A second view on the X-ray polarization of NGC 4151 with IXPE
| Autor: | Gianolli, V. E., Bianchi, S., Kammoun, E., Gnarini, A., Marinucci, A., Ursini, F., Parra, M., Tortosa, A., De Rosa, A., Kim, D. E., Marin, F., Matt, G., Serafinelli, R., Soffitta, P., Tagliacozzo, D., Di Gesu, L., Done, C., Marshall, H. L., Middei, R., Mikusincova, R., Petrucci, P-O., Ravi, S., Svoboda, J., Tombesi, F. |
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| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | We report on the second observing program of the active galactic nucleus NGC 4151 with simultaneous Imaging X-ray Polarimetry Explorer (IXPE; {\sim}750 ks), NuSTAR ({\sim}60 ks), XMM-Newton ({\sim}75 ks), and NICER ({\sim}65 ks) pointings. NGC 4151 is the first Type 1 radio-quiet Seyfert galaxy with constrained polarization properties for the X-ray corona. Despite the lower flux state in which the source is re-observed and the resulting higher contribution of the constant reflection component in the IXPE energy band, our results are in agreement with the first detection. From the polarimetric analysis, a polarization degree {\Pi} = 4.7 {\pm} 1.3 per cent and angle {\Psi} = 77{\deg} {\pm} 8{\deg} east of north (68 per cent confidence level) are derived in the 2.0 - 8.0 keV energy range. Combining the two observations leads to polarization properties that are more constrained than those of the individual detections, showing {\Pi} = 4.5 {\pm} 0.9 per cent and {\Psi} = 81{\deg} {\pm} 6{\deg} (with detection significance {\sim}4.6{\sigma}). The observed polarization angle aligns very well with the radio emission in this source, supporting, together with the significant polarization degree, a slab or wedge geometry for the X-ray corona. However, a switch in the polarization angle at low energies (37{\deg} {\pm} 7{\deg} in the 2 - 3.5 keV bin) suggests the presence of another component. When it is included in the spectro-polarimetric fit, a high polarization degree disfavors an interpretation in terms of a leakage through the absorbers, rather pointing to scattering from some kind of mirror. Comment: 10 pages, 8 figures, 3 tables. Submitted to Astronomy & Astrophysics |
| Databáze: | arXiv |
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