论文标题
带有黑洞观测的Kerr-Sen度量测验
Test of Kerr-Sen metric with black hole observations
论文作者
论文摘要
Kerr-Sen黑洞是由异性弦理论引起的旋转带电的黑洞溶液。在4二维有效理论中，骨器场是：a $ u（1）$ gauge boson，一种kalb-ramond 3形式，相当于4二维中的伪尺度轴，dilaton和graviton。该理论中的耦合常数为$α^{\ prime} $（反向字符串张力）和$κ$（4二维中的planck质量），以及$ u（1）$ field的费用和Axion-Photon耦合与这两个相关。森发现了黑洞溶液（Kerr-Sen黑洞），这些磁场是黑洞的外发。在本文中，我们研究了从观测结果确定SEN解决方案的可能性。可以测试Kerr-Sen黑洞的观测值是：（a）测定光子阴影的形状，以及（b）由于轴发头发而导致光子偏振的旋转。与圆形的偏差给出了黑洞的$ u（1）$电荷，并根据光子耦合而识别该电荷的识别，从而在已经确定的黑洞参数方面可以预测频率独立的“法拉第旋转”。与轴心头发的Kerr-Newman黑洞的类似测量值在图像的形状与“法拉第旋转”的量之间没有相关性。这种相关性可以是对SEN度量的独特测试。在M87*阴影EHT的最新观察结果中，与圆形的偏差为10％。如果将该观察结果完善至1％的精度，则可以对Kerr-Sen黑洞的电荷和“法拉第旋转”的明确预测。有趣的是，对“法拉第旋转”的观察结果表明，该效果与指向轴突发式解释的频率无关。
The Kerr-Sen black hole is a rotating charged black hole solution arising from heterotic string theory. In 4-dimensions effective theory the bosonic fields are: a $U(1)$ gauge boson, a Kalb-Ramond 3-form which is equivalent to a pseudoscalar axion in 4-dimensions, the dilaton and the graviton. The coupling constants in the theory are $α^{\prime}$ (inverse string tension) and $κ$ (inverse reduced Planck mass in 4-dimensions) and the charge of the $U(1)$ field and the axion-photon coupling are related to these two. Sen found a black hole solution (the Kerr-Sen black hole) with these fields as the external hair of the black hole. In this paper we investigate the possibility of determining the Sen solution from observations. The observations which can test the Kerr-Sen black hole are: (a) determination of the shape of the photon shadow, and (b) the rotation of polarization of photon due to axion hair. The deviation from circularity gives the $U(1)$ charge of the black hole and identification of this charge in terms of the photon coupling leads to a prediction of frequency independent "Faraday rotation" in terms of black hole parameters already determined from the shadow. Similar measurements of Kerr-Newman black hole with axion hair have no correlation between the shape of the image and the amount of "Faraday rotation". This correlation can be a distinctive test of the Sen metric. In the recent observation from EHT of M87* shadow, the deviation from circularity has an upper bound of 10%. If this observation is refined to 1% accuracy then a definitive prediction of the charge of the Kerr-Sen black hole and the "Faraday rotation" can be made. Interestingly observations of "Faraday rotation" have shown that the effect is independent of frequency pointing to an axionic hair interpretation for the effect.
