1. ESA’s INTEGRAL Mission
and US support for it
Gerry Skinner
Univ. Md / CRESST / NASA-GSFC
Neil Gehrels
NASA-GSFC 1

2. INTEGRAL Mission Summary
ESA-led Gamma-Ray Mission with significant US and Russian Participation
Launch October 17, Operations approved by ESA until at least Dec 2012
Science
Gamma-ray astronomy (20 keV – 10 MeV)
2 Main gamma-ray instruments – SPI (spectrometer) & IBIS (imager)
INTEGRAL is the only operating or planned mission providing imaging and spectrometry in the MeV energy band
SPI Ge Detectors
IBIS
JEM-X
SPI
OMC
IBIS CdTe Detectors 2 2 2

3. Integral Mission highlights
First detection of polarization in hard X-rays from the Crab nebula - high significance result with independent confirmation by two teams using different instrument configurations
Discovery of supergiant fast X-ray transients and their recognition as a new class of High Mass X-ray Binaries
Gamma-ray line astronomy
First clear detection of 1173 and 1333 keV 60Fe lines
Mapping of 26Al 1809 keV line in galactic distribution and velocity space
Mapping of 511 keV positron annihilation radiation; detection of asymmetry in disk emission
Key role in detecting highly obscured sources
Extragalactic: Obscured AGN
Galactic : highly absorbed transients
Discovery of hard powerlaw spectral components in the quiescent emission of many AXPs and SGRs
INTEGRAL has played a key role in detecting highly obscured AGN, finding that obscured AGN are rarer than required by earlier explanations of the CXB.
The discovery of hard powerlaw spectral components in the quiescent emission of six AXPs and SGRs, lending support to the resonant Compton upscattering model. 3

4. Highlights 1 Gamma-ray Polarization of the Crab Nebula
SPI: Dean et al. Science 2008; IBIS: Forot et al ApJ 2008
π = 46 ± 10 %
Ψ = 123° ± 10°  aligned with pulsar spin axis
Two independent analyses using different Integral instruments reach highly consistent conclusions
MeV ; MeV
More tentative detections of polarization in 2 GRBs and in Cyg X-1 4

5. Highlights 2 Gamma-ray line spectroscopy
26Al keV line
Galactic distribution mapped
Doppler shifts due to rotation measurable
60Fe & 1332 keV lines
Ratio 26Al : 60Fe ± 0.09
constrains mixing and IMF of massive stars
511 keV e+ annhilation line
Strong central bulge inconsistent with 26Al decay chain being dominant origin of positrons
Unexpected asymmetry in inner disk emission 5

6. The US Role in Integral
Flight Hardware contribution to SPI Spectrometer
Pulse Shape Discrimination system (UCSD, UCB) Support ceased 2008
Provision of Ground Support Equipment and technical design input for IBIS Imager (MSFC) Support ceased 2008
One US Mission Scientist (Teegarden) Support ceased 2008
Software and analysis system support for SPI (GSFC) Support ceased 2008
Timing analysis software; Response matrix calculation and updates
Software support at the Integral Science Data Centre (ISDC), Geneva
Support ceased 2008
Provision of Goldstone ground station Still available to ESA, but no longer needed
Funding for US PIs and Co-Is with successful Guest Observer proposals
Support ceased 2010
US Guest Observer Facility
Support ceased 2010; limited support through HEASARC
US Data Archive Mirror
Support continues through HEASARC
PSD to reduce BG
Software support at ISDC - one software person supported at the Geneva Integral Science Data Center through development 6

7. US Refereed Publications
US Scientist Participation in Observations
Statistics up to 2010
137 winning GI proposals with US PIs in AO-1 to 7 (18.5% of total)
55% of AO-6 and AO-7 proposals have US participation
~35 proposals from ~15 institutions funded per year
83 US first author publications (12% of total)
246 US author publications (37% of total)
368 ATELs containing either INTEGRAL direct or follow-up observations
16% of all ATELs 2003-present
US Refereed Publications 7 7

8. Impact of termination of NASA support
No GI program funding - US scientists with Integral time must find other funding sources (e.g. ADAP) or leave active participation to Non-US collaborators.
No GOF ; no user support
Negative message to ESA when they consider further mission extensions
Potential problem if further SPI detectors fail and a modified response matrix is needed
But mirror archive will continue at HEASARC (subject to 2011 Senior Review recommendations being endorsed)
7 Pis doesn’t sound much, but only 98 were approved world-wide (Integral observations tend to be long)
Dont know if any ADAP proposals were submitted 8

9. INTEGRAL project and ADAP funding of US PIs and Co-Is
+ in ADAP 07 there were 3 INTEGRAL-related proposals of which 1 was funded at $146K over 3 years 9