Spectropolarimetry of NGC 1275 reveals a narrow-line radio galaxy with polarization parallel to its radio jet axis

Abstract

<p>Concomitant with the Imaging X-ray Polarimetry Explorer (IXPE) observation of the Perseus cluster, we obtained optical spectropolarimetry of its central active galactic nucleus, NGC 1275, using the Alhambra Faint Object Spectrograph and Camera (ALFOSC) on the Nordic Optical Telescope (NOT). While the total-light spectrum confirms its edge-on, core obscured (type-2) classification, the polarized spectrum shows a polarization angle aligned with the arcsecond radio jet axis – an exceptional behavior for type-2 objects. Our polarization analysis also reveals wavelength-dependent linear polarization at a level of 2−3% in the continuum, likely arising from a combination of variable synchrotron emission and scattering; this supports a narrow-line radio galaxy classification with characteristics of a jet-dominated source.<br></p>