Followup of X-CLASS galaxy clusters with GROND Jethro Ridl, Nicolas - - PowerPoint PPT Presentation

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followup of x class galaxy clusters with grond
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Followup of X-CLASS galaxy clusters with GROND Jethro Ridl, Nicolas - - PowerPoint PPT Presentation

Jan 27, 2023 490 likes •673 views

Followup of X-CLASS galaxy clusters with GROND Jethro Ridl, Nicolas Clerc - MPE A. Rau, J. Greiner, K. Nandra, M.Salvato - also MPE M. Pierre, T. Sadibekova, L. Faccioli - CEA Saclay F. Pacaud - Bonn X-CLASS/GROND: Project Overview Data

slide-1
SLIDE 1

Followup of X-CLASS galaxy clusters with GROND

Jethro Ridl, Nicolas Clerc - MPE

  • A. Rau, J. Greiner, K. Nandra, M.Salvato - also MPE
  • M. Pierre, T. Sadibekova, L. Faccioli - CEA Saclay
  • F. Pacaud - Bonn
slide-2
SLIDE 2 CR HR

MCMC

Background

Data

Reduction Astrometry Photometry PSF modeling Calibration Galaxy photometry Standards Stellar locus

Photo-z

GROND SDSS Red sequence Multiple colours Beta-model Richness

Photometric catalogue Cosmology

Cosmological parameters Simulations GROND X-ray CR, HR Position Extension

Z [ CR, HR, z ]

Uncertainty Calibration and comparision Generic algorithm

X-CLASS/GROND:

Project Overview

slide-3
SLIDE 3 CR HR

MCMC

Background

Data

Reduction Astrometry Photometry PSF modeling Calibration Galaxy photometry Standards Stellar locus

Photo-z

GROND SDSS Red sequence Multiple colours Beta-model Richness

Photometric catalogue Cosmology

Cosmological parameters Simulations GROND X-ray CR, HR Position Extension

Z [ CR, HR, z ]

Uncertainty Calibration and comparision Generic algorithm

X-CLASS/GROND:

Project Overview

Data

Optical X-rays

slide-4
SLIDE 4 CR HR

MCMC

Background

Data

Reduction Astrometry Photometry PSF modeling Calibration Galaxy photometry Standards Stellar locus

Photo-z

GROND SDSS Red sequence Multiple colours Beta-model Richness

Photometric catalogue Cosmology

Cosmological parameters Simulations GROND X-ray CR, HR Position Extension

Z [ CR, HR, z ]

Uncertainty Calibration and comparision Generic algorithm

X-CLASS/GROND:

Project Overview

Photo-z

Photometry Position Extension

slide-5
SLIDE 5 CR HR

MCMC

Background

Data

Reduction Astrometry Photometry PSF modeling Calibration Galaxy photometry Standards Stellar locus

Photo-z

GROND SDSS Red sequence Multiple colours Beta-model Richness

Photometric catalogue Cosmology

Cosmological parameters Simulations GROND X-ray CR, HR Position Extension

Z [ CR, HR, z ]

Uncertainty Calibration and comparision Generic algorithm

X-CLASS/GROND:

Project Overview

Cosmology

Number of clusters as a function of redshift, count rate and hardness ratio

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SLIDE 6

XMM Cluster Archive Super Survey (X-CLASS)

  • Serendipitous cluster catalogue

for archival XMM pointings

  • 2774 high galactic latitude
  • bservations
  • ~830 galaxy clusters extracted

based purely on X-rays

  • Pointings cut to 10ks and 20ks
  • Same methodology as XMM-

XXL/LSS

  • Optical veto from DSS (nearby

galaxies, etc) + ‘guessed-z’

Clerc et al. 2012b

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SLIDE 7

XMM Cluster Archive Super Survey (X-CLASS)

  • Higher signal-to-noise sample

extracted for cosmological analysis leaving 347 (264) clusters

  • EXT_LIKE > 40
  • EXT > 5 arcsec
  • 0.009 < CR < 0.5 cts/s ([0.5-2]keV)
  • 0.05 < HR < 2 ([1-2]keV/[0.5-1]keV)
  • ~130 (104) clusters have

photometric or spectroscopic redshifts in various catalogues

Clerc et al. 2012b

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SLIDE 8

GROND

  • Simultaneous 7-channel (grizJHK) imager on the

MPG/ESO 2.2m telescope at La Silla

  • Pixel size and FOV - griz: 0.156” over 4.5 arcmin

  • JHK: 0.6”over 10 arcmin
  • Median r-band seeing: 1.11
  • Optical confirmation of X-ray identified clusters
  • Identification of red-sequence galaxy cluster

members

  • Rapid determination of photometric redshifts
  • Immediate characterisation of the cluster for

future analyses

  • Predefined observing blocks to optimize

efficiency

  • 8(20)min4TD = 460s (1475s) in griz

Seeing (arcsec) r-band seeing

Number of observations

Filter 8min4TD 20min4TD g 23.2 24.1 r 22.9 23.8 i 22.3 23.1 z 22.3 23.0 J 20.5 21.0 H 19.9 20.4 K 19.1 19.4

5-sigma point source limiting magnitudes

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SLIDE 9

z=0.13 z=0.75 z=0.31 z=0.55

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SLIDE 10

X-CLASS/GROND:

Data reduction

  • Standard GROND pipeline at MPE provides flat-fielded co-added

images in each channel

  • Photometric part of GROND pipeline at MPE developed for
  • GRBs. Not ideal for use on clusters.
  • Pipeline developed using SExtractor, PSFEx, Swarp and

Scamp (all from Bertin et al.)

  • Galaxy photometry extracted in consistent aperture across all

bands to give accurate colours (SExtractor: MAG_DETMODEL)

  • Fields in SDSS footprint calibrated with common stars
  • Those not in SDSS are calibrated with using standard fields
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SLIDE 11

X-CLASS/GROND:

Photometric redshift

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SLIDE 12

X-CLASS/GROND:

Photometric redshift

  • 1. Distance in multi-colour space to

expected red sequence position

1 2σ exp " − ✓cobs − cmodel 2σ ◆2#

Σ

gal

L =

  • Cluster members and redshift

determination based on red- sequence - z relation

  • Try to find the most likely z for

each X-ray detected cluster based on:

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SLIDE 13

X-CLASS/GROND:

Photometric redshift

  • 1. Distance in multi-colour space to

expected red sequence position

1 2σ exp " − ✓cobs − cmodel 2σ ◆2#

Σ

gal

L =

  • Cluster members and redshift

determination based on red- sequence - z relation

  • Try to find the most likely z for

each X-ray detected cluster based on:

slide-14
SLIDE 14

X-CLASS/GROND:

Photometric redshift

  • Cluster members and redshift

determination based on red- sequence - z relation

  • Try to find the most likely z for

each X-ray detected cluster based on:

1 2σ exp " − ✓cobs − cmodel 2σ ◆2#

Σ

gal

L =

  • 2. Weighted by position relative to

beta-model from X-rays

  • 1. Distance in multi-colour space to

expected red sequence position

 B (1 +

r ext)2

1.5

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SLIDE 15

X-CLASS/GROND:

Photometric redshift

  • 1. Distance in multi-colour space to

expected red sequence position

1 2σ exp " − ✓cobs − cmodel 2σ ◆2#

NgalΣ

gal

L =

  • 3. Further weighted by number of

galaxies

 B (1 +

r ext)2

1.5

  • 2. Weighted by position relative to

beta-model from X-rays

  • Cluster members and redshift

determination based on red- sequence - z relation

  • Try to find the most likely z for

each X-ray detected cluster based on:

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SLIDE 16

Spectro-z Photo-z

X-CLASS/GROND:

Photo-z’s - Early results

  • Code run on 29 known-z

clusters that fall in GROND and SDSS footprints

  • Combination of spectro-z’s
  • Early results are

encouraging

  • There are a few problems

that have been identified

1. BCG often flagged out of the catalogue 2. Model for the red sequence needs modification 3. Photometric calibration

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SLIDE 17

In summary

  • GROND is an efficient instrument for getting photo-

z’s: to z=0.8 in ~30 min/cluster

  • Still some challenges outstanding e.g. photometric

calibration in non-SDSS fields, el Nino …

  • Not possible to get a local galaxy background in

photo-z calculations

  • Catalogue coming soon
  • Next step: Cosmology and high redshift clusters

σz = 0.02