The image of the CMB
•
Mapping the CMB is very important, since
the properties of the image of the CMB are
determined by:
1) The physical processes happening in the
early Universe
2) The large scale geometry of the Universe
3) The expansion history of the Universe
Long Duration Balloon Flights
William Field, McMurdo, Ross-Sea
167o 5.76’E ; 77o 51.76’ S
• NASA-National Scientific
Balloons Facility (based in
Palestine-Texas), provides circumAntarctic long-duration balloon
flights during the Antarctic
summer. 37 km for 7-14 days.
• This enables long integrations,
wide sky coverage and extensive
tests for systematic effects,
through the repetition of
measurements under different
experimental conditions:
• Different locations: control ground
spillover
• Different day: control Sun in the
far sidelobes
• “day” vs “night”observations have
different scan directions on the
same area, producing crosslinked
maps.
The launch: Dec. 29, 1998
The launch: Dec. 29, 1998
CMB anisotropy results:
images of the early Universe
The sky scan
• The image of the sky is obtained by
slowly scanning in azimuth (+30o) at
constant elevation
• The optimal scan speed is between 1
and 2 deg/s in azimuth
crosslink in BOOM ERanG LDB scans (1 scan/hour shown)
0-11h
-35
• The scan center
constantly tracks the
azimuth of the lowest
foreground region
• Every day we obtain a
fully crosslinked map.
declination (degrees)
12-23h
-40
-45
-50
-55
elev. = 45
3
4
5
Right Ascension (hours)
6
o
BOOMERanG: the MAP
• 1998:
BOOMERanG
mapped the
temperature
fluctuations of
the CMB at
sub-horizon
scales (<1O).
• The signal
was well
above the
noise:
2 indep. det.
at 150 GHz
The next BIG step:
CMB polarization measurements
Velocity fields in the early
Universe
The Polarization-sensitive
BOOMERanG: B2K
• BOOMERanG can give an important contribution to
CMB polarization research
• We have modified the focal plane after the
anisotropy flight of 1998 to accomodate
Polarization Sensitive Bolometers (PSB).
• We have flown the instrument in Jan. 2003 to
detect E-modes
• We plan to fly it again to detect E and B modes
polarization of the foreground from ISD at high
galactic latitudes.
06/01/2003
BOOM03 Flight
Launched:
January 6, 2003
From:
McMurdo Station,
Antarctica
11.7 days of good data
Measurements OK
for 11.6 days
BOOMERanG landed
near Dome Fuji
(h=3700m) after 14
days of flight. The data
have been recovered
immediately . The
payload has been
recovered in Jan 2004.
BOOMERANG / B2K
Polarization measurements
Preliminary results
Optimal CMB anoisotropy maps obtained with IGLS, the Rome
pipeline (Natoli et al. 2001). The anisotropy signal is much larger than
the instrument noise. This is the CMB map with highest S/N ever.
For the polarization signal the problem is harder.
Shallow
region:
polarization
signal
smaller
than the
noise
Rods show measured
polarization (signal +
noise)
Deep region:
polarization signal
similar to the noise
Next BOOMERANG:
B2K5
• We plan to re-fly B2K with an
upgraded focal plane, to go after
foreground cirrus dust polarization.
• This information is essential for all
the planned B-modes experiments
(e.g. BICEP, Dome-C etc.) and is very
difficult to measure from ground.
• The BOOMERanG optics can host an
array of >100 PSB at >350 GHz.
B2K
128 detectors
B2K5
16 detectors
30’
30’
30’
30’
Higher resolution images of the
early Universe
Shading light on the dark ages
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
CMB anisotropy
SZ clusters
Galaxies
150 GHz 220 GHz 340 GHz 540 GHz
30’
mm-wave sky vs OLIMPO arrays
Olimpo: list of Science Goals
• Sunyaev-Zeldovich effect
– Measurement of Ho from rich clusters
– Cluster counts and detection of early clusters ->
parameters (L)
• Distant Galaxies – Far IR background
– Anisotropy of the FIRB
– Cosmic star formation history
• CMB anisotropy at high multipoles
– The damping tail in the power spectrum
– Complement interferometers at high frequency
• Cold dust in the ISM
– Pre-stellar objects
– Temperature of the Cirrus / Diffuse component
(http://oberon.roma1.infn.it/olimpo)
OLIMPO
Test flight from Trapani (Italy)
(July 2005)
Long Duration Balloon flight from
polar regions
(Peterzen et al. ESA Symposium 2003 – St. Gallen)
Svalbard LDB tests
Test launch July 24, 2004
Feasibility of LDB flight from Svalbard proven
More than 40 days at float
IRIDIUM telemetry module for OLIMPO succesfully tested
Solar panels/charge control tested
Forecasted OLIMPO LDB scientific balloon flight in Summer 2006
BOOMERANG launch movie (10 min.)
Click on the black frame to start
Possible Synergies on LDBs
• Technical subsystems:
– Attitude control (ACS) and reconstruction
– Power control (solar panels for daylight flights: experience
with BOOM and OLIMPO)
– Telemetry (Iridium-based global telemetry for moderate data
rates: experience with Pegaso – G.Romeo, 2400 bps; new
parallel system for higher throughput under development for
OLIMPO)
• Stratospheric background radiance from
– Archeops star sensor data
– B2K star camera data
– Models
Il Sistema di Puntamento
Se il puntamento non è preciso, la foto viene sfuocata:
si perdono le informazioni a piccola scala
Errore introdotto da un
pendolamento della gondola
D (Arc min)
90GHz (mK)
150GHz (mK)
240GHz (mK)
400GHz (mK)
1
62
56
121
209
2
124
112
242
418
3
186
168
364
628
E. Pascale, Nov.2000
Attitude Control System (ACS)
Boomerang ha un beam di ~10 minuti d’arco. L’ACS deve garantire:
La ricostruzione della linea di
vista entro 1 arc-min rms
Massimizzare la copertura di
cielo
Sensori di posizione
Scansioni in azimut a velocità
costante
Controllare effetti sistematici:
•Gradienti di temp. sulle strutture
•Residuo atmosferico
Minimizzare i pendolamenti
per ridurre il segnale indotto dalla modulazione
dell’atmosfera
Hardware di puntamento
Pendulation Damper
(UCB)
E. Pascale, Nov.2000
Il Pivot
Connette la Gondola al Pallone
Scansioni in azimut tramite la
torsione Sulla catena di volo e la
rotazione di una Ruota di inerzia
Ava Hristov
Movimento di elevazione: Inner frame
ruotato Tramite un attuatore lineare
E. Pascale, A. Boscaleri, Nov.2000
I sensori di posizione
BOMERanG conta un volo di test, notturno, nel 1997 e quello
ANTARTICO, diurno, del ’98
Ci vogliono quindi due serie di sensori
Puntamento in Elevazione: Encoder assoluto ottico a 16bit (20 Arc sec)
Tipo volo
Notturno
Puntamento in Azimut
Sensori Grossolani
Sensori Fini
Magnetometro Flux Gate (1)(4)
(alta sensibilità, scarsa accuratezza)
Star Tracker (1)(3)
(determina completamente la
soluzione attitudinale entro 2
arc-min rms)
Diurno
Coarse Sun Sensor (2)(4)
(Sei foto-resistenze, accuratezza ~ 1°)
CCD bilineare solare (2)(4)
(~ 1 arc-min rms)
Entrambe
GPS Differenziale: assetto entro 10’
Giroscopio a tre assi (3)
(10 arc-sec rms)
(1) – IROE
(2) – “La Sapienza”
(3) – Caltech
(4) - ING
Il Controllo
Un sistema completamente digitale permette grande versatilità
Raggi Cosmici possono indurre errori nell’elettronica
Due CPU 386 ridondanti:
• acquisiscono i sensori
• controllano i motori (controller PWM)
Un Watch Dog in pochi ms commuta il controllo fra le due CPU
nel caso una fosse ferma per un evento da CR
Interfaccia comandi tdress – gondola
Elettronica di potenza motori
E. Pascale, A. Boscaleri Nov. 2000
BOOMERanG Scan Strategy
Esploriamo il cielo con scansioni lineari in azimut tutto
l’esperimento è ruotato d i +30°, 1 o 2°/s. Il centro della
scansione traccia l’azimuth a minore foreground
crosslink in BOOMERanG LDB scans (1 scan/hour s
0-11h
-35
12-23h
declination (degrees)
Abbiamo
una
sovrapposizione
ottimale
sulla regione
di cielo
osservata
-40
-45
-50
-55
elev. = 45
3
4
5
o
6
Right Ascension (hours)
P.de Bernardis Oct.2000
Performance
Volo di test:
La telecamera stellare fornisce la posizione della navicella negli angoli di azimut,
elevazione e rollio entro 2 ar-min rms a 5 Hz
Su questa vengono integrati i tre giroscopi per la rimozione degli offset
Attitude reconstruction: migliore di 0.5 arc-min rms
Volo Anntartico:
Il Sensore Solare provvede un misura precisa e ripetibile di azimut ed
elevazione della navicella, tuttavia il segnale è difficile da calibrare
essendo dipendente sia dall’azimut che dall’elevazione del Sole
(accuratezza ~6 arc-min rms)
Per questo si integrano i tre giroscopi sul SS.
Il Giroscopio di roll fornisce il rollio ignoto al SS
Attitude reconstruction: migliore di 3 arc-min rms
E. Pascale, Nov. 2000
Archeops Star Sensor
• A linear array of 46 photodiodes in the
focus of a 40cm f/5 telescope.
• Heavily baffled.
• Red filter to maximize stars to
atmosphere ratio.
• Attitude reconstruction: better than 1
arcmin.
• See Nati et al. RSI 74, 4169, 2003.
The polar-night
flight of Archeops
Stars
Great night-time performance: 1300 stars/circle
During the Trapani flight we got also day-time data:
Poor day-time performance: payload reflections and large-scale
atmospheric diffusion of sun light. (stars are around ten ADU !)
Scattered
sunlight
one azimuth rotation
Poor day-time performance: payload reflections and large-scale
atmospheric diffusion of sun light. (stars are around ten ADU !)