Athena status and a focus on its timing capabilities Didier Barret IRAP, Toulouse, France High Throughput X-ray Astronomy in the extp Era February 6-8th, 2017 Roma, Italy Special thanks to Ph. Peille, Th. Dauser, the Athena Science Study Team, the ESA Athena team, CNES and the X-IFU Consortium and its end-to-end simulation team
Athena science - ScientiNic theme: The Hot and Energetic Universe - How does ordinary matter assemble in large scale structures? - Probe: X-ray emitting gas in clusters - How do black holes work, grow and shape the Universe? - Probe: Accretion powered X-rays onto compact objects - A multi purpose observatory: - Observatory science from planets, stars, supernova remnants, interstellar medium - Discovery science enabled by its giant leap in spectral-imaging sensitivity and a fast ToO capability to respond to transient alerts Need to combine a large aperture X-ray telescope, wide Nield imaging, highresolution spatially resolved spectroscopy and an agile spacecraft
Athena in a nutshell - Second Large (L) mission of the ESA Cosmic Vision 2015-2035 - Launch year: end of 2028 - with the newly developed Ariane 6 (64) - A 7 ton spacecraft to be placed in a L2(L1) orbit - Unprecedented collecting area in X-rays: - 2 m 2 at 1 kev and 0.17 m 2 at 7 kev - 5 angular resolution - Two focal plane instruments with a movable mirror assembly: - The Wide Field Imager (WFI) for Nine imaging and timing Medinger+, SPIE 2016 - The X-ray Integral Field Unit (X-IFU) for high-resolution spectroscopy Barret+, SPIE 2016
Athena science payload Optics Wide Field Imager X-ray Integral Field Unit Light-weight Si-pore optics QualiNication model level 5 (HEW) 2 m 2 at 1 kev Active Pixel Sensors based on DEPFETs A fast DEPFET chip for bright sources 40 x 40 arcmin Yield of view Dedicated fast chip for bright sources Cryogenic imaging spectrometer, based on a large format of Transition Edge Sensors cooled at 50 mk with an active background shielding 2.5 ev spectral resolution 5 equivalent diameter Yield of view ESA & industry Consortium led by MPE (K. Nandra), with other European partners and NASA/JAXA Consortium led by IRAP/CNES-F (D. Barret), with SRON-NL (J.W. den Herder), INAF/IAPS-IT (L. Piro) and other European partners, NASA and JAXA.
Athena status - Currently in the middle of its feasibility study phase (ends Q4/17) - Involves ESA, two industrial Primes and the WFI and X-IFU consortia - On-going delta Mission Consolidation Review (ends Q1/17) - Strong focus on system level optimization (including the payload) - to Nit the total mass within the Ariane 6-4 lift off capability at L2 (7 tons) - to denine a stable baseline conniguration for follow-up studies - Cost at completion consolidation work on-going in parallel by ESA - International partner contributions being denined (NASA and JAXA) - The Athena Science Ground Segment will involve ESA and two Instrument Science Centers - Vigorous technology development plans on critical components to reach TRL 5/6 at mission adoption (Q1/20), e.g. coolers
Driver for high count rate capabilities - Athena Core science goal: «Athena shall measure black hole spins of Galactic Black Holes (GBH) and Neutron Stars (NS) to provide insight into black hole birth events (GRBs and/or SN) that set stellar-mass black hole spins, and to study the relationship between accretion and outdlows (winds and jets).» - Measure spins of 10 GBH and 10 NS through various methods and probe their accretion geometry and jet properties through reverberation mapping - Measure winds in the same 10 GBH and 10 NS through absorption line spectroscopy 1 Crab = 90 000-100 000 cps (depending on detector) WFI (fast chip defocussed) 80% (2-10 kev) throughput 170 ev spectral resolution <1% pile-up X-IFU (TES array defocussed) 30% (2-10 kev) throughput (tbc) <30 ev spectral resolution <1% pile-up
WFI fast chip performance Readout time per pixel = 2.5 µs 64 x 64 pixels split in two halves read in parallel Time resolution = 32 (lines) x 2.5 µs = 80 µs Count rate 10 3 10 4 10 5 0.95 Broand band throughput 0.90 0.85 0.80 0.75 Pile-up fraction less than 1% Requirement (throughput of 80% at 1 Crab) 10 100 1000 Flux (mcrab) WFI FC Cygnus X-1 spectrum (10 ks). The iron line proyile consists of a skew symmetric relativistic line originating close to the black hole, and a narrow core from material further away rom the black hole. Motch, Wilms et al., Athena supporting paper.
X-IFU fast count rate capabilities Time resolution = 10 µs (pile-up negligible) Spectral grade depends on pulse separation tprevious 60 35 mm optics defocussing Cross-talk not considered (under assessment) 1.0 tnext 0.9 0.8 Broadband throughput Amplitude (arbitrary units) 50 40 30 20 0.7 0.6 0.5 0.4 Current requirement 0.3 0.2 10 0.1 0 2 High resolution event (goal) 0 2 4 6 8 10 Time (arbitrary units) 12 14 16 1 High resolution events - 35 mm High + Mid + Low resolution events - 35 mm 10 100 Source flux [mcrab] 1000
Addition of a Be Nilter X-IFU defocussed image of a bright point source 0.2 5-8 kev effective source count rate (cps) 2000 1000 500 200 100 50 35 mm defocus - No Be filter 35 mm defocus - Be filter 100% throughput 50% throughput 100 1000 Source flux (mcrab) 5-8 kev effective count rate with and without the Be Filter (cross-talk under assessment) x 2 Normalized counts/s/kev/cm 2 0.1 0.05 0.02 Fe XXV Heα Fe XXVI Hα Fe XXV Heβ Fe XXVI Hβ 6 7 8 9 Energy (kev) X-IFU simulated observation lasting only ~1000 seconds of the Black Hole binary GRS1915+105. Strong spectral features can be clearly seen in the spectrum, enabling unprecedented studies of the structure of the disk winds. Courtesy. J. Miller Barret+ SPIE 2016
Conclusions - Athena will provide breakthrough capabilities in wide Nield imaging and high resolution spatially resolved X-ray spectroscopy - Athena feasibility studies are progressing well with the large mirror conniguration as the current baseline (2 m 2 at 1 kev) - S/C and P/L baseline connigurations being optimized - Science impact of a modest reduction (~20% level) in P/L capabilities being currently assessed by the Athena science panels - Athena will provide high count rate capabilities: - to study accretion/ejection physics in the stellar mass range - to respond to observatory and discovery science with «obvious» synergies with facilities like EXTP, with e.g. its wide Nield monitor for GRBs (WHIM studies & Nirst black hole probes) and transients
Hold on and thank you for your support The wealth of information provided by such a spectrum, that will be measured on sub-arc minute scales enables in depth studies of the physical properties of the hot cluster gas (e.g. temperature, density, turbulence, bulk motion, abundance,... ) High-z GRB afterglows probing the ISM composition at z>7-10 and tracing the Nirst generation of stars to understand cosmic re-ionization, the formation of the Nirst seed black holes, and the dissemination of the Nirst metals. 1000 X-IFU - Perseus core Photons m -2 s -1 kev -1 100 10 1000 500 100 νf ν 500 200 400 200 Fe complex 0.25 0.30 Al, Si, S 10 1.0 1.2 6.5 7.0 0.5 1 2 5 Energy (kev) 0.2 0.5 1 Energy (kev) Perseus core X-IFU simulated spectrum based on Hitomi - Model courtesy of C. Pinto and A. Fabian Barret et al. (2016) - Courtesy of L. Piro