A1 Refereed original research article in a scientific journal
The X-ray polarization of the Seyfert 1 galaxy IC 4329A
Authors: Ingram A., Ewing M., Marinucci A., Tagliacozzo D., Rosario D.J., Veledina A., Kim D.E., Marin F., Bianchi S., Poutanen J., Matt G., Marshall H.L., Ursini F., De Rosa A., Petrucci P.O., Madejski G., Barnouin T., Di Gesu L., Dovčiak M., Gianolli V.E., Krawczynski H., Loktev V., Middei R., Podgorny J., Puccetti S., Ratheesh A., Soffitta P., Tombesi F., Ehlert S.R., Massaro F., Agudo I., Antonelli L.A., Bachetti M., Baldini L., Baumgartner W.H., Bellazzini R., Bongiorno S.D., Bonino R., Brez A., Bucciantini N., Capitanio F., Castellano S., Cavazzuti E., Chen C.T., Ciprini S., Costa E., Del Monte E., Di Lalla N., Di Marco A., Donnarumma I., Doroshenko V., Enoto T., Evangelista Y., Fabiani S., Ferrazzoli R., García J.A., Gunji S., Heyl J., Iwakiri W., Jorstad S.G., Kaaret P., Karas V., Kislat F., Kitaguchi T., Kolodziejczak J.J., Monaca F.L., Latronico L., Liodakis I., Maldera S., Manfreda A., Marscher A.P., Mitsuishi I., Mizuno T., Muleri F., Negro M., Ng C.Y., O'dell S.L., Omodei N., Oppedisano C., Papitto A., Pavlov G.G., Peirson A.L., Perri M., Pesce-Rollins M., Pilia M., Possenti A., Ramsey B.D., Rankin J., Roberts O.J., Romani R.W., Sgrò C., Slane P., Spandre G., Swartz D.A., Tamagawa T., Tavecchio F., Taverna R., Tawara Y., Tennant A.F., Thomas N.E., Trois A., Tsygankov S.S., Turolla R., Vink J., Weisskopf M.C., Wu K., Xie F., Zane S.
Publisher: Oxford University Press
Publication year: 2023
Journal: Monthly Notices of the Royal Astronomical Society
Journal name in source: Monthly Notices of the Royal Astronomical Society
Volume: 525
Issue: 4
First page : 5437
Last page: 5449
eISSN: 1365-2966
DOI: https://doi.org/10.1093/mnras/stad2625
Web address : https://academic.oup.com/mnras/article/525/4/5437/7258650
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/181475005
We present an X-ray spectro-polarimetric analysis of the bright Seyfert galaxy IC 4329A. The Imaging X-ray Polarimetry Explorer (IXPE) observed the source for ∼500 ks, supported by XMM–Newton (∼60 ks) and NuSTAR (∼80 ks) exposures. We detect polarization in the 2–8 keV band with 2.97σ confidence. We report a polarization degree of 3.3 ± 1.1 per cent and a polarization angle of 78° ± 10° (errors are 1σ confidence). The X-ray polarization is consistent with being aligned with the radio jet, albeit partially due to large uncertainties on the radio position angle. We jointly fit the spectra from the three observatories to constrain the presence of a relativistic reflection component. From this, we obtain constraints on the inclination angle to the inner disc (<39° at 99 per cent confidence) and the disc inner radius (<11 gravitational radii at 99 per cent confidence), although we note that modelling systematics in practice add to the quoted statistical error. Our spectropolarimetric modelling indicates that the 2–8 keV polarization is consistent with being dominated by emission directly observed from the X-ray corona, but the polarization of the reflection component is completely unconstrained. Our constraints on viewer inclination and polarization degree tentatively favour more asymmetric, possibly out-flowing, coronal geometries that produce more highly polarized emission, but the coronal geometry is unconstrained at the 3σ level.
Downloadable publication This is an electronic reprint of the original article. |  |
