S.U. .E.R.M.A.N.

1. S.U. .E.R.M.A.N. SUnyaev-Zeldovich B-Polarization ExploRing Microwave ANtenna Laila Alabidi (UK); Paul Beck (Austria); Marcos Cruz (Spain);Árdís Elíasdóttir (Denmark); Henning Gast (Germany); Lara Sousa (Portugal); Thomas Kronberger (Germany); Gemma Luzzi (Italy); Jens Melinder (Sweden); Peter Predehl (Germany); Oliver Preuß (Germany); Mirko Tröller (Finland); Elisabetta Valiante (Germany); Paul Anthony Ward (Ireland)

2. OVERVIEW • Short Introduction to the Mission; • Science case: • B-Modes; • Sunyaev-Zel‘dovich; • Engineering: • Mission scenario; • Spacecraft design/Platform; • Telescope and Instrumentation; • Cost and administrative affairs; • Summary

3. INTRODUCTION

4. The Su erman Mission As the name suggests, this mission will be leaping over tall orders to achieve what might appear to the mere mortal as impossible! The most accurate and complete measurement of the B-mode polarisation anistropy to date; An all sky Sunyaev-Zel‘dovich survey, at a resolution of 1 arcmin;

5. IMPORTANCE FOR DARK MATTER AND DARK ENERGY • It is an indication for a variable cosmological constant (Quintessence); • It is a measurement of the reionization bump which is due to dark matter annihilation and will therefore probe primordial dark matter;

6. IMPLICATIONS OF DARK ENERGY (I)

7. IMPORTANCE OF DARK MATTER (II)

9. B-MODE POLARIZATION

10. B-MODE SCIENCE • Polarization of CMB is due to Thomson scattering which occurs post photon decoupling and is enhanced during reionization; • The amount of polarization depends on the free electron density in the direction of observation; • Gravitational waves lead to an in-homogeneity in electron density in the plane perpendicular to the direction; • This in-homogeneity leads to a phase shift in the photons, leading to B-mode polarization with an amplitude

11. BY MEASURING THE B-MODE WE CAN (I): • Independantly measure the thickness of the optical depth as measured by WMAP. This is a strong indicator of Dark Matter in the early universe; • Make an Indirect measurement of gravitational waves; • Constrain (or obtain a value) on the tensor to scalar ratio (r);

12. BY MEASURING THE B-MODE WE CAN (II): • Obtain more information on the type and energy scale of inflationary scenarios; • Probe quantum gravity; • Confirm or Refute magnetic Parity Conservation; • Study Physics of energy scales inaccessible to particle acelerators; • Probe re-ionization history;

13. WHY SPACE? • Stable environment that allows the reduction of system noises • No disturbances caused by earth´s atmosphere and the earth itself; INCREASE SENSITIVITY • All sky coverage that allows: • Improved statistics; • Detectionof the lowest polarization modes, i. e., PROBE RE-IONIZATION BUMP,

14. FOREGROUND EMISSION • Free-free emission (negligably polarized); • Synchroton emission → low frequencies; • Dust emission → high frequencies; • Extragalactic emission from radiogalaxies and weak-lensing; Deduced by making measurements at low and high frequency channels

17. COMPLEMENTARITY AND COMPETITION • Current missions don‘t have enough sensitivity; • There are, at least, 8 missions planned for measuring the B-mode: • Ground-based missions; • Balloon-borne missions; • Space missions; Detectability of B-mode constrained by limited observed area and atmospheric disturbances • Our expected sensitivity of r~0,001 is of the same order as that of the next generation ground-based and balloon experiments; • We will be probing the lower l modes which cannot be done without performing an all sky survey;

18. SUNYAEV-ZEL‘DOVICH EFFECT

19. COSMOLOGY WITH THE SUNYAEV-ZEL´DOVICH EFFECT • Very powerful and versatile tool to study large scale structure of the universe • Inverse-Compton scattering of the CMB photons off the high energy electrons of the ICM

20. PHYSICAL PRINCIPLES • Expressed as a temperature change at dimensionless frequency : Compton y-parameter: Kinetic SZE:

21. BASIC FEATURES Carlstrom et al., 2002 • Mass threshold nearly redshift independent; • Highly complementary to other observational diagnostics;

22. SCIENTIFIC RATIONALE • Cluster based Hubble diagram: • Uses different electron density dependencies of the SZE and X-ray emission, Quantities evaluated along the line of sight through the centre; Carlstrom et al., 2002

23. SCIENTIFIC RATIONALE • SZ-selected samples almost mass limited; • Cluster counts and distribution strongly depends on cosmological parameters and cluster formation physics; Da Silva et al., 2000

24. SCIENTIFIC RATIONALE • FURTHER POSSIBLE APPLICATIONS: • Intra-supercluster gas; • Time dependence of dark energy density (Bartelmann et al. 2005); • Test TCMB ≈ (1 + z) by ratio of SZ at 2 different frequencies; • Kinetic SZE unique way to measure large scale velocity fields; Couchman, 1997

25. NECESSITY OF GOING TO SPACE • The most powerful use of SZE are deep, large scale surveys; • Ground based observations suffer from systematics coming from atmospheric variations;

26. COMPLEMENTARITY AND COMPETITION • PLANCK will measure the SZE but due to relatively large beam width, resolve only around 20.000 clusters; • Atacama Cosmology Telescope: ground based; OVRO millimetre wavelength array

27. FOREGROUND AND SYSTEMATICS • Galactic emission, such as synchrotron and dust emission and fluctuations of CMB itself; • Point sources; • Assumption as spherical symmetry, isothermality and absence of clumping often used;

28. EXPECTED RESULTS • In a ΛCDM we expect around 20 clusters per deg2, thus with the all sky survey we should get 700.000 clusters; • In a τCDM we expect around 3 clusters per deg2, thus with the all sky survey we should get 105.000 clusters;

29. ENGINEERING

30. STARTING WITH PLANCK

31. Mission Scenario L2 (after ¼ year) L2 0,2 rpm

32. Solar Panel Launch Adapter (10,5m2) Spacecraft Design starting from the bottom 3800

33. S/C Bus"Service Module", SVM SPACECRAFT DESIGN starting from the bottom 3566

34. Prim. Reflector Shield / Baffle 6545 Sec. Reflector V-Grooves Service Module Solarpanel DOES IT FIT INTO ST-FAIRING?

35. Panels “TULIP“ V-Groove

36. S/C Design Telescope PayloadSupport Structure V-Grooves "Tulip"-Extension Service Module

37. Goals: SZ Effect high angular resolution B-Mode large field of view no cross and instrumental-polarization Solutions: 3m diameter paraboloid aperture stop off-axis Gregorian satisfying the Mizuguchi-Dragone condition THE TELESCOPE

40. The focal plane unit – basic layout The focal plane size given by the optical design is 5° (or 300 mm in physical units). The FPU accomodates two different instruments sharing the same cryostat, the Total intensity Instrument (TI) and the Polarimetry Instrument (PI). PI focal plane TI To secondary mirror INSTRUMENTATION

41. Filters/Channels- The TI will observe the CMB in 3 channels; 143, 220 and 330 GHz optimized to study the SZ effect.- The PI will observe in 3 channels; 40, 100 and 220 GHz Polarimetry- Uses a combination of a rotating half-wave plate (HWP) and a fixed polarizing grid (FPG) to modulate the signal.- This technique provides immunity to a number of systematic effect (no detector differencing needed). INSTRUMENTATION

42. INSTRUMENTATION PI TI Filter

43. Detector array setup- For each of the six channels there will be an array of hornfed TES bolometers. The arrays will be constructed to fill the focal plane (diameter of 300 mm).- In total a number of 690 detectors can be fitted inside the focal plane divided between the different channels and instruments (PI/TI).- The number of detectors is limited by the fact that each horn has to have a diameter of at least the wavelength observed. INSTRUMENTATION

44. Transition edge sensors (TES)- Has a great advantage in that they can be produced in large arrays (thin film deposition and optical lithography)- Readout multiplexing technologies (SQUIDs) have been developed/are in development. These makes it possible to readout many detectors at once.- Have low impedance => more insensitive to vibration. - Optimal sensitivity is achieved at very low temperatures (100 mK), good cryostat needed. Detector noise power is on the order of 2·10-17 W/√Hz. INSTRUMENTATION

45. INSTRUMENTATION

46. Sensitivity calculations- In modern bolometers the sensitivity is no longer determined by the detector noise but rather by background optical loading (photon noise) => Larger amount of detectors- The photon noise in the instrument is complicated to determine (depends, among other things, on transmissivity of the optics and the crystat effectivity).- In the sensitivity estimates presented here, we are assuming the photon noise level reached by PLANCK. INSTRUMENTATION

47. INSTRUMENTATION * In some cases under sampling of the beam means the resolution may increase by a factor of 21/2. ** Calculations using NET values from Planck.

48. INSTRUMENTATION * In some cases under sampling of the beam means the resolution may increase by a factor of 21/2. ** Calculations using NET values from Planck.

49. INSTRUMENTATION * In some cases under sampling of the beam means the resolution may increase by a factor of 21/2. ** Calculations using NET values from Planck.

50. COOLING SYSTEM V-Groove Radiator (TO 60k) 20K H2 sportion cooler (TPL) (Planck HFI cooling system) 4K stirling cooler (RAL/MMS) O,1K 3He/4He dilution Cooler The cooling chain includes a hydrogen sorption cooler, providing a 18K stage; a closed-loop Joule-Thomson refrigerator which provides a temperature of 4K; and a diluition refrigerator which provides the final operating temperature of the bolometers of 0.1K, with a cooling power of 100nW.