Discovery of a variable energy-dependent X-ray polarization in the accreting neutron star GX 5-1

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F24%3A00585714" target="_blank" >RIV/67985815:_____/24:00585714 - isvavai.cz</a>

Result on the web

<a href="https://hdl.handle.net/11104/0353908" target="_blank" >https://hdl.handle.net/11104/0353908</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202347374" target="_blank" >10.1051/0004-6361/202347374</a>

Result language

angličtina

Original language name

Discovery of a variable energy-dependent X-ray polarization in the accreting neutron star GX 5-1

Original language description

We report on the coordinated observations of the neutron star low-mass X-ray binary (NS-LMXB) GX 5-1 in X-rays (IXPE, NICER, NuSTAR, and INTEGRAL), optical (REM and LCO), near-infrared (REM), mid-infrared (VLT VISIR), and radio (ATCA). This Z-source was observed by IXPE twice in March-April 2023 (Obs. 1 and 2). In the radio band the source was detected, but only upper limits to the linear polarization were obtained at a 3 sigma level of 6.1% at 5.5 GHz and 5.9% at 9 GHz in Obs. 1 and 12.5% at 5.5 GHz and 20% at 9 GHz in Obs. 2. The mid-IR, near-IR, and optical observations suggest the presence of a compact jet that peaks in the mid- or far-IR. The X-ray polarization degree was found to be 3.7%+/- 0.4% (at 90% confidence level) during Obs. 1 when the source was in the horizontal branch of the Z-track and 1.8%+/- 0.4% during Obs. 2 when the source was in the normal-flaring branch. These results confirm the variation in polarization degree as a function of the position of the source in the color-color diagram, as for previously observed Z-track sources (Cyg X-2 and XTE 1701-462). Evidence of a variation in the polarization angle of similar to 20(degrees) with energy is found in both observations, likely related to the different, nonorthogonal polarization angles of the disk and Comptonization components, which peak at different energies.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

<a href="/en/project/GX21-06825X" target="_blank" >GX21-06825X: Accreting Black Holes in the new era of X-ray polarimetry missions</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Volume of the periodical

684

Issue of the periodical within the volume

April

Country of publishing house

FR - FRANCE

Number of pages

15

Pages from-to

A137

UT code for WoS article

001203444100003

EID of the result in the Scopus database

2-s2.0-85191066187