Constraints on neutrino density and velocity isocurvature modes from WMAP-9 data

Peer reviewe

Constraints on Scalar and Tensor Perturbations in Phenomenological and Two-field Inflation Models : Bayesian Evidences for Primordial Isocurvature and Tensor Modes

Peer reviewe

Obstacles to Online Yoga – Empirical Study on Yoogaia’s Passive Customers

Yoga is an ancient Indian physical and mental practice that has become extremely popular in the Western World, and is nowadays also available on Internet. The case firm of the study is a Finnish start-up company Yoogaia that offers yoga and other body and mind exercises online. Yoogaia’s special feature is that an online class can be attended with a web camera, which enables two-way interaction. Yoogaia has a large register of customers, but only a minority of them is currently paying for the service. The research purpose is thus to find out what are the obstacles for Yoogaia’s passive registered customers to buy the service. In order to answer the research problem three objectives were set: 1) to define the potential beneficial elements in this field of business: yoga service online, 2) to examine empirically what are regarded as Yoogaia’s beneficial elements, and 3) to empirically discover the reasons for customers’ passive behavior. As the study is quantitative by its nature a theoretical framework was created to serve as a basis for the empirical analysis. Yoga, online environment and membership were recognized as the beneficial elements in Yoogaia’s business idea. In addition four supplementary theme interviews were performed before creating the questionnaire. All in all 599 valid answers were received, of which 26 were from sign-ups who had not taken advantage of the free trial. The results were analyzed with IBM SPSS program using factor analysis and cluster analysis as methods. It appeared that Yoogaia’s main benefits were relaxation from yoga practice, price, flexibility, quick reactivity and communication provided by Yoogaia. The main reasons for having joined Yoogaia were free trial and special offers. That there no longer was a possibility to attend a singular class was considered as a disadvantage. Three segments were created according to their considerations about Yoogaia: True yogis, Happy customers and Busy yogis, and their potential for Yoogaia were estimated. Happy customers appeared to be the most potential ones. The only reason for passive behavior that came out was the fact that Yoogaia is not available via tablet. The identified obstacles for buying the service were: the assumption that signing up was done out of curiosity or because of the free trial, or reluctance to pay the full price for the service.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

Planck 2013 results. XXII. Constraints on inflation

We analyse the implications of the Planck data for cosmic inflation. The Planck nominal mission temperature anisotropy measurements, combined with the WMAP large-angle polarization, constrain the scalar spectral index to be n(s) = 0.9603 +/- 0:0073, ruling out exact scale invariance at over 5 sigma Planck establishes an upper bound on the tensor-to-scalar ratio of r = 2 do not provide a good fit to the data. Planck does not find statistically significant running of the scalar spectral index, obtaining dn(s)/dln k = -0.0134 +/- 0.0090. We verify these conclusions through a numerical analysis, which makes no slowroll approximation, and carry out a Bayesian parameter estimation and model-selection analysis for a number of inflationary models including monomial, natural, and hilltop potentials. For each model, we present the Planck constraints on the parameters of the potential and explore several possibilities for the post-inflationary entropy generation epoch, thus obtaining nontrivial data-driven constraints. We also present a direct reconstruction of the observable range of the inflaton potential. Unless a quartic term is allowed in the potential, we find results consistent with second-order slow-roll predictions. We also investigate whether the primordial power spectrum contains any features. We find that models with a parameterized oscillatory feature improve the fit by delta 2 10; however, Bayesian evidence does not prefer these models. We constrain several single-field inflation models with generalized Lagrangians by combining power spectrum data with Planck bounds on fNL. Planck constrains with unprecedented accuracy the amplitude and possible correlation (with the adiabatic mode) of non-decaying isocurvature fluctuations. The fractional primordial contributions of cold dark matter (CDM) isocurvature modes of the types expected in the curvaton and axion scenarios have upper bounds of 0.25% and 3.9% (95% CL), respectively. In models with arbitrarily correlated CDM or neutrino isocurvature modes, an anticorrelated isocurvature component can improve the 2 by approximately 4 as a result of slightly lowering the theoretical prediction for the 40 multipoles relative to the higher multipoles. Nonetheless, the data are consistent with adiabatic initial conditions.Peer reviewe

Planck intermediate results XVI : Profile likelihoods for cosmological parameters

Peer reviewe

Characterization of Primordial Perturbations by Observations

We constrain cosmological models where the primordial perturbations have an adiabatic and a (possi- bly correlated) cold dark matter (CDI), neutrino density (NDI) or neutrino velocity (NVI) isocurvature component. We use both a phenomenological approach, where the power spectra of primordial per- turbations are parametrized with two amplitudes at two different scales, and a slow-roll two-field inflation approach where inflation slow-roll parameters are used as primary parameters, determining the spectral indices and the ratio of tensor perturbations to scalar perturbations. We use WMAP 7- year and 9-year data combined with other CMB data and Planck 2013 CMB temperature anisotropy data. Bayesian methods indicate no preference for any of the isocurvature modes: the CMB data set tight upper bounds on any non-adiabatic contribution to the observed CMB temperature variance. We show that allowing for a primordial tensor contribution has a negligible effect on the determi- nation of the non-adiabatic contribution and vice versa, as long as the tensor spectral index obeys the first inflationary consistency relation. On large scales, the WMAP CMB data seem to constrain isocurvature tighter than the Planck data. This is due to the lack of power at low multipoles, l ∼ 2...40, in the Planck data compared to the prediction of the best-fitting adiabatic ΛCDM model. Hence the Planck data prefer a power-reducing mechanism, which the mixed adiabatic and isocurva- ture models with negative correlation or full anticorrelation can offer. With WMAP 9-year data we find that in the NDI and NVI cases larger isocurvature fractions are allowed than in the correspond- ing models with CDI. For uncorrelated perturbations, the upper limit to the primordial NDI (NVI) fraction is 24% (20%) at k = 0.002Mpc−1 and 28% (16%) at k = 0.01Mpc−1. For maximally correlated (anticorrelated) perturbations, the upper limit to the NDI fraction is 3.0% (0.9%). The non-adiabatic contribution to the CMB temperature variance can be 10% ( 13%) for the NDI (NVI) modes. For Planck data the non-adiabatic contribution to the temperature variance can be up to 7%, 9%, 5% in the CDI, NDI, NVI models. The Planck data constrain the primordial CDI fraction in specific curvaton and axion scenarios to 0.25% and 3.9%, respectively. All bounds above are at 95% CL. With the WMAP data, relaxing the pure adiabaticity assumption leads to large shifts of the preferred values of standard cosmological parameters and broadening of their posterior probability distributions. In contrast, as the Planck data determines the acoustic peak structure precisely up to the sixth acoustic peak, allowing for a mixture of the primordial adiabatic and an isocurvature mode does not significantly affect the determination of standard cosmological parameters.Väitöskirjassa tarkastellaan varhaisen maailmankaikkeuden tiheysvaihteluiden (eli häiriöiden) luonnetta. Adiabaattisen häiriön eli avaruuden kaarevuushäiriön tapauksessa aineen kaikkien muotojen tiheysvaihtelut ovat samoja. Isokurvatuurihäiriöt (vakiokaarevuushäiriö) puolestaan säilyttävät kokonaistiheyden vakiona ja häiriöt ovat ainoastaan aineosien suhteellisia vaihteluja. Alkuräjähdysteorian mukaan maailmankaikkeus on laajennut jatkuvasti. Aluksi laajenemisen uskotaan olleen eksponentiaalisen nopeaa. Tätä vaihetta kutsutaan kosmologiseksi inflaatioksi. Kvanttimekaniikan lakien mukaan mikroskooppisen pienille alueille syntyy väistämättä häiriöitä, kvanttifluktuaatioita. Inflaatio laajentaa nämä pienen alueen kvanttifluktuaatiot kosmologisiin mittakaavoihin. Mikäli voimme havainnoin määritellä kosmologisten tiheysvaihteluiden luonteen, voimme myös päätellä, minkä tyyppiset fysiikan lainalaisuudet hallitsivat näiden häiriöiden syntyhetkellä, inflaation aikakautena, ja näin arvioida erilaisten teoreettisten inflaatiomallien todennäköisyyksiä. Kosminen mikroaaltotausta (CMB) on varhaisen maailmankaikkeuden lähettämä kuva meille ajalta, jolloin valo vapautui muusta aineesta eli maailmankaikkeus tuli läpinäkyväksi. Avaruuden laajeneminen on muuttanut tämän näkyvän (keltaisen) aallonpituuden valon mikroaaltosäteilyksi. Mittaamalla tarkkaan CMB:n voimakkuutta (kirkkautta) eri suunnissa taivaalla saamme tietoa varhaisen maailmankaikkeuden lämpötilavaihteluista, joista taas voidaan laskea tiheysvaihtelut. WMAP- ja Planck-satelliittihankkeet ovat kartoittaneet taivaan CMB:tä. Väitöskirjassa esitetään näistä CMB kartoituksista tilastollisin menetelmin arvioituja isokurvatuurihäiriöiden ylärajoja suhteessa adiabaattiseen häiriöön. Työssä tarkastellaan eri tyyppisiä isokurvatuurihäiriöitä, kuten kylmän pimeän aineen (CDM) ja säteilyn välinen tiheysvaihtelu (CDI), neutriinojen tiheyden ja säteilyn välinen vaihtelu (NDI) ja neutriinojen nopeuden vaihtelu suhteessa säteilyn keskimääräiseen nopeuteen (NVI). Väitöskirjan tuloksena esitetään, että yksinkertainen inflaatiomalli riittää selittämään havaitut CMB mittaukset ja niistä johdetut arviot isokurvatuurihäiriöiden suuruudelle. CDI, NDI tai NVI häiriöiden lisääminen kosmologiseen malliin, ei lisää mallin todennäköisyyttä verrattuna yksinkertaiseen adiabaattiseen häiriömalliin

Characterization of Primordial Perturbations by Observations

We constrain cosmological models where the primordial perturbations have an adiabatic and a (possi- bly correlated) cold dark matter (CDI), neutrino density (NDI) or neutrino velocity (NVI) isocurvature component. We use both a phenomenological approach, where the power spectra of primordial per- turbations are parametrized with two amplitudes at two different scales, and a slow-roll two-field inflation approach where inflation slow-roll parameters are used as primary parameters, determining the spectral indices and the ratio of tensor perturbations to scalar perturbations. We use WMAP 7- year and 9-year data combined with other CMB data and Planck 2013 CMB temperature anisotropy data. Bayesian methods indicate no preference for any of the isocurvature modes: the CMB data set tight upper bounds on any non-adiabatic contribution to the observed CMB temperature variance. We show that allowing for a primordial tensor contribution has a negligible effect on the determi- nation of the non-adiabatic contribution and vice versa, as long as the tensor spectral index obeys the first inflationary consistency relation. On large scales, the WMAP CMB data seem to constrain isocurvature tighter than the Planck data. This is due to the lack of power at low multipoles, l ∼ 2...40, in the Planck data compared to the prediction of the best-fitting adiabatic ΛCDM model. Hence the Planck data prefer a power-reducing mechanism, which the mixed adiabatic and isocurva- ture models with negative correlation or full anticorrelation can offer. With WMAP 9-year data we find that in the NDI and NVI cases larger isocurvature fractions are allowed than in the correspond- ing models with CDI. For uncorrelated perturbations, the upper limit to the primordial NDI (NVI) fraction is 24% (20%) at k = 0.002Mpc−1 and 28% (16%) at k = 0.01Mpc−1. For maximally correlated (anticorrelated) perturbations, the upper limit to the NDI fraction is 3.0% (0.9%). The non-adiabatic contribution to the CMB temperature variance can be 10% ( 13%) for the NDI (NVI) modes. For Planck data the non-adiabatic contribution to the temperature variance can be up to 7%, 9%, 5% in the CDI, NDI, NVI models. The Planck data constrain the primordial CDI fraction in specific curvaton and axion scenarios to 0.25% and 3.9%, respectively. All bounds above are at 95% CL. With the WMAP data, relaxing the pure adiabaticity assumption leads to large shifts of the preferred values of standard cosmological parameters and broadening of their posterior probability distributions. In contrast, as the Planck data determines the acoustic peak structure precisely up to the sixth acoustic peak, allowing for a mixture of the primordial adiabatic and an isocurvature mode does not significantly affect the determination of standard cosmological parameters.Väitöskirjassa tarkastellaan varhaisen maailmankaikkeuden tiheysvaihteluiden (eli häiriöiden) luonnetta. Adiabaattisen häiriön eli avaruuden kaarevuushäiriön tapauksessa aineen kaikkien muotojen tiheysvaihtelut ovat samoja. Isokurvatuurihäiriöt (vakiokaarevuushäiriö) puolestaan säilyttävät kokonaistiheyden vakiona ja häiriöt ovat ainoastaan aineosien suhteellisia vaihteluja. Alkuräjähdysteorian mukaan maailmankaikkeus on laajennut jatkuvasti. Aluksi laajenemisen uskotaan olleen eksponentiaalisen nopeaa. Tätä vaihetta kutsutaan kosmologiseksi inflaatioksi. Kvanttimekaniikan lakien mukaan mikroskooppisen pienille alueille syntyy väistämättä häiriöitä, kvanttifluktuaatioita. Inflaatio laajentaa nämä pienen alueen kvanttifluktuaatiot kosmologisiin mittakaavoihin. Mikäli voimme havainnoin määritellä kosmologisten tiheysvaihteluiden luonteen, voimme myös päätellä, minkä tyyppiset fysiikan lainalaisuudet hallitsivat näiden häiriöiden syntyhetkellä, inflaation aikakautena, ja näin arvioida erilaisten teoreettisten inflaatiomallien todennäköisyyksiä. Kosminen mikroaaltotausta (CMB) on varhaisen maailmankaikkeuden lähettämä kuva meille ajalta, jolloin valo vapautui muusta aineesta eli maailmankaikkeus tuli läpinäkyväksi. Avaruuden laajeneminen on muuttanut tämän näkyvän (keltaisen) aallonpituuden valon mikroaaltosäteilyksi. Mittaamalla tarkkaan CMB:n voimakkuutta (kirkkautta) eri suunnissa taivaalla saamme tietoa varhaisen maailmankaikkeuden lämpötilavaihteluista, joista taas voidaan laskea tiheysvaihtelut. WMAP- ja Planck-satelliittihankkeet ovat kartoittaneet taivaan CMB:tä. Väitöskirjassa esitetään näistä CMB kartoituksista tilastollisin menetelmin arvioituja isokurvatuurihäiriöiden ylärajoja suhteessa adiabaattiseen häiriöön. Työssä tarkastellaan eri tyyppisiä isokurvatuurihäiriöitä, kuten kylmän pimeän aineen (CDM) ja säteilyn välinen tiheysvaihtelu (CDI), neutriinojen tiheyden ja säteilyn välinen vaihtelu (NDI) ja neutriinojen nopeuden vaihtelu suhteessa säteilyn keskimääräiseen nopeuteen (NVI). Väitöskirjan tuloksena esitetään, että yksinkertainen inflaatiomalli riittää selittämään havaitut CMB mittaukset ja niistä johdetut arviot isokurvatuurihäiriöiden suuruudelle. CDI, NDI tai NVI häiriöiden lisääminen kosmologiseen malliin, ei lisää mallin todennäköisyyttä verrattuna yksinkertaiseen adiabaattiseen häiriömalliin

Planck 2015 results. XXIII. The thermal Sunyaev-Zeldovich effect--cosmic infrared background correlation

We use Planck data to detect the cross-correlation between the thermal Sunyaev-Zeldovich (tSZ) effect and the infrared emission from the galaxies that make up the the cosmic infrared background (CIB). We first perform a stacking analysis towards Planck-confirmed galaxy clusters. We detect infrared emission produced by dusty galaxies inside these clusters and demonstrate that the infrared emission is about 50% more extended than the tSZ effect. Modelling the emission with a Navarro--Frenk--White profile, we find that the radial profile concentration parameter is $c_{500} = 1.00^{+0.18}_{-0.15}$. This indicates that infrared galaxies in the outskirts of clusters have higher infrared flux than cluster-core galaxies. We also study the cross-correlation between tSZ and CIB anisotropies, following three alternative approaches based on power spectrum analyses: (i) using a catalogue of confirmed clusters detected in Planck data; (ii) using an all-sky tSZ map built from Planck frequency maps; and (iii) using cross-spectra between Planck frequency maps. With the three different methods, we detect the tSZ-CIB cross-power spectrum at significance levels of (i) 6 $\sigma$, (ii) 3 $\sigma$, and (iii) 4 $\sigma$. We model the tSZ-CIB cross-correlation signature and compare predictions with the measurements. The amplitude of the cross-correlation relative to the fiducial model is $A_{\rm tSZ-CIB}= 1.2\pm0.3$. This result is consistent with predictions for the tSZ-CIB cross-correlation assuming the best-fit cosmological model from Planck 2015 results along with the tSZ and CIB scaling relations.Comment: 18 pages, 16 figure