The “Holey” Grail of Pulsars

1. The “Holey” Grail of Pulsars By: Jurni Fink, Alexx Lee, and Annie Nealon (Broadway High School, Broadway, VA ) The Binary Question… Imagine a radically, nigh-impossible idea: the co-existence of a pulsar and a black hole in a binary system. This poster seeks to explain how that binary system would be possible and by using the analysis of a medley of pointings and deductive reasoning, attempts to predict how a theoretical binary system would appear, as observed by a radio telescope. Relation to Singular Pulsars Basically, if an observer were to find this theoretical binary system, initially it would appear as an ordinary pulsar. In an ideal observation the profile plot would look much like as in Figure 1, as would the time-phase, sub-band-phase and reduced χ2-DM plots (taking into account however that DM-χ2 and strength of signal will vary). However, two exceptions are required to be taken into account. First, the period of the pulsar would not only change, but also have a spin-up rate rather than a spin-down rate, due to the gained momentum as the pulsar approaches the singularity. Second, the DM would have to be adjusted slightly due to the warped signal from the gravitational waves. However, the initial observation of a binary pulsar-black hole system would appear much like that of a singular pulsar (Figure 2). Figure 1; an FFT plot of J1910-259. A black hole-pulsar binary system plot would be very similar to this FFT plot. How the System Works A Kerr vacuum is so massive that as it rotates it warps and makes waves in the fabric of space-time. A pulsar could stay in orbit using these waves, which are located in the ergosphere, an elliptical area surrounding the event horizon. There are a few ways to detect such a system. First of all, the timing of the pulses would speed up as the pulsar gains momentum and would therefore “feed” the pulsar. The period would also speed up as the pulsar moves closer to the event horizon drawn from the singularity. Another way to detect this is a normally timed eclipse of the pulsar; as it orbits the black hole, the black hole would periodically cover up its signal. Defined Assumptions There are four different types of black holes, or exact solutions to the Einstein field equation of general relativity. The most ideal candidate for a binary system with a pulsar is a Kerr metric or Kerr vacuum. A Kerr black hole is an uncharged rotating black hole, proposed in 1963 by Roy Kerr. Because the mass and gravitational pull of a black hole is much greater than that of its conceivable companion, the improbable pulsar would at some point it its existence be a millisecond pulsar. Even if it did not start as a millisecond pulsar, it would slowly speed up as the black hole draws it nearer to its singularity. Figure 2; a single pulse plot of J1910-259. Conclusion Ultimately, if such a binary system were to exist betwixt a black hole and a pulsar, its signal would not differ initially from that of a single pulsar. However, further observation would illuminate the prospective binary system and revolutionize astrophysics due to supporting or refuting Einstein’s Theory of General Relativity. The strength of the black hole ebbs as it strays from the singularity outwards toward the ergosphere, where the theoretical pulsar would exist. A. Rushton et al; A black hole’s gravitaional force bends space-time, warping the orbit of the pulsar that follows the gravitational waves it creates. Acknowledgements We thank the sky, the stars, and Mufasa above For teaching us things or locking us up The Scientists, the geniuses, and the men in white coats Till we go mad looking for pulsars in all our lost luck McLaughlin, Maura, and Francis Graham-Smith. "A Magnetopause in the Double-pulsar Binary System." A&G, Feb. 2005. Web. 20 May 2013 Wikipedia. Rushton, A., and R. Ferdman. "BLACK HOLES IN A VIOLENT UNIVERSE." BLACK HOLES IN A VIOLENT UNIVERSE. "Inside a Black Hole." Inside a Black Hole. Nrumiano).