Wide Field X-ray Telescope (WFXT)

Transcription

1 Wide Field X-ray Telescope (WFXT) Stephen Murray on behalf of The WFXT Team JHU, CfA, MSFC, GSFC, ESO, INAF-Brera, INAF- Bologna, INAF-Trieste, INAF-Capodimonte, U.Naples, U. Trieste, ASI Science Center,

2 WFXT Collaboration JHU: Stephen S. Murray (PI), Kip Kuntz, Riccardo Giacconi, Timothy Heckman, Suvi Gezari APL: Hal Weaver, Carey Lisse, Neil Miller, Cheryl Reed CfA: Alexey Vikhlinin, William Forman, Christine Jones, Andrew Goulding, Paul Reid, Andreas Zezas, Pepi Fabbiano MSFC: Martin Weiskopf, Brian Ramsey, Ron Elsner, Steve ODell GSFC: Andrew Ptak MIT: Mark Bautz Dartmouth: Ryan Hickox PSU: Niel Brandt, Eric Feigleson, Don Schneider Princeton: Neta Bahcall Stanford: Steve Allen MSU: Megan Donahue, Mark Voit U. Michigan: Gus Evrard STScI: Kathryn Flanagan, Carol Christian U. Chicago: Andrey Kravtsov U. Waterloo: Brian McNamara ESO: Piero Rosati, Paolo Padovani MPE: Rashid Sunyaev U. Trieste: Stefano Borgani U. Naples: Maurizio Paolillo INAF-Brera: Giovanni Pareschi, Oberto Citterio, Gianpiero Tagliaferri, Sergio Campana, Ginevra Trinchieri, Marta Civitani, Alberto Moretti, Anna Wolter INAF-Bologna: Roberto Gilli INAF-Trieste: Paolo Tozzi, Joana Santos, Barbara Sartoris INAF-Capodimonte: Massimo Della Valle, Domitilla de Martino ASI Science Data Center: Paolo Giommi

3 Mission Science Goals Cosmology with Clusters of Galaxies Dark Energy EoS and its evolution Growth of structure, deviations from GR Physics of Clusters of Galaxies ICM entropy, metalicity enrichment, feedback AGN Growth and Evolution Accretion and feedback history of SMBHs AGN clustering and dark matter halos The Milky Way and Nearby Galaxies Hot gas distribution on Milky Way Star formation rate and X-ray properties

4 Science of Future of X-ray Surveys First SMBHs, galaxy/agn co-evolution, feedback mechanisms, cosmic cycle of baryons, structure formation, precision cosmology - all require: High sensitivity Wide survey area Good angular resolution Can be done with a specific X-ray optical design and modest technological development, ready to be done now

5 Enabling Technology is (essentially) in hand Wide field X-ray optics design is understood Wide field performance has been demonstrated by Brera/MSFC ( improved manufacturing in development) Detectors based on MIT Lincoln Lab CCDs that have already been flown (Chandra and Suzaku) May consider newer APS (CMOS) detectors Spacecraft requirements are far from state-ofthe art (roughly 5-10 times less demanding than Chandra) Photon counting image reconstruction standard for X-ray spatial-spectral detectors

6 Beyond erosita: WFXT Three co-aligned telescopes 5 HEW 1 degree FoV CCD camera 10x Chandra effective 1 kev Chandra-like HEO or Sun-Earth L2 Low-earth orbit (550 6 deg) minimizes particle background Robust multiple telescope/ detector system Large field of regard Long observations

7 WFXT: SDSS for X-rays Shallow, Medium and Deep Surveys Dramatic advance over existing/planned missions in combined solid angle/ sensitivity Proven large discovery space XBootes Three (two) surveys Shallow 15-20,000 deg 2 Medium 3000 deg 2 (750 times COSMOS) Deep 100 deg 2 (800 times CDF) GO Program 40% Observing time

8 WFXT Surveys WFXT Deep Survey = 100 sq deg ~800 times solid angle equivalent of Chandra Deep Fields Description of the WFXT Surveys Quantity Survey Deep Medium Shallow Ω (deg 2 ) 100 3,000 15,000 Exposure 400 * ksec ksec 2-3 ksec Total Time 1.5 yr 1.5 yr 2.0 yr Shallow Medium Smin(0.5-2 kev) point-like erg s -1 cm -2 at 3σ 4.0x x x10-15 Total AGN Detected ~4.7x10 5 ~4.4x10 6 ~7x10 6 Smin(0.5-2 kev) extended erg s -1 cm -2 at 5σ 1x x x10-15 Deep Total Clusters/Groups ~5x10 4 ~3x10 5 ~2x10 5 * Deep surveys will consist of ~10 x 40 ksec exposures over several years for time variability studies

9 Angular resolution HEW= 5 over the entire FoV Improve sensitivity for point and extended sources, AGN/cluster/group discernment at any redshift Minimize source confusion, especially confusion free Deep survey Efficient identification of optical counterparts, Chandra-like id accuracy (<1 radius error circle, >90% right IDs), essential for 5x10 6 AGN and clusters! Detect sharp features of the ICM (shocks, cold fronts, cavities) Resolve cool cores of z>1 clusters (essential for cosmological applications, reliable mass proxy) HRI PSPC ROSAT Lockman Hole survey (25 vs 5 resolution) (Lehmann et al. 2001)

10 Figure of Merit: Discovery Speed Speed in carrying out large sensitive surveys and identifying distinct sources. M = (FoV) x (A eff )/(HEW avg ) 2 cm 2 Insert shows the figure of merit for survey discovery speed (Grasp/HEW 2 ). WFXT is about 100 times better than any past or planned X-ray mission. Wide field design matters!!! Cumulative field of view available at a given angular resolution (HEW) as a function of HEW for five missions.

11 Simulation: one medium survey tile Chandra COSMOS- 1.8 Msec (1 sq deg) Elvis 2009 [0.5-2] kev [2-4.5] kev [4.5-7] kev 36 Chandra 50 ksec each

12 Simulation: one medium survey tile Chandra COSMOS- 1.8 Msec (1 sq deg) WFXT 13 Ksec Elvis 2009 Rosati and Tozzi [0.5-2] kev [2-4.5] kev [4.5-7] kev 36 Chandra 50 ksec each 1 WFXT 13 ksec Bands (kev) [0.5-1] [1.0-2] [2.0-7]

13 Simulation: one medium survey tile Chandra COSMOS- 1.8 Msec (1 sq deg) WFXT 13 Ksec Elvis 2009 Rosati and Tozzi [0.5-2] kev [2-4.5] kev [4.5-7] kev 36 Chandra 50 ksec each 1 WFXT 13 ksec Bands (kev) [0.5-1] [1.0-2] [2.0-7] WFXT simulation: Same sources as Chandra 5 arc second HEW, not confusion limited ~100 x faster surveys than Chandra

14 Simulation: one medium survey tile Chandra COSMOS- 1.8 Msec (1 sq deg) WFXT 13 Ksec Elvis 2009 Rosati and Tozzi AGN counts (Medium + Deep Surveys) With > 400 counts [0.5-2] kev [2-4.5] kev [4.5-7] kev ~500,000 AGN with >400 cts, with full spectral characterization (obscuration, z, etc.) Bands (kev) [0.5-1] [1.0-2] [2.0-7] 36 Chandra 50 ksec each 1 WFXT 13 ksec WFXT simulation: Same sources as Chandra 5 arc second HEW, not confusion limited ~100 x faster surveys than Chandra

15 Obscured AGN with WFXT L(2-10 kev) = 6x10 44 erg/s z > N thick Norman 2002, Comastri 2011 Pessimistic case assumes an exponential decline towards high-z in the space density of AGN at all luminosities. Simulated 400 ksec spectrum of CT, high redshift AGN N H =10 24, Γ=1.82, F(2-10 kev)=3x10-15 erg cm -2 s -1 EW=1 kev, Centroid to ~2%. 530 counts total Strong iron line and allows an accurate redshift determination from the X-ray data alone.

16 AGN at z>6 with WFXT WFXT detects close to 1000 unobscured z>6 QSO s with more than 400 cts, similar number obscured Synergistic: Euclid and LSST identify the WFXT sources, WFXT picks out the AGN (especially high-z, obscured) On the right is a plot of the limiting bolometric magnitude versus sky coverage for various surveys. The shaded regions show the number of unobscured AGN at z.6 that would be detected in these surveys, under the assumption that there is a rapid exponential decline in the space density of AGN at all luminosities. WFXT will detect ~1000 high-z unobscured AGN with more than 400 counts (and in fact a similar number of obscured AGN). This complements Euclid and LSST (and WFIRST) in two ways- WFXT identifies the high-z AGN in these surveys and provides directly their redshifts from Fe the Fe line (if present)

17 AGN Clustering Correlation function <=> halo mass & interactions correlation function separation Clustering on large scales tells us HALO MASS: How is the growth of black holes related to the growth of largescale structure? log (halo mass) Radio X-ray clear trends, but still large IRACuncertainties redshift

18 AGN Clustering Correlation function <=> halo mass & interactions correlation function separation Clustering on large scales tells us HALO MASS: How is the growth of black holes related to the growth of largescale structure? log (halo mass) Radio X-ray clear trends, but still large clear uncertainties trends, but still large IRACuncertainties redshift

19 log (halo mass) correlation function AGN Clustering Correlation function <=> halo mass & interactions Clustering on small scales tells us MERGERS AND INTERACTIONS Theoretical make different predictions for AGN clustering but differences can be small we need much better statistics: WFXT Radio X-ray IRAC redshift

20 log (halo mass) correlation function AGN Clustering Correlation function <=> halo mass & interactions? small scales poorly understood for AGN Clustering on small scales tells us MERGERS AND INTERACTIONS Theoretical make different predictions for AGN clustering but differences can be small we need much better statistics: WFXT Radio X-ray IRAC redshift

21 WFXT simulation: 13 ksec WFXT simulation (one tile from the medium survey) using 13 the Chandra catalog (Bignamini, Santos, Tozzi for the WFXT team) 13

22 z=1.6 WFXT simulation: 13 ksec z=2.0 WFXT simulation (one tile from the medium survey) using 13 the Chandra catalog (Bignamini, Santos, Tozzi for the WFXT team) 13

23 z=1.6 WFXT simulation: 13 ksec z=2.0 Cluster counts (Medium + Deep Surveys) >3,000 clusters at z>0.5, from which z can be be measured from Fe line WFXT simulation (one tile from the medium survey) using 13 the Chandra catalog (Bignamini, Santos, Tozzi for the WFXT team) 13

24 Not just a cluster counting machine Characterize ICM properties and measure mass proxies for thousands of clusters at z>1. Trace the epoch of entropy injection and metal enrichment of the ICM. Study the intense dynamics of protocluster assembly at z~2. Multi-λ synergies: a vast scientific legacy for decades to come Path finder for follow-up studies with ELTs, ALMA, Cluster Survey Directly measured z and kt: >~5000 total z>1: ~2,000 T profiles and abundances z>0.5: ~500 ROSAT WFXT z>1 XMM, z>1 Detected clusters: ~200,000 total z>0.5: ~125,000 z>1: ~50,000

25 Cluster Science Examples z=1.5 The Bullet Cluster (z=0.3, T=14 kev) as observed with WFXT Deep survey: 400 ksec z=1.0 Structure Cosmology z= Piero Rosati and Joana Santos (INAF, Trieste) and the WFXT Team Redshifts and mass proxies are derived from the WFXT alone. w 0 and Ω DE are measured with 6% and 1% accuracy (68% c.l.), when a flat Universe is assumed.

26 Mission Implementation - WFXT Three modules approximately co-aligned Telescope, detector, aspect system, bench Photon-counting, post-facto image reconstruction Modified Suzaku CCDs (2048x2048) Area 55 fused silica shells/module 2-3 mm thick, m diameter m long 5.5 m focal length 300 kg/module (with structure)

27 Wide Field Telescope Manufacturing Process Prototype Shell X-ray Test at Panter - Dec 12, 2011 ~10X increase in area/mass compared with Chandra

28 X-ray Testing at MPE Panter Prototype in Panter Chamber Ring Focus (200 mm out of focus) Round shell shows that the support mount works 0.28 kev Metrology predicts X-ray performance

29 Spacecraft and Launch:WFXT Payload fits within the standard Atlas V fairing System requirements are all well within current capabilities. WFXT is an order of magnitude less demanding than Chandra for attitude control and knowledge. Margins on mass ( 30%) and power ( 80%) are large Item Mass (kg) includes contingency Power (W) includes contingency S/C Bus - dry Science Payload Flight System - dry Propellant 49 Flight System - launch Capacity Margin 30% 79%

30 Cost EstimateS Element Estimated Cost (FY12$) PM/SE/QA 91.0 Science Team 32.5 Science Instrument SpaceCraft Ground System 65.0 System I&T 71.5 MO&DA 48.0 EPO 10.0 GO 25.0 Total Launch Total Example: Each element includes reserves of 30% except for EPO and GO WFXT has been studied three times in the past two years: 1. Submitted to 2010 Decadal Survey RFI Estimate 2. Notional Wide Field Imager Mission studied by GSFC- MDL as part of the X-ray Community Science Team 3. WFXT studied at NASA MSFC Advanced Concepts Office (ACO) All estimates consistent!

31 WFXT: The Ultimate X-Ray Survey WFXT addresses many science objectives Cosmology with Clusters of Galaxies Physics of Clusters of Galaxies AGN Growth, Evolution and Variability The Milky Way and Nearby Galaxies WFXT is technically ready to start and launch in 5.5 years Large mass and power margins above standard contingencies TRL >= 6, except for telescope currently at TRL=4, development already in place to achieve TRL 6 by the end of Phase A WFXT is a moderate class mission Cost < $1B (US FY12) including 30% reserves, launch, operations and a funded GO program Validated by several independent cost estimate $780M + launch wfxt.pha.jhu.edu or