ABSTRACT  We  inves.gate  the  proper.es  of  the  galaxies  hos.ng  quasar  ac.vity  in  ~400  low  redshiB  (z  <  0.5)  SDSS  QSO  that  are  in  the  "Stripe  82"  sky  area  .  For  this  sky  region  deep  (r~22.4  mag)  u,  b,v,r  and  i  images  are  available  and  allow  us  to  study  both  the  host  galaxy  and  the  Mpc  scale  environments.  This  sample  greatly  outnumber  previous  studies  of  low-­‐z  QSOs.  We  present  preliminary  results  of  the  proper.es  of  quasars  ac.vity  and  in  par.cular  we  focus  on  the  rela.onships  among  host  galaxy  luminosity,  black  hole  mass,  radio  emission  and  the  surrounding  galaxy  environments.  

Renato  Falomo                INAF  -­‐  Osservatorio  Astronomico  di  Padova,  Italy  Daniela  Be.oni              INAF  -­‐  Osservatorio  Astronomico  di  Padova,  Italy  Kalle  Karhunen              Tuorla  Observatory  ,  University  of  Turku,  Finland  Jari  Ko4lainen                  Finnish  Center  for  Astronomy  with  ESO  (FINCA),  University  of  Turku,  Finland  Michela  Uslenghi        INAF  -­‐  IASF,  Milano  

The  low  z  QSO  sample   AIDA  –  Image  analysis  

QSO  host  galaxies  proper4es  

REFERENCES  

Annis, J. et al. 2011, astro-ph1111.6619 Schneider, D. P. et al. 2007 AJ, 134, 102 Shen, Y. et al. 2008 ApJ, 680, 982 Uslenghi, M. & Falomo, R., 2011 Proc. SPIE 8135, 813524 (2011)

IAU Symposium 295 - The intriguing life of massive galaxies.    IAU  XXVIII  General  Assembly,  Beijing  ,  August  2012  

Fig. 2 Examples of our targets: in the left panels we show the sdss DR7 i-band image, in the middle panel the same i-band image from stripe82 and in the right panel the isophotes of a zoom of the central region. Three different environments are shown.

SDSSJ205212.28-002645.2 z=0.2675

SDSSJ235818.86-000919.4 z=0.4022

SDSSJ004032.10-001350.8 z=0.242

Images of selected Targets

Fig.1 Distribution of our QSO sample in the z-Mi plane

Fig. 3 The rest frame (k-corrected) absolute magnitude in R band of low z QSO host galaxies. Filled and open red points are for resolved and marginally resolved QSO respectively. Blue open squared represent QSO from HST images.

Fig. 4 The comparison between host and nucleus absolute magnitude of QSO. Filled and open red points are for resolved and marginally resolved sources , respectively. The solid (dashed) green line represents the loci with Host/Nuc=1.0 (0.1))

We implemented an automated procedure using AIDA (Uslenghi & Falomo 2011) to decompose the QSO images into nucleus and host galaxy luminosity (see example on the left and bottom figures)

After masking of all contaminating sources in the field a 2D fitting is performed using PSF + galaxy model (Sersic index ). Example of resulting decomposition for resolved, marginally resolved and unresolved objects are shown in the right panel.

We   select   from   the   SDSS   –   QSO  Catalogue  (Schneider  et  al.  2007)    all  the   QSOs   in   the   range   of   redshiB  0.1<z<0.5   and   in   the   Stripe82   (Annis  et   al.   2011)   region   i.   e.   -­‐1.0<δ<1.0,  0<α<   59.8   and   300.2<α<360.   This  gives   a   total   of   416   QSO   .   In   this  sample   we   are   dominated   by   radio  quiet   quasars   (about   5%   are   radio  loud).     In   Fig.   1   we   report   the  distribu.on   of   QSO   in   the   plane  redshiB-­‐Mi  (H0=70).      The  mean  redshit  of    the  sample  is  <z>  =0  .39±0.08  and  the  average  absolute  magnitude    is  :    <Mi>  =  -­‐22.68±0.61

QSO Black Hole mass

Log (BH mass) M(R) host galaxy

Log

(BH

mas

s)

The relationship (left) between QSO host galaxy luminosity (R) and BH mass (Shen et al. 2008) for 240 resolved objects. The average BH mass of these QSO is : <Log(MBH)> = 8.33±0.43 (right)