OLIMPO

1. (http://oberon.roma1.infn.it/olimpo) 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

2. (http://oberon.roma1.infn.it/olimpo) 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 4 Gly distance from us 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. 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. SZ effect Inverse Compton scattering of CMB photons against hot electrons in the intergalactic medium of rich clusters of galaxies CMB g [CMB through cluster – CMB] (mJy/sr) Cluster e- e- g About 1% of the photons acquire about 1% boost in energy, thus slightly shifting the spectrum of CMB to higher frequencies. US

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 Dn/n˜ kTe/mec2˜10-2 for 10 keV e-, and the probability of scattering in a typical cluster is nsL ˜ 10-2. So we expect a CMB temperature change DT/T˜ (nsL)(kTe/mec2)˜ 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 106 km..) have been heavily used for CMB research.

9. At balloon altitude (41km): At 90 and 150 GHz balloon observations can be CMB-noise limited O2 & Ozone lines

10. CMB anisotropy SZ clusters Galaxies Total @ 150 GHz mm-wave sky at 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. CMB anisotropy SZ clusters Galaxies 150 GHz 220 GHz 340 GHz 540 GHz 30’ mm-wave sky vs OLIMPO arrays

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 Te . - + + 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 1o/s, amplitude of the scans 3o p-p, detector noise 150 mK s1/2, 1/f knee = 0.1 Hz, total observing time = 4 hours 3o 3o

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 mK CMB anisotropy • In 2 hours of integration over 1 square degree of sky centered on the cluster • Y can be determined to +10-6, • DTCMB can be measured to +10mK • Te can be measured to +3keV

16. 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 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

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 Ho (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 Ho • Despite the relative large scatter of results for a single cluster, we expect to be able to measure Ho to 5% accuracy from our 40 clusters sample.

18. Olimpo vs XMM • The XMM-LSS and MEGACAM survey region is centered at dec=-5 deg and RA=2h20', and covers 8ox8o. 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 150mKCMBs1/2, we can have as many as 5600 independent 8' pixels with a noise per pixel of7 mKCMBfor each of the 2 and 1.4 mm bands. • 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 L • Since Y depends on n (and not on n2), 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 toL.

20. Simulations show that the background from unresolved SZ clusters is very sensitive to L (see e.g. Da Silva et al. astro-ph/0011187) L=0. 7 L=0.0

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 Ho from rich clusters • Cluster counts and detection of early clusters -> parameters (L) • 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. Olimpo: CMB anisotropy Power Spectrum (a.u.) • 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 multipolesl»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 tailof the PS is an excellent way to map the dark matter distribution (4) and to measureWdarkmatter(5). Compare! Power Spectrum (a.u.)

26. Power spectrum of unresolved AGNs Giommi & Colafrancesco 2003

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 • 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. z = 0 z > 0 B B n n no n o(1+z) Blain, astro-ph/0202228

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 OLIMPO M16 - In the constellation Serpens The SED of L1544 with 10  1 second sensitivities

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 telescope2) Scan strategy3) Detector Arrays & readout4) Long Duration Cryogenics5) Long Duration Balloon Flights6) Telemetry, TC, data acquisition for LDB

33. 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. • 50mm 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 0o to 60o of elevation. Structural analysis complies to NASA standards.

37. Telescope test @ IASF Roma, March 2006

38. Olimpo: reimaging optics • 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.

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

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 primaryb) 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