Spectral Distortions of CMB C. Burigana, A. De Rosa, L. Valenziano, G. Morgante, F. Villa, R....

Spectral Distortions of CMB

C. Burigana, A. De Rosa, L. Valenziano, G. Morgante, F. Villa, R. Salvaterra,

P. Procopio and N. Mandolesi

Cosmic Microwave Background Radiation

Anisotropies

Angular power spectrum

Polarization

P 2 = Q 2 + U 2

Example:

Scattering Thomson of radiation with quadrupole anisotropy generates linear polarization

Spectrum

Photon distribution function

Frascati workshop, May 7, 2007 - Burigana, De Rosa, Valenziano, Morgante, Villa, Salvaterra, Procopio, Mandolesi

CMBRSPECTRUM

T0 = 2.725 ± 0.002 °K(Mather et al. 1999)

Redshift

Dimensioneless frequency

Has the CMBR a black body spectrum?


CMB Spectrum measuresWP 1430 – C. Burigana, N. Mandolesi, L. Valenziano

Recent measures of CMB spectrum (collected by Burigana and Salvaterra, 1999)

FIRAS measures: typical error ±0.0001 K

>1cm: typical error > 0.1 K

Impact of various sources of errors: note the

atmosphere relevance


Spectral distortions

In the primordial universe some processes can lead the matter-radiation fluid out of the thermal equilibrium(energy dissipation because of density fluctuations,Physical processes out of the equilibrium,radiative decay of particles, energy release related to the first stages of structures formation,free-free distortions)

The photon distribution function isn’t a Planckian one

The Kompaneets equation in cosmological contest provides the best tool to compute the evolution of the photon distribution function, but a numerical code is needed!

KYPRIX

An extremely precise fortran based code, able to simulate the effects of the primordial physical processes that can affect the thermodynamic equilibrium of the CMBR


Cosmological applications

BIG

BANG z

today

zterm zBE zricz

Superposition of black bodies

where

Primordial distortions

Late distortions Related (mainly) to the reionization history of the universe

Free-free distortions

Bose-Einstein like spectrum

with µ function of X

Cosmological application of a numerical code for the solution of the Kompaneets equation, P.Procopio and C.Burigana, INAF-IASF Bologna, Internal Report, 421


Theoretical CMB Spectral Distortions

Distorted spectra in the presence of a late energy injection with Δ/i = 5 x 10-6 plus an early/intermediate energy injection with Δ/i = 5 x 10-6 occurring at yh=5, 1, 0.01 (from the bottom to the top; in the figure the cases at yh=5 and 1 are indistiguishable at short wavelengths; solid lines) and plus a free-free distortion with yB=10-6 (dashes).

Bose-Einstein like

Comptonizationlike

Free-free

Early

Late

Middle age


Cosmological application

Distortions due to reionization of the universe at low redshifts

m = 0.29 = 0.73

One of the representative cases

m = 1 = 0

Te/TR = 104

zR = 20

d/ = 10-5


In the Planckian Hypothesis:

limits achievable with a new low frequency experiment –

DIMES Example: 6 freq. channels between 2 & 90 GHz

Current limits

Limits achievable with a low frequency experiment with the same FIRAS sensitivity

Hypothesis to be checked

Burigana and Salvaterra, 2003

Cosmic time


CMB spectrum: Key parameters

Configuration A and B•Frequency operating range: 0.4 – 50 GHz (75 - 0.6 cm)•Spectral resolution: 10%•Angular resolution: 7°/8°•Sensitivity: < 1 mK sec-1/2

•Field of View: > 104 deg2

•Final sensitivity (E.O.L) better than 0.1 mK per resolution element•Low sidelobes optics•Ground shield

–avoid ground signal pickup–thermal stability

Channel Frequency (GHz) Wavelength (cm)

1 100 0.300000

2 63.0957 0.475468

3 39.8107 0.753566

4 25.1189 1.19432

5 15.8489 1.89287

6 10.0000 3.00000

7 6.30957 4.75468

8 3.98107 7.53566

9 2.51189 11.9432

10 1.58489 18.9287

11 1.00000 30.0000

12 0.630957 47.5468

13 0.398107 75.3566


Calibrator requirements

• Return Loss < -60dB in the whole frequency range

• Intercalibration between frequency bands better than 30 K

• Thermal stability better than 1 mK with well sampled temperature monitoring (temperature accuracy better than 10 K)

The ARCADE calibrator


Radiometers

• Differential radiometers (using low noise amplifiers)

• Absolute calibration

One of the ARCADE radiometers (Kogut, 2002)


Sketch of the large payload

Mass: ~1000 Kg, height ~ 6 m, deployed in a shaded crater

Scientific performance as function of (low) frequency coverageC = 2, 5, 8 freq. channels, 0.48, 1.9, 7.54 cm

D = 3, 6, 9 freq. channels, 0.75, 3.0, 11.9 cm

E = 3, 5, 7 freq. Channels, 0.75, 1.9, 4.75 cm

R = recent data @ ≥ 1cm

F = COBE/FIRAS

Note that even with

observations @ ≤ 5cm

the improvement is

very good!


New Concept Design Requirements

• Mass < 300 Kg

• Simplify cooling system

• Location at the pole

• Continuous operation (day and night)

• Simplify pointing system

• Autonomous, unmanned operation

• Simplify deployment


Reduce Dimension and Mass

• Reduce the number of channels Use a smaller payload Use a smaller cooler

• Select highest frequency bands Reduce horn and calibrator dimension

• Enlarge FOV (14° FWHM) Reduce horn dimensions

• Passive cooling for the optics Use a smaller cooler

• Introduce steerable optical system Reduce horn dimension Avoid an alt-az mounting


New Location

• Select a location at the Pole Reduce the size of passive cooling radiators Reduce the observed portion of the sky (acceptable from the

scientific point of view) Avoid rover and deployment system (reduce mass)

• Shaded crated location not strictly required Simplified deployment on the final site Operation on the landing module possible Power generation from solar panels on the payload

• Operation from the near side of the Moon Higher frequency less affected by man-made interference


New Payload Concept (conf. E)

• 3 channels– 6 GHz – 15 GHz– 63 GHz

• FOV: 14 deg• Passive cooling for

the optics• Steerable optical

element at horn aperture

Absolute

Reference@4K

Feed Horn

Steerable Mirror

Thermal Link @4K

Cold Head

Radiometer @4K

Internal Reference @4K

Thermal Link @4K

6GHz Channel15GHz Channel

63GHz Channel


New Payload Concept

CompressorElectonics box

Cold Head

6GHz Channel

15GHz Channel

63GHz Channel

• Pointing system obtained using steerable mirrors and Moon rotation


Location

• Location at the Pole– Passive cooling possible.

Smaller radiators

• Easy deployment, unmanned operation– Shields deployed in-situ

– Operation from the lander possible

– Solar panels on the payload

Solar panel

Cooler’s

Radiators

External passive

cooling Shield

Middle ShieldInternal passive

cooling shield

Instrument


• Estimated mass: < 200 Kg• In situ overall dimension: diameter: 8 m, height: 3 m

• Passive shield deployed

• Estimated power requirements: 3 kW• Continuous operation possible


CONCLUSIONS

• The Moon is a unique opportunity for accurate cm & dm CMB spectrum measures free from atmosphere contamination

• dm observations requires ≈ 103 Kg experiments

• cm observations need ≈ 102 Kg experiments and represents,

@ 0.1 mK sensivity, a great improvement with respect to the current observation status

in particular for free-free distortions & BE-like (early) distortions

• A compact design for early cm experiments has been proposed

• Definitive cm & dm missions will map the cosmic thermal history with high precision up redshifts of ~ 107


Thanks for the attention!


KYPRIX

How does it work?

Subroutine for boundary cond.in point A

D03PCFDiscretization of the Kompaneets

Increasing time y

Subroutine for boundary cond.in point B

FUNCTIONFor specific phys. quant.Cosmic exp

Output files(,t)Integral quan.

Input parameters

a)cosmological par. b)integration par.

MAIN PROGRAM

Initialization of the solution vector U

Subroutine PDEDEF

Discretization in the x axis

Computation of the rates of the physical processes


KYPRIX’ update(s)

2004-2005 update related to the NAG libraries* sensitivity e efficiency increased** introduction of the cosmological constant**

2006-2007 CPU platform transfer (still in progress)activity update related to the relative abundances of H and He

introduction of the ionization fraction of e-

‘90 first KYPRIX release by Carlo Burigana

* Updating a numerical code for the solution of the Kompaneets equation in cosmological context, P.Procopio and C.Burigana, INAF-IASF Bologna, Internal Report, 419;

**Accuracy and performance of a numerical code for the solution of hte Kompaneets equation in cosmological context, P.Procopio and C.Burigana, INAF-IASF Bologna, Internal Report, 420;


ReionizationNowday, the most precise measurements related to the parameters of the standard model (of the universe) are those realized by the NASA satellite WMAP

optical depth of the universe =0.09 +- 0.03• (3-years WMAP data)

Effects of a reionization are visible in all the properties of the CMBR:--- Temperature anisotropies suppression at high multipoles*--- gain of power in T-E cross-correlation PS and in the E and B modes mainly at low and middle multipoles--- raising of free-free and compotonization like distortions in the spectrum

Given that, we need a performing tool able to simulate the stages of evolution of the reionization as better as possible not only for effects

related to the anisotropies, but also for what concern the CMBR spectrum

*Planck-LFI scientific goals: implications for the reionization history

L.Popa, C.Burigana, N.Mandolesi,…,P.Procopio,et. al., Publ. By New Astronomy

Spectral Distortions of CMB C. Burigana, A. De Rosa, L. Valenziano, G. Morgante, F. Villa, R....

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