Hard Xray Black Hole Surveys in Space and Time: EXIST Concept

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Hard X-ray Black Hole Surveys in Space and Time
EXIST Concept

• Josh Grindlay
• Harvard
• International Workshop
• High Energy Astrophysics in the Next Decade
• (Tokyo)
• June 21, 2006

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Outline of talk

• Key HEA and EXIST science questions
• Overview of EXIST as Black Hole Finder Probe
  (BHFP)
• Current surveys to answer them
• X-ray Chandra, XMM, Swift-XRT, Suzaku
• Hard X-ray INTEGRAL, Swift-BAT, Suzaku/HXD
  BAT-slew
• TeV HESS, VERITAS
• Upcoming surveys
• Agile, GLAST, LSST (approved)
• MAXI, Lobster/eROSSITA, HXMT, Symbol-X
  (uncertain?)
• Ultimate spectral-temporal HX survey EXIST
• Mission study for BHFP in Beyond Einstein
  Program

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Key HEA Survey EXIST Science (from the Galaxy
to Pop III GRBs)

• Nature/number of BHs vs. NSs, WDs in Galaxy
• Blazar spectra _at_TeV vs. 100keV origin of EBL
• Dormant AGN (tidal disruption by SMBHs)
• SMBHs in every galaxy? BH masses from power spec.
• Obscured AGN and origin of CXB
• GRBs from Pop III stars birth of First BHs
  probes of IGM

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Overview of BHFP-EXIST Science and Design

• Hard X-ray (3-600 keV) all-sky imaging each
  orbit to measure
• Obscured AGN and accretion (BHs) vs. nuclear
  (stars) luminosity of universe
• GRBs out to z 20 and first stellar Black Holes (
  5-20X Swift sensitivity)
• Stellar Black Holes in Galaxy IMBHs in Local
  Group BHs as probes

IMDC design Dec. 2004
e.g., EXIST measures Cen-A every orbit
characteristic time variability (QPOs) constrain
BH mass

• Mission Design parameters
• Extend ROSAT sens. (5 x 10-13cgs) to 3-150 keV
  with 0.9-5 resolution 10 positions
• Two wide-field coded aperture telescopes 10-600
  keV (6m2 CZT) 3-30 keV (1m2 Si)

http//EXIST.gsfc.nasa.gov
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Expected EXIST Survey Sensitivity
Continuum
Narrow Line
LET 3-30 keV HET 10-600 keV 0.05mCrab 5 x
10-13 cgs, (over any band Elow 2Elow) 5s,
?1yr, 20-40 duty cycle any source
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Hard X-ray Sky

• Hard X-ray (10-600 keV) sky not yet surveyed to
  ROSAT sensitivity. EXIST would be 20X more
  sensitive than Swift or INTEGRAL and cover full
  sky
• EXIST will detect 3 x 104 sources, 10?
  positions, 3-600 keV spectra
• EXIST would provide unique temporal survey full
  sky imaging each orbit

Previous Hard X-ray Sky HEAO-1, BeppoSAX
2010 Hard X-ray Sky Swift INTEGRAL
2016(?) Hard X-ray Sky EXIST
HXMT, eROSSITA?
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Survey BHs, NSs and WDs in Galaxy

• Integral and Swift/BAT discovery of hard,
  variable giants

Wind-fed accretion onto NS or BH Provides
variable, high NH hard sources, with Lx gt1036
erg/s as seen by Integral
Simulations by J. Blondin
Complements Swift discovery of transients
hard pulsars (15-150 keV) Lx gt1036 erg/s HESS
(TeV) discovery of Be-binary PSRs
Complements ChaMPlane Lx1032 erg/s, high NH
sources which are qLMXBs and CVs
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The Chandra Multiwavelength Plane Survey
(ChaMPlane)

• Josh Grindlay, Ping Zhao, JaeSub Hong, Maureen
  van den Berg, Silas Laycock (Harvard, CfA)

Distribution of ChaMPlane fields (?ACIS-I, vs.
oACIS-S) locations, exp. Times, NH See
Grindlay et al, Hong et al, Laycock et al, Zhao
et al (2005, ApJ)
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Stellar mass BHs vs. CVs in Galactic Bulge?

• ChaMPlane survey and optical-IR followups a
  mixture of magnetic CVs, NSs and BHs in SgrA and
  Bulge

IR variable (red star in 0.5 Chandra circle)
for a Muno source in H1 class Possible
CH-Cam BH-LMXB? (Laycock et al 2006)
Optical IDs with OGLE variables In Stanek
Window probable Wind-fed CVs, symbiotics
(IPs?) (van den Berg et al 2006)
Quantile diagram (see Hong et al 2004) for 900
sources within 7 of SgrA spectral
classification IDs (Hong et al 2006)
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Survey Stellar BHs IMBHs in Local Group with
EXIST

• EXIST detects all bright stellar BHs in
  transients (Lx(gt10 keV) 1037-38 erg/s)
  throughout Galaxy, LMC/SMC and M31. Reveal
  population of obscured HX sources found with
  INTEGRAL/Swift discrete sources at gt20 keV
• Isolated stellar BHs in Galaxy and IMBHs in Local
  Group accreting
• via Bondi-Hoyle (with 10-4 efficiency) from
  GMCs nearly Compton thick
• Faint BH transients in Central Galactic Bulge?
  BHs in
• nuclear cusp (cf. Alexander Livio 04) detected
  if Lx(gt10 keV) 1035 erg/s
• CI Cam type outbursts (1-2d?) of Bulge BH vs.
  WD binaries around SgrA

Chandra view of central Bulge ( 2o x 1o)
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New Swift/BAT Slew Survey (BATSS) (being
developed at CfA for Swift/BAT science EXIST
testing)

• BAT slews 60X/day between pointings photon data
  could be sent down (1min/slew) for imaging
  all-sky survey (15-150 keV), 1h/day fast timing
  gives
• GRBs Long (High z) GRBs (30 more coverage)
• New transients pulsar monitoring
  (70mCrab/orbit)
• Stacked sky images for fainter transients
  (20mCrab/d90sky)
• New persistent sources
• Test scanning for EXIST

70sec BAT slew image across CygX-1 (S/N19) to a
GRB (which was the z 6.3 event!)
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BATSS enables 30 more GRBs 90 sky/day
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BATSS coverage sensitivity vs. time(e.g.
10days in May, 2006)
30 increased detection probability for GRBs,
transients, or steady sources is relatively
constant w.r.t. GRB/transient duration. BUT
only BATSS would provide photon timing normal
BAT data binned in 5min integ. Enables first
all-sky PSR monitoring Survey since BATSE
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TeV Blazar surveys constrain EBL IRB(but only
if constrain HX spectrum and variability)

• Ongoing HESS and (soon) VERITAS surveys
  discover new Blazars for comparison with X-ray
  HX spectra

New blazars detected by HESS at large z !
H2356-309 (z0.165), 1ES1101-232 (z0.186)
Reconstructing EBL (HESS collab., submitted to
Nature)
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X-? Blazar surveys

• Agile GLAST will discover flaring Blazars
  (30MeV-30 GeV)
• Swift/BAT, INTEGRAL give partial HX coverage
• Swift/XRT, Suzaku, Chandra, XMM give partial
  X-ray coverage
• Need 5-300 keV imaging monitoring to constrain
  SSC

Blazar SSC models
Synch. IC
GLAST
Mkn 421 flares 0.5h 2d
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Blazar Spectral variability Extragalactic
Background Light (EBL) Stellar vs. Accretion
Luminosity of Universe

• EBL Hard x-ray (synchrotron) spectral breaks
  (5-200keV) for Blazars at known redshift allow
  SSC ?-ray (10 GeV - 10 TeV) spectral breaks
  measured by GLAST and HESS/VERITAS to constrain
  origin of diffuse IR background
• Time-variability spectral breaks required from
  simultaneous HX measurements. Wide-field HX
  imaging needed to match GLAST

EXIST
VERITAS
GLAST
SSC model for Mkn 501 (Coppi Aharonian 1999)
EXIST will provide the continuous HX
spectral-monitoring to study Blazars and
non-thermal AGN to constrain diffuse IR
(10-100µ) background from obscured AGN and thus
nuclear vs. accretion luminosity of the
universe Complements GRB science star formation
vs. redshift from LGRBs vs. z
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Dormant SMBHs revealed by Tidal disruption(and
BH masses from AGN power spectra)
Tidal disruption of stars spiraling into
Dormant SMBHs with mass 107 Mo if 1 of Lacc
in HX band, 10-5 events/year/Mpc3 allow EXIST to
see 10-30 flares/yr out to 200Mpc! (Grindlay
2004). HX spectral comp. confirmed with PL
spectral decay of RX1242 Sub-giants with WD
cores are gravitational wave LISA triggers.
Artists conception of tidal disruption of star
in RXJ1242-1119 detected with ROSAT (1991) and
confirmed with Chandra (Komossa et al 2004).
Possible soft (5keV) prompt (1d) burst
detectable out to 30 Mpc directly with EXIST
(LET) and with MAXI or LOBSTER LISA
trigger Measure 106-7M? SMBH content/evolution
of nearby galaxies (understand BH-Bulge mass
relation BH-galaxy evolution!)
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Obscured AGN and origin of the CXB
NGC1068 NGC6240 (Vignati et al 99)
Chandra XMM surveys find gt40 unresolved CXB
from obscured AGN
EXIST will find gt1-10 obscured AGN/square degree
and obtain first all-sky measure of Seyfert 2
QSO 2 luminosity function and
constrain obscuration vs. z for supermassive BHs.
Provide required all-sky survey for rare (Type 2
QSOs) and Lx dependence of NH
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Birth of Stellar BHs at z5-20

• Long-GRBs are from SNIb,c likely due to
  stellar BH formation
• Likely that first stars were 100Mo and collapse
  to BHs GRBs
• Short-GRBs from merging NSs in globulars
  (Grindlay et al 2006) suggests Short GRBs
  enhanced at z of globular cluster formation?

EXIST detects GRBs to z20 from PopIII BHs at
re-ioniz. epoch suggested by WMAP. Photometric z
from Lum-Epeak need response to
Egt300keV, And from Lum-Variability
(Paczynski Relation) need large area
det. X-ray flashes and high z GRBs need
response to E5 keV 5sr instantaneous GRB
coverage And increased sensivity Rare (high z?)
events 3-5GRBs/d!
Flux vs. detected Epeak for GRBs from z1 (top )
to 10 (bottom ) for Epeak 30, 100, 300,
1000keV if emitted at z1 vs. sensitivities (Band
2004).
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Highest z stellar universe uniquely from GRBs

• Swift GRB at z 6.3 shows
• high z universe is accessible
• Broader energy band, higher
• sensitivity needed for z20 PopIII
• IR from space needed for z!
• GRBs provide back-light
• for IR spectroscopy of
• IGM, gas, galactic structure
• back to re-ionization
• EXIST JWST?

Record-setting z vs. time GRBs are gaining fast!
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EXIST Current Baseline Mission Design Concept
(GSFC ISAL IMDC runs Oct. Dec. '04)
High Energy Telescopes (HET 10 600 keV)
Zenith (Yaw)
Thermal Radiator
Orbit Normal (Pitch)
Velocity (Roll)
Low Energy Telescopes (LET 3-30 keV)
Solar Panels (fold-down)

• Survey the hard X-ray sky 50x deeper than
  previous,
• with 10? source positions (5?)
• Cover the 3 to 600 keV band with two telescope
  systems
• HET 10 - 600 keV (5.6 m2 CZT ) and LET
  3 - 30 keV (1.1 m2 Si)

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EXIST Mission Design Parameters

• Free-Flyer (500km, i ? 5-7º, low bkgnd)
• Zenith pointer - scanning nodding for ?full sky
  coverage each orbit (95min)
• 18 coded aperture HE telescopes (6m2 total area
  CZT pixel det.)
• 28 coded aperture LE telescopes (1m2 total area
  Si drift det.)
• Mass, power, telemetry 9500kg, 3KW, 3Mbs
• Delta IV launch (to i 5o orbit)
• Mission lifetime 5 years

Zenith
Nod direction, - scan (/-20o ea. 10min)
Orbit Normal
Orbital scan direction (orbital velocity vector)
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Detector packaging DCU, DCA, DM, Sub-Tel
HET Building a very large area CZT
detector/telescope
Detector Crystal Unit (DCU) Crystal (2x2 cm2)
(with Interposer Board?) 2 x 128 channel
ASIC (with micro-via tech?)
Detector Crystal Array (DCA) 2x2 DCUs (4x4
cm2) FPGA Board
HET 3x6 Sub-Tels (5.6 m2)
Detector Module (DM) 7x7 DCAs (28x28 cm2)
MicroProcessor Board
Sub-Tel Module 2x2 DMs (56x56 cm2) each of
18! Active Passive shields
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Baseline Mission parameters EXIST/HET LET
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Advancing the Mission Design

• The contiguous layout of HET sub-tel modules
  allows very efficient shield sharing and makes
  the overall instrument design simple and
  straightforward.
• The current mission design already meets the
  mission parameters required for science goals.
• However, the current layout introduces some
  unnecessary constraints on spacecraft design due
  to asymmetric packaging for launch.
• Goal Redistribute sub-tel modules symmetric for
  launch and increase total area in LET (and HET).

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New (General Dynamics) Design Concept Symmetric,
smaller solar panels increased LET Area FoV
Zenith
Orbit Normal
HET
Velocity
LET
Solar Panels
Spacecraft Bus
Stowed Delta IV (5m Fairing)
On Orbit
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Side and Top Views of New Design
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Instrument Layout FoV Comparison
HET
HET
LET
LET
131?
112?
154?
160?
64?
64?
65?
65?
Baseline Design HET 5.6m2 (18 mods) LET 1.1m2
(28 mods)
New Configuration HET 6.0m2 (19 mods) LET 1.3m2
(32 mods)
?
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Mission parameters for the new configuration
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Ensuring EXIST Imaging Performance

• A wide dynamic range (gt103-4) to achieve high
  sensitivity impose challenges for coded-aperture
  imaging.
• The main factor for limiting the performance in
  coded-aperture telescopes is noise caused by
  unknown systematics in the system.
• These systematics include non-uniformity in the
  detectors such as detector gaps, dead pixels,
  efficiency variations, background variations,
  etc.
• EXISTs scanning/nodding motion designed for
  surveying the sky is also a key to reduce the
  unknown systematics.
• We demonstrate imaging performance of EXIST by a
  series of progressively realistic simulations.
  Swift/BAT slew imaging tests are in progress and
  demonstration of EXIST detectors and imaging
  planned with ProtoEXIST balloon experiments.

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Example Imaging noise caused by detector
gaps (click for movies)
Artifacts due to gaps start appearing at 0.5 mm
gap in the sky image generated by a simple
correlation without any correction
Scanning motion automatically averages out the
coding noise without need for additional
correction
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Simulated Scanning vs. Pointing with dead-pixels
Assuming a fraction of unknown dead pixels in the
detector, 1 day exposure of one sub-tel in EXIST
HETs
5 ? detection limit with no other source or with
a 1.5 Crab source
Dynamic Range with a 1.5 Crab source
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Scanning vs. Pointing with a partially-coded
source
Assuming a partially coded source in the FoV
unknown 1 mm crystal gap, apply a CLEAN procedure
for the partially coded source
5 ? detection limit with no other source or with
a 1.5 Crab source
Dynamic Range with a 1.5 Crab source
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BAT slew imaging provides on-orbit test And new
Swift/BAT survey science
70sec scan detects CygX-1 _at_19? vs. 14? for
pointing with BAT Noise reduced due to averaging
effects of scan
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Prototyping EXIST

• Balloon program to develop ProtoEXIST
• (Harvard, GSFC, Caltech, Stanford collaboration)
• Phased development (ProtoEXIST1
  ProtoEXIST2)
• (2.5mm 1.2mm pixel pitch direct-bonded
  ASIC)
• Demonstrate detectors packaging, scanning
  imaging and (if ULDB?!) early
• EXIST survey science

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The current test board (poptart) allows testing 4
Detector Crystal Units (DCUs crystal
IPBASIC)
1 DCU 2cm x 2cm X 0.5 cm CZT
Custom ASIC 64ch, 3 x 9mm pkg.,
150microW/channel
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Prototype Detector Performance
Parasitic Capacitance of Input traces on
Interposer board (IPB) (from simulations)
FWHM measurements of a bare IPB using
pulser Internal to ASIC
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Radiation Tests on prototype DCUs for ProtoEXIST1
4.7 keV FWHM from 120 keV (57Co)
4.5 keV FWHM from 60 keV (241Am)
We expect 3 keV FWHM from the next batch (Aug
06) of DCUs with improved (lower capac.)
IPBs. (vs. 1.5 keV for direct-bonded ASICs in
ProtoEXIST2 and EXIST)
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Detector Crystal Arrays (DCAs) for ProtoEXIST1
Detector Crystal Unit (DCU)
ASIC
Top Socket Board
Bottom FPGA Board
FPGA (controls/reads out 8 ASICs on DCA)
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Assembled ProtoEXIST1 DCA (design complete
under fab.)
Enable tiling of 4cm x 8cm CZT arrays with 0.4mm
gaps
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Detector Module for ProtoEXIST1 (256cm2
close-tiled array of 8 DCAs)
HV bias
Detector Crystal Arrays (DCAs)
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Detector Module for ProtoEXIST1
Near gapless Packaging of 16cm x16cm CZT arrays
EXIST sub-tels will have 56 cm x 56 cm CZT arrays.
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Summary

• INTEGRAL and Swift imaging have revealed the rich
  HX sky (obscured binaries, AGN, high z GRBs!)
• Broad band (3 300 keV), large area and wide
  FoV are key. Unique all-sky imaging each orbit
• HX surveys have enormous synergy with GeV-TeV
  (GLAST-VERITAS) studies of Blazars (and EBL)
• Both obscured and dormant SMBHs best studied with
  wide-field very sensitive HX imager
• Highest z universe uniquely measured via GRBs
• EXIST under study for BHFP could launch in
  2016
• See EXIST website (http//EXIST.gsfc.nasa.gov)
  for Study team
• ProtoEXIST1 balloon in 2008, ProtoEXIST2 in 2010