ne and O line ratios very well with enhanced plasma densities and plasma temperature between 1 MK and 10 MK. Magnetospheric Accretion Shocks