Cosmic Microwave Background and Planck: science and challenges Carlo Baccigalupi

Outline  CMB physics  Status of the CMB observations and future experimental probes  The science goals of the Planck satellite  Planck data analysis and the creation of the Trieste Planck Analysis Center (TPAC)  Opportunities and challenges for Trieste  More talks to come…

CMB physics

CMB: from where and when?  Opacity: λ = (n e σ T ) -1 « H -1  Decoupling: λ ≈ H -1  Free streaming: λ » H -1  Cosmological expansion, constants and baryon abundance conspirate to activate decoupling about years after the Big Bang, at about 3000 K photon temperature

CMB anisotropy: phenomenology  Primordial perturbations in the curvature affect all cosmological species  Perturbation evolution for all components proceeds accordingly to the cosmic geometry and expansion  The anisotropy in the CMB represents the snapshot of cosmological perturbations in the photon component only, at decoupling time

CMB physics: Boltzmann equation d ɣ black body = metric + Compton scattering dt d baryons+leptons = metric + Compton scattering dt

CMB physics: dark sector metric = ɣ + Ʋ + baryons + leptons + dark matter

CMB physics: metric

CMB Physics: Compton scattering  Compton scattering is anisotropic  An anisotropic incident intensity determines a linear polarization in the outgoing radiation  At decoupling that happens due to the finite width of last scattering and the cosmological local quadrupole

CMB anisotropy: total intensity + +

CMB anisotropy: polarization Gradient (E): Curl (B):

Status of the CMB observations and future experimental probes

CMB angular power spectrum Angle ≈ 200/ l degrees

CMB angular power spectrum Angle ≈ 200/ l degrees Primordial power Gravity waves Acoustic oscillations Reionization Lensing

Known CMB angular power spectrum Angle ≈ 200/ l degrees

CMB angular power spectrum boomerang dasi Wmap+CBI+ACBAR

CMB anisotropy statistics: unknown, probably still hidden by systematics  Evidence for North south asymmetry (Hansen et al. 2005)  Evidence for Bianchi models (Jaffe et al. 2006)  Poor constraints on inflation, the error is about 100 times the predicted deviations from Gaussianity (Komatsu et al. 2003)  Lensing detection out of reach

Other cosmological backgrounds  Neutrinos: abundance comparable to photons, decoupling at MeV, cold as photons , weak interaction   Gravity waves: decoupling at Planck energy, abundance unknown , gravitational interaction   Morale: dig into the CMB, still for many years…that’s the best we have for long…

Forthcoming CMB polarization probes  Planck  EBEx (US, France, Italy), baloon, same launch time scale as Planck for the north american flight  QUIET (US, UK), ground based  Clover (UK, …)  Brain  …  Complete list available at the Lambda archive lambda.gsfc.nasa.gov

Cosmic vision beyond Einstein  NASA and ESA put out separate calls of opportunity for a polarization oriented future (2020 at least) CMB satellite  Technologies, design, options for joint or separate missions are being discussed in these months Cosmic vision program logo Beyond einstein logo

The science goals of the Planck satellite Source: Planck scientific program bluebook, available at

Planck  Hardware: third generation CMB probe, ESA medium size mission, NASA (JPL, Pasadena) contribution  Software from 400 collaboration members in EU and US  Two data processing centers (DPCs): Paris + Cambridge (IaP + IoA), Trieste (OAT + SISSA)

Planck contributors

Davies Berkeley Pasadena Minneapolis Rome Helsinki Copenhagen Brighton Oviedo Santander Padua Bologna Trieste Milan Paris Toulouse Oxford Cambridge Munich Heidelberg

Planck data processing sites Trieste Paris Cambridge

Planck data deliverables  All sky maps in total intensity and polarization, at 9 frequencies between 30 and 857 GHz  Angular resolution from 33’ to 7’ between 30 and 143 GHz, 5’ at higher frequencies  S/N ≈ 10 for CMB in total intensity, per resolution element  Catalogues with tens of thousands of extra- Galactic sources

Planck scientific deliverables: CMB total intensity and the era of imaging

Planck scientific deliverables: CMB polarization

Planck and polarization CMB B modes

Planck scientific deliverables: cosmological parameters

Non-CMB Planck scientific deliverables  Thousands of galaxy clusters  Tens of thousands of radio and infrared extra-Galactic sources  Templates for the diffuse gas in the Galaxy, from 30 to 857 GHz  …

Planck data analysis

Planck scanning strategy and data collection  Two complete all sky surveys in 14 months  Data comes in the form of Time Ordered Data (TOD) from each one of the 63 detectors, sampling the sky at tens of kHz  10 Tb disk space

Planck data analysis  Level S: mission simulation  Level 1: telemetry processing and instrument control, early source catalogue  Level 2: calibration and map-making  Level 3: component separation, CMB spectrum estimation, source catalogue  Level 4: product delivery

Planck data analysis  Level S: mission simulation  Level 1: telemetry processing and instrument control, early source catalogue  Level 2: calibration and map-making  Level 3: component separation, CMB spectrum estimation, source catalogue  Level 4: product delivery

Planck schedule  Launch between agoust 2007 and 2008  Observations start after about two months  14 months of data acquisition  1 year data proprietary period  1 year data release, publications, archive  Over within 2012

Planck DPC schedule  Software acquisition and integration ongoing  Ongoing hardware acquisition: minimum requirement for a 128 Opteron processors parallel machine, 2 or 4 Gb RAM per CPU, 10 Tb disk space  Hardware and software installation and maintainance  Data analysis pipeline testing beginning april 2006  Pipeline for the operations ready 6 months before launch

Planck DPC work status  Pipeline simulations ongoing for the 70 GHz detectors,  Results review from the pipeline testing web page  More details in the forthcoming talk by Sam Leach, May 2006

Opportunities and challenges for Trieste

Opportunities  You may exploit the proprietary period of data to propose and carry out your own science, provided that there is no overlap with the official deliverables  You may provide ideas and algorithms, and take the opportunity of being in physical contact with the DPC in order to carry out your research  With the exception of the Paris Cambridge parallel DPC, none in the world will have this opportunity during the Planck proprietary period

Challenges  The scientific impact of Planck is huge: Galactic structure, populations of galaxies and galaxy clusters, dark matter, energy, early universe  We will suffer a tremendous international attention and pressure during the operation and data reduction phases (just look how many times the keyword “Planck satellite” appears in modern astrophysics and cosmology literature)  A community may form on the basis of a large project like Planck, as already happened for cosmologists in europe

Trieste Planck Analysis Center (TPAC)  joint OAT and SISSA initiative lasting for the Planck operation time  Different from DPC: the interface is with the community in Trieste, not ESA  Goal: full exploitation of the Planck data, covering non-Planck deliverables which might be of interest for our community in Trieste  Tasks: driver for local interests in Planck, management of hardware and human resources in the Trieste area

Conclusions  Together with other experiments (LHC, GWs and DM searches, …), Planck is one of the major forthcoming appointments for cosmology, particle physics and astrophysics  It happens to have one of the two data analysis here in Trieste  If it works instrumentally, a world wide community, of particle physicists, cosmologists and astrophysicists, will have the eyes fixed on us  The challenge is not only allocating resources, but developing a community, understanding that the success in the data analysis process is crucial for how the community trusts us on large scale international projects

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CMB physics: Boltzmann equation d ɣ black body = + dt d baryons+leptons = + dt

Dark energy, gravity and CMB  Relation between dark energy and gravity (Perrotta et al.)  Production of Boltzmann codes for cosmological perturbations with dark energy and scalar-tensor gravity theories, (Perrotta, Baccigalupi, Acquaviva)  N-body and strong lensing simulations in dark energy cosmologies (collaboration with Matthias Bartelmann at Heidelberg, Klaus Dolag at MPA, …)  Constraints on scalar-tensor gravity from CMB and large scale structure (Acquaviva, Leach et al., 2005, in collaboration with Andrew Liddle, Sussex)  Theory of the weak gravitational lensing (Acquaviva et al. 2004)  Weak lensing on CMB and implications for the dark energy (Giovi et al. 2005, Acquaviva et al. 2005)  CMB foreground studies and data analysis algorithm design (Stivoli et al., collaboration with people at LBL Berkeley, …)  Direct involvement in the EBEx experiment (Shaul Hanany PI, university of MInnesota) for measuring the CMB B modes from primordial gravity waves  More than 30 referred papers on these issues in the past 5 years, three PhD thesis, one NASA Long Term Space Astrophysics program funded ( , about 0.5 million dollars), about ten students and post-docs (Berkeley, SISSA, Trieste university and observatory, …) currently working Figure on top: CMB spectra in dark energy cosmologies (Perrotta et al. 2000) Bottom: the EBEx forecasted performance on B modes detection from primordial gravitational waves

The promise of Planck  All sky survey of CMB temperature and polarization with 5 arcminutes angular resolution  Cosmic variance limited up to the nominal resolution in temperature, and up to 10 arcminutes in polarization  Frequency range from 30 to 857 GHz  Cosmological science goals: percent precision or better on the global cosmic geometry, abundance of dark and baryonic matter, dark energy dynamics, reionization optical depth, spectrum and statistics of primordial perturbations, abundance of cosmic gravitational waves  Secondary goals: discovery of thousands of galaxy clusters, radio and infrared point sources, physics of the diffuse gas in the Milky Way Figures reproducing simulations carried out at the Trieste Data Processing Center (DPC) and NERSC (LBL, Berkeley)

Planck facts  ESA medium size mission, the first one of the third generation CMB experiments, launch in Agoust 2007  Instrument mainly built by ESA, with a participation from NASA (JPL, Pasadena)  World wide scientific collaboration for the data exploitation, the keyword ``Planck satellite” appears hundreds of times in the abstract of astronomy papers (font: NASA ADS)  Two separate Data Processing Centers (DPCs): Trieste (OAT+SISSA, channels from 30 to 70 GHz), Paris and Cambridge (IAP and IoA, channels from 100 to 857 GHz)  One year observation time, first results released to the community in late 2008 (early release compact source catalogue) and middle 2009 (main scientific results)  Planck people currently at SISSA: 2 staff, 3 post-docs, 3 PhD students; a SISSA Planck plan for long term recruitment starting from the PhD admission in april 2006 is being submitted to the school senate (January 2006)