Transcript Photo-zs for XMM-COSMOS sources

Variability: who cares?
or….
Photometric redshift
for XMM-COSMOS sources
M.Salvato, G. Hasinger, O. Ilbert, G. Zamorani, M.Brusa
+
COSMOS collaboration
Salvato et al. 2009,ApJ, accepted
In order to better understand the role (if any) of the
AGN phase in Galaxy evolution, a complete CENSUS of AGN is crucial.
get them all : Due to the interplay between host and
Active Nucleous, No criterion can exist
that can identify all AGN using a single
waveband (i.e. see talks at this conference).
get the right redshift: most of the sources are faint and we
must rely on photometric redshifts.
even for Xray selected AGN usually, for z<1, the accuracy is
not better than 0.06 (after removing 20% of outliers ...)
…or, in other words,
something linke this…
Our results:
I+AB<22.5
I+AB>22.5
Our results:
I+AB<22.5
I+AB>22.5
Our results:
.
I+AB<22.5
I+AB>22.5
HOW?
• Correction for variability
• New templates
• Tons of photometric points
WHAT IS MORE IMPORTANT ?
About 2/5 of the
XMM sample has
clearly detected
long term variability
BB
IB1
SDSS
SUBARU
IB2
Sources vary in a unpredictable way
?
Templates
Sy2
Sy1.8
I22491
M82
Sp
Sb
S0
}
QSO2+S0
MRK231
}
TQSO1+I22491
QSO
Relevance of templates and variability correction
Both factors are crucial to reducing the number of outliers.
Among other results:
• Correct stellar/galaxy separation
• Correct relation between hardness ratio and
SED and variability
• Correct relation between Xray luminosity and
SED
QSO selection at high z via Lyman break
Siana et al. 2008
Normal gals
type II
type I
Thank you!
.
Ilbert et al
Salvato et al.
SUMMARY
Variability effects your work more than you think…
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