A Caltech Library Service

X-Ray Reverberation Mapping of Ark 564 Using Gaussian Process Regression

Lewin, Collin and Kara, Erin and Wilkins, Dan and Mastroserio, Guglielmo and García, Javier A. and Zhang, Rachel C. and Alston, William N. and Connors, Riley and Dauser, Thomas and Fabian, Andrew and Ingram, Adam and Jiang, Jiachen and Lohfink, Anne M. and Lucchini, Matteo and Reynolds, Christopher S. and Tombesi, Francesco and van der Klis, Michiel and Wang, Jingyi (2022) X-Ray Reverberation Mapping of Ark 564 Using Gaussian Process Regression. Astrophysical Journal, 939 (2). Art. No. 109. ISSN 0004-637X. doi:10.3847/1538-4357/ac978f.

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item:


Ark 564 is an extreme high-Eddington narrow-line Seyfert 1 galaxy, known for being one of the brightest, most rapidly variable soft X-ray active galactic nuclei (AGN), and for having one of the lowest temperature coronae. Here, we present a 410 ks NuSTAR observation and two 115 ks XMM-Newton observations of this unique source, which reveal a very strong, relativistically broadened iron line. We compute the Fourier-resolved time lags by first using Gaussian processes to interpolate the NuSTAR gaps, implementing the first employment of multitask learning for application in AGN timing. By simultaneously fitting the time lags and the flux spectra with the relativistic reverberation model reltrans, we constrain the mass at 2.3_(-1.3)^(+2.6) x 10^(6)M_(⊙), although additional components are required to describe the prominent soft excess in this source. These results motivate future combinations of machine learning, Fourier-resolved timing, and the development of reverberation models.

Item Type:Article
Related URLs:
URLURL TypeDescription
Lewin, Collin0000-0002-8671-1190
Kara, Erin0000-0003-0172-0854
Wilkins, Dan0000-0002-4794-5998
Mastroserio, Guglielmo0000-0003-4216-7936
García, Javier A.0000-0003-3828-2448
Zhang, Rachel C.0000-0002-2905-9239
Alston, William N.0000-0003-2658-6559
Connors, Riley0000-0002-8908-759X
Dauser, Thomas0000-0003-4583-9048
Fabian, Andrew0000-0002-9378-4072
Ingram, Adam0000-0002-5311-9078
Jiang, Jiachen0000-0002-9639-4352
Lucchini, Matteo0000-0002-2235-3347
Reynolds, Christopher S.0000-0002-1510-4860
Tombesi, Francesco0000-0002-6562-8654
van der Klis, Michiel0000-0003-0070-9872
Wang, Jingyi0000-0002-1742-2125
Additional Information:E.K., G.M., and J.A.G. acknowledge support from NASA grant 80NSSC20K0575. J.J. acknowledges support from the Leverhulme Trust, the Isaac Newton Trust, and St Edmund's College, University of Cambridge. A.I. acknowledges support from the Royal Society. G.M. and J.A.G. acknowledge support from NASA grant 80NSSC19K1020. J.A.G. also acknowledges support from the Alexander von Humboldt Foundation. This work was partially supported under NASA contract No. NNG08FD60C and made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software, and Calibration teams for their support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (nustardas), jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). M.K. acknowledges support through an NWO (Nederlandse Organisatie voor Wetenschappelijk Onderzoek) Spinoza grant. C.S.R. thanks the UK Science and Technology Facilities Council (STFC) for support under the Consolidated Grant ST/S000623/1, as well as the European Research Council (ERC) for support under the European Unionâs Horizon 2020 research and innovation program (grant 834203).
Group:Space Radiation Laboratory, NuSTAR
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)ST/S000623/1
European Research Council (ERC)834203
Leverhulme TrustUNSPECIFIED
Isaac Newton TrustUNSPECIFIED
St. Edmund's College, University of CambridgeUNSPECIFIED
Alexander von Humboldt FoundationUNSPECIFIED
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)UNSPECIFIED
Issue or Number:2
Record Number:CaltechAUTHORS:20221128-494241100.41
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:118079
Deposited By: Research Services Depository
Deposited On:20 Dec 2022 18:00
Last Modified:20 Dec 2022 18:00

Repository Staff Only: item control page