October 3, 2015

Gamma ray pulsars; a test for separate sources? Or internal physical phase change? MSP in globular clusters?

Approximately 5% of pulsars are gamma ray pulsars? Why? Even if electron degeneracy (effectively filling phase space?) suggests a surface, wouldn’t a given mass density imply nuclear processes for interior of compact object? So why would a gamma ray subset differ from other pulsars? The assumption is that there is only one source for gamma rays emission. But could the companion for example be a red dwarf if gamma ray emission were associated with a fission star with a solid core?

Might one indirectly ascertain an edge on binary, assuming a separate gamma ray source, with eclipsing of pulsar by separate gamma ray source? That is, might such gamma ray source interfere with the radio pulsar signal, for such edge on view; resulting in a periodic noisy radio signal distortion? Then might such data base examination, and accumulating larger set, suggest two separate sources for gamma ray and radio pulsar respective signals?

Might LS1 +61° 303 gamma ray binary, with gamma flux modulation varying with orbital period of 26.5 days, possibly be a converse consideration, wherein a gamma ray source were somewhat affected; more affected if such binary were a pulsar? But are only ~1/1000 gamma ray binaries sources also pulsarsIf the same source, might gamma rays suggest a possible physical phase change for interior of a compact object? That is, might one have in part a solid – like interior portion, in addition to a fluid component? But could one have any solid-like description for nucleons (quanta)? For example, perhaps a pressure related increased viscosity (?) for nucleon (neutron fluid with protons) fluid, sufficient for solid-like rapidly rotating central region? Or higher mass fermion generations? Hence enhancement of magnetic field, and perhaps physical phase change (from increased pressure?), resulting in additional nuclear processes and associated gamma ray production? Thus might one have physical phase change just from increased pressure, such as demonstrated with diamond anvil? Or alternatively perhaps just central mass density increase leading to additional nuclear processes? So rendering the equation of state in different ways?

Might equation of state (mass density and pressure) be irrelevant? That is, for iron core with 1% uranium, would this be sufficient to account for observed infrared signature of a red dwarf?

Perhaps solid-like or gel-like physical phase transition, such as change in order parameter, liquid to gel-like; or such as changing precession of nucleons, with spin and magnetic moment, in magnetic field? But the latter is not a physical phase change? Or physical phase change as symmetry breaking? Would any physical phase change be of sufficient energetics; leading to additional nuclear processes associated with gamma ray production; or is energetics not a consideration?

Might glitches be related to vortices pinning and unpinning, but to an interior solid-like surface or gel, rapidly rotating as a unit; thus obviating the necessity of an external solid crust? Is it more plausible that all (most?) of magnetic field strength of pulsar comes from such rapidly rotating solid-like (gel?) core, rather than from precursor collapsing massive star?

Would such solid-like core ensure a more constrained milieu for gamma ray production? Analogous to mathematical existence proof? That is, not describing a specific physical phase change, or nuclear interaction, associated with gamma rays; rather describing a general milieu in which production of gamma rays would seem to ensue.

Like for black hole, might rapid rotation of pulsar, and just associated electric and magnetic fields, be insufficient for copious gamma rays generation? Rather additional interior nuclear processes (at higher mass density, or just at increased pressure?); the latter associated with a physical phase change, required for significant gamma rays production?

Does a gamma ray pulsar have an infrared sigmature? If so, might interior processes not be that different from a red dwarf? In fact, might a gamma ray pulsar be a red dwarf?

Is magnetic field strength greater for gamma ray pulsar than for just a pulsar? Further suggesting perhaps changes in conduction and/or circulation for a nucleon fluid with conductive impurities (such as plasma wakefield accelerator, with cycling of charges giving a wave for protons to acellerate on?); or physical phase change, giving more central rapid rotation, as a unit i.e. solid-like?

Might one experimentally ascertain what might enhance a magnetic field? For example would a solid-like rapid rotating core, of different volumes, enhance such field; as opposed to a plasma nucleon fluid (i.e. degenerate neutron fluid) with varying impurities’ concentration? Hence indirect hints as to general nature of interior? Or is collapsing progenitor star the only basis for magnetic field strength of a neutron star?

Need such high mass density object suggest only a neutron star? Is a crust essential to alternative models of pulsars, and of any star (white dwarf?) in general? For example, might one render a pulsar as a dark star with increasing gravitational potential, and associated higher mass density, and with very intense magnetic field? Might there be very little difference (other than mass) between gamma rays pulsar (with no crust) and dark star with no horizon, or red dwarf?

Also a number of MSP millisecond pulsars have been detected in globular clusters; how is this possible, if from supernova asymmetrical explosions long ago, since globular clusters are old, and no massive new star formation? That is, even if MSP (binary system?) were older, it should have been ejected; which is consistent with few compact objects in such globular clusters. However need pulsars (and in particular, MSP) all result just from supernova explosions, and from mass inflow from a binary, as considered for MSP in globular clusters?

More specifically, might magnetic pole of precursor star wander, and eventually have a small incidence angle i.e. near to rotation axis; thus seemingly resulting in a shorter period MSP, with no change in star’s rotation? However even though angular velocity is less; still unchanging frequency period? Thus still not consistent with MSP; nor obviating necessity for supernova or a binary companion off loading mass? So still necessity of interior of neutron star as source of such gamma ray pulsar MSP?

What is infrared signature of such globular cluster MSP? Might it have infrared, as well as gamma ray, signature; both suggestive of interior processes that differ from our fusion star Sun? Might such gamma ray MSP be a red dwarf, or interior processes similar to a red dwarf?

Isabelle A. Grenier, Alice K. Harding, arXiv:1509.08823v1 astro-ph.HE 29 Sep 2015, Gamma rays pulsars: a gold mine.

Guillaume Dubus,  arXiv:1307.7083v2 astro-ph HE Sept 5 2013. Gamma rays binaries and related systems.

A. Akmal,  V. R. Pandharipande,  D.G. Ravenhall,  The equation of state of nuclear matter and neutron star structure, arXiv:nucl-th/9804027v1 April 13, 1998.

Gibley E., Nature, vol 526, p. 173, Oct 8 2015. plasma wakefield accelerators.


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