Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2609.34102

Discovery of a 62-min long-period transient with near-orthogonal rotator geometry

Scott D. Hyman·Natasha Hurley-Walker·Dale A. Frail·Emil Polisensky·W. M. Cotton
View original source ↗Read source document ↗Export metadata ↓

Abstract

We report the serendipitous discovery of J155543.7$-$563102 (hereafter LPT J1555$-$5631) with a period of 62.2 min in MeerKAT and ASKAP survey data. The source emitted bright (10-30 mJy), steep-spectrum ($α\sim-1.5$), highly polarized radio pulses during a 15-hr active window in May 2022, with no other quiescent or pulsed emission detected before or after over $\sim5$ years. The mean light curve exhibits two alternating pulses per cycle. A main pulse (MP) and an interpulse (IP) separated by $Δϕ=165.4^\circ$ with similar amplitudes, but different polarization properties: the wider MP (3.9\%) is partially linearly and circularly polarized and shows a constant polarization position angle, while the narrow IP (1.1\%) is $\sim$100\% circularly polarized. We classify LPT J1555$-$5631 as a near-orthogonal rotator, for which emission from both magnetic poles is visible during one rotation and the magnetic and rotation axes are almost perpendicular. The 14.6$^\circ$ deviation from an antipodal separation and the nearly constant polarization position angle suggest that the emission does not arise from the standard dipolar polar-cap geometry of ordinary pulsars, but instead originates within a broader, more complex magnetosphere. The observed properties of LPT J1555$-$5631 can be accommodated by extended emission regions, and favor coherent emission mechanisms such as the electron cyclotron maser instability, although they do not uniquely determine the progenitor or emission physics. If these inferences apply more broadly to the LPT population, they could account for why their beam widths are decoupled from rotation periods, the prevalence of flat polarization position angles, and may favor an elevated incidence of orthogonal rotators.

Explore related subjects

astro-ph.HE

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Scott D. Hyman, Natasha Hurley-Walker, Dale A. Frail, Emil Polisensky, W. M. Cotton. 2026-09-28. Discovery of a 62-min long-period transient with near-orthogonal rotator geometry. https://arxiv.org/abs/2609.34102

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Nuclear Physics of Binary Neutron Star Mergers

Binary neutron star mergers provide a unique laboratory for studying matter under conditions that cannot be reproduced in terrestrial experiments. They probe dense matter at supranuclear density, finite temperature, rapid rotation, strong gravity, and extreme neutron excess, while producing observable signals in gravitational waves, electromagnetic radiation, and, in principle, neutrinos. This review focuses on the nuclear physics of binary neutron star mergers. We discuss the dense-matter equation of state (EoS), the inspiral and merger dynamics, the structure and lifetime of the post-merger remnant, transport and dissipative processes, weak interactions and neutrino transport, and the production of heavy elements through $r$-process nucleosynthesis. Particular emphasis is placed on the connection between microscopic physics and multimessenger observables, including tidal deformability, post-merger gravitational-wave spectra, kilonova light curves, short gamma-ray bursts, and afterglows. We also review how observations of events such as GW170817, together with neutron star mass and radius measurements, laboratory nuclear experiments, and theoretical many-body calculations, constrain the EoS and the composition of dense matter. The goal is to summarize the current understanding of how nuclear physics controls the dynamics and observable signatures of binary neutron star mergers, and to identify the open questions that future multimessenger observations and improved nuclear theory will address.

astro-ph.HE↗
arXiv2026

Hunting for Compact Object Binaries from eRASS1 Optical Counterparts through ZTF Time-domain Photometry and Multi-wavelength Surveys

Capitalizing on the eRASS1 optical counterpart catalog, we conduct a systematic census of compact object binary (COB) candidates, with a primary focus on X-ray binaries (XRBs), by integrating ZTF time-domain photometry with multi-wavelength observations. This framework establishes two complementary pipelines, yielding two distinct source samples. The first sample consists of 151 periodically variable sources, from which a highly refined subset of 43 high-priority COB candidates is identified. The second sample comprises 1958 distance-constrained sources selected based on elevated X-ray luminosities or high $\log(F_{\mathrm{X}}/F_{\mathrm{opt}})$. Crucially, cross-matching both samples with radio catalogs reveals seven radio-emitting sources, highlighting four promising XRB candidates. Our results underscore that coupling eROSITA with wide-field time-domain photometric and multi-wavelength surveys offers a highly efficient strategy for uncovering the hidden population of COBs.

astro-ph.HE↗
arXiv2026

Fermi-eROSITA cross-correlations suggest annihilation lines of a $\sim70$ GeV WIMP

Galaxy clusters, with their deep potential wells, provide some of the strongest constraints on the velocity-dependent ($p$-wave) annihilation of weakly interacting massive particle (WIMP) dark matter. Even weaker signals can be extracted from sufficiently many aggregated clusters, by cross-correlating $γ$-rays with large-scale structure tracers. Cross-correlating 16.3 years of Fermi-LAT data with the eROSITA map of the western Galactic hemisphere, a blind composite matched-filter scan of the X-ray-correlated spectrum for the $χχ\toγγ$, $γZ$, and $γh$ annihilation-line triad of a single WIMP $χ$ finds $\overline{m}_χc^2\simeq71.9$ and $67.5$ GeV triads, each with a local $Z$-score $\sim3$ corresponding to a (trial-corrected) global $\sim2σ$. The $\sim72$ GeV candidate coincides with the mass implied by interpreting the recently reported $\sim43.2$ GeV $γ$-ray line in three nearby clusters as its $γZ$ channel. At this externally fixed mass, the triad reaches $\sim3σ$ alone, and combines with the cluster line to $3.9$-$5.1σ$ (depending on the significance of the latter). The inferred intrinsic channel cross sections are a few $10^{-19}$ cm$^3$ s$^{-1}$ for WIMPs tracing the X-ray-emitting gas. Future tests of this interpretation are outlined.

astro-ph.HE↗