the xmm large scale structure (xmm-lss) survey andy read university of leicester university of...

The XMM Large Scale Structure The XMM Large Scale Structure (XMM-LSS) Survey(XMM-LSS) Survey

Andy ReadAndy Read

UniversityUniversity ofof LeicesterLeicester (for the XMM-LSS Consortium)(for the XMM-LSS Consortium)

University of LeicesterUniversity of Leicester2525thth November 2003 November 2003

Andy ReadAndy ReadUniversity of LeicesterUniversity of Leicester

A EuropeA Europe/Chile/Chile Consortium Consortium

Birmingham Birmingham BristolBristol CopenhagenCopenhagen DublinDublin ESO/ SantiagoESO/ Santiago LeidenLeiden LiègeLiège

Marseille (LAM)Marseille (LAM) Milano (AOB)Milano (AOB) Milano (IFCTR)Milano (IFCTR) Munich (MPA)Munich (MPA) Paris (IAP)Paris (IAP) Santiago (Uni. Cato.)Santiago (Uni. Cato.)

PI : Saclay, France



XMM sensitivityXMM sensitivity

12.5Å 1.25Å

EffectiveArea



The XMM-LSS SurveyThe XMM-LSS Survey

- Goal: determine the cluster correlation function in two redshift bins 0 < z < 0.5, 0.5 < z < 1, each bin containing 450 clusters

- Fixes the XMM-LSS survey characteristics: 8x8 sq.deg. area covered by 10 ksec XMM pointings

- Sensitivity: 5e-15 ergs/s/cm² in [0.5-2 keV] band

- XMM’s unrivalled sensitivity, large FOV (d~25’) and good PSF opens a new area for the study of the cluster Large Scale Structure (LSS)

- Able to Map the evolution of the LSS of the universe out to z~1, with both the galaxy cluster and the QSO

populations for the first time



Expected number of clustersExpected number of clusters in an 8x8 sq. deg. area in an 8x8 sq. deg. area

~ 900 clusters 0 < z < 1 for CDM~ 300 clusters z > 1



Expected numbers of objectsExpected numbers of objects

200200 QSO QSO/AGN /AGN (( 40% 40% z < 1) z < 1)

15 clusters z<115 clusters z<1 5 clusters 1< z <2 ?5 clusters 1< z <2 ? Galaxies + stars Galaxies + stars

At the survey sensitivity: ~ 5e-15 erg/s/cm² (0.5-2 keV)

~ 250 X-ray sources per square degree:



The XMM-LSS … The XMM-LSS … so farso far

- Aim: 64 sq.deg. 10 ksec exposures

-Already observed: 46 XMM pointings ~5 sq.deg. (May 03)



Multi-wavelength follow-upMulti-wavelength follow-up CFHT/CFH12K (VVDS Deep): 2 sq.deg. GT(WL)CFHT/CFH12K (VVDS Deep): 2 sq.deg. GT(WL) CFHT/CFH12K (VVDS Wide): 3 sq.deg. GO(WL)CFHT/CFH12K (VVDS Wide): 3 sq.deg. GO(WL) CFHT/Megacam: 72 sq.deg. (WL)CFHT/Megacam: 72 sq.deg. (WL) CTIO 4m/MOSAIC: ~16 sq.deg.CTIO 4m/MOSAIC: ~16 sq.deg. UKIRT/WFCAM: 8.75 sq.deg.UKIRT/WFCAM: 8.75 sq.deg. VLA A array: 110 sq.deg. @ 74 MHzVLA A array: 110 sq.deg. @ 74 MHz VLA A array: 5.6 sq.deg. @325 MHzVLA A array: 5.6 sq.deg. @325 MHz OCRA: all XMM clusters @ 30 GHzOCRA: all XMM clusters @ 30 GHz AMIBA: 70 sq.deg. @ 95 GHzAMIBA: 70 sq.deg. @ 95 GHz SIRTF/IRAC: 8.7 sq.deg. (SWIRE Legacy)SIRTF/IRAC: 8.7 sq.deg. (SWIRE Legacy) SIRTF/MIPS: 8.9 sq.deg. (SWIRE Legacy)SIRTF/MIPS: 8.9 sq.deg. (SWIRE Legacy) GALEX: ~ 20 sq.deg. GALEX: ~ 20 sq.deg.



XMM Subaru Deep Survey

VIRMOS VVDS wide

XMDS & VIRMOS VVDS deep

SIRTF Legacy : SWIRE

NOAO Deep Survey

Galex

XMM-LSS

Survey Survey LocationLocation

HI map NH~1.4-3.5 e20



First XMM pointings (GT) – 20 ksec First XMM pointings (GT) – 20 ksec



The First Data: 15 GO PointingsThe First Data: 15 GO Pointings 15 Pointings (MOS1, MOS2 & pn, all with ~10 ksec)15 Pointings (MOS1, MOS2 & pn, all with ~10 ksec) Standard XMM-SAS (emchain and epchain) processingStandard XMM-SAS (emchain and epchain) processing Flare-cleaned to common level of low backgroundFlare-cleaned to common level of low background Bad pixel analysis and removalBad pixel analysis and removal RGB mosaic constructed (0.3-1, 1-2.5, 2.5-10 keV)RGB mosaic constructed (0.3-1, 1-2.5, 2.5-10 keV) Rigorous background subtraction, to account for Rigorous background subtraction, to account for

extended sources, involving background event filesextended sources, involving background event files

(Read & Ponman 2003) and closed datasets (Marty(Read & Ponman 2003) and closed datasets (Marty

et al. 2002)et al. 2002)



Imaging: Background subtraction

Source data Closed data Background data

Source (vignetted) +

Background: - Photons (vignetted) Particles (non-vignetted)

Background: -

Particles (non-vignetted)

Background: - Photons (vignetted) Particles (non-vignetted)

Only BG particles appear in out-of-field-of-view (out-of-FOV) areas [i.e. corners]



Imaging: Double-background subtractionSource Closed data (Particles) Background data (photons+particles)

- Evaluate all out-of-FOV events – calculate scalings

Create image Create scaled P image Create scaled BG image

-Subtract to give Source image (no particles)

-Subtract to give scaled BG image (no particles)

- Create exposure map in small energy band – use to create full field `soft excess’ image

Create large-R annular image Create large-R annular P image Create large-R annular BG image

Scale to source Scale to source

-Subtract to give Source annulus (no particles)

-Subtract to give BG annulus (no particles)

-Subtract to calculate ‘soft excess’ at large-R for particular energy

* Start `soft excess’ loop over several small energy bands

* End Loop over energies to accumulate total energy, full field `soft excess’ image

-Add `soft excess’ to Scaled BG image to create double background

-Add double background to scaled particles image to create total background

(source-free)



The First Data: Flare-cleaned exposure The First Data: Flare-cleaned exposure



Part of the XMM-LSS mosaic : 15 pointings (~1.6 sq.deg.) Part of the XMM-LSS mosaic : 15 pointings (~1.6 sq.deg.)

Red[0.3-1]keV Green[1-2.5]keV Blue[2.5-10]keV

Andy ReadAndy Read

Circles: ROSATAll-Sky Survey



‘‘Big C’ – XMMUJ022540-031111Big C’ – XMMUJ022540-031111Hardness map of centre

-Hotter at interface (kT~7.6keV)

All-EPIC, BG-sub, exp-corr. contours on CFHT I band imagez~0.29, kT~6.2 keV, Lx~3e44 erg/s



Detection Algorithm OverviewDetection Algorithm Overview- Standard SAS processing - emchain & epchain + flare removal- Wavelet filtering of images (M1-M2-PN) - in counts (preserving Poisson stats) - computing threshold by histogram auto-convolution- Exposure correction on a per instrument basis- Addition of exposure-corrected images- 1st detection step: Sextractor (XMM-PPS uses eboxdetect)

- on co-added images - with low detection threshold, to avoid missing faint sources - with parameters adjusted for X-ray filtered images- Max. Likelihood fit step: EMLdetect (with extension fit & CAL psf) - source input list from Sextractor - X/Y & extent tied for 3 instruments, normalization free - ML min = 8.5 - Final X-ray catalogue: - Mix of Sextractor/EMLdetect results

Sergio Dos Santos, Saclay



Detection Algorithm ValidationDetection Algorithm Validation

On instrument by instrument basis: - Instrumental effects included:

PSF (analytic), vignetting (energy dependent), CCD gaps, bad pixels

- Background (Read & Ponman 2003): Cosmic (vignetted) & Particles (non-vignetted)

- Source modelling (in at least two bands): - Point sources (random positioning in FOV): Flux distribution: LogN-LogS (Moretti et al. 2003) - Extended sources: King model surface brightness - β = 2/3 - Rcore = Rvirial/10 (Rvirial from temperature) Flux from local Lx-T (Arnaud & Evrard 1999)

XMM Simulations



Simulated XMM ImagesSimulated XMM Images

Single pointing (10ks) Photon image [0.4-4 keV]

Wavelet-filtered + Poisson photonstatistics model (Starck & Pierre 1998) [pre-Sextractor detection]



Detection Algorithm ValidationDetection Algorithm ValidationResultsResults

-Results encouraging:

- Most, if not all clusters (T>4keV) up to z~1 can be detected using 10 ksec XMM pointings - Richest clusters should be detected at z<2 (if they exist!) - Very small rate of spurious detections (<1 per pointing), due to 2-stage process



• ~60 Candidate extended sources over ~ 3.5 sq.deg. i.e. as expected ~15+ extended sources per sq.deg.

• 10 ksec XMM + 2h VLT allow T (±1 keV) measurement and velocity dispersion at z~0.8

• Intermediate mass systems are being uncovered by XMM

• First results described in four papers• Pierre et al, 2003, astro-ph/0305191• Valtchanov et al, 2003, astro-ph/0305192• Willis et al, 2003, in prep• Andreon et al, in prep

XMM-LSS: Selected ResultsXMM-LSS: Selected Results



Identification procedureIdentification procedureXMM EPIC image + contours CFHT 3-colour VRI image + EPIC contours



PhotometricPhotometricredshift redshift

CFHT I-band image

EPIC contours



Predicted z (photometric) Predicted z (photometric) from VBRI images: from VBRI images:

Measured z: Measured z: 0.61 !0.61 !

Sources ~1’ from centre

All sources



CFH12k I-bandCFH12k I-band

EPIC contours

Nearby group



Cluster without X-ray counterpart

(z~0.3-0.4)

Image: zImage: z´́-band CTIO-band CTIO

EPIC contours



A relaxed medium cluster at z~0.84A relaxed medium cluster at z~0.84



A collapsing cluster at z~0.77 A collapsing cluster at z~0.77



Some AGNs in the same fieldSome AGNs in the same field



A structure at z~1



Z > 1 CandidateZ > 1 Candidate

CFH12k VRI imagesVIRMOS DS

~ 560 cts [0.5-5] keV

XMM-EPIC X-ray contours from wavelet filtering



NIR identification of z~1 XMM-LSS clustersNIR identification of z~1 XMM-LSS clusters

XMM (PN) image (+X-ray detection ellipse)

SOFI (NTT) K-band image (galaxies hardly seen on deep I (CFHT) and z’ (CTIO) images)



NIR confirmed clustersNIR confirmed clustersExtended X-ray sources showing spatially coincident, statistically significant galaxyoverdensity

EPIC contours on K-band images ~1’x1’



006 012

EPIC contours on CFHT images – cluster candidates at z~0.4



2-D fitting of X-ray emission2-D fitting of X-ray emission• Simultaneous fitting of MOS1, MOS2 and pn images

- Images and exposure maps required• PSF images required (created via XMM-SAS-calview)• Masks can be used to ignore e.g. nearby point sources• Source (src) and background (BG) boxes are chosen

2-D fitting: β-model (using CIAO-sherpa)

• 3 separate models (with tied parameters) for M1, M2, pn• Constant BG level(s) fit to BG emission• src+BG model fit to source emission (src = β-model)• Core radius Ro, slope β, ellipticity ε, pos.angle θ tied between 3 instruments, normalization free

f(x,y) = f(r) = A_________(1+[r/r0])

3β-½ [r=f(x,y,ε,θ)]



2-D model contours overlayed on XMM-EPIC X-ray emission

Ro=24.0" β=0.63 Ro=24.2" β=0.40 Ro=59.8" β=0.72 Ro=8.7" β=0.44

Ro=12.9" β=0.73 Ro=37.4" β=0.51 Ro=11.8" β=0.67 Ro=4.7" β=0.40

Ro=6.5" β=0.40 Ro=2.5" β=0.42 Ro=12.1" β=0.55 Ro=5.3" β=0.41



2-D model contours overlayed on residuals (data – model)



First accepted papers:

astro-ph/0305191

astro-ph/0305192

http://vela.astro.ulg.ac.be/themes/spatial/xmm/LSS/index_e.html

XMM-LSSXMM-LSS



Data releaseData release• 2003: clusters published (coordinates, z) 2003: clusters published (coordinates, z)

astro-ph/0305191 astro-ph/0305192

• 2004:2004: publication of the X-ray catalogue from publication of the X-ray catalogue from the XMM A01 datathe XMM A01 data

• Database increased/updated annually: Database increased/updated annually: X-ray, optical, VLA, then SIRTFX-ray, optical, VLA, then SIRTF



QSOs

the xmm large scale structure (xmm-lss) survey andy read university of leicester university of...

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