A. Nepomuk Otte: Detection of the Crab pulsar above 25 GeV with the MAGIC telescope

The Crab pulsar was detected with ~6 sigma significance at >25GeV using MAGIC. Detection of the Crab has been called the holy grail of ground based gamma ray astronomy, since sensitivity below 100GeV is very difficult to achieve using the air Cherenkov detectors. The interpulse amplitude was larger than the main pulse, indicating that the interpulse has a much harder spectrum than the main pulse.

Jason Hessels: Uncovering the population of nearby neutron stars at low radio frequencies

Looking for nearby pulsars

• Look for pulsars at distances below 2 kpc.
  
• Get luminosity distributions.
• Since they're close, they can easily be follow up at other wavelengths.
• Look for pulsars at low frequencies. Low dispersion measurement (DM) sources easy to distinguish from noise. Low frequencies have not been exploited. Unfortunately, these sources will have many dispersion trials.

Galactice Plane Survey with the Green Bank Telescope (GBT)

• GBT survey at 350-MHz. Look for pulsars and radio transients. Sensitive to Low DM sources. The entire Northern Galactic Plane has been covered. 33 new pulsars so far! Examples of sources discovered because of low frequency observing:

1. PSR J0243+62 discovered in a single pulse search. P=592 ms. At a distance of 400 kpc. Very low luminosity L400~0.2 mJy kpc^2.
   
2. PSR J0054+66 also identified in a single pulse search. P=1.39 s. D~ 1kpc.

• GBT350 discoveries show there are still many nearby intermittent sources.
• These are the types of sources that the LOw Frequency ARray (LOFAR) will find.

Pulsars with LOFAR

• 30-80 MHz.
• 2x24 High band antennae (HBA) tiles.
• 96 Low Band Antennae (LBA) tiles.
• Ideal for surveying the local Galaxy for pulsars.
• Single pulses from B0329+54 found "blindly" using just 6 LOFAR HBA tiles.
• Simulations show that there is the potential to find +1000 new pulsars.
• LOFAR will be online soon and will provide unparalleled sensitivity.
  

Maxim Lyutikov: Crab giant pulses at sub-nanosecond resolution: quantitative model of non-trivial spectrum

A model for the emission of giant pulses from the Crab pulsar is proposed by Lyutikov and is based on anomalous cyclotron resonance on the ordinary modes. His main conclusions are: 1. giant pulses come from closed field lines; 2. giant pulses are seen by chance, i.e. produced in narrow emission windows; 3. closed field lines are not dead, but populated by plasma with n >> n_{GJ}; 4. Earth analogues: magnetosperic hiss, roars.

Rene Breton: "New test of gravity using eclipses in the double pulsar PSR J0737-3039A/B"

Rene Breton showed how he and collaborators have used the eclipses of pulsar A in the double pulsar system to perform a new test of gravity:

• Double pulsar system is observed almost edge on (i ~ 89 deg): eclipses of pulsar A by the magnetosphere of B.
• Eclipses last for ~30 seconds, no strong frequency dependence.
• Can see modulation during the eclipse at the spin rate of pulsar B.
• Synchrotron absorbtion in the magnetosphere of pulsar B.
• "rotating doughnut" model, very sensitive to the geometry of the system.
• Very good evidence for dipolar magnetic field.
• Kramer et al. 2006: measured 5 relativistic effects from pulsar timing (most precise test of GR in the strong-field regime)
• Breton et al. 2008 in Science: Eclipse profile changing with time: precession of pulsar B's spin axis measured: 4.77+0.66 deg/yr (consistent with GR prediction)

Some very nice movies showing this result are available here.

Vyacheslav Zavlin: Pulsar high energy emission: Soft X-rays

This presentation was a broad overview of soft x-ray emission from pulsars/NSs. Observations of NSs in the soft X-ray band are important since the bulk of the flux from NSs falls in this range and since some NSs/pulsars have still not been detected outside this range. Both thermal and non-thermal emission can be observed. The thermal emission, due to internal heat (or from a small hot spot), is ideal to constrain the equation of state. It is important to note that a blackbody interpretation of the thermal radiation implies an emission area much smaller than with a H-atmosphere interpretation. The non-thermal emission can be due to the magnetosphere, pulsar wind nebula, or inter-binary shocks. Young objects (~1 kyr) are dominated by non-thermal emission, while middle-aged and old pulsar (>1 Gyr) are dominated by thermal radiation, from the surface and hot polar caps respectively. The author presented different objects that have been observed in different wavelength bands (Vela, PSR J0538+2817, Geminga, ...). In most cases,  polar caps (thermal emission) were (very likely) detected. However, non-thermal emission can be used in many cases to explain the X-ray emission. Finally, regarding the cooling models of pulsars/NSs, we notice large difference in the cooling curve whether or not proton superfluidity is included in the model.

Matthew Baring: Theoretical Perspectives on Non-Thermal Pulsar Emission

At present, there are over 1700 radio pulsars, around 30 optical pulsars, over 60 X-ray pulsars, and 7 gamma ray pulsars known. The main focus of this talk was how to distinguish between the polar cap and outer gap emission models, in particular how to do this using the 30MeV to 300GeV capabilities of the newly launched GLAST telescope.
The predicted populations of pulsars detectable with GLAST differ depending on whether one uses a polar cap model or an outer gap model. If pulsar emission originates from a polar cap, one expects 150-200 new pulsars detected with GLAST, while one expects 300-800 new pulsar detections if the emission originates from around the surface, as in the outer gap model.
The predicted spectrum of the Vela pulsar differs in the two models, and simulations indicate that GLAST should be able to resolve this difference.
In general, the polar cap model predicts that the highest detectable energies from pulsars decrease with increasing magnetic field, while the outer gap model predicts increasing maximum energy with increasing magnetic field. The present data cannot rule out either model on this basis, but GLAST data may be able to do so.
In the future, polarimetry in X-ray and soft gamma ray bands would be valuable in constraining pulsar emission mechanisms, by distinguishing between synchrotron and curveature polarization throgh the polarization swing profiles.

Ben Stappers: "Pulsar radio emission: overview of observational status"

• Better chance of finding drifting subpulses at longer observing wavelengths? (Weltevrede et al. 2006, 2007). Drifting a general property of radio emission from neutron stars?

• "swooshes": epsiodic emission in "new" region (pulse phase) turns on when the "normal" emission turns off. Hard to reconcile with carousel model.
• "flaring": similar to "swooshing" phenomenon, occasional bright pulses at different pulse longitudes.
  
• "RRAT-alogue" (catalogue of known RRATs): more than 24 RRATs now known (11 presented in original McLaughlin et al. paper). New, very nearby RRATs being found.
  
• Some RRATs show bursts of several pulses, closely spaced: "bursters".
  
• Four "intermittent pulsars" (e.g. PSR B1931+24) now known. Switch on/off on timescales of weeks to months and show different Pdot when on/off.
• Very high degree of modulation in single pulses of radio-emitting magnetar XTE J1810-197.
• Is there a continuum of processes across the different "off" states from the single/few pulse nulls, extreme nullers, RRATs, and intermittent pulsars?