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X-ray Photons in the CO 2-1 'Lacuna' of NGC 2110
A recent ALMA study of the Seyfert 2 Active Galactic Nucleus (AGN) NGC 2110
by Rosario et al. (2019) has reported a remarkable lack of CO 2-1 emission from
the circumnuclear region, where optical lines and H2 emission are observed,
leading to the suggestion of excitation of the molecular clouds by the AGN.
Since interaction with X-ray photons could be the cause of this excitation, we
have searched the archival Chandra data for corroborating evidence. We report
an extra-nuclear ~1'' (~170 pc) feature found in the soft (<1.0 keV) Chandra
data of the Seyfert 2 Active Galactic Nucleus (AGN) NGC 2110. This feature is
elongated to the north of the nucleus and its shape matches well that of the
optical lines and H2 emission observed in this region, which is devoid of CO
2-1 emission. The Chandra image completes the emerging picture of a multi-phase
circumnuclear medium excited by the X-rays from the AGN, with dense warm
molecular clouds emitting in H2 but depleted of CO 2-1 emission.Comment: ApJ Letters - in pres
An Examination of the Spectral Variability in NGC 1365 with Suzaku
We present jointly analyzed data from three deep Suzaku observations of NGC
1365. These high signal-to-noise spectra enable us to examine the nature of
this variable, obscured AGN in unprecedented detail on timescales ranging from
hours to years. We find that, in addition to the power-law continuum and
absorption from ionized gas seen in most AGN, inner disk reflection and
variable absorption from neutral gas within the Broad Emission Line Region are
both necessary components in all three observations. We confirm the clumpy
nature of the cold absorbing gas, though we note that occultations of the inner
disk and corona are much more pronounced in the high-flux state (2008) than in
the low-flux state (2010) of the source. The onset and duration of the "dips"
in the X-ray light curve in 2010 are both significantly longer than in 2008,
however, indicating that either the distance to the gas from the black hole is
larger, or that the nature of the gas has changed between epochs. We also note
significant variations in the power-law flux over timescales similar to the
cold absorber, both within and between the three observations. The warm
absorber does not vary significantly within observations, but does show
variations in column density of a factor of more than 10 on timescales less
than 2 weeks that seem unrelated to the changes in the continuum, reflection or
cold absorber. By assuming a uniform iron abundance for the reflection and
absorption, we have also established that an iron abundance of roughly 3.5
times the solar value is sufficient to model the broad-band spectrum without
invoking an additional partial-covering absorber. Such a measurement is
consistent with previous published constraints from the 2008 Suzaku observation
alone, and with results from other Seyfert AGN in the literature.Comment: 19 pages, 11 figures, accepted for publication in MNRA
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