Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published July 10, 2019 | Submitted + Published
Journal Article Open

Testing the Kerr metric with X-ray Reflection Spectroscopy of Mrk 335 Suzaku data


Einstein's gravity has undergone extensive tests in the weak field gravitational limit, with results in agreement with theoretical predictions. There exist theories beyond general relativity (GR) which modify gravity in the strong field regime but agree with GR in the weak field. Astrophysical black holes are believed to be described by the Kerr metric and serve as suitable candidates to test strong gravity with electromagnetic radiation. We perform such a test by fitting one Suzaku data set of the narrow-line Seyfert 1 (NLS1) galaxy Mrk 335 with X-ray reflection spectroscopy, using the Johannsen metric to model the black hole spacetime and test for deviations from Kerr. We find the data is best modeled with a hybrid model that includes both partial covering absorption and a reflection component. This is the first time such a model has been proposed for a high-flux (low reflection) Mrk 335 data set. We constrain the Johannsen deformation parameter α_(13) to −1.5 < α_(13) < 0.6 with spin parameter a* > 0.8, and the α_(22) parameter to −0.4 < α_(22) < 2.1 with a* > 0.7, both at the 99% confidence level. Although additional solutions at large deviations from the Kerr metric show statistical similarity with the ones above, further analysis suggests these solutions may be manifestations of uncertainties beyond our control and do not represent the data. Hence, our results are in agreement with the idea that the supermassive compact object at the center of Mrk 335 is described by the Kerr metric.

Additional Information

© 2019 The American Astronomical Society. Received 2018 September 20; revised 2019 April 24; accepted 2019 May 25; published 2019 July 9. We extend our gratitude to the anonymous referees for suggesting helpful tips in order to improve the quality of the paper. K.C. thanks Michael Parker and Matteo Guainazzi for their helpful comments on the data analysis part. The work of K.C., D.A., A.B.A., and C.B. was supported by the Innovation Program of the Shanghai Municipal Education Commission, grant No. 2019-01-07-00-07-E00035, the National Natural Science Foundation of China (NSFC), grant No. U1531117, and Fudan University, grant No. IDH1512060. K.C. also acknowledges support from the China Scholarship Council (CSC), grant No. 2015GXYD34. S.N. acknowledges support from the Excellence Initiative at Eberhard-Karls Universität Tübingen. A.B.A. also acknowledges the support from the Shanghai Government Scholarship (SGS). C.B. and J.A.G. also acknowledge support from the Alexander von Humboldt Foundation.

Attached Files

Published - Choudhury_2019_ApJ_879_80.pdf

Submitted - 1809.06669.pdf


Files (2.1 MB)
Name Size Download all
1.1 MB Preview Download
1.0 MB Preview Download

Additional details

August 19, 2023
October 18, 2023