Bibcode
Gonzalez-Martin, O.; Acosta-Pulido, J. A.; Pérez-García, A. M.; Ramos-Almeida, C.
Bibliographical reference
The Astrophysical Journal, Volume 723, Issue 2, pp. 1748-1761 (2010).
Advertised on:
11
2010
Journal
Citations
20
Refereed citations
18
Description
We present a study of the circumnuclear region of the nearby Seyfert
galaxy Mrk 573 using Chandra, XMM-Newton, and Hubble Space Telescope
(HST) data. We have studied the morphology of the soft (<2 keV)
X-rays comparing it with the [O III] and Hα HST images. The soft
X-ray emission is resolved into a complex extended region. The X-ray
morphology shows a biconical region extending up to 12 arcsec (4 kpc) in
projection from the nucleus. A strong correlation between the X-rays and
the highly ionized gas seen in the [O III]λ5007 Å image is
reported. Moreover, we have studied the line intensities detected with
the XMM-Newton Reflection Grating Spectrometer (RGS) and used them to
fit the low-resolution EPIC/XMM-Newton and ACIS/Chandra spectra. The
RGS/XMM-Newton spectrum is dominated by emission lines of C VI, O VII, O
VIII, Fe XVII, and Ne IX, among other highly ionized species. A good fit
is obtained using these emission lines found in the RGS/XMM-Newton
spectrum as a template for Chandra spectra of the nucleus and extended
emission, coincident with the cone-like structures seen in the [O
III]/Hα map. The photoionization model Cloudy provides a
reasonable fit for both the nuclear region and the cone-like structures
showing that the dominant excitation mechanism is photoionization. For
the nucleus the emission is modeled using two phases: a high ionization
[log (U) = 1.23] and a low ionization [log (U) = 0.13]. For the
high-ionization phase the transmitted and reflected components are in a
1:2 ratio, whereas for the low ionization the reflected component
dominates. For the extended emission, we successfully reproduced the
emission with two phases. The first phase shows a higher ionization
parameter for the northwest (log (U) = 0.9) than for the southeast cone
(log (U) = 0.3). Moreover, this phase is transmission dominated for the
southeast cone and reflection dominated for the northwest cone. The
second phase shows a low-ionization parameter (log (U) = -3) and is
rather uniform for northwest and southeast cones and equally distributed
in reflection and transmission components. In addition, we have also
derived the optical/infrared spectral energy distribution (SED) of the
nucleus from high spatial resolution images of Mrk 573. The nuclear
optical/infrared SED of the nucleus has been modeled by a clumpy torus
model. The torus bolometric luminosity agrees very well with the active
galactic nucleus (AGN) luminosity inferred from the observed hard X-ray
spectrum. The optical depth along the line of sight expected from the
torus modeling indicates a high neutral hydrogen column density in
agreement with the classification of the nucleus of Mrk 573 as a
Compton-thick AGN.
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