Using LOFAR to link X-ray binaries and AGN

Robert Dunn
LOFAR and the Transient Radio Sky, Amsterdam, December 2008

Transcript

1. Using LOFAR to link X-ray binaries and AGN Robert Dunn Alexander von Humboldt Fellow Excellence Cluster “Universe”, TUM Rob Fender, Elmar Körding, Clement Cabanac & Tomaso Belloni
2. Outline •  Black hole scaling relations •  Motivation •  Data analysis outline •  Comparing Diagnostic Diagrams •  Including the current radio coverage •  LOFARs contribution.
3. Accreting Black Holes •  Black Holes are described by only a few parameters. •  A variety of links between different observables have been determined: –  L R α L X 0.7M0.6 (Merloni+03, Falcke+04)‏ –  t b α M-2L bol -1 α M/(m/ m Edd )‏ (McHardy+06, Koerding+07)‏
4. AGN - XRB •  The problem with AGN is that they do not vary very quickly •  AGN outbursts in clusters are important for the evolution of clusters. •  However, X-ray binaries vary on a much more human timescale. Mirabel&Rodriguez98
5. Motivation •  Why present X-ray analysis at a conference for a radio telescope? •  X-ray binaries will be amongst the brightest transient sources observed by LOFAR in the galactic plane. •  The more detailed the current understanding, the more LOFAR can add to the picture. •  With the demise of RXTE, LOFAR will be one of the triggering telescopes for multi-wavelength observing campaigns for future outbursts. –  Therefore we need to know how the radio ties into the X-ray observations.
6. X-ray Study •  We aim to comprehensively and consistently analyse as much RXTE data on galactic black-hole X-ray binaries as is publicly available in the archives. •  This study uses one data reduction scheme and few simple X- ray spectral models to extract information on the state of the objects. •  Simple spectral models can only give limited information, however they can be fitted to ALL spectra, regardless of count rate.
7. ...continued •  We fit powerlaw, broken powerlaw & disc+powerlaw to all observations. –  Gaussian line component also fitted. •  Test using χ2 which is the best fitting model. •  Fitted ~3800 observations of 25 black-hole binaries. •  15 Ms of observations over the last decade or so.
8. X-ray Binary Outbursts
9. Hardness Intensity Diagram (Dunn+ in prep)‏
10. Disc Fraction Luminosity Diagram (Dunn+ in prep)‏
11. DFLD vs HID? (Dunn+ in prep)‏
12. Radio on the DFLD (Dunn+08, Dunn+ in prep)‏ 8.4 GHz
13. What LOFAR will do. •  Currently X-ray binary transients are monitored using the RXTE ASM. As L R α L X , any rise from‏  • quiescence can also be done .in radio •  LOFARs ASM can monitor the rise of the binary out of quiescence 50d XTE J1720-318 4U 1543-47
14. •  After the radio flare has occurred the ejecta will mask the core emission. •  Will be able to monitor the jets over time during the decay of the soft state using international baselines (θ<1as). •  Monitor the jet-ISM interaction over months-years after the outburst finishes.
15. Tracing longer term Jet evolution •  The jets inject synchrotron plasma into the ISM. •  The historical emission will be well traced by LOFAR. (Heinz +08)‏ •  Mechanical energy injection to the galaxy could be determined. –  Cf Galaxy Cluster AGN Fabian+06 Gallo+05
16. Summary •  Combining X-ray and Radio observations extremely enlightening when studying X-ray binaries (as well as other sources). •  The Disc Fraction Luminosity Diagram is a more physical way of investigating the outbursts of XRBs. •  LOFAR will be able to monitor the rise out of quiescence of the binary in the early stages of an outburst. •  After the outburst LOFAR will be able to track the ejecta as it travels out into the ISM. –  Trace the historical jet emission over time.
17. The speaker‘s attendance at this conference was sponsored by the Alexander von Humboldt Foundation http://www.humboldt-foundation.de