X-Ray and Optical Polarization Aligned with the Radio Jet Ejecta in GX 339–4

G. Mastroserio; B. De Marco; M. C. Baglio; F. Carotenuto; S. Fabiani; T. D. Russell; F. Capitanio; Y. Cavecchi; S. Motta; D. M. Russell; M. Dovčiak; M. Del Santo; K. Alabarta; A. Ambrifi; S. Campana; P. Casella; S. Covino; G. Illiano; E. Kara; E. V. Lai; G. Lodato; A. Manca; I. Mariani; A. Marino; C. Miceli; P. Saikia; A. W. Shaw; J. Svoboda; F. M. Vincentelli; J. Wang

doi:10.3847/2041-8213/ad9913

X-Ray and Optical Polarization Aligned with the Radio Jet Ejecta in GX 339–4

G. Mastroserio, B. De Marco, M. C. Baglio, F. Carotenuto, S. Fabiani, T. D. Russell, F. Capitanio, Y. Cavecchi, S. Motta, D. M. Russell, M. Dovčiak, M. Del Santo, K. Alabarta, A. Ambrifi, S. Campana, P. Casella, S. Covino, G. Illiano, E. Kara, E. V. LaiG. Lodato, A. Manca, I. Mariani, A. Marino, C. Miceli, P. Saikia, A. W. Shaw, J. Svoboda, F. M. Vincentelli, J. Wang

Physics

Research output: Contribution to journal › Article › peer-review

Abstract

We present the first X-ray polarization measurements of GX 339-4. IXPE observed this source twice during its 2023-2024 outburst, once in the soft-intermediate state and again during a soft state. The observation taken during the intermediate state shows a significant (4σ) polarization degree P_X = 1.3% ± 0.3% and polarization angle θ_X = −74° ± 7° only in the 3-8 keV band. FORS2 at the Very Large Telescope observed the source simultaneously, detecting optical polarization in the B, V, R, and I bands (between ∼0.1% and ∼0.7%), all roughly aligned with the X-ray polarization. We also detect a discrete jet knot from radio observations with the Australia Telescope Compact Array taken later in time; this knot would have been ejected from the system around the same time as the hard-to-soft X-ray state transition, and a bright radio flare occurred ∼3 months earlier. The proper motion of the jet knot provides a direct measurement of the jet orientation angle on the plane of the sky at the time of the ejection. We find that both the X-ray and optical polarization angles are aligned with the direction of the ballistic jet.

Original language	English
Article number	L19
Journal	The Astrophysical Journal Letters
Volume	978
Issue number	2
DOIs	https://doi.org/10.3847/2041-8213/ad9913
State	Published - Jan 10 2025

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Mastroserio, G., Marco, B. D., Baglio, M. C., Carotenuto, F., Fabiani, S., Russell, T. D., Capitanio, F., Cavecchi, Y., Motta, S., Russell, D. M., Dovčiak, M., Santo, M. D., Alabarta, K., Ambrifi, A., Campana, S., Casella, P., Covino, S., Illiano, G., Kara, E., ... Wang, J. (2025). X-Ray and Optical Polarization Aligned with the Radio Jet Ejecta in GX 339–4. The Astrophysical Journal Letters, 978(2), Article L19. https://doi.org/10.3847/2041-8213/ad9913

Mastroserio, G, Marco, BD, Baglio, MC, Carotenuto, F, Fabiani, S, Russell, TD, Capitanio, F, Cavecchi, Y, Motta, S, Russell, DM, Dovčiak, M, Santo, MD, Alabarta, K, Ambrifi, A, Campana, S, Casella, P, Covino, S, Illiano, G, Kara, E, Lai, EV, Lodato, G, Manca, A, Mariani, I, Marino, A, Miceli, C, Saikia, P, Shaw, AW, Svoboda, J, Vincentelli, FM & Wang, J 2025, 'X-Ray and Optical Polarization Aligned with the Radio Jet Ejecta in GX 339–4', The Astrophysical Journal Letters, vol. 978, no. 2, L19. https://doi.org/10.3847/2041-8213/ad9913

@article{f9c61765f3ec4dc6ba2a29bfdba15b9d,

title = "X-Ray and Optical Polarization Aligned with the Radio Jet Ejecta in GX 339–4",

abstract = "We present the first X-ray polarization measurements of GX 339-4. IXPE observed this source twice during its 2023-2024 outburst, once in the soft-intermediate state and again during a soft state. The observation taken during the intermediate state shows a significant (4σ) polarization degree PX = 1.3% ± 0.3% and polarization angle θX = −74° ± 7° only in the 3-8 keV band. FORS2 at the Very Large Telescope observed the source simultaneously, detecting optical polarization in the B, V, R, and I bands (between ∼0.1% and ∼0.7%), all roughly aligned with the X-ray polarization. We also detect a discrete jet knot from radio observations with the Australia Telescope Compact Array taken later in time; this knot would have been ejected from the system around the same time as the hard-to-soft X-ray state transition, and a bright radio flare occurred ∼3 months earlier. The proper motion of the jet knot provides a direct measurement of the jet orientation angle on the plane of the sky at the time of the ejection. We find that both the X-ray and optical polarization angles are aligned with the direction of the ballistic jet.",

author = "G. Mastroserio and Marco, {B. De} and Baglio, {M. C.} and F. Carotenuto and S. Fabiani and Russell, {T. D.} and F. Capitanio and Y. Cavecchi and S. Motta and Russell, {D. M.} and M. Dov{\v c}iak and Santo, {M. Del} and K. Alabarta and A. Ambrifi and S. Campana and P. Casella and S. Covino and G. Illiano and E. Kara and Lai, {E. V.} and G. Lodato and A. Manca and I. Mariani and A. Marino and C. Miceli and P. Saikia and Shaw, {A. W.} and J. Svoboda and Vincentelli, {F. M.} and J. Wang",

note = "Publisher Copyright: {\textcopyright} 2025. The Author(s). Published by the American Astronomical Society.",

year = "2025",

month = jan,

day = "10",

doi = "10.3847/2041-8213/ad9913",

language = "English",

volume = "978",

journal = "The Astrophysical Journal Letters",

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TY - JOUR

T1 - X-Ray and Optical Polarization Aligned with the Radio Jet Ejecta in GX 339–4

AU - Mastroserio, G.

AU - Marco, B. De

AU - Baglio, M. C.

AU - Carotenuto, F.

AU - Fabiani, S.

AU - Russell, T. D.

AU - Capitanio, F.

AU - Cavecchi, Y.

AU - Motta, S.

AU - Russell, D. M.

AU - Dovčiak, M.

AU - Santo, M. Del

AU - Alabarta, K.

AU - Ambrifi, A.

AU - Campana, S.

AU - Casella, P.

AU - Covino, S.

AU - Illiano, G.

AU - Kara, E.

AU - Lai, E. V.

AU - Lodato, G.

AU - Manca, A.

AU - Mariani, I.

AU - Marino, A.

AU - Miceli, C.

AU - Saikia, P.

AU - Shaw, A. W.

AU - Svoboda, J.

AU - Vincentelli, F. M.

AU - Wang, J.

PY - 2025/1/10

Y1 - 2025/1/10

N2 - We present the first X-ray polarization measurements of GX 339-4. IXPE observed this source twice during its 2023-2024 outburst, once in the soft-intermediate state and again during a soft state. The observation taken during the intermediate state shows a significant (4σ) polarization degree PX = 1.3% ± 0.3% and polarization angle θX = −74° ± 7° only in the 3-8 keV band. FORS2 at the Very Large Telescope observed the source simultaneously, detecting optical polarization in the B, V, R, and I bands (between ∼0.1% and ∼0.7%), all roughly aligned with the X-ray polarization. We also detect a discrete jet knot from radio observations with the Australia Telescope Compact Array taken later in time; this knot would have been ejected from the system around the same time as the hard-to-soft X-ray state transition, and a bright radio flare occurred ∼3 months earlier. The proper motion of the jet knot provides a direct measurement of the jet orientation angle on the plane of the sky at the time of the ejection. We find that both the X-ray and optical polarization angles are aligned with the direction of the ballistic jet.

AB - We present the first X-ray polarization measurements of GX 339-4. IXPE observed this source twice during its 2023-2024 outburst, once in the soft-intermediate state and again during a soft state. The observation taken during the intermediate state shows a significant (4σ) polarization degree PX = 1.3% ± 0.3% and polarization angle θX = −74° ± 7° only in the 3-8 keV band. FORS2 at the Very Large Telescope observed the source simultaneously, detecting optical polarization in the B, V, R, and I bands (between ∼0.1% and ∼0.7%), all roughly aligned with the X-ray polarization. We also detect a discrete jet knot from radio observations with the Australia Telescope Compact Array taken later in time; this knot would have been ejected from the system around the same time as the hard-to-soft X-ray state transition, and a bright radio flare occurred ∼3 months earlier. The proper motion of the jet knot provides a direct measurement of the jet orientation angle on the plane of the sky at the time of the ejection. We find that both the X-ray and optical polarization angles are aligned with the direction of the ballistic jet.

UR - https://doi.org/10.3847/2041-8213/ad9913

U2 - 10.3847/2041-8213/ad9913

DO - 10.3847/2041-8213/ad9913

M3 - Article

VL - 978

JO - The Astrophysical Journal Letters

JF - The Astrophysical Journal Letters

IS - 2

M1 - L19

ER -

X-Ray and Optical Polarization Aligned with the Radio Jet Ejecta in GX 339–4

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