Spitzer Space Telescope - Guaranteed Time Observer Proposal #30291


IRS spectroscopy of a complete sample of Seyfert galaxies in the local
universe

Principal Investigator: Giovanni Fazio
           Institution: Harvard-Smithsonian Astrophysical Observatory

Co-Investigators: 
Luigi Spinoglio, IFSI-CNR                                             
Howard Smith, CfA                                                     
Matt Ashby, CfA                                                       
Matt Malkan, UCLA                                                     
Leslie Hunt, Arcetri, INAF                                            
Paola Andreani, Trieste, INAF                                         
Eduardo Gonzalez, Alcala                                              

Science Category: AGN/quasars/radio galaxies 
 Observing Modes: IrsStare 
  Hours Approved: 22.9 

Abstract:
As AGNs are intimately related to dust, it is essential to study them
at wavelengths which minimize the obscuring effects of dust
extinction, while maximizing the dust emission diagnostics.  IRS
spectroscopy will be able to measure the fine structure lines from the
ionized gas excited both from black hole accretion and from stellar
ionization, and also lines from H2 as diagnostics of PDRs, shock
excitation from starbursts, and hard X-ray heating from the AGN.  By
combining our proposed observations with similar ones in the ROC, we
will assemble a complete database sample of active galaxies - the "12
Micron Sample" of 53 Seyfert 1s and 63 Seyfert 2's.  We will address
five goals.  (i) Test the evolutionary scenario (of HII, Seyfert 2,
Seyfert 1) by comparing over activity type observable physical
quantities such as:  the hardness of the ionizing continuum;  the star
formation rate and the dust extinction;  (ii) establish what is the
contribution to the total energy budget in each galaxy arising from
black hole accretion and from star formation activity in the Local
Universe.  This will be done by separating spectroscopically through
detailed modeling the AGN from the starburst component;  (iii)
characterize the star formation activity in Seyfert galaxies;  (iv)
derive the fraction of radiant energy in the local Universe produced
by stars and that produced by accretion onto massive black holes, and
derive the respective luminosity functions;  (v) assess the importance
of bolometric luminosity, ionizing radiation, and nuclear physical
conditions to classification schemes.  Our observations will enable us
to produce accurate local templates for application to AGNs in the
early epochs of the Universe.