Pulsars

Presented by Rico Bürgler & Shuting Ling What is a pulsar?

• Stands for pulsating radio star • Is a type of neutron star • Heavily magnetized • Very high rotation speed • Continuous radiation, emits beams across the spectrum

29.04.16 Pulsars, Rico Bürgler & Shuting Ling 2 Discovery First observation in 1967 by Jocelyn Bell Burnell and Anthony Hewish in the UK Pulses in 1.33s intervals LGM-1 à CP1919 à PSR B1919+21 Theories on how the radiation is emitted exist “We did not really believe that we had picked up signals from another civilization, but obviously the idea had crossed our minds and we had no proof that it was an entirely natural radio emission. It is an interesting problem - if one thinks one may have detected life elsewhere in the universe how does one announce the results responsibly? Who does one tell first?”

29.04.16 Pulsars, Rico Bürgler & Shuting Ling 3 Illustration

Cones = beam, located on the magnetic axis Golden lines: magnetic field lines Purple line: rotational axis

29.04.16 Pulsars, Rico Bürgler & Shuting Ling 4 The beam’s origin (rotation-powered pulsars)

Electric field is created Accelerates protons and electrons on surface Intense electromagnetic beam results Loss of energy à slowing down «death-line» after ~10-100M yrs

29.04.16 Pulsars, Rico Bürgler & Shuting Ling 5 Other categories

Accretion-powered pulsars Magnetars Millisecond pulsars

29.04.16 Pulsars, Rico Bürgler & Shuting Ling 6 Accretion-powered

Binary star system Accounts for most X-ray pulsars Energy source: Gas/Matter from stellar companion. Stellar wind Gravitational pull due to distance Short visible pulsars

29.04.16 Pulsars, Rico Bürgler & Shuting Ling 7 Millisecond Pulsar

Rotational period of 1-10ms How are they born? Recycled/Accretion powered with additional angular momentum Breaking the chandrasekhar limit Great clocks Great for observing nearby matter

29.04.16 Pulsars, Rico Bürgler & Shuting Ling 8 Magnetars

Pulsar with high magnetic SGR 1745-29, found close to field Sagittarius A* in Rotation period of 1-12s Mily Way Non-periodic flares also generating weaker after flares

Soft Gamma Repeater(SGR)

29.04.16 Pulsars, Rico Bürgler & Shuting Ling 9 Crab pulsar

Relatively young neutron star Center of Crab nebula Pulses in 33ms intervals, roughly 30 times per second Remnant of SN 1054, observed in 1054

29.04.16 Pulsars, Rico Bürgler & Shuting Ling 10 Applications

Probes of the Interstellar Medium Gravitational Waves Detectors Clocks

29.04.16 Pulsars, Rico Bürgler & Shuting Ling 11