1. OLIMPO An arcmin-resolution survey of the sky at mm and sub-mm wavelengths (http://oberon.roma1.infn.it/olimpo) Silvia Masi Dipartimento di Fisica La Sapienza, Roma and the OLIMPO team

2. OLIMPO (http://oberon.roma1.infn.it/olimpo) An arcmin-resolution survey of the sky at mm and sub-mm wavelengths Silvia Masi Dipartimento di Fisica La Sapienza, Roma and the OLIMPO team

3. Spectroscopic surveys (SDSS, 2dF) have now mapped the 3D large scale structure of the Universe at distances up to 1000 Mpc Clusters of Galaxies are evident features of this distribution. But when did they form ? How did gravity coagulate them from the unstructured early universe, and was this process affected by the presence of Dark Energy ? 4 Gly distance from us

4. OLIMPO and clusters Answer these questions in a completely independent way is one of the science goals of the OLIMPO mission. Observing clusters of galaxies in the microwaves, this telescope has the ability to detect them at larger distances (and earlier times) than optical and X-ray observations. The number count of clusters at early times is one very sensitive to the presence and kind of Dark Energy and Dark Matter in the Universe, so OLIMPO can provide timely and important data for the current cosmology paradigm.

5. US CMB Cluster   SZ effect e-e- e-e- Inverse Compton scattering of CMB photons against hot electrons in the intergalactic medium of rich clusters of galaxies About 1% of the photons acquire about 1% boost in energy, thus slightly shifting the spectrum of CMB to higher frequencies. [CMB through cluster – CMB] (mJy/sr)

6. S-Z SZ effect has been detected in several clusters (see e.g. Birkinshaw M., Phys.Rept. 310, 97, (1999) astro-ph/9808050 for a review, and e.g. Carlstrom J.E. et al., astro-ph/0103480 for current perspectives) The order of magnitude of the relative change of energy of the photons is  ˜ kT e /m e c 2 ˜ 10 -2 for 10 keV e -, and the probability of scattering in a typical cluster is n  L ˜ 10 -2. So we expect a CMB temperature change  T/T ˜ (n  L)(kT e /m e c 2 ) ˜ 10 -4. The strength of the effect does not depend on the distance of the Cluster ! So it is possible to see very distant clusters (not visible in optical/X).

7. Carlstrom J., et al. Astro-ph/0208192 ARAA 2002 The SZ signal from the clusters does not depend on redshift.

8. mm observations of the SZ However, these detections are at cm wavelengths. At mm wavelengths, the (positive) SZ effect has been detected only in a few clusters. Expecially for distant and new clusters (in the absence of an optical/X template) both cm (negative) and mm (positive) detections are necessary to provide convincing evidence of a detection. The Earth atmosphere is a strong emitter of mm radiation. An instrument devoted to mm/submm observations of the SZ must be carried outside the Earth atmosphere using a space carrier. Stratospheric balloons (40 km), sounding rockets (400 km) or satellites (400 km to 10 6 km..) have been heavily used for CMB research.

9. At balloon altitude (41km): O 2 & Ozone lines At 90 and 150 GHz balloon observations can be CMB-noise limited

10. CMB anisotropySZ clustersGalaxies mm-wave sky at 150 GHz Total @ 150 GHz

11. OLIMPO Is the combination of –A large (2.6m diameter) mm/sub-mm telescope with scanning capabilities –A multifrequency array of bolometers –A precision attitude control system –A long duration balloon flight The results will be high resolution (arcmin) sensitive maps of the mm/sub-mm sky, with optimal frequency coverage (150, 220, 340, 540 GHz) for SZ detection, Determination of Cluster parameters and control of foreground/background contamination.

12. 30’ CMB anisotropySZ clustersGalaxies mm-wave sky vs OLIMPO arrays 150 GHz220 GHz340 GHz540 GHz

13. The uniqueness of OLIMPO OLIMPO measures in 4 frequency bands simultaneously. These bands optimally sample the spectrum of the SZ effect. Opposite signals at 410 GHz and at 150 GHz provide a clear signature of the SZ detection. 4 bands allow to clean the signal from any dust and CMB contamination, and even to measure T e. - 0 ++

14. OLIMPO observations of a SZ Cluster Simulated observation of a SZ cluster at 2 mm with the Olimpo array. The large scale signals are CMB anisotropy. The cluster is the dark spot evident in the middle of the figure. Parameters of this simulation: comptonization parameter for the cluster y=10 -4 ; scans at 1 o /s, amplitude of the scans 3 o p-p, detector noise 150 K s 1/2, 1/f knee = 0.1 Hz, total observing time = 4 hours 3o3o 3o3o

15. Simulations show that: For a –Y=10 -5 cluster, –in a dust optical depth of 10 -5 @ 1 mm, –In presence of a 100 K CMB anisotropy In 2 hours of integration over 1 square degree of sky centered on the cluster –Y can be determined to +10 -6, – T CMB can be measured to +10K –T e can be measured to +3keV

16. Clusters sample We have selected 40 nearby rich clusters to be measured in a single long duration flight. For all these clusters high quality data are available from XMM/Chandra Number Cluster z Number Cluster z 1 A168 0.0452 11 A1317 0.0695 2 A400 0.0232 12 A1367 0.0215 3 A426 0.0183 13 A1656 0.0232 4 A539 0.0205 14 A1775 0.0696 5 A576 0.0381 15 A1795 0.0616 6 A754 0.0528 16 A2151 0.0371 7 A1060 0.0114 17 A2199 0.0303 8 A1185 0.0304 18 A2256 0.0601 9 A1215 0.0494 19 A2319 0.0564 10 A1254 0.0628 20 A2634 0.0312

17. Corrections For each cluster, applying deprojection algorithms to the SZ and X images (see eg Zaroubi et al. 1999), and assuming hydrostatic equilibrium, it is possible to derive the gas profile and the total (including dark) mass of the cluster. The presence of 4 channels (and especially the 1.3 mm one) is used to estimate the peculiar velocity of the cluster. Both these effects must be monitored in order to correct the determination of H o (see e.g. Holtzapfel et al. 1997). It should be stressed that residual systematics, i.e. cluster morphology and small-scale clumping, have opposite effects in the determination of H o Despite the relative large scatter of results for a single cluster, we expect to be able to measure H o to 5% accuracy from our 40 clusters sample.

18. The XMM-LSS and MEGACAM survey region is centered at dec=-5 deg and RA=2h20', and covers 8 o x8 o. It is observable in a trans-mediterranean flight, like the one we can do to qualify OLIMPO. During the test flight we will observe the target region for 2 hours at good elevation, without interference from the moon and the sun. Assuming 19 detectors working for each frequency channel, and a conservative noise of 150  K CMB s 1/2, we can have as many as 5600 independent 8' pixels with a noise per pixel of 7  K CMB for each of the 2 and 1.4 mm bands. Olimpo vs XMM The correlations could provide:  Relative behavior of clusters (Dark Matter) potential, galaxies and clusters X-ray gas.  Detailed tests of structure formation models.  Cosmological parameters and structure formation

19. Clusters and  Since Y depends on n (and not on n 2 ), clusters can be seen with SZ effect at distances larger than with X-ray surveys. There is the potential to discover new clusters and to map the evolution of clusters of galaxies in the Universe. This is strongly related to .

20. Simulations show that the background from unresolved SZ clusters is very sensitive to  (see e.g. Da Silva et al. astro-ph/0011187) 

21. Diffuse SZ effect A hint for this is present in recent CBI data. Bond et al, astro-ph/0205384,5,6,78 The problem is that the measurement was single wavelength (30 GHz), and used an interferometer. (A bolometric follow-up by ACBAR was not sensitive enough to confirm this measurement). OLIMPO is complementary in two ways: it is single dish and works at four, much higher, frequencies.

22. Olimpo: list of Science Goals Sunyaev-Zeldovich effect –Measurement of H o from rich clusters –Cluster counts and detection of early clusters -> parameters () CMB anisotropy at high multipoles –The damping tail in the power spectrum –Complement interferometers at high frequency Distant Galaxies – Far IR background –Anisotropy of the FIRB –Cosmic star formation history Cold dust in the ISM –Pre-stellar objects –Temperature of the Cirrus / Diffuse component

23. Taking advantage of its high angular resolution, and concentrating on a limited area of the sky, OLIMPO will be able to measure the angular power spectrum (PS) of the CMB up to multipoles l 3000, significantly higher than BOOMERanG, MAP and Planck. In this way it will complement at high frequencies the interferometers surveys, producing essential independent information, in a wide frequency interval, and free from systematics like sources subtraction. The measurement of the damping tail of the PS is an excellent way to map the dark matter distribution (4) and to measure  darkmatter (5). Olimpo: CMB anisotropy Compare! Power Spectrum (a.u.)

26. Giommi & Colafrancesco 2003 Power spectrum of unresolved AGNs

27. mm/sub-mm backgrounds Diffuse cosmological emission in the mm/sub- mm is largely unexplored. A cosmic far IR background (FIRB) has been discovered by COBE-FIRAS (Puget, Hauser, Fixsen) It is believed to be produced by ultra- luminous early galaxies (Blain astroph/0202228) Strong, negative k- correction at mm and sub-mm wavelengths enhances the detection rate of these early galaxies at high redshift.

28. mm/sub-mm galaxies Blain, astro-ph/0202228 B z = 0 B z > 0    (1+z) In the sub-mm we are in the steeply rising part of the emission spectrum: if the galaxy is moved at high redshift we will see emission from a rest-frame wavelength closer to the peak of emission.

29. Olimpo: Cold Cirrus Dust Sub-mm observations of cirrus clouds in our Galaxy are very effective in measuring the temperature and mass of the dust clouds. See Masi et al. Ap.J. 553, L93-L96, 2001; and Masi et al. “Interstellar dust in the BOOMERanG maps”, in “BC2K1”, De Petris and Gervasi editors, AIP 616, 2001.

30. OLIMPO can be used to survey the galactic plane for pre-stellar objects M16 - In the constellation Serpens The SED of L1544 with 10  1 second sensitivities OLIMPO

31. OLIMPO: the Team Dipartimento di Fisica, La Sapienza, Roma –S. Masi, et al. IFAC-CNR, Firenze –A. Boscaleri et al. INGV, Roma –G. Romeo et al. Astronomy, University of Cardiff –P. Mauskopf et al. CEA Saclay –D. Yvon et al. CRTBT Grenoble –P. Camus et al. Univ. Of San Diego / Tel Aviv –Y. Rephaeli et al.

32. Technology Challenges for OLIMPO: 1) Angular resolution – size of telescope 2) Scan strategy 3) Detector Arrays & readout 4) Long Duration Cryogenics 5) Long Duration Balloon Flights 6) Telemetry, TC, data acquisition for LDB

33. 1)Angular Resolution & Telescope Size We need few arcmin resolution @ 2 mm wavelength: this requires a >2m mirror.

34. Olimpo: The Primary mirror The primary mirror (2.6m) has been built and verified. 50m accuracy at large scales; nearly optical polishing. It is the largest mirror ever flown on a stratospheric balloon. It is slowly wobbled to scan the sky. Test of the OLIMPO mirror at the ASI L.Broglio base in Trapani

35. Olimpo: The Payload The inner frame can point from 0 o to 60 o of elevation. Structural analysis complies to NASA standards.

36. TelescopeCassegrain f/# Cassegrain3.48 Primary Mirror Max Diam = 2600mm Min Diam = 300mm R Curv = 2495mm Conic constant = -1.009 Secondary Mirror Diam = 520mm R Curv = 708mm Conic constant = -2.11 Reimaging Optics2 Spherical Mirrors + Spherical Lyot Stop Lyot Stop Max Diam = 54mm Min Diam = 12mm R Curv = 175mm 3rd & 5th MirrorsDiam = 172mm R Curv = 350mm Efective f/#3.44 F.o.v. per pixel5 arcmin Total F.o.v.15 x 20 arcmin OptimizationZemax and Physical Optics

37. Telescope test @ IASF Roma, March 2006

38. The cryogenic reimaging optics is being developed in Rome. It is mounted in the experiment section of the cryostat, at 2K, while the bolometers are cooled at 0.3K. Extensive baffling and a cold Lyot stop reduce significantly straylight and sidelobes. Olimpo: reimaging optics

39. 5th Mirror 3rd Mirror Lyot Stop Splitters Focal Plane

43. 2) Scan Strategy We need to scan the sky at 0.1 deg/s or more in order to avoid 1/f noise and drifts in the detectors. Solutions: a) scanning primary b) optimized map-making software

44. The OLIMPO telescope has been optimized for diffraction limited performance at 0.5mm, even in the tilted configuration of the primary.

46. The primary modulator is ready and currently being integrated on the payload

47. Data cleaning : TOD de-spiking And we have a complete data pipeline, tested on BOOMERanG, very complete and efficient…

48. Data co-adding: one data chunk

49. Data co-adding: naive combination of chunks

50. Data co-adding: optimal map-making

51. OLIMPO observations of a SZ Cluster Simulated observation of a SZ cluster at 2 mm with the Olimpo array. The large scale signals are CMB anisotropy. The cluster is the dark spot evident in the middle of the figure. Parameters of this observation: scans at 1 o /s, amplitude of the scans 3 o p-p, detector noise 150 K s 1/2, 1/f knee = 0.1 Hz, total observing time = 4 hours, comptonization parameter for the cluster y=10 -4. 3o3o 3o3o

52. 3) Detector Arrays & Readout We need a) large format bolometer arrays b) multiplex readout Solutions: a) photolitgraphed TES b) SQUID series arrays and multiplexer (f)

53. Photon noise limit for the CMB

54. Polarization-sensitive bolometers JPL-Caltech 3  m thick wire grids, Separated by 60  m, in the same groove of a circular corrugated waveguide Planck-HFI testbed B.Jones et al. Astro-ph/0209132

55. Bolometer Arrays Once bolometers reach BLIP conditions (CMB BLIP), the mapping speed can only be increased by creating large bolometer arrays. BOLOCAM and MAMBO are examples of large arrays with hybrid components (Si wafer + Ge sensors) Techniques to build fully litographed arrays for the CMB are being developed. TES offer the natural sensors. (A. Lee, D. Benford, A. Golding …) Bolocam Wafer (CSO) MAMBO (MPIfR for IRAM)

56. A large  is important for high responsivity. Ge thermistors: Superconducting transition edge thermistors: Cryogenic Bolometers S.F. Lee et al. Appl.Opt. 37 3391 (1998)

57. Are the future of this field. See recent reviews from Paul Richards, Adrian Lee, Jamie Bock, Harvey Moseley … et al. In Proc. of the Far-IR, sub-mm and mm detector technology workshop, Monterey 2002. TES arrays

58. Why TES are good: 1. Durability - TES devices are made and tested for X-ray to last years without degradation 2. Sensitivity - Have achieved few x10 -18 W/Hz at 100 mK good enough for CMB and ground based spectroscopy 3. Speed is theoretically few s, for optimum bias still less than 1 ms - good enough 4. Ease of fabrication - Only need photolithography, no e-beam, no glue 5. Multiplexing with SQUIDs either TDM or FDM, impedances are well matched to SQUID readout 6. 1/f noise is measured to be low What is difficult: 1. Not so easy to integrate into receiver - SQUIDs are difficult part 2. Coupling to microwaves with antenna and matched heater thermally connected to TES - able to optimize absorption and readout separately

59. Waveguide Radial probe Nb Microstrip Silicon nitride Absorber/ termination TES Thermal links Similar to JPL design, Hunt, et al., 2002 but with waveguide coupled antenna PROTOTYPE FULLY LITOGRAPHED SINGLE PIXEL - 150 GHz (Mauskopf, Orlando)

60. Details: Absorber - Ti/Au: 0.5  /square - t = 20 nm Need total R = 5-10  w = 5  m  d = 50  m Microstrip line: h = 0.3  m,  = 4.5  Z ~ 5  TES Thermal links PROTOTYPE FULLY LITOGRAPHED SINGLE PIXEL - 150 GHz (Mauskopf)

61. Cryo: 0.3K Space qual. receiver (1pixel of 1000) antenna stripline filter membrane island load TES Si substrate with Si3N4 film SQUID Readout MUX TES for mm waves (Cardiff, Phil Mauskopf) … and many others … 150  m

62. 3) Detector Arrays & Readout We need a) large format bolometer arrays b) multiplex readout Solutions: a) photolitgraphed TES b) SQUID series arrays and multiplexer (f)

63. frequency-domain multiplexing row i bias row i+1 bias jj+1 Ref: Berkeley/NIST design

64. Cryogenic Resonant Filters We have developed cryogenic resonant filters for the MUX. Based on 5 mH Nb wire Inductors and MICA Capacitors Measured Q around 1000

65. 4) Long Duration Cryogenics We need a Long Duration Balloon to produce a sizeable catalog of clusters. Detectors must operate remotely at 0.3K for weeks Solutions: Long Duration LN/L 4 He Cryostat and 3 He Fridge

66. The dewar is being developed in Rome. It is based on the same successfull design of the BOOMERanG dewar Masi et al. 1998, 1999 25 days at 290 mK.

67. Images of the OLIMPO cryostat

68. Test of the OLIMPO cryostat

69. 1 st flight Jul.2007 2 nd flight Jul.2008 OLIMPO is now included in the 2006- 2008 planning of the Italian Space Agency The baseline flight will be LDB from SVALBARD

70. OLIMPO will soon shed light on the “Dark Ages” between cosmic recombination (z=1000) and cosmic dawn (z=10).