OLIMPOAn 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

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

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 fro

m us

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.

US

CMB

Cluster

SZ effect

e-

e-

Inverse Compton scattering of CMB photons against hot electrons in the intergalacticmedium of rich clusters of galaxies

0 200 400 600 800-4.0x10

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I (

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About 1% of the photons acquire about 1% boost in energy, thus slightly shifting the spectrum of CMB to higher frequencies.

[CM

B th

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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 ˜ kTe/mec2 ˜10-2 for 10 keV e-, and the probability of scattering in a typical cluster is nL ˜ 10-2. So we expect a CMB temperature change T/T ˜ (nL)(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).

Carlstrom J.,et al. Astro-ph/0208192ARAA 2002

The SZ signal from the clusters does not depend on redshift.

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.

At balloon altitude (41km):

1011

1012

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10-13 h=41 km, z=45 deg CMB CMB anisotropy (rms) 250K BB 250K BB , =0.1

250K BB , =0.01

Bri

gh

tne

ss (

W / m

2 sr

Hz)

Frequency (Hz)

O2 & Ozone lines

At 90 and 150 GHz balloon observations can be CMB-noise limited

CMB anisotropy SZ clusters Galaxies

mm-wave sky at 150 GHz

Total @ 150 GHz

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.

30’

CMB anisotropy SZ clusters Galaxies

mm-wave sky vs OLIMPO arrays

150 GHz 220 GHz 340 GHz 540 GHz

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 .

0 200 400 600 800-4.0x10

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/sr)

(GHz)

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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 K s1/2, 1/f knee = 0.1 Hz, total observing time = 4 hours

3o

3o

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,

– TCMB can be measured to +10K

– Te can be measured to +3keV

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 0.06952 A400 0.0232 12 A1367 0.0215 3 A426 0.0183 13 A1656 0.0232 4 A539 0.0205 14 A1775 0.06965 A576 0.0381 15 A1795 0.0616 6 A754 0.0528 16 A2151 0.03717 A1060 0.0114 17 A2199 0.03038 A1185 0.0304 18 A2256 0.0601 9 A1215 0.0494 19 A2319 0.0564 10 A1254 0.0628 20 A2634 0.0312            

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.

• 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 150 KCMBs1/2, we can have as many as 5600 independent 8' pixels with a noise per pixel of 7 KCMB 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

Clusters and

• 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 to .

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

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.

Olimpo: list of Science Goals• Sunyaev-Zeldovich effect

– Measurement of Ho 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

• 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

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6 detectors, 150 K rt(s)

10 days12 arcmin FWHM2000 square degreesl(l

+1)c

l

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)cl /

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Compare!

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er S

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rum

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Power spectrum of unresolved AGNs

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.

mm/sub-mm galaxies

Blain, astro-ph/0202228

'4

1

'

)1(

2

df

fL

D

zS z

L

B

z = 0B

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.

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.

OLIMPO can be used to survey the galactic plane for pre-stellar

objects

M16 - In the constellation SerpensThe SED of L1544 with 10 1 second sensitivities

OLIMPO

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.

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

1) Angular Resolution & Telescope Size

We need few arcmin resolution @ 2 mm wavelength: this requires a >2m mirror.

Olimpo: The Primary mirror • The primary mirror

(2.6m) has been built and verified.

• 50m 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

Olimpo: The Payload

The inner frame can point from0o to 60o of elevation.Structural analysis complies to NASA standards.

Telescope Cassegrain

f/# Cassegrain 3.48

Primary Mirror

Max Diam = 2600mm

Min Diam = 300mm

RCurv = 2495mm

Conic constant = -1.009

Secondary Mirror

Diam = 520mm

RCurv = 708mm

Conic constant = -2.11

Reimaging Optics 2 Spherical Mirrors + Spherical Lyot Stop

Lyot Stop

Max Diam = 54mm

Min Diam = 12mm

RCurv = 175mm

3rd & 5th Mirrors Diam = 172mm

RCurv = 350mm

Efective f/# 3.44

F.o.v. per pixel 5 arcmin

Total F.o.v. 15 x 20 arcmin

Optimization Zemax and Physical Optics

Telescope test @ IASF Roma, March 2006

• 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

5th Mirror

3rd Mirror

Lyot Stop

SplittersFocal Plane

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

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

The primary modulator is readyand currently being integrated on the payload

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

Data co-adding: one data chunk

Data co-adding: naive combination of chunks

Data co-adding: optimal map-making

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 1o/s, amplitude of the scans 3op-p, detector noise 150 K s1/2, 1/f knee = 0.1 Hz, total observing time = 4 hours, comptonization parameter for the cluster y=10-4. 3o

3o

3) Detector Arrays & Readout

We need

a) large format bolometer arraysb) multiplex readout

Solutions:a) photolitgraphed TES b) SQUID series arrays and multiplexer (f)

1900 1920 1940 1960 1980 2000 2020 2040 2060

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107

1012

1017

Langley's bolometer

Golay Cell

Golay Cell

Boyle and Rodgers bolometer

F.J.Low's cryogenic bolometer

Composite bolometer

Composite bolometer at 0.3K

Spider web bolometer at 0.3KSpider web bolometer at 0.1K

1year

1day

1 hour

1 second

Development of thermal detectors for far IR and mm-waves tim

e re

quire

d to

mak

e a

mea

sure

men

t (se

cond

s)

year

Photon noise limit for the CMB

Polarization-sensitive bolometersJPL-Caltech

3 m thickwire grids,Separated by60 m, in the same groove of a circular corrugatedwaveguide

Planck-HFItestbed

B.Jones et al. Astro-ph/0209132

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)

• A large is important for high responsivity.

• Ge thermistors:• Superconducting

transition edge thermistors:

Cryogenic Bolometers

221

)(

)(

1

effG

Ri

dT

TdR

TR

110 K

11000 K

S.F. Lee et al. Appl.Opt. 37 3391 (1998)

• 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

Why TES are good:1. Durability - TES devices are made and tested for X-ray to last years without degradation2. Sensitivity - Have achieved few x10-18 W/Hz at 100 mK good enough for CMB and ground based spectroscopy3. Speed is theoretically few s, for optimum bias still less than 1 ms - good enough4. Ease of fabrication - Only need photolithography, no e-beam, no glue5. Multiplexing with SQUIDs either TDM or FDM, impedances are well matched to SQUID readout6. 1/f noise is measured to be lowWhat is difficult:1. Not so easy to integrate into receiver - SQUIDs are difficult part2. Coupling to microwaves with antenna and matched heaterthermally connected to TES - able to optimize absorption and readout separately

Waveguide

Radial probe

Nb Microstrip

Silicon nitride

Absorber/termination

TESThermal links

Similar to JPL design, Hunt, et al., 2002 but with waveguide coupled antenna

PROTOTYPE FULLY LITOGRAPHEDSINGLE PIXEL - 150 GHz (Mauskopf, Orlando)

Details:

Absorber - Ti/Au: 0.5 /square - t = 20 nmNeed 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 LITOGRAPHEDSINGLE PIXEL - 150 GHz (Mauskopf)

Cryo:0.3K

Space qual.

receiver (1pixel of 1000)

antenna

stripline

filter

membraneisland

loadTES

Si substrate withSi3N4 film

SQUIDReadout

MUX

TES for mm waves(Cardiff, Phil Mauskopf)… and many others …

150m

3) Detector Arrays & Readout

We need

a) large format bolometer arraysb) multiplex readout

Solutions:a) photolitgraphed TES b) SQUID series arrays and multiplexer (f)

frequency-domain multiplexing

row i bias

row i+1 bias

j j+1

Ref: Berkeley/NIST design

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

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/L4He Cryostat and 3He Fridge

• 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.

Images of the OLIMPO cryostat

Test of the OLIMPO cryostat

1st flightJul.2007

2nd flightJul.2008OLIMPO is now

included in the 2006-2008 planning of the Italian Space Agency

The baseline flight will be LDB from SVALBARD

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