XMM monitoring of the state transition of the supersoft source CAL 83 Robert Schwarz Astrophysikalisches Institut Potsdam Jochen Greiner MPE Garching Gloria Sala Uni Barcelona Ronald Mennickent Uni Concepcion Super Soft X-ray Sources – New developments ESAC, May 18, 2009
20
Embed
XMM monitoring of the state transition of the supersoft source CAL 83 Robert Schwarz Astrophysikalisches Institut Potsdam Jochen Greiner MPE Garching Gloria.
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
XMM monitoring of the state transition of the supersoft source CAL 83
Robert SchwarzAstrophysikalisches Institut Potsdam
Jochen Greiner
MPE Garching
Gloria Sala
Uni Barcelona
Ronald MennickentUni Concepcion
Super Soft X-ray Sources – New developments ESAC, May 18, 2009
Introducing CAL 83
• Canonical SSS source in the LMC
• 1-day orbital period
• Low amplitude orbital modulation in optical and X-rays
• Inclination < 30
• Tentative X-ray pulsations at 38 min
High-resolution X-ray spectrum
• Good fit to the data with a NLTE model (Lanz et al. 2004)
• log g = 8.5, Teff = 500 kK
• Suggests a massive WD of 1.3 Msun
X-ray off-states in CAL 83
MACHO light curve (Greiner & di Stefano 2002)
Anti-correlated brightness changes in SSSObservations of RXJ 0513-69• Short transition times• only high or low states • X-ray on state shorter than off
state
Anti-correlated brightness changes in SSS
Models• Expansion and cooling of the envelope• Limit cycle regulated by changing mass accretion rate
Hachisu & Kato 2003• Stripping of the companions
surface by a strong wind
• X-ray off: wind absorption optical high: expanded disk
Reinsch et al. 2000• Radius/temperature changes
of the WD
• Increased irradiation of the outer disk
Wind regulated accretion in RXJ 0513-69
Smarts/XMM monitoring of CAL 83
Comparison with MACHO observations
Similar pattern
Different timescale
Long term behaviour from OGLE
Recurrence time: 430 days Duty cycle: 50%
X-ray/optical lightcurves
• Sharp drop (t < 1 d) to intermediate brightness level