The evolving radio jet from the neutron star X-ray binary 4U 1820−30
| Autor: | A. Segreto, Nathalie Degenaar, Aru Beri, J. van den Eijnden, J. C. A. Miller-Jones, Diego Altamirano, Thomas D. Russell, M. Del Santo, M. Diaz Trigo |
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| Přispěvatelé: | High Energy Astrophys. & Astropart. Phys (API, FNWI) |
| Rok vydání: | 2021 |
| Předmět: |
High Energy Astrophysical Phenomena (astro-ph.HE)
Physics Jet (fluid) Accretion (meteorology) Astrophysics::High Energy Astrophysical Phenomena X-ray binary FOS: Physical sciences Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Radio spectrum Luminosity Neutron star Space and Planetary Science Connection (algebraic framework) Astrophysics - High Energy Astrophysical Phenomena Jet quenching Astrophysics::Galaxy Astrophysics |
| Zdroj: | Monthly Notices of the Royal Astronomical Society: Letters, 508(1), L6-L11. Oxford University Press |
| ISSN: | 1745-3933 1745-3925 |
| Popis: | The persistently bright ultra-compact neutron star low-mass X-ray binary 4U 1820$-$30 displays a $\sim$170 d accretion cycle, evolving between phases of high and low X-ray modes, where the 3 -- 10 keV X-ray flux changes by a factor of up to $\approx 8$. The source is generally in a soft X-ray spectral state, but may transition to a harder state in the low X-ray mode. Here, we present new and archival radio observations of 4U 1820$-$30 during its high and low X-ray modes. For radio observations taken within a low mode, we observed a flat radio spectrum consistent with 4U 1820$-$30 launching a compact radio jet. However, during the high X-ray modes the compact jet was quenched and the radio spectrum was steep, consistent with optically-thin synchrotron emission. The jet emission appeared to transition at an X-ray luminosity of $L_{\rm X (3-10 keV)} \sim 3.5 \times 10^{37} (D/\rm{7.6 kpc})^{2}$ erg s$^{-1}$. We also find that the low-state radio spectrum appeared consistent regardless of X-ray hardness, implying a connection between jet quenching and mass accretion rate in 4U 1820$-$30, possibly related to the properties of the inner accretion disk or boundary layer. Comment: 6 pages, 2 Figures. Online supplementary information supplied in the appendix. Accepted for publication by MNRAS Letters |
| Databáze: | OpenAIRE |
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