Cosmology with Multifrequency Observations of the Cosmic Microwave

Cosmology with Multifrequency Observations of the Cosmic Microwave Background: the WMAP and Planck experiments Carlos Hernández-Monteagudo Max Planck Institut für Astrophysik (MPA) Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 1

OUTLINE (i) Why is the CMB “cosmological” - The fireball model - The CMB within the model (ii) PLANCK’s view on three long standing problems in Cosmology: - The secondary anisotropies during reionization - The missing baryons and the t. SZ and k. SZ effects - The signature of Dark Energy on CMB: the cross ISW – t. SZ approach (iii) Conclusions Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 2

Why is the CMB “Cosmic”. . . Cosmological Principle: the universe looks the same in every direction, and we are not in a particular place. Isotropic and homogeneous universe: GR: (FRW models) In the 1920 -s, E. Hubble discovers the relation between galaxies' distance and their recession: no need for an stable universe The fireball model for the Universe is born. . . Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 3

Big Bang clear cut predictions: Nucleosynthesis and radiation background The combination of Einstein equations with the knowledge of the physics relevant for each of the components of the universe (baryons, neutrina, radiation, etc) allowed evolving the Boltzmann equation at those very early stages: Those computations predicted the abundances of primordial nuclei in the universe, together with an recombination epoch of electrons to form neutral hydrogen and the subsequent decoupling of a thermal bath of photons. . . Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 4

Dependence of abundance of He-4, D, He-3 and Li -7 on Omega_b according to nucleosynthesis. Observed values are given by shaded regions, (E. Wright, UCLA) Arno Penzias and Robert Wilson discovered an excess when manipulating an antenna of Bell laboratories at almost 3 K. Only 40 kms away, in Princeton University, Dicke, Peebles ad Wilkinson were planning to build their own antenna to detect the relic radiation of the Big Bang. . . Bell Labs. antenna Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 5

THE OVERALL PICTURE: Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 6

Po th we is r o m f ap (Top) One realization of a temperature CMB sky and the corresponding angular power spectrum (diamonds in right panel) as compared to theoretical power spectrum around which it is distributed (solid line) Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 7

PREDICTIONS MOTIVATED BY THEORY: The CMB must have a black body energy spectrum, contain Gaussian anisotropies, and with an angular power spectrum denoting anisotropies generated both inside and outside the causal horizon during decoupling, show linear polarization induced by Thomson scattering off electrons, but also, some level of B-type polarization generated by the background of gravitational waves that arose at the end of the primeval epoch of acceleration expansion (inflation) Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 8

COBE, 1992 FWHM~7 degs Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 9

WMAP 7 years, (2010) WMAP V-band FWHM~0. 23 degs Effective horizon at recombination Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 10

WMAP 7 years, (2010) WMAP V-band Suprahorizon anisotropies “Causal” anisotropies Effective horizon at recombination Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 11

WMAP VERSUS PLANCK 5 different channels at 22, 33, 44, 63, 94 GHz ü Maximum angular resolution of ~0. 23 degrees ü Max. sensitivity of ~5 mu. K per square degree (94 GHz) ü 10 different channels at 30, 44, 70, 100, 143, 217, 353, 545 and 857 GHz ü Maximum angular resolution of ~0. 075 degrees ü Max. sensitivity of ~0. 25 mu. K per square degree (143 GHz) ü PLANCK, with many more frequency channels and better angular resolution, should: Improve CMB measurements to smaller angular scales Remove more efficiently the contaminants (mostly due to the Milky Way or point sources) Characterize secondary effects much more accurately Map the E mode of the polarization to much better precision and smaller angular scales Set constraints on the amount of B-mode polarization Establish stronger constraints on primordial non-Gaussianity Provide much more complete t. SZ source catalog Etc. . . All this should translate into better precision in the cosmological parameters. . . Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 12

SECONDARY ANISOTROPIES IN THE CMB Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 13

(LINEAR) SECONDARY ANISOTROPIES IN THE CMB Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 14

But there are way more secondary effects in the CMB. . . Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 15

MORE ON SECONDARY ANISOTROPIES. . . Since the CMB has a black body spectrum whose brightness temperature does not depend on frequency, If. . . we divide the secondary anisotropies into two separate groups: * Anisotropies which respect the CMB black body spectrum (and therefore do not change the total number of CMB photons): - Thomson scattering of CMB photons on free electrons during reionization and in galaxy, resonant scattering on fine structure lines in ions, metals and molecules, mainly during reionization, crossing of time varying gravitational wells, etc * Anisotropies which distort the CMB black body spectrum (introduce freq. -dependent temperature fluctuations): - Inverse Compton scattering of CMB photons off hot gas, collisional or UV-induced emission on resonant transitions of ions, metals and molecules, free-free and syncrotron emission from electron plasmae Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 16

I shall use these secondary anisotropies to address three fundamental problems in Cosmology: Explore the Dark Ages and the epoch of Reionization preceding the formation of the first galaxies, which to date has remained hidden to observations ü Find and characterize the physical state of the missing baryons (~50% of baryons are not detected in the local universe) ü Characterize Dark Energy by studying its impact on CMB temperature anisotropies ü Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 17

Let us move onto Reionization. . . Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 18

Biggest effect is frequency independent. . . Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 19

FREQUENCY DEPENDENT SECONDARY EFFECTS DURING REIONIZATION: Effects preserving the CMB black body spectrum: * Resonant scattering on fine structure lines of ions, metals and molecules Effects distorting the CMB black body spectrum: * Collisional emission on fine structure lines of ions, metals and molecules * Wouthuysen-Field effect (UV pumping) in OI 63. 2 micron transition * Reprocessed UV emission in the microwave range by dust particles Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 20

The presence of LINES in the CMB: If a given species X has a resonant transition with a given resonant frequency, the observed CMB will interact with that species at a redshift In multifrequency experiments like Planck, a low frequency channel can be used as reference, since it will probe highest redshifts (for which the species abundance should be lowest) By changing the observing frequency, one can perform tomography of the species during reionization Basu, CHM & Sunyaev (A&A, 2004), CHM & Sunyaev (MNRAS, 2005), CHM, Rubiño. Martín & Sunyaev (A&A 2005), CHM, Verde & Jimenez (Ap. J, 2006) Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 21

@ 100 GHz Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 22

@ 143 GHz Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 23

@ 217 GHz Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 24

End of the Dark Ages and beginning of Reionization Imprint of metals and molecules synthesized during reionization on the CMB via frequency dependent signals: Resonant scattering on fine structure lines of metal and ionic species Collisional emission on those same lines and species + on molecules like CO UV pumping on the Balmer-alpha line of OI at 63. 2 micron Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 25

IMPACT OF RESONANT SCATTERING ON CMB POWER SPECTRUM Basu, CHM & Sunyaev (04) Change in angular power spectrum (Cl) ~ Optical depth in the line ~ Abundance of metals at resonant redshift ~ PLANCK will set constraints on 26 metal/ion abundances at very high redshift (z~8 -50) with CMB observations !

Collisionally induced emission in dense regions: the clustering of star forming regions The spectral width of the observing experiment conditions the width of the redshift shell interacting with the CMB: this allows projecting out all “non-line” foregrounds (including CMB!) Righi, CHM & Sunyaev, (A&A 2008) Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 27

Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 28

Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 29

For relative spectral width of 1 e-3, the CO J=1 -0 115 GHz is the largest foreground at ell~2, 000 between 30 – 70 GHz Righi, CHM & Sunyaev, (A&A 2008) Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 30

UV pumping induced distortion of the CMB CHM, Haiman, Verde & Jimenez, Ap. JLetters 2007 UV background generated by first stars changes Tspin in fine structure transitions of neutral oxygen OI (64 micron, 148 micron) ~ distortion in CMB spectrum and temperature anisotropies ~ constraints on neutral oxygen during reionization. 31

Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 32

PLANCK will set first constraints on the Dark Ages and early reionization epoch We switch gears and move to the missing baryon problem Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 33

THE MISSING BARYON PROBLEM Counting the amount of baryons in the local universe yields a result that falls a factor of 2 -4 short when compared to observations at redshifts z~5 -6 (Ly-alpha absorbers) and z~1, 050 (CMB observations) The Universe has grown bigger and transparent since then. . . The hidden baryons should be found in a diffuse low density warm hot phase (WHIM) at T in [1 e 5, 1 e 7] K Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 Nicastro et al. (05) 34

On photon – free electron encounters: Thomson, Compton scatterings and thermal and kinetic Sunyaev-Zel'dovich effects Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 35

SECONDARY EFFECTS DUE TO HOT, MOVING GAS AT LOW REDSHIFT (Compton – Thomson scattering) If the electron plasma is moving with respect to the CMB (kinetic Sunyaev-Zel'dovich [k. SZ] effect): If the electron cloud is hotter than the CMB, then it also injects energy in the scattering, distorting the black body (thermal Sunyaev-Zel'dovich [t. SZ] effect, its T_B is freq. dependent) Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 New tools to probe missing gas in the universe! 36

Thermal Sunyaev-Zel'dovich effect (t. SZ) Compton inverse scattering off hot electrons by CMB photons: electrons transfer energy to CMB photon field, distorting CMB black body spectrum and introducing frequency dependent brightness temperature anisotropies The symbol y is known as the Comptonization parameter x = (nu / 56. 8 GHz)

By cross-correlating the 2 MASS galaxy survey with WMAP data, we provided the first significant detection of the t. SZ in the local population of clusters of galaxies, [CHM et al. , Ap. JLetters, 2004] First identification of galaxy clusters via t. SZ prior to its identification in other wavelenght/frequency ranges First characterization of the t. SZ profile for the local 38 population of galaxy clusters

First spectral detection of the t. SZ by combining ARCHEOPS and WMAP data. . . [CHM & ARCHEOPS collab. , A&A, 2005] WMAP bands ARCHEOPS bands 39

Searching for missing baryons When searching for the missing baryons, however, the t. SZ seems to be largely unsensitive to the uncollapsed baryons: Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 40

Searching for missing baryons Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 41

Searching for missing baryons (CHM, Trac, Verde & Jimenez, Ap. JLetters, 2006) Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 42

(CHM, Trac, Verde & Jimenez, Ap. JLetters, 2006) Searching for missing baryons Most (80%) t. SZ is arising in overdense regions which contain only ~20% of the total mass, therefore missing a considerable fraction of the missing baryons. . . Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 43

Searching for missing baryons Strong correlation between galaxy density and gas pressure (or t. SZ emissivity)! In Working Group 5 of Planck we are now implementing crosscorrelation methods between galaxy surveys and t. SZ maps from Planck data to search for the gas (CHM, Trac, Verde & Jimenez, Ap. JLetters, 2006) Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 44

Searching for missing baryons What about the k. SZ and the missing baryons? Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 45

Searching for missing baryons The k. SZ, instead, is coherent due to the large scale correlation of the peculiar velocities (~20 Mpc/h), and involves most of baryons. However, it flips sign and cannot be spectrally distinguished from the intrinsic CMB, and this makes its detection hard (none to date): Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 46

Searching for missing baryons A second order (in linear theory) computation of the k. SZ provides a S/N~5 -8 when cross-correlating with velocity templates built upon density surveys CHM & Ho, MNRAS, 2009 mu. K S/N k. SZ cannot be spectrally distinguished from CMB, and has smaller amplitude… ü … but can be extracted by cross-correlating PLANCK maps with templates built from galaxy catalogs ü LAL, Orsay, March 16 h 2010 47

Dark Energy, the Integrated Sachs Wolfe (ISW) effect and its Cross Talk with the t. SZ ISWxt. SZ Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 48

A couple of facts about the ISW. . . ISWxt. SZ The ISW arises in linear (large) scales if gravitational potentials evolve in time. In particular, in the LCDM scenario, when the accelerated expansion of the Universe makes linear gravitational potentials shallower: Due to the Laplacian present in the Poisson equation, the potential fluctuations arise at scales typically larger than the density field. This effect arises mostly in the redshift range z in [0. 3, 1. 2] This effect probes Dark Energy!! Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 49

ISWxt. SZ Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 50

ISWxt. SZ CMB (simulated maps) ISW Projected matter density Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 (ISW arises at z in [0. 3, 1. 2]) 51

Projected matter density ISWxt. SZ X-angular power spectrum ISW Projected density (ISW arises at z in [0. 3, 1. 2]) CHM, A&A (2008, 2009) Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 52

ISWxt. SZ Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 53

Projected matter density Thermal SZ x ISW X-angular power spectrum ISW Carlos Hernández-Monteagudo However, the need for a wide and deep density (galaxy) survey can be avoided by profiting the known spectral dependence of the t. SZ and the different frequencies of Planck: LAL, Orsay, March 16 h 2010 54

ISWxt. SZ The frequency dependence of the t. SZ allows for its separation from CMB ü No need to use galaxy catalogs, t. SZ and hence cross correlation is PLANCK data contained, (CHM & Sunyaev, 2005) ü Work under progress in Working Group 5 of PLANCK ü 55

CONCLUSIONS The CMB, due to its large degree of isotropy and its black body energy spectrum, constitutes by itself one of the most solid pieces of evidence supporting the Big Bang theory. Its angular intensity and polarization anisotropies provide a unique frame in which confronting predictions of the inflationary paradigm with observations. These observations are so far in absolute agreement with theory, and experiments like Planck may provide in the following months the first detection of gravitational waves, or, in its defect, strong constraints on different inflation models. In its journey from the surface of last scattering to the observer, the CMB witnesses an evolving universe: the birth of the first stars, causing the ionization of the intergalactic medium and contamining it with the first metals, leave an imprint on the CMB which can be studied with upcoming multifrequency observations The CMB provides an independent way to study thermal energy and the motion of the missing baryons of the local universe. § The CMB is sensitive to the presence of a component of Dark Energy causing a late accelerated phase in the universal expansion. A multifrequency experiment like Planck constitutes a new window to the presence of this acceleration. Carlos Hernández-Monteagudo LAL, Orsay, March 16 h 2010 56