1. eROSITA + group meeting, Ringberg, February 2008 z>3 QSOs in XMM-COSMOS: lessons for eROSITA Marcella Brusa (MPE) with help from: A. Comastri M. Salvato, G. Hasinger, O. Ilbert J. Trump + IMACS, M. Mignoli + zCOSMOS K. Iwasawa, V. Mainieri R. Gilli N. Cappelluti, F. Civano

2. eROSITA + group meeting, Ringberg, February 2008 ? The population of z>3 QSO Radio QSO (Wall et al., 2005) Optical QSOs (Schmidt et al., 1995, Fan et al. 2001,2004) X-ray: What happens at z>3? decline or ~costant ? Soft X-ray ROSAT/Chandra/ XMM (Hasinger, Miyaji & Schmidt 2005) Chandra/ROSAT (Silverman et al. 2005/2007)  statistics still low at z~3-5 (NO statistics at z>6) COSMOS eROSITA

3. eROSITA + group meeting, Ringberg, February 2008 Cosmos Survey 2 deg 2 (PI: N. Scoville) with deep multiwavelength coverage at all lambda XMM-COSMOS survey (PI: G. Hasinger) Mosaic of 55 XMM observations One of the main goal: “Characterization of The z>3 QSO population” soft 0.5-2.0 keV medium 2.0-4.5 keV hard 4.5-10.0 keV 1608 soft 0.5-2.0 keV 1103 medium 2.0-4.5 keV 250 hard 4.5-10.0 keV

4. eROSITA + group meeting, Ringberg, February 2008 at S(0.5-2 keV) >1e-15 cgs Predictions: (from Gilli et al. 2007 model) unabs+abs 30 deg-2 (exponential cutoff at z.2.7) Schmidt et al. 1995 80 deg-2 (constant evolution) z>3 QSO counts: expectations Models from Gilli+07

5. eROSITA + group meeting, Ringberg, February 2008 compilation from ongoing spectroscopic projects [IMACS/Magellan+VLT/ESO + SDSS + literature data] Flux limited sample (50% of the area coverage in at least one band) 1651 XMM sources - 10% problematic ID using IR+Chandra info ~670 “secure” spectroscopic redshifts (40%) Incompleteness especially for high-z and Type 2 AGN XMM-COSMOS sources redshifts (adapted from Brusa et al. 2007 ApJS)

6. eROSITA + group meeting, Ringberg, February 2008  LESS than 10% catastrophic outliers (to be compared with COMBO-17, Wolf et al. 2004) 434 objects with “super-secure” spectro-z (further refinement/analysis) Photo-z computed using >30 bands: SDSS, Subaru including IB, CFHT, J, K, IRAC.. AGN photometric redshifts Salvato et al. (in prep)

7. eROSITA + group meeting, Ringberg, February 2008 AGN redshift distribution (99% complete spec-z + phot-z sample) X-ray sample (AGN) Empty: specz+photz Filled: specz z>3 XMM QSO sample: 39 at F(0.5-2) > 1e-15 + 2 hard X-ray detected = 41 (18 specz + 23 photoz) Additional 16 objects, no photoz available. Candidates very high-z AGN (EXOs, Koekemoer et al. 2004) 13 at F(0.5-2 keV)>1e-15 3 hard X-ray detected

8. eROSITA + group meeting, Ringberg, February 2008 Few examples of images & spectra ACS image, 15”x15” I=23.5 B g v r I z IRAC 3.6 z(phot)=4.269 XID 54439 z=4.241

9. eROSITA + group meeting, Ringberg, February 2008 Other spectra… z=3.328 z=3.333 z=3.345 z=3.715 M. Mignoli

10. eROSITA + group meeting, Ringberg, February 2008 Some examples of photoz

11. eROSITA + group meeting, Ringberg, February 2008 General properties Magnitude distribution: I=20-26 (25% I>24) Luminosities distribution: Log(Lx) = 44 - 45

12. eROSITA + group meeting, Ringberg, February 2008 Contribution to source counts Flat evolution completely ruled out Tightest constraints to date (largest and cleanest sample) Lower bound: spectro-z Upper-bound: adding EXOs z>4 point: Rhook & Haenelt 08 predict a factor of ~3 higher wrt model Models: Gilli, Comastri & Hasinger 2007, A&A

13. eROSITA + group meeting, Ringberg, February 2008 Space densities model folded with selection effects (limiting flux) Red curve: ALL AGN Lx>44 (unobscured + obscured + CT) Excellent agreement also in the observed space densities Insensible to CT objects at z>1

14. eROSITA + group meeting, Ringberg, February 2008 Optical colors Color color selection v-I vs. b-v (proposed, e.g. in Casey et al. 2008, Saina et al. 2007) High-z (>3) locus Interm-z (2-3) Lower-z (0-2) 8 (red circles) would not have been selected ~40 (magenta/yellow) contaminants

15. eROSITA + group meeting, Ringberg, February 2008 X-ray properties: … hard? HR vs. redshift Population of absorbed BL? Green: HR ~0 Blue: HR > -0.2 Stacked spectra K. Iwasawa  Ratio of obscured/unobscured objects also in agreement with XRB models

16. eROSITA + group meeting, Ringberg, February 2008 Summary Flat evolution at z>3 definitively ruled out (space densities & number counts) Results based only on XMM-COSMOS selection and exploitation of COSMOS database (no need to combine with other X-ray surveys… ) 33/41 X-ray selected quasars would have been selected also by optical color-color criteria (but with a comparable number of low-z contaminants)  not a significant population with unusual optical colors… Sizable sample of obscured AGN (also BL..)

17. eROSITA + group meeting, Ringberg, February 2008 Lessons and prospects for eROSITA -z>3 QSO expected in eROSITA surveys: 400 deg2 on “north+south pole”, F(0.5-2) > 4e-15 cgs ~1600 in the “Deep survey”: 400 deg2 on “north+south pole”, F(0.5-2) > 4e-15 cgs 30.000 deg2 all sky, F(0.5-2) > 1e-14 cgs ~25000 in the All Sky survey: 30.000 deg2 all sky, F(0.5-2) > 1e-14 cgs (500 at z>4) - 6 QSO in XMM-COSMOS at Flux > 4e-15 cgs, I(AB)=20-22  problems of misidentifications ~10% with current eROSITA PSF (15” HEW on axis, 25” HEW averaged on FOV) - Need optical follow-up at I~23 and complete (!!) spectroscopy (or good quality multiband photometry)  Synergies with other (big) observatories is mandatory… - PanSTARRS (all sky) + GROND (for faintest sources) - SDSS-like survey? LAMOST ? - (ESO facilities can be used on 200 deg2 – South pole) - LBT/GTC deep U+Bband imaging (on 200 deg2…) CFHTLS Wide Survey ~100 deg2 (u,g,r,i,z) AB~25-26 - CFHTLS Wide Survey ~100 deg2 (u,g,r,i,z) AB~25-26

18. eROSITA + group meeting, Ringberg, February 2008 a factor of 30 deeper than ROSAT (0.5-2 keV) expect ~ 100,000 clusters, 3.4 Mio AGN (0.5-2 keV) eROSITA X-ray Surveys Expect [450,120, 36, 10] AGN@z >[ 6, 7, 8, 9]

19. eROSITA + group meeting, Ringberg, February 2008

20. Effective area [cm 2 ] Grasp [cm 2 deg 2 ] E- ROSITA Grasp of 7 eROSITA telescopes is 3-4 x higher than 3 XMM- Newton telescopes in the energy range 0.3-2 keV

21. eROSITA + group meeting, Ringberg, February 2008 Multiple spectra… improve reliability! Xid 5219, z=3.322 XID 5594 z=4.174

22. eROSITA + group meeting, Ringberg, February 2008 Single line spectra: low-z or high-z? IMACSVIMOS/Bright  High-z solution is preferred (photometry) z=1.41 z=3.356 XID 187

23. eROSITA + group meeting, Ringberg, February 2008 Other spectra… z=3.038 z=3.092z=3.104z=3.143 z=3.165z=3.328 z=3.333z=3.345 z=3.499 z=3.524 z=3.609z=3.715