Transcript OLIMPO

(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
(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
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 ?
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.
Inverse Compton scattering of CMB photons
against hot electrons in the intergalactic
medium of rich clusters of galaxies
SZ effect
CMB
[CMB through cluster
– CMB] (mJy/sr)
I (mJy/sr)
-4
g
e-
Cluster
e-
g
US
6.0x10
-4
4.0x10
7keV
10keV
15keV
20keV
-4
2.0x10
150
0.0
240
410
600
400
 (GHz)
600
-4
-2.0x10
-4
-4.0x10
0
200
800
About 1% of the photons acquire about 1%
boost in energy, thus slightly shifting the
spectrum of CMB to higher frequencies.
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 nsL ˜ 10-2. So we expect a CMB
temperature change T/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).
Carlstrom J.,
et al.
Astro-ph/0208192
ARAA 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.
2
Brightness (W / m sr Hz)
At balloon altitude (41km):
At 90 and 150 GHz balloon
observations can be
O2 &
CMB-noise limited
10
-13
10
-14
10
-15
10
-16
10
-17
10
-18
10
-19
10
-20
10
-21
10
-22
Ozone lines
h=41 km, z=45 deg
CMB
CMB anisotropy (rms)
250K BB
250K BB , =0.1
250K BB , =0.01
10
11
Frequency (Hz)
10
12
CMB anisotropy
SZ clusters
Galaxies
Total @ 150 GHz
mm-wave sky at 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.
CMB anisotropy
SZ clusters
Galaxies
150 GHz 220 GHz 340 GHz 540 GHz
30’
mm-wave sky vs OLIMPO arrays
The uniqueness of OLIMPO
I (mJy/sr)
• 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 .
-4
6.0x10
-4
4.0x10
7keV
10keV
15keV
20keV
-4
2.0x10
150
0.0
240
410
600
400
 (GHz)
600
+
+
-4
-2.0x10
-4
-4.0x10
0
200
-
0
800
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
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,
– TCMB can be measured to +10mK
– 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
1
2
3
4
5
6
7
8
9
10
Cluster
A168
A400
A426
A539
A576
A754
A1060
A1185
A1215
A1254
z
0.0452
0.0232
0.0183
0.0205
0.0381
0.0528
0.0114
0.0304
0.0494
0.0628
Number
11
12
13
14
15
16
17
18
19
20
Cluster
A1317
A1367
A1656
A1775
A1795
A2151
A2199
A2256
A2319
A2634
z
0.0695
0.0215
0.0232
0.0696
0.0616
0.0371
0.0303
0.0601
0.0564
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
mKCMBs1/2, we can have as many
as 5600 independent 8' pixels
with a noise per pixel of 7 mKCMB
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 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 to L.
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
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 (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
Olimpo: CMB anisotropy
OLIMPO
l=30
3000
20 detectors, 150 mK rt(s)
2500
10 days
4 arcmin FWHM
300 square degrees
l
2
l(l+1)c
/ 2 (mK ) (a.u.)
Spectrum
Power
3500
2000
1500
1000
500
0
0
500
1000
1500
2000
2500
3000
multipole
Compare!
3500
3000
BOOMERanG
l=30
6 detectors, 150 mK rt(s)
10 days
12 arcmin FWHM
2000 square degrees
2500
2000
l
(a.u.)
Power Spectrum
l(l+1)c
• 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 Wdarkmatter (5).
1500
1000
500
0
0
500
1000
1500
multipole
2000
2500
3000
2
l(l+1)Cl/2 (mK )
10
4
10
3
10
2
Power spectrum of unresolved AGNs
41 GHz
60 GHz
94 GHz
143 GHz
217 GHz
340 GHz
540 GHz
CMB
1
10
10
100
1000
multipole l
mm/sub-mm backgrounds
• Diffuse cosmological
emission in the mm/submm 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 ultraluminous early galaxies
(Blain astroph/0202228)
• Strong, negative kcorrection at mm and
sub-mm wavelengths
enhances the detection
rate of these early
galaxies at high redshift.
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
o


 o(1+z)
f (1 z )
1 z
S =
L
2
4DL  f ' d '
Blain, astro-ph/0202228
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
OLIMPO
M16 - In the constellation Serpens
The SED of L1544 with 10 s 1 second sensitivities
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 telescope
2)
3)
4)
5)
6)
Scan strategy
Detector Arrays & readout
Long Duration Cryogenics
Long Duration Balloon Flights
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.
• 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
Olimpo: The Payload
The inner frame can
point from
0o to 60o of
elevation.
Structural analysis
complies to NASA
standards.
Telescope
Cassegrain
f/# Cassegrain
3.48
Max Diam = 2600mm
Primary Mirror
Min Diam = 300mm
RCurv = 2495mm
Conic constant = -1.009
Diam = 520mm
Secondary Mirror
RCurv = 708mm
Conic constant = -2.11
Reimaging Optics
2 Spherical Mirrors + Spherical Lyot Stop
Max Diam = 54mm
Lyot Stop
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
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.
Focal Plane
Splitters
5th Mirror
Lyot Stop
3rd Mirror
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
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 ready
and currently being integrated
on the payload
Data cleaning : TOD de-spiking
And 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 mK 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 arrays
b) multiplex readout
Solutions:
a) photolitgraphed TES
b) SQUID series arrays and multiplexer (f)
Development of thermal detectors for far IR and mm-waves
17
10
Langley's bolometer
time required to make
a measurement (seconds)
Golay Cell
12
Golay Cell
10
Boyle and Rodgers bolometer
1year
7
F.J.Low's cryogenic bolometer
10
Composite bolometer
1day
Composite bolometer at 0.3K
1 hour
2
10
1 second
Spider web bolometer at 0.3K
Spider web bolometer at 0.1K
Photon noise limit for the CMB
1900
1920
1940
1960
1980
year
2000
2020
2040
2060
Polarization-sensitive bolometers
JPL-Caltech
3 mm thick
wire grids,
Separated by
60 mm, in the
same groove
of a circular
corrugated
waveguide
Planck-HFI
testbed
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)
Cryogenic Bolometers
1 dR(T )
a=
R (T ) dT
iaR
=
Geff 1   2 2
• A large a is
important for high
responsivity.
1
• Ge thermistors: a  10 K
• Superconducting
transition edge
1
thermistors: a  1000 K
S.F. Lee et al. Appl.Opt. 37 3391 (1998)
TES arrays
• 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.
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 ms, 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
PROTOTYPE FULLY LITOGRAPHED
SINGLE PIXEL - 150 GHz (Mauskopf,
Orlando)
Similar to JPL design, Hunt, et al., 2002
but with waveguide coupled antenna
Silicon nitride
Waveguide
Absorber/
termination
Nb Microstrip
TES
Radial probe
Thermal links
PROTOTYPE FULLY LITOGRAPHED
SINGLE PIXEL - 150 GHz (Mauskopf)
Details:
TES
Thermal links
Absorber - Ti/Au: 0.5 W/square - t = 20 nm
Need total R = 5-10 W
w = 5 mm  d = 50 mm
Microstrip line: h = 0.3 mm,  = 4.5  Z ~ 5 W
receiver (1pixel of 1000)
filter
Cryo:
0.3K
Space qual.
load
TES
stripline
antenna
TES for mm waves
(Cardiff, Phil Mauskopf)
… and many others …
membrane
island
SQUID
Readout
MUX
Si substrate with
Si3N4 film
150
mm
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)
frequency-domain multiplexing
row i bias
row i+1 bias
j
Ref: Berkeley/NIST design
j+1
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
OLIMPO is now
included in the 20062008 planning of the
Italian Space Agency
1st flight
Jul.2007
2nd flight
Jul.2008
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).