We present results of a 100 ks XMM-Newton observation of the Seyfert 1.5 AGN NGC 3227. Our best-fit broadband model to the European Photon Imaging Camera (EPIC)-pn spectrum consists of a moderately flat (photon index of 1.57) hard X-ray power law absorbed by cold gas with a column density of 3 × 10^21 cm2, plus a strong soft excess, modeled as a steep power law with a photon index of 3.35, absorbed by cold gas with a column density of 9 × 10^20 cm-2. The soft excess increases in normalization by ~ 20% in ~ 20 ks, independently of the hard X-ray emission component, and the UV continuum, tracked via the Optical Monitor, also shows a strong increasing trend over the observation, consistent with reprocessing of soft X-ray emission. Warm absorber signatures are evident in both the EPIC and the Reflection Grating Spectrometer spectra; we model two absorbing layers, with ionization parameters log ξ = 1.2 and 2.9 erg cm s-1, and with similar column densities (~10^21 to 2 × 10^21 cm-2). The outflow velocities relative to systemic of the high- and low-ionization absorbers are estimated to be -(2060+240 -170) km s-1 and -(420+430 -190) km s-1, respectively. The Fe Kα line FWHM width is 7000 ± 1500 km s-1 its inferred distance from the black hole is consistent with the broad-line region and with the inner radius of the dust reverberation mapped by Suganuma et al. An emission feature near 6.0 keV is modeled equally well as a narrow redshifted Fe K line, possibly associated with a disk "hot spot," or as the red wing to a relativistically broadened Fe line profile. Swift Burst Alert Telescope and archival Rossi X-Ray Timing Explorer (RXTE) data suggest at most a weak Compton reflection hump (R<~0.5), and a high-energy cutoff near 100 keV. From RXTE monitoring, we find tentative evidence for a significant fraction of the Fe line flux to track variations in the continuum on timescales < 700 days.
Markowitz A., Reeves J. N., George I. M., Braito V., Smith R., Vaughan S., et al. (2009). A Comprehensive X-Ray Spectral Analysis of the Seyfert 1.5 NGC 3227. THE ASTROPHYSICAL JOURNAL, 691, 922-945 [10.1088/0004-637X/691/2/922].
A Comprehensive X-Ray Spectral Analysis of the Seyfert 1.5 NGC 3227
TOMBESI, FRANCESCO
2009
Abstract
We present results of a 100 ks XMM-Newton observation of the Seyfert 1.5 AGN NGC 3227. Our best-fit broadband model to the European Photon Imaging Camera (EPIC)-pn spectrum consists of a moderately flat (photon index of 1.57) hard X-ray power law absorbed by cold gas with a column density of 3 × 10^21 cm2, plus a strong soft excess, modeled as a steep power law with a photon index of 3.35, absorbed by cold gas with a column density of 9 × 10^20 cm-2. The soft excess increases in normalization by ~ 20% in ~ 20 ks, independently of the hard X-ray emission component, and the UV continuum, tracked via the Optical Monitor, also shows a strong increasing trend over the observation, consistent with reprocessing of soft X-ray emission. Warm absorber signatures are evident in both the EPIC and the Reflection Grating Spectrometer spectra; we model two absorbing layers, with ionization parameters log ξ = 1.2 and 2.9 erg cm s-1, and with similar column densities (~10^21 to 2 × 10^21 cm-2). The outflow velocities relative to systemic of the high- and low-ionization absorbers are estimated to be -(2060+240 -170) km s-1 and -(420+430 -190) km s-1, respectively. The Fe Kα line FWHM width is 7000 ± 1500 km s-1 its inferred distance from the black hole is consistent with the broad-line region and with the inner radius of the dust reverberation mapped by Suganuma et al. An emission feature near 6.0 keV is modeled equally well as a narrow redshifted Fe K line, possibly associated with a disk "hot spot," or as the red wing to a relativistically broadened Fe line profile. Swift Burst Alert Telescope and archival Rossi X-Ray Timing Explorer (RXTE) data suggest at most a weak Compton reflection hump (R<~0.5), and a high-energy cutoff near 100 keV. From RXTE monitoring, we find tentative evidence for a significant fraction of the Fe line flux to track variations in the continuum on timescales < 700 days.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
