ausblenden:
Schlagwörter:
Astrophysics, High Energy Astrophysical Phenomena, astro-ph.HE
Zusammenfassung:
Using MeerKAT, we have discovered three new millisecond pulsars (MSPs) in the
bulge globular cluster M62: M62H, M62I, and M62J. All three are in binary
systems, which means all ten known pulsars in the cluster are in binaries. M62H
has a planetary-mass companion with a median mass $M_{\rm c,med} \sim 3$
M$_{\rm J}$ and a mean density of $\rho \sim 11$ g cm$^{-3}$. M62I has an
orbital period of 0.51 days and a $M_{\rm c,med} \sim 0.15$ M$_{\odot}$.
Neither of these low-mass systems exhibit eclipses. M62J has only been detected
in the two UHF band (816 MHz) observations with a flux density $S_{816} = 0.08$
mJy. The non-detection in the L-band (1284 MHz) indicates it has a relatively
steep spectrum ($\beta < -3.1$). We also present 23-yr-long timing solutions
obtained using data from the Parkes "Murriyang", Effelsberg and MeerKAT
telescopes for the six previously known pulsars. For all these pulsars, we
measured the second spin-period derivatives and the rate of change of orbital
period caused by the gravitational field of the cluster, and their proper
motions. From these measurements, we conclude that the pulsars' maximum
accelerations are consistent with the maximum cluster acceleration assuming a
core-collapsed mass distribution. Studies of the eclipses of the redback M62B
and the black widow M62E at four and two different frequency bands,
respectively, reveal a frequency dependence with longer and asymmetric eclipses
at lower frequencies. The presence of only binary MSPs in this cluster
challenges models which suggest that the MSP population of core-collapsed
clusters should be dominated by isolated MSPs.
