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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• NASA-National Scientific Balloons
Facility (based in Palestine-Texas), provides circum-Antarctic 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.
William Field, McMurdo, Ross-Sea167o 5.76’E ; 77o 51.76’ S
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
3 4 5 6
-55
-50
-45
-40
-35
crosslink in BOOMERanG LDB scans (1 scan/hour shown)
elev. = 45o
0-11h
12-23h
de
clin
ati
on
(d
eg
ree
s)
R ight Ascension (hours)
• The scan center constantly tracks the azimuth of the lowest foreground region
• Every day we obtain a fully crosslinked map.
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
11.7 days of good data
Launched:
January 6, 2003
From:
McMurdo Station,
Antarctica
Measurements OKfor 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.
Rods show measured polarization (signal + noise)
Deep region: polarization signal similar to the noise
Shallow region: polarization signal smaller than 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.
30’ 30’ 30’
30’
B2K
B2K5
16 detectors128 detectors
Higher resolution images of the early Universe
Shading light on the dark ages
OLIMPO
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
30’
CMB anisotropy SZ clusters Galaxies
mm-wave sky vs OLIMPO arrays
150 GHz 220 GHz 340 GHz 540 GHz
Olimpo: list of Science Goals• Sunyaev-Zeldovich effect
– Measurement of Ho from rich clusters – Cluster counts and detection of early clusters ->
parameters ()
• 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
OLIMPO(http://oberon.roma1.infn.it/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
(Arc min) 90GHz (K) 150GHz (K) 240GHz (K) 400GHz (K)
1 62 56 121 209
2 124 112 242 418
3 186 168 364 628
Errore introdotto da un pendolamento della gondola
E. Pascale, Nov.2000
Se il puntamento non è preciso, la foto viene sfuocata: si perdono le informazioni a piccola scala
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
Sensori di posizione
Scansioni in azimut a velocità costante
Massimizzare la copertura di cielo
Controllare effetti sistematici:
•Gradienti di temp. sulle strutture
•Residuo atmosferico
Hardware di puntamento
Minimizzare i pendolamentiper ridurre il segnale indotto dalla modulazione
dell’atmosferaE. Pascale, Nov.2000
Pendulation Damper (UCB)
E. Pascale, A. Boscaleri, Nov.2000
Connette la Gondola al Pallone
Scansioni in azimut tramite la torsione Sulla catena di volo e la rotazione di una Ruota di inerzia
Il Pivot
Ava Hristov
Movim
ento di elevazione: Inner frame
ruotato Tram
ite un attuatore lineare
I sensori di posizioneBOMERanG conta un volo di test, notturno, nel 1997 e quello
ANTARTICO, diurno, del ’98Ci vogliono quindi due serie di sensori
Tipo volo Sensori Grossolani Sensori Fini
Notturno 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)
Puntamento in Elevazione: Encoder assoluto ottico a 16bit (20 Arc sec)
Puntamento in Azimut
(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
Abbiamo una sovrapposi-zione ottimale sulla regione di cielo osservata
3 4 5 6
-55
-50
-45
-40
-35
crosslink in BOOMERanG LDB scans (1 scan/hour shown)
elev. = 45o
0-11h
12-23h
de
clin
atio
n (
de
gre
es)
R ight Ascension (hours)
P.de Bernardis Oct.2000
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
PerformancePerformance
Volo Anntartico: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 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
Volo di test: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
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
Poor day-time performance: payload reflections and large-scaleatmospheric diffusion of sun light. (stars are around ten ADU !)
During the Trapani flight we got also day-time data:
Poor day-time performance: payload reflections and large-scaleatmospheric diffusion of sun light. (stars are around ten ADU !)
Scattered sunlight
one azimuth rotation
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