the xmm large scale structure (xmm-lss) survey: x-ray analysis and first results andy read...

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

X-rayX-ray analysisanalysis andand firstfirst resultsresults

Andy ReadAndy Read

UniversityUniversity ofof LeicesterLeicester

For the XMM-LSS consortiumFor the XMM-LSS consortium

EPIC Consortium Meeting, Palermo, October 2003EPIC Consortium Meeting, Palermo, October 2003

EPIC Consortium Meeting EPIC Consortium Meeting Palermo 14-16 Oct 2003Palermo 14-16 Oct 2003

Andy Read, University of LeicesterAndy Read, University of LeicesterFor the XMM-LSS consortiumFor the XMM-LSS consortium

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



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 and good PSFopens a new area for the study of the cluster 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 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



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 SAS (emchain and epchain) processingStandard 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: 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



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:RASS



‘‘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

- 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 & Ext. 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

- XMM Simulations: (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)

-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

Sergio Dos Santos, Saclay



• 55 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 procedureEPIC image + contours CFHT 3-colour VRI image + EPIC contours



photo-zphoto-z

CFHT I-band image

EPIC contours



Predicted z (photometric): Predicted z (photometric):

MeasuredMeasuredz = 0.61 !z = 0.61 !

Sources ~1’ from centre

All sources



CFH12k I-bandCFH12k I-band

EPIC contours

Nearby group



Cluster without X-ray counterpart

(‘red sequence’ detection, z~0.3-0.4)

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

EPIC contours



A structure at z~1



006 012

EPIC contours on CFHT images



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 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 tied between 3

instruments, normalization free



2-D model contours overlayed on 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)

the xmm large scale structure (xmm-lss) survey: x-ray analysis and first results andy read...

Documents

xmmlss survey characteristics

cluster lss able

university of leicesterfor

clusters z

galaxy cluster

cluster correlation

large fov

new area