2020/10/31 by Ashutosh Tripathi, Askar B. Abdikamalov, Dimitry Ayzenberg +4
Physics and Astronomy · #Accretion (finance) #Adaptive optics and wavefront sensing #Astrophysical Phenomena and Observations #Astrophysics #Binary number #Black hole (networking) #Emissivity #Kerr metric #Optics #Physics #Pulsars and Gravitational Waves Research #Reflection (computer programming) #Rotating black hole #Thermal #astro-ph.HE #gr-qc
paper · pdf · doi:10.3847/1538-4357/abccbd
published as Astrophys.J. 907: 31 (2021) · 10 pages, 5 figures. v2: refereed version
openalex created_date 2020/10/29 · openalex publication_date 2021/01/01 · arxiv created 2021/01/22 · arxiv updated 2021/01/26 · openalex updated_date 2026/08/05
Abstract We analyze simultaneous observations with NuSTAR and Swift of the black hole binary GX 339–4 in which we clearly detect both a strong thermal component and prominent relativistic reflection features. We employ nkbb and relxill _ nk , which are the state of the art of, respectively, the thermal and reflection models to test the Kerr black hole hypothesis. We obtain unprecedented precise measurements of the Johannsen deformation parameter α 13 : <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>α</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>13</mml:mn> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mo>−</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>0.012</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.039</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.011</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> (lamppost coronal geometry) and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>α</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>13</mml:mn> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mo>−</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>0.010</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.018</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.024</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> (broken power-law emissivity profile) at a 90% confidence level, where the Kerr metric corresponds to α 13 = 0. We investigate the systematic uncertainties by fitting the data with different models.