Uncovering the Primary X-Ray Emission and Possible Starburst Component in the Polarized NLS1 Mrk 1239

Abstract

X-ray observations of the unique NLS1 galaxy Mrk 1239 spanning 18 yr are presented. Data from XMM-Newton, Suzaku, Swift, and NuSTAR are combined to obtain a broadband, multi-epoch view of the source. There is spectral variability in the 3–10 keV band over the 18 yr. An analysis of the NuSTAR and Suzaku lightcurves also suggests rapid variability in the 3–10 keV band, which is consistent with the NLS1 definition of the source. However, no variability is seen below 3 keV on any timescale. Two distinct physical models are adopted to describe the data above and below . The low energies are dominated by a hot, diffuse gas likely associated with a starburst component at large physical scales. The higher-energy spectrum is dominated by emission from the central region. Ionized partial covering and relativistic blurred reflection are considered for the central region emission. In both cases, the underlying power law has a photon index of Γ ∼ 2.3–2.4. A distant reflector, a neutral partial covering component with a covering fraction near ∼1, and contributions from starburst emission are always required. The blurred reflection model requires a reflection-dominated spectrum, which may be at odds with the low emissivity index and radio properties of the source. By contrast, the two absorption components required in the ionized partial covering model may correspond to the two distinct regions of polarization observed in the optical. Regardless of the physical model, spectral changes between epochs are driven by the absorption components—and on short timescales, by intrinsic active galactic nucleus variability.

Unravelling the origin of extended radio emission in narrow-line Seyfert 1 galaxies with the JVLA

“…Consistent with this its star formation rate was estimated to be 3.47 M yr −1 based on SED modelling (Gruppioni et al 2016). Buhariwalla et al (2020) modelled the X-ray spectrum of J0952-0136 with alternative models and found that the < 3 keV emission cannot be modelled without a starburst component, whose extent they estimate to be less than 400 pc from the nucleus. This is interesting since the other star formation proxies do not predict starburst level star formation.…”

A highly accreting low-mass black hole hidden in the dust: Suzaku and NuSTAR observations of the NLS1 Mrk 1239

“…. Buhariwalla et al (2020) found an Eddington ratio of Edd = 1 − 1.5. Yao et al (2018) applied a correction factor to the 5100 of Mrk 1239 and obtained Edd = 1.12.…”

“…A super-solar Ne abundance of Ne = 4.9 +1.2 −1.3 is needed. Buhariwalla et al (2020) suggested that these hot plasma components may be associated with the star-burst region in the host galaxy of Mrk 1239. This component has been often found in the soft X-ray emission of many obscured sources (e.g.…”

“…The left and right grey dashed lines show the values Edd given in Yao et al (2018) and Grupe et al (2004) respectively. The shaded region shows the range of Edd estimated by Buhariwalla et al (2020).…”

“…The iron band of Mrk 1239 is dominated by fluorescence emissions of the torus. But some disc reflection may still exist (Buhariwalla et al 2020) and make contribution in the hard X-ray band, the observed Compton hump in particular.…”