Testing the AGN unified model using spectropolarimetry

1
Testing the AGN unified model using
spectropolarimetry

• Cristina Ramos Almeida
  
  Andrés Asensio Ramos, María Jesús Martínez
  González, Rafael Manso Sáinz, José Antonio Acosta
  Pulido the CanariCam AGN team Los Piratas

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Modeling
Clumpy Torus Models

• Torus dust grains absorb optical UV photons
  from matter accretion ? re-emission in the
  infrared (peaking at mid-IR ? 5-30 µm).
• Dust distributed in clumps instead of
  homogeneously filling torus volume (Nenkova et
  al. 2002 Hönig et al. 2006 Schartmann et al.
  2008).

Nenkova et al. (2002)
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Observations
Isolation of Torus emission

• IR range (mid-IR) key to constrain parameters of
  torus models.
• Goal isolation of torus emission (Rolt 10 pc
  interferometry mid-IR).
• Large aperture data (e.g. ISO, Spitzer, IRAS)
  contaminated with circunnuclear stellar emission.
• High-spatial resolution infrared observations
  (e.g., CanariCam, T-ReCS, Michelle, VISIR) key to
  isolate torus emission.

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Observations
Isolation of Torus emission
8 m Gemini
85 cm Spitzer
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• Mid-IR imaging space (Spitzer/IRAC) vs. ground
  (Gemini/T-ReCS) observations

Díaz-Santos (2009, PhD)
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Observations
RA et al. 2009, 2011 Alonso-Herrero et al. 2011

• Ground-based subarcsecond resolution mid-IR
  imaging data for 21 nearby Seyfert galaxies.
• Compilation of near-IR nuclear fluxes from the
  literature of similar resolutions as mid-IR data.
• Herschel far-IR data also available (GT GO
  programmes).
• AGN-dominated SEDs torus emission (Sy2)
  torusAGN emission (Sy1).

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Results
NIR MIR spectral energy distributions
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SED modelling
BayesClumpy

• Bayesian code to fit the clumpy models of Nenkova
  et al. 2008a,b.
• PCA decomposition Neural networks to
  approximate Clumpy Database (6 parameters-based
  models).
• Solution to the Clumpy Database degeneracy ?
• Possibility of interpolating within the database
  ?
• Simultaneous fit of both SED spectrum ?
• Prediction of next observation to add to SED ?
• Available for the astrophysical community ?
• Asensio Ramos Ramos Almeida 2009, 2012

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Circinus
NGC 7469
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Results
Are the obscuring tori of Type 1 and 2 Seyferts
different?
NIRMIR emission reproduced with small tori (Rolt
6 pc)
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Results
Are the obscuring tori of Type 1 and 2 Seyferts
different?

• Sy1 tori covering factors lt Sy2
  tori covering factors
• Sy1
  Sy1
• Sy2
  Sy2
• Sy1 photon escape prob. gt Sy2
  photon escape prob.

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Results
Are the obscuring tori of Type 1 and 2 Seyferts
different?
-Expected from warped disk torus models
(Lawrence Elvis 2010) -also from X-ray
observations of Seyfert galaxies
(Ricci et al. 2011)
Lawrence Elvis (2010)

• -Highly inclined Seyfert 1 tori
• Bi-conical outflows (SINFONI Müller-Sanchez et
  al. 2011)
• Accretion disk orientation from X-ray data
  (Nandra et al. 2007)

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Results
Are the obscuring tori of Type 1 and 2 Seyferts
different?

• If all Seyfert nuclei are identical, as
  simple unification predicts, only the viewing
  angle determines the classification.
• Our results suggest that the classification
  as Type-1 or Type-2 may also depend on the
  intrinsic properties of the torus.

Schartmann et al. (2008)
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Project
Are the obscuring tori of Type 1 and 2 Seyferts
different?

• Origin of unification scheme for Seyfert galaxies
  (Antonucci Miller 1985) ? detection of
  polarized broad lines in NGC 1068 nuclei.
• Only 30-50 of nearby Sy2s show a Sy1-type
  polarized spectrum (Tran 2001). Implications?
• 1) not all Seyferts harbour a hidden BLR (Tran
  2001, 2003 Gu Huang 2002)
• 2) distribution of dust within the torus and its
  inclination not as simple as predicted by the
  unified model.

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Project
Are the obscuring tori of Type 1 and 2 Seyferts
different?

• Results from our modelling with torus models
  could explain lack of polarized broad lines in
  50-70 of nearby Seyfert 2 galaxies.
• The torus has to have a determined orientation
  (close to edge-on) and enough clumps to make the
  broad lines visible in polarized light.
• GALAXY NGC 7582 IC 5063
• POLARIZED
• BROAD LINES ? ?
• i FROM
• MODELLING 431922 8158

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Project
Are the obscuring tori of Type 1 and 2 Seyferts
different?

• Results from our modelling with torus models
  could explain lack of polarized broad lines in
  50-70 of nearby Seyfert 2 galaxies.
• The torus has to have a determined orientation
  (close to edge-on) and enough clumps to make the
  broad lines visible in polarized light.
• NGC 7582 ? IC 5063 ?
• POLARIZED
• BROAD LINES ? ?
• i FROM
• MODELLING 8158 431922

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Project
Are the obscuring tori of Type 1 and 2 Seyferts
different?

• Results from our modelling with torus models
  could explain lack of polarized broad lines in
  50-70 of nearby Seyfert 2 galaxies.
• The torus has to have a determined orientation
  (close to edge-on) and enough clumps to make the
  broad lines visible in polarized light.
• Comparison between RA11AH11 results and a
  homogeneous data set of spectropolarimetric data.
  

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Futre observations
Are the obscuring tori of Type 1 and 2 Seyferts
different?

• Homogeneous dataset of polarized optical spectra
  of a representative sample of Seyfert galaxies
  for which we have constraints on their torus
  properties.
• ISIS/WHT observations scheduled in Jan 2013 ? 16
  objects.
• FORS2/VLT observations requested in 2013A ? 18
  objects.
• Sample contains similar numbers of Seyfert 1,
  1.2, 1.5, 1.9 and 2 types ? study how
  polarization signal varies between types.

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Futre observations
GOALS

• Analize in a consistent way linear polarization
  signal and high angular resolution infrared data
  using torus models.
• Confirm whether or not the lack of polarized
  broad lines in 50-70 of Sy2 population due to
  low torus inclinations and/or small covering
  factors.
• Directly compare between linear polarization
  signal in Sy1s and Sy2s.

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• Thanks!