@@ -16,17 +16,16 @@ They are rapidly spinning neutron stars that emit pulses, observable from radio
gamma-ray wavelengths.</p>
<p>Searching for new pulsars is an enormous computational challenge, because their spin
frequencies, sky position and other parameters are unknown. Thus, this requires a blind
search, where one explicitly searches over a dense grid in parameter space. However, the
frequencies, sky position and other parameters are unknown in advance. Hence this is called a "blind" search, where one explicitly searches over a dense grid in parameter space. However, the
number of discrete grid points to cover such multi-dimensional parameter spaces is
tremendous and renders "brute forces approaches" computationally unfeasible.</p>
<p>We have developed novel and much more efficient data-analysis methods for the volunteer
supercomputer Einstein@Home, which ranks among the fastest 25 computer systems worldwide.
Einstein@Home has now discovered four new gamma-ray pulsars that were previously
Einstein@Home has enabled the discoveries of new gamma-ray pulsars that were previously
inaccessible on computational grounds.</p>
<p>These radio and gamma-ray pulsar discoveries provide important contributions to advance
<p>These gamma-ray pulsar discoveries provide important contributions to advance
our (yet very poor) understanding these stellar objects, their population, and their role
<p>The above plot illustrates the number of gamma-ray pulsars discovered in blind searches using NASA's Fermi Gamma-ray Space Telescope as a function of time (when the discoveries were published). Since the launch of the Fermi satellite in 2008, it has continuously scanning the entire sky and thus is providing an ever increasing data set. In principle, having more data available allows us to do more sensitive pulsar searches. However, at the time, the computational cost increases also rapidly with the longer data time spans. Thus, as the graphics shows, over the last few years the only new such discoveries were made with Einstein@Home, owing to the massive collective computing power provided by the Einstein@Home volunteers.</p>
<br>
<h3>The discoveries made by Einstein@Home volunteers in detail</h3>
<p>Below we list for each pulsar the volunteers whose computers discovered the pulsar,
and the date at which the pulsar was found.</p>
<p>We also provide a list of selected characteristics for each
of the pulsars. Right ascension is one of the two celestial coordinates that specify the
sky position of the pulsar. Declination is the second of these. The spin frequency describes
how many time per second the pulsar is rotating. The first frequency derivative describes
how much the pulsar is slowing down over time. The energy required to emit electromagnetic
radiation is drawn from the pulsar rotation. The characteristic age is a rough estimate of
the pulsar's age, computed from the spin frequency and its derivative. Finally, the
spin-down power is a measure of the total energy emitted by the pulsar. For comparison, our
Sun outputs roughly 4 x 10<sup>33</sup> erg per second. All pulsars below have a much higher
spin-down power.</p>
<p>The graphics on the right show the pulse profile of each pulsar in green, and the phase-folded
arrival times of all the gamma-ray photons on the far right. These plots require precise
knowledge of the pulsar sky position, its spin frequency, and spin frequency derivative.
Using these, each photon can be assigned a rotational phase, i.e., in which direction the
pulsar was pointing when the gamma-ray photon was emitted. Thus, we can reconstruct the
gamma-ray emission as a function of pulsar rotation phase and resolve the pulse profile.</p>
