Source association: XXL case study Sotiria Fotopoulou in association - - PowerPoint PPT Presentation

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Source association: XXL case study Sotiria Fotopoulou in association - - PowerPoint PPT Presentation

Jan 04, 2024 445 likes •620 views

Source association: XXL case study Sotiria Fotopoulou in association with: S. Paltani, L. Chiappetti, M. Brusa, A. Bongiorno, P . Ciliegi and the XXL collaboration The XXL survey 2 x 25 sq. deg. PI: M. Pierre 6Ms XMM Newton fmux

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SLIDE 1

Source association: XXL case study

Sotiria Fotopoulou in association with:

  • S. Paltani, L. Chiappetti, M. Brusa, A. Bongiorno, P

. Ciliegi and the XXL collaboration

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SLIDE 2

The XXL survey

  • 2 x 25 sq. deg.
  • 6Ms XMM Newton
  • fmux limit : 1e-15 erg/s/cm2

XXL-N XXL-S ~104 X-ray sources ~106 optical sources

PI: M. Pierre

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SLIDE 3

Multiwavelength SED

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Source Detection: nature vs nurture

Source's physical properties: bluer or redder, star formation vs absorption Survey properties: exposure, seeing, image noise.

g u i z r

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SLIDE 5
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SLIDE 6
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SLIDE 7

X-ray – optical association

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SLIDE 8

multiplicity = N(optical) / N(X-ray)

How many?

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SLIDE 9

Likelihood Ratio

  • Introduced in Sutherland & Sanders 1992
  • Used regularly in XMM-Newton surveys

e.g. COSMOS (Brusa et al., 2005, 2007),

Lockman Hole (Rovilos et al., 2010)

f(x, y): probablity distribution function of positional errors q(m, c): probablity distribution in magnitude and type n(m,c): surface density per magnitude of background objects

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SLIDE 10

Likelihood Ratio

Probability j object is the correct identifjcation Where Q the expected identifjcation rate

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Application

  • Step-by-step per catalog: depth and/or wavelength
  • accept gaussian uncertainties
  • built appropriate control sample per catalog

e.g., Brusa et al., 2005, 2007, Rovilos et al., 2010, Civano et al., 2015

q(m, c): probablity distribution in magnitude and type n(m,c): surface density per magnitude of background objects

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SLIDE 12
  • Find sources around 3'' from X-ray position
  • Create magnitude distribution
  • Find magnitude distribution of background

sources

  • USNO B1.0 catalog: bright unsaturated sources
  • CFHTLS/BCS/DECam i/y magnitude
  • CFHTLS/BCS/DECam r magnitude
  • WIRcam K magnitude
  • VISTA K magnitude
  • IRAC [3.6]

XXL X-ray – optical/IR associations

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SLIDE 13
  • USNO B1.0 catalog: bright unsaturated sources

XXL X-ray – optical/IR associations

Field X-ray galaxies stars all

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Wide area X-ray surveys: XXL-1000-AGN

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Wide area X-ray surveys: XXL-1000-AGN

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Wide area X-ray surveys: XXL-1000-AGN

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 As long as the multiplicity is > 1, LR is needed.  Planned X-ray surveys: wide area, not small PSF  counterpart also in catalogs of bright objects  SDSS too “deep”

Take home message: – What is the difgerence between theory and pratice? – In theory, they are the same. In practice... Conclusion