Capabilities and Science Drivers
for an X-ray Surveyor Mission
Harvey Tananbaum (SAO)
On behalf of the X-ray Surveyor community
The Universe in High-resolution X-ray Spectra
August 20, 2015
X-ray Surveyor Strawman Mission Concept
•
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:
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
• Angular resolution at least as good as Chandra
• Much higher photon throughput than Chandra
Incorporates relevant
prior (Con-X, IXO,
AXSIO) development
and Chandra heritage
 Limits
most
spacecraft
requirements to
Chandra-like
 Achieves
Chandralike cost
($2.95B for Phase B
through Launch)
Optics & Instruments
• High-resolution telescope
• X-ray Microcalorimeter
Imaging Spectrometer
• High Definition Imager
• Critical Angle Transmission
Grating
Concept Payload for:
Feasibility
Mass
Power
Mechanical
Costing
NOT THE FINAL
CONFIGURATION
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) 22’ x 22’
30’ x 30’ (HRC)
Light-Weight, Sub-Arcsecond Optics
• 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
Fabrication
Alignment &
Mounting
Integration
Optics – Specifications & Performance
• Wolter-Schwarzschild optical scheme
• 292 nested shells, 3m outer diameter, segmented design
• 50×more effective area than Chandra
Angular Resolution Versus Off-axis Angle
E < 2 keV
Short segments and WolterSchwarzschild 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
Adjustable Optics – Piezoelectric (SAO/PSU)
Deposited
actuator layer
Outer electrode
segment
X-ray reflecting
coating
•
•
•
•
•
•
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
Differential Deposition (MSFC/RXO)
7.1″ to 2.9″ (HPD – 2 reflections) in two passes
Calculated HPD
Profile pre- & post- correction
8
pre-correction
post1-correction
post2-correction
arc seconds
500
Angstroms
Angstroms
1000
0
-500
-1000
-1500
-2000
HPD (arcseconds)
1500
mm along surface
0
20
40
60
80
100
mm
120
140
160
180
7
6
pre-correction
post1-correction
post2-correction
7.08
7.1
5
4
3.68
3
3.7
2
1
0
2.87
2.9
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?
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☉
What is their origin?
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
• 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).
• 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.
• 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
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
T~100,000 K
T<10,000 K
T>1,000,000 K
150 kpc
Simulated 500 kpc box around a Milky Way type galaxy.
~ 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
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
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
(50× throughput and 20×
resolving power compared
to XMM Newton)
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 image
ripples with
thin (< 1″) interfaces
Chandra image of Perseus cluster: energy output from SMBH balances radiative cooling.
Sound waves (in-plane motions) in viscous plasma (Fabian et al 2003)?
Turbulence (line of sight motions) in stratified atmosphere (Zhuravleva et al
2015)?
Athena
X-ray Surveyor
Key Goals:
• Sensitivity (50× better
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)
•
•
than Chandra)
R≈1000 spectroscopy
on 1″ scales, adding
3rd dimension to data
R≈5000 spectroscopy
for point sources
✓ Area
Chandra
is built up while
preserving Chandra
angular resolution
(0.5″)
✓ 16× field of view with
sub-arcsec imaging
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 Committee
Jessica 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)
2020 Decadal Prioritization
•
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
http://cor.gsfc.nasa.gov/copag/rfi/
X-ray Surveyor
• 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