TY - JOUR

T1 - Irradiated but not eclipsed, the case of PSR J0610-2100

AU - van der Wateren, E.

AU - Bassa, C. G.

AU - Clark, C. J.

AU - Breton, R. P.

AU - Cognard, I

AU - Guillemot, L.

AU - Janssen, G. H.

AU - Lyne, A. G.

AU - Stappers, B. W.

AU - Theureau, G.

N1 - Funding Information: Acknowledgements. We thank the anonymous referee for the careful reading of and useful comments on the manuscript. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 386.D-0207. This research was made possible by support from the Dutch National Science Agenda, NWA Startim-puls – 400.17.608. C.J.C. and R.P.B acknowledge support from the ERC under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 715051; Spiders). This work was supported by the Max-Planck-Gesellschaft (MPG). The Nançay Radio Observatory is operated by the Paris Observatory, associated with the French Centre National de la Recherche Scien-tifique (CNRS). We acknowledge financial support from ‘Programme National de Cosmologie et Galaxies’ (PNCG) of CNRS/INSU, France. The Westerbork Synthesis Radio Telescope is operated by the Netherlands Institute for Radio Astronomy (ASTRON) with support from The Netherlands Foundation for Scientific Research (NWO). The Parkes radio telescope is part of the Australia Telescope National Facility (grid.421683.a) which is funded by the Australian Government for operation as a National Facility managed by CSIRO. We acknowledge the Wiradjuri people as the traditional owners of the Observatory site.

PY - 2022/5/3

Y1 - 2022/5/3

N2 - We report on radio timing observations of the black widow binary pulsar J0610 2100 and optical observations of its binary companion. The radio timing observations extend the timing baseline to 16 yr and reveal a marginal detection of the orbital period derivative, but they show no significant evidence of orbital variations such as those seen in other black widow pulsars. Furthermore, no eclipses are seen in the observations at observing frequencies ranging from 310 to 2700 MHz. The optical VRI light curves were modulated with the orbital period, reaching maximum brightness of V = 26.8, R = 25.4, and I = 23.8 at superior conjunction of the companion, confirming irradiation of the companion by the pulsar. Modelling the light curves indicates that the companion is likely not filling its Roche lobe, while having a moderate inclination (i > 54 degrees). We find an unusually low temperature and a low irradiation for the irradiated hemisphere of the companion. We investigate the absence of radio eclipses in PSR J0610 2100 and in other black widow systems in relation to their binary, pulsar, and companion properties. We also discuss the suitability of PSR J0610 2100 for pulsar timing array observations aimed at detecting nano-Hertz gravitational waves.

AB - We report on radio timing observations of the black widow binary pulsar J0610 2100 and optical observations of its binary companion. The radio timing observations extend the timing baseline to 16 yr and reveal a marginal detection of the orbital period derivative, but they show no significant evidence of orbital variations such as those seen in other black widow pulsars. Furthermore, no eclipses are seen in the observations at observing frequencies ranging from 310 to 2700 MHz. The optical VRI light curves were modulated with the orbital period, reaching maximum brightness of V = 26.8, R = 25.4, and I = 23.8 at superior conjunction of the companion, confirming irradiation of the companion by the pulsar. Modelling the light curves indicates that the companion is likely not filling its Roche lobe, while having a moderate inclination (i > 54 degrees). We find an unusually low temperature and a low irradiation for the irradiated hemisphere of the companion. We investigate the absence of radio eclipses in PSR J0610 2100 and in other black widow systems in relation to their binary, pulsar, and companion properties. We also discuss the suitability of PSR J0610 2100 for pulsar timing array observations aimed at detecting nano-Hertz gravitational waves.

KW - binaries: close

KW - pulsars: individual: PSR J0610 2100

KW - stars: neutron

KW - Stars: neutron

KW - Pulsars: individual: PSR J0610-2100

KW - Binaries: close

UR - http://www.scopus.com/inward/record.url?scp=85129785650&partnerID=8YFLogxK

U2 - 10.1051/0004-6361/202142741

DO - 10.1051/0004-6361/202142741

M3 - Article

VL - 661

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

M1 - A57

ER -