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The VLA Survey of the Chandra Deep Field South X-ray Properties of Radio Sources

The VLA Survey of the Chandra Deep Field South X-ray Properties of Radio Sources. Shaji Vattakunnel. - University of Trieste. Paolo Tozzi - Francesca Matteucci. 25 th May 2010. AGN9 – Ferrara. Outline. Deep Radio and X-ray Surveys of the Chandra Deep Field South

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The VLA Survey of the Chandra Deep Field South X-ray Properties of Radio Sources

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  1. The VLA Survey of the Chandra Deep Field SouthX-ray Properties of Radio Sources Shaji Vattakunnel - University of Trieste Paolo Tozzi - Francesca Matteucci 25th May 2010 AGN9 – Ferrara

  2. Outline • Deep Radio and X-ray Surveys of the Chandra Deep Field South • X-ray properties of Radio Sources • The sub-mJy radio source population

  3. Deep Radio and X-ray Surveys Flattening of the radio counts below one mJy Possibly due to Star Forming Galaxies VLA/Chandra Surveys 1Ms X-ray observation Kellerman et al 2008 Mainieri et al 2008 Tozzi et al 2008 Padovani et al 2009 Flattening below 1 mJy Kellerman et al. 2008 Radio and X-ray observations are efficient in identifying star formation vs nuclear activity at high redshifts.

  4. X-ray luminosity vs Radio power Padovani et al. 2009

  5. Number Counts Padovani et al. 2009 Emerging of the star forming galaxies in the sub-mJy population Analogous to results found by Gruppioni et al (1999) Prandoni et al (2009)

  6. The Extended Chandra Deep Field South (E-CDFS) 6 pointings of the Very Large Array 1.4 GHz (20 cm) 34’.1 x 34’.1 image sensivity 6-8μJy 1571 sources at 4 σ (N. Miller) Radio image (1.4 GHz)

  7. The Chandra Deep Field South (CDFS) 0.3 – 1 keV 1 – 2 keV 2 – 7 keV 23 observations(8 years) for a total of 2 Ms - 16’ x 16’ image Sensitivity: ~10-17 erg cm-2 s-1 448 sources (441 with redshifts) [0.3-7 keV] X-ray color image of the 2Ms derived from Luo et al. 2008

  8. The Extended Chandra Deep Field South (E-CDFS) 4 pointings 250 ks 9 observations 32’ x 32’ image sensitivity ~10-16 erg cm-2 s-1 753 sources (Lehmer et al. 2005) X-ray color image of the flanking field

  9. The 2Ms X-ray Survey Improvements: • deeper X-ray image in the CDFS • deeper radio catalog • larger number of found matches 1Ms/VLA (2001) observation 347 266 89 77% 2Ms/EVLA (2007) observation 448 1571 227 95% X-ray sources in the CDFS Radio sources in the ECDFS Radio sources with an X-ray counterpart redshift available

  10. Identification of X-Ray Counterparts Positional match between X-ray and radio sources Counterparts if the separation is less than 3σd , where: σ2d = σ2x + σ2r X-ray rms 0.3” < σx < 1.9” Radio rms estimated at 0.2” Optical X-Ray Radio

  11. AGN / SFG discrimination Luminosity from: Sources with few counts Sources with high counts (full spectral analysis) Total sources: 227 # of AGNs: 177 # of SFG candidates: 50 • Discriminating AGNs: • X-ray Luminosity • Lx > 1042 erg/s • column density • NH > 1021 cm-2 • Radio Power • Pr > 1024.5 W/Hz

  12. AGN / SFG discrimination Low Lum AGNs Absorbed AGNs Star Forming Gal Unabsorbed AGNs

  13. - - = = 40 40 SFR SFR 2 1 . . 0 6 10 10 L L M M / / yr yr x x - - 2 2 10 10 keV keV L = 1 . 4 GHz SFR M / yr 28 4 . 0 10 x Star Formation Rates sources with 0.1 < z < 0.5 sources with 0.5 < z < 1.2 Condon (1992) 0 < z < 1.2 The normalization is consistent with Ranalli (2003) There is no evidence of evolution in redshift

  14. Conclusions A detailed analysis of the E-CDFS sub-mJy population • X-ray and radio data are a powerfull tool to separate AGNs from SFGs: ~1/4 can be classified as star forming galaxies ~ 3/4 as AGNs • Found a correlation between X-ray and the radio power for star-forming galaxies, in agreement with previous studies • Evaluation of relation between SFR and X-ray luminosities in our sample in the redshift range 0 < z < 1.2 X-ray stacking of the 1307 radio sources without a catalogued X-ray counterpart Compute the Cosmic Star Formation History Add data from other wavelenghts (optical, IR) Another 2Ms set of observations of the CDFS has been approved and will be concluded in the next year. This will allow us the improve our analysis with deeper data.

  15. Thanks for your attention

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