Anti-glitches in the Ultraluminous Accreting Pulsar NGC 300 ULX-1 Observed with NICER. (arXiv:1811.09218v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Ray_P/0/1/0/all/0/1">Paul S. Ray</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guillot_S/0/1/0/all/0/1">Sebastien Guillot</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ho_W/0/1/0/all/0/1">Wynn C.G. Ho</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kerr_M/0/1/0/all/0/1">Matthew Kerr</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Enoto_T/0/1/0/all/0/1">Teruaki Enoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gendreau_K/0/1/0/all/0/1">Keith C. Gendreau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Arzoumanian_Z/0/1/0/all/0/1">Zaven Arzoumanian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Altamirano_D/0/1/0/all/0/1">Diego Altamirano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bogdanov_S/0/1/0/all/0/1">Slavko Bogdanov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Campion_R/0/1/0/all/0/1">Robert Campion</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chakrabarty_D/0/1/0/all/0/1">Deepto Chakrabarty</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jaisawal_G/0/1/0/all/0/1">Gaurava K. Jaisawal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kozon_R/0/1/0/all/0/1">Robert Kozon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Malacaria_C/0/1/0/all/0/1">Christian Malacaria</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Strohmayer_T/0/1/0/all/0/1">Tod E. Strohmayer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wolff_M/0/1/0/all/0/1">Michael T. Wolff</a>
We report the discovery of three spin-down glitches (or `anti-glitches’) in
the ultraluminous accreting X-ray pulsar NGC 300 ULX-1 in timing observations
made with the Neutron Star Interior Composition Explorer (NICER). We find
evidence for three sudden spin-down events of magnitudes $Deltanu = -23,
-30,$ and $-43 ,mu$Hz (fractional amplitudes $Deltanu/nu = -4.4, -5.5,$
and $-7.7 times 10^{-4}$). These are larger in magnitude (and opposite in
sign) than any radio pulsar glitch. This may be caused by the prolonged rapid
spin-up of the pulsar causing a sudden transfer of angular momentum between the
superfluid and non-superfliud components of the star. We find no evidence for
profile or spectral changes at the epochs of the glitches, supporting the
conclusion that these are due to the same process as in normal pulsar glitches,
but in reverse.
We report the discovery of three spin-down glitches (or `anti-glitches’) in
the ultraluminous accreting X-ray pulsar NGC 300 ULX-1 in timing observations
made with the Neutron Star Interior Composition Explorer (NICER). We find
evidence for three sudden spin-down events of magnitudes $Deltanu = -23,
-30,$ and $-43 ,mu$Hz (fractional amplitudes $Deltanu/nu = -4.4, -5.5,$
and $-7.7 times 10^{-4}$). These are larger in magnitude (and opposite in
sign) than any radio pulsar glitch. This may be caused by the prolonged rapid
spin-up of the pulsar causing a sudden transfer of angular momentum between the
superfluid and non-superfliud components of the star. We find no evidence for
profile or spectral changes at the epochs of the glitches, supporting the
conclusion that these are due to the same process as in normal pulsar glitches,
but in reverse.
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