Capabilities and Science Drivers for an X-ray Surveyor Mission

Harvey Tananbaum (SAO)On behalf of the X-ray Surveyor community

August 20, 2015The Universe in High-resolution X-ray Spectra

• MSFC ACO Team Led by Randall Hopkins & Andrew Schnell

• Strawman definition: Spacecraft, instruments, optics, orbit, radiation environment, launch vehicle and costing

• Performed under the guidance of an informal mission concept team comprised by:

X-ray Surveyor Strawman Mission Concept

J. A. Gaskin (MSFC), A. Vikhlinin (SAO), M. C. Weisskopf (MSFC), H. Tananbaum (SAO), S. Bandler (GSFC), M. Bautz (MIT), D. Burrows (PSU), A. Falcone (PSU), F. Harrison (Cal Tech), R. Heilmann (MIT), S. Heinz (Wisconsin), C.A. Kilbourne (GSFC), C. Kouveliotou (GWU), R. Kraft (SAO), A. Kravtsov (Chicago), R. McEntaffer (Iowa), P. Natarajan (Yale), S.L. O’Dell (MSFC), A. Ptak (GSFC), R. Petre (GSFC), B.D. Ramsey (MSFC), P. Reid (SAO), D. Schwartz (SAO), L. Townsley (PSU)

The Strawman X-ray Surveyor Concept is a Successor to Chandra

Incorporates relevant prior (Con-X, IXO, AXSIO) development and Chandra heritage

• Angular resolution at least as good as Chandra

• Much higher photon throughput than Chandra

Limits most spacecraft requirements to Chandra-like

Achieves Chandra-like cost

($2.95B for Phase B through Launch)

Optics & Instruments

Chandra X-Ray Surveyor

Relative effective area (0.5 – 2 keV) 1 (HRMA + ACIS) 50

Angular resolution (50% power diam.) 0.5” 0.5”

4 Ms point source sensitivity (erg/s/cm2) 5x10-18 3x10-19

Field of View with < 1” HPD (arcmin2) 20 315

Spectral resolving power, R, for point sources

1000 (1 keV)160 (6 keV)

5000 (0.2-1.2 keV)1200 (6 keV)

Spatial scale for R>1000 of extended sources

N/A 1”

Wide FOV Imaging 16’ x 16’ (ACIS)30’ x 30’ (HRC)

22’ x 22’

• High-resolution telescope

• X-ray Microcalorimeter Imaging Spectrometer

• High Definition Imager

• Critical Angle Transmission Grating

Concept Payload for:FeasibilityMassPowerMechanicalCosting

NOT THE FINAL CONFIGURATION

• Build upon segmented optics approaches for Con-X, IXO, AXSIO- The segmented optics approach for IXO was progressing and a

~10″ angular resolution was demonstrated

• Follow multiple technology developments for the reflecting surfaces

Light-Weight, Sub-Arcsecond Optics

IntegrationFabrication Alignment & Mounting

Optics – Specifications & Performance

• Wolter-Schwarzschild optical scheme

• 292 nested shells, 3m outer diameter, segmented design

• 50×more effective area than Chandra

Short segments and Wolter-Schwarzschild design yields excellent wide-field performance.

• 16x larger solid angle for sub- arcsecond imaging

• 800x higher survey speed at the CDFS limit

Chandra Surveyor - Flat surface - Optimum

Angular Resolution Versus Off-axis AngleE < 2 keV

Adjustable Optics – Piezoelectric (SAO/PSU)

• Micron-level corrections induced with <10V applied to 5–10 mm cells• No reaction structure needed• High yield — exceeds >90% in a university lab• High uniformity — ~5% on curved segments demonstrated• Uniform stress from deposition can be compensated by coating• Row/column addressing

• Implies on-orbit correction feasible• 2D response of individual cells is a good match to that expected

X-ray reflectingcoating

Depositedactuator layer

Outer electrodesegment

Differential Deposition (MSFC/RXO)

7.1″ to 2.9″ (HPD – 2 reflections) in two passes

0 20 40 60 80 100 120 140 160 180-2000

-1500

-1000

-500

0

500

1000

1500

mm

Ang

stro

ms

Profile pre- & post- correction

pre-correctionpost1-correctionpost2-correction

Ang

stro

ms

mm along surface0

1

2

3

4

5

6

7

8

7.08

3.68

2.87arc

sec

on

ds

Calculated HPD

pre-correctionpost1-correctionpost2-correction

HP

D (

arcs

econ

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3.72.9

7.1

Black Holes: From Birth to Today’s Monsters

What is their origin? How do they co-evolve with galaxies and affect environment?

Black Holes: What is the Nature of Their Seeds?

What is their origin?

Light seeds: Pop III star remnants, MBH~102 M☉

Collapse of nuclear star cluster, MBH~103 M☉

Massive seeds: Direct collapse of supermassive star or a quasi-star object, MBH~105 M☉

Sustained super-Eddington growth to MBH~104 M☉

Nature of Black Hole Seeds — First Accretion Light in the Universe

Simulated 2x2 arcmin deep fields with JWST, X-ray Surveyor, and ATHENA

• X-ray confusion limit for ATHENA is 2.5×10-17 erg/s/cm2 (5× worse than current depth of CDFS). Corresponds to MBH ~ 3×106 M☉ at z=10 — above seed mass range. Confusion in O&IR id’s further increases the limit (MBH~107 M☉ at z=8 per ATHENA team).

• Each X-ray Surveyor source will be associated with a unique JWST-detected galaxy. Limiting sensitivity, ~1×10-19 erg/s/cm2, corresponds to LX ~ 1×1041 erg/s or MBH ~ 10,000 M☉ at z=10 —well within the plausible seed mass range.

• JWST will detect ~2×106 gal/deg2 at its sensitivity limit (Windhorst et al.). This corresponds to 0.03 galaxies per 0.5″ X-ray Surveyor beam (not confused), and 3 galaxies per ATHENA 5″ beam (confused).

Cycles of Baryons In and Out of Galaxies

Generation of hot ISM in young star-forming regions. How does hot ISM push molecular gas away and quench star formation?

How did the “universe of galaxies” emerge from

initial conditions?

Structure of Cosmic Web through X-ray observations of hot

IGM in emission

Galaxy Formation: The Nature of Feedback

~ 40% of baryons are converted to stars, ~ 60% ejected outside

~ 30% observable in UV absorption

~ 30% heated to X-ray temperatures — unique feedback signature

Required observations: detect and characterize hot halos around Milky Way-size galaxies to z~1.

Required capability: ~ 100× sensitivity & angular resolution to separate diffuse emission from bright central sources

T<10,000 KT~100,000 K T>1,000,000 K

150 kpc150 kpc

Simulated 500 kpc box around a Milky Way type galaxy.Simulated 500 kpc box around a Milky Way type galaxy.

What Physics is Behind the Structure of Astronomical Objects?

Plasma physics, gas dynamics, relativistic flows in astronomical objects:

•Plasma flows in Solar system, stellar winds & ISM via charge exchange

•Supernova remnants

•Neutron star (EOS) and particle acceleration in pulsar wind nebulae

•Jet-IGM interactions

•Hot-cold gas interfaces in galaxy clusters and Galactic ISM

•Off-setting radiative cooling in clusters, groups & galaxies

•…

Required capability: high-resolution spectra and resolving relevant physical scales

Capability Leap: High Throughput X-ray Gratings Spectroscopy

Chandra HETG spectrum of NGC 3783. Note the wealth of emission and absorption lines with λ>~10Å (E<~1 keV)

X-ray Surveyor gratings will provide R≈5000 and 4000 cm2 effective area: 250× throughput and 5× resolving power compared to Chandra

(50× throughput and 20× resolving power compared to XMM Newton)Physics of the “New Worlds”, e.g:

•Star-planet interactions & atmospheres of “hot Jupiters”

•Stellar coronae, winds, & dynamos in sub-stellar regime

Neutron star photospheres

Inner workings of the black hole central engine, e.g:•spectroscopy of outflows

•tidal disruption events

New Capability: Add 3rd Dimension to the Data

X-ray microcalorimeter will provide high-resolution, high throughput spectroscopy with 1 arcsec pixels — detailed kinematics, chemistry & ionisation state of hot plasmas

Plasma Physics with Detailed 3D Tomography

Unsharp mask imageUnsharp mask image

ripples with ripples with thin (< 1″) interfacesthin (< 1″) interfaces

Sound waves (in-plane motions) in viscous plasma (Fabian et al 2003)?

Turbulence (line of sight motions) in stratified atmosphere (Zhuravleva et al 2015)?

Chandra image of Perseus cluster: energy output from SMBH balances radiative cooling.

Athena X-ray Surveyor

Chandra

Key Goals:• Sensitivity (50× better

than Chandra)

• R≈1000 spectroscopy on 1″ scales, adding 3rd dimension to data

• R≈5000 spectroscopy for point sources

✓ Area is built up while preserving Chandra angular resolution (0.5″)

✓ 16× field of view with sub-arcsec imaging

Key Goals:•Microcalorimeter spectroscopy (R≈1000)

•Wide, medium-sensitivity surveys

Area is built up at the expense of coarser angular resolution (10× worse) & sensitivity (5× worse than Chandra)

X-Ray Surveyor Science Workshop

•Location: National Museum of the American Indian, Washington, D.C.

•Date: October 6, 7, 8th

•Website: http://cxc.harvard.edu/cdo/ xray_surveyor/

•Registration: $100

•Format: Invited + Contributed + Posters + Breakout Sessions

Science Organizing CommitteeJessica A. Gaskin (MSFC), Martin C. Weisskopf (MSFC), Harvey Tananbaum (SAO), Alexey Vikhlinin (SAO), Fabbiano Giuseppina (SAO), Christine Jones (SAO), Eric Feigelson (PSU), Neil Brandt (PSU), Leisa Townsley (PSU), Dave Burrows (PSU), Priya Natarajan (Yale), Maxim Markevitch (GSFC), Andrey Kravtsov (Chic.), Steve Allen (Stanford), Sebastian Heinz (Wisc.), Chryssa Kouveliotou (GWU), Roger Romani (Stanford), Feryal Ozel (Ariz.), Richard Mushotzky (UMD), Mike Nowak (MIT), Rachel Osten (STSCI)

• NASA Astrophysics Division white paper: Planning for the 2020 Decadal Survey

• Provided an Initial list of missions drawn from 2010 Decadal Survey and 2013 Astrophysics Roadmap that includes the X-ray Surveyor

• The three NASA Program Analysis Groups (PAGs) to coordinate community discussion to review and update list of missions

• PAG reports will be sent to the Astrophysics Subcommittee and then to the Astrophysics Division for selection of mission concepts to study

• Will result in a call for Science and Technology Definition Teams and assignment of lead NASA Center for each study

2020 Decadal Prioritization

http://cor.gsfc.nasa.gov/copag/rfi/

• Scientifically compelling: frontier science from Solar system to first accretion light in Universe; revolution in understanding physics of astronomical systems

• Leaps in Capability: large area with high angular resolution for 1-2 orders of magnitude gains in sensitivity, field of view with subarcsec imaging, high resolution spectroscopy for point-like and extended sources

• Feasible: Chandra-like mission with regards to cost and complexity with the new technology for optics and instruments already at TRL3 and proceeding to TRL6 before Phase B

Unique opportunity to explore new discovery space and expand understanding of how the Universe works and how it came to look the way we see it

X-ray Surveyor