A Novel Method of Modeling Extended Emission of Compact Jets: Application to Swift J1727.8−1613
Flat radio spectra of compact jets launched by both supermassive and stellar-mass black holes (BHs) are explained by an interplay of self-absorbed synchrotron emission up to some distance along the jet and optically thin synchrotron at larger distances. Their spatial structure is usually studied usi...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal Letters |
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| Online Access: | https://doi.org/10.3847/2041-8213/ade13b |
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| author | Andrzej A. Zdziarski Callan M. Wood Francesco Carotenuto |
| author_facet | Andrzej A. Zdziarski Callan M. Wood Francesco Carotenuto |
| author_sort | Andrzej A. Zdziarski |
| collection | DOAJ |
| description | Flat radio spectra of compact jets launched by both supermassive and stellar-mass black holes (BHs) are explained by an interplay of self-absorbed synchrotron emission up to some distance along the jet and optically thin synchrotron at larger distances. Their spatial structure is usually studied using core shifts, in which the position of the peak (core) of the emission depends on the frequency. Here, we propose a novel and powerful method to fit the spatial dependence of the flux density at a given frequency of the jet and counterjet (when observed), using the theoretical spatial dependencies provided as simple analytical formulae. We apply our method to the spatial structure of the jets in the luminous hard spectral state of the BH X-ray binary Swift J1727.8−1613. It was the most resolved continuous jet from an X-ray binary ever observed. We find that the observed approaching jet is significantly intrinsically stronger than the receding one, which we attribute to an increase in the emission of both jets with time (observationally confirmed), together with the light travel effect, causing the receding jet to be observed at an earlier epoch than the approaching one. The jets are relatively slow, with a velocity of ∼(0.3–0.4) c . Our findings imply that the magnetic field strength increased with time. Additionally, the magnetic flux is significantly lower than in jets launched by “magnetically arrested disks.” Our method is general, and we propose that it be applied to jets launched by both stellar-mass and supermassive BHs. |
| format | Article |
| id | doaj-art-d61adcb0e87f44fa8d7b0a65c57155ce |
| institution | Kabale University |
| issn | 2041-8205 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj-art-d61adcb0e87f44fa8d7b0a65c57155ce2025-08-20T03:31:27ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019862L3510.3847/2041-8213/ade13bA Novel Method of Modeling Extended Emission of Compact Jets: Application to Swift J1727.8−1613Andrzej A. Zdziarski0https://orcid.org/0000-0002-0333-2452Callan M. Wood1https://orcid.org/0000-0002-2758-0864Francesco Carotenuto2https://orcid.org/0000-0002-0426-3276Nicolaus Copernicus Astronomical Center , Polish Academy of Sciences, Bartycka 18, PL-00-716 Warszawa, Poland ; aaz@camk.edu.plInternational Centre for Radio Astronomy Research, Curtin University , GPO Box U1987, Perth, WA 6845, AustraliaINAF—Osservatorio Astronomico di Roma , Via Frascati 33, I-00078, Monteporzio Catone, ItalyFlat radio spectra of compact jets launched by both supermassive and stellar-mass black holes (BHs) are explained by an interplay of self-absorbed synchrotron emission up to some distance along the jet and optically thin synchrotron at larger distances. Their spatial structure is usually studied using core shifts, in which the position of the peak (core) of the emission depends on the frequency. Here, we propose a novel and powerful method to fit the spatial dependence of the flux density at a given frequency of the jet and counterjet (when observed), using the theoretical spatial dependencies provided as simple analytical formulae. We apply our method to the spatial structure of the jets in the luminous hard spectral state of the BH X-ray binary Swift J1727.8−1613. It was the most resolved continuous jet from an X-ray binary ever observed. We find that the observed approaching jet is significantly intrinsically stronger than the receding one, which we attribute to an increase in the emission of both jets with time (observationally confirmed), together with the light travel effect, causing the receding jet to be observed at an earlier epoch than the approaching one. The jets are relatively slow, with a velocity of ∼(0.3–0.4) c . Our findings imply that the magnetic field strength increased with time. Additionally, the magnetic flux is significantly lower than in jets launched by “magnetically arrested disks.” Our method is general, and we propose that it be applied to jets launched by both stellar-mass and supermassive BHs.https://doi.org/10.3847/2041-8213/ade13bLow-mass x-ray binary starsRadio jetsRelativistic jetsX-ray transient sources |
| spellingShingle | Andrzej A. Zdziarski Callan M. Wood Francesco Carotenuto A Novel Method of Modeling Extended Emission of Compact Jets: Application to Swift J1727.8−1613 The Astrophysical Journal Letters Low-mass x-ray binary stars Radio jets Relativistic jets X-ray transient sources |
| title | A Novel Method of Modeling Extended Emission of Compact Jets: Application to Swift J1727.8−1613 |
| title_full | A Novel Method of Modeling Extended Emission of Compact Jets: Application to Swift J1727.8−1613 |
| title_fullStr | A Novel Method of Modeling Extended Emission of Compact Jets: Application to Swift J1727.8−1613 |
| title_full_unstemmed | A Novel Method of Modeling Extended Emission of Compact Jets: Application to Swift J1727.8−1613 |
| title_short | A Novel Method of Modeling Extended Emission of Compact Jets: Application to Swift J1727.8−1613 |
| title_sort | novel method of modeling extended emission of compact jets application to swift j1727 8 1613 |
| topic | Low-mass x-ray binary stars Radio jets Relativistic jets X-ray transient sources |
| url | https://doi.org/10.3847/2041-8213/ade13b |
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