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Magnetars..

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Presentation on theme: "Magnetars.."— Presentation transcript:

1 Magnetars.

2 Diagram from 1994 Magnetars, High B field Pulsars unknown!

3 From Kaplan (PhD 2004) This is a P-Pdot diagram and not B-P But B2 proportional to P x Pdot

4 Reviews There are no major reviews but try the following:
Kaspi (astroph/ ) Hurley (astroph/ ) Paczynski (1992, Acta Astronomica) Baring (1991, A&A) The classic set of papers in this field are Thompson & Duncan (1995, MNRAS) Thompson & Duncan (1996, ApJ)

5 Giant Burst from SGR 1900+14 (August 1998)

6 Giant Burst of August 1998 Peak Luminosity of short spike, 1045 erg/s
Energy in the hard spike, 1044 erg Total Energy radiated, 1045 erg (not including neutrinos) The luminosity exceeds LEddington

7 A strong B field reduces Thomson cross-section
Paczynski 1992 where the cyclotron energy QED effects become important for BQED > 4.3x1013 G (electron rest mass) and photons with energy of 511 keV

8 Hurley

9 Anomalous X-ray Pulsars
Periods in the range 5-20 s No companion (either through reflex motion or as optical/IR counterpart) Luminous X-ray sources (4U ) But Pdot not sufficient to power LX (see Table) Hence the name

10

11 Bursts from 1E Kaspi

12 Conclusions Soft gamma-ray repeaters and anomalous X-ray pulsars are highly magnetized neutron stars The relationship between the two classes is unknown (is one descendent of the other?) High B field radio pulsars (1014 G) appear to be different from magnetars. Something in the interior does care about 1014 G.

13 Why are magnetars of some interest?
Some have argued that the birth (hot convective core) results in a magnetar. In any case at least magnetars constitute about 10% of the birthrate. Magnetars have been suggested to be the central sources for GRBs Exotic QED Phenomena (Photon splitting & Vacuum Polarization; see Baring paper)


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