Planck intermediate results LI. Features in the cosmic microwave background temperature power spectrum and shifts in cosmological parameters

The six parameters of the standard ΛCDM model have best-fit values derived from the Planck temperature power spectrum that are shifted somewhat from the best-fit values derived from WMAP data. These shifts are driven by features in the Planck temperature power spectrum at angular scales that had nev...

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Published in:Astronomy & Astrophysics
Main Authors: Aghanim, N, Akrami, Y, Ashdown, M, Aumont, J, Baccigalupi, C, Ballardini, M, Banday, AJ, Barreiro, RB, Bartolo, N, Basak, S, Benabed, K, Fantaye, Y, Finelli, F, Forastieri, F, Frailis, M, Franceschi, E, Frolov, A, Galeotta, S, Galli, S, Ganga, K, Genova-Santos, RT, Mennella, A, Gerbino, M, Gonzalez-Nuevo, J, Gorski, KM, Gratton, S, Gruppuso, A, Gudmundsson, JE, Herranz, D, Hivon, E, Huang, Z, Jaffe, AH, Migliaccio, M, Jones, WC, Keihanen, E, Keskitalo, R, Kiiveri, K, Kim, J, Kisner, TS, Knox, L, Krachmalnicoff, N, Kunz, M, Kurki-Suonio, H, Millea, M, Lagache, G, Lamarre, J-M, Lasenby, A, Lattanzi, M, Lawrence, CR, Le Jeune, M, Levrier, F, Lewis, A, Liguori, M, Lilje, PB, Miville-Deschenes, M-A, Lilley, M, Lindholm, V, Lopez-Caniego, M, Lubin, PM, Ma, Y-Z, Macias-Perez, JF, Maggio, G, Maino, D, Mandolesi, N, Mangilli, A, Molinari, D, Maris, M, Martin, PG, Martinez-Gonzalez, E, Matarrese, S, Mauri, N, McEwen, JD, Meinhold, PR, Moneti, A, Montier, L, Morgante, G, Moss, A, Narimani, A, Bersanelli, M, Natoli, P, Oxborrow, CA, Pagano, L, Paoletti, D, Partridge, B, Patanchon, G, Patrizii, L, Pettorino, V, Piacentini, F, Polastri, L, Bielewicz, P, Polenta, G, Puget, J-L, Rachen, JP, Racine, B, Reinecke, M, Remazeilles, M, Renzi, A, Rocha, G, Rossetti, M, Roudier, G, Bonaldi, A, Rubino-Martin, JA, Ruiz-Granados, B, Salvati, L, Sandri, M, Savelainen, M, Scott, D, Sirignano, C, Sirri, G, Stanco, L, Suur-Uski, A-S, Bonavera, L, Tauber, JA, Tavagnacco, D, Tenti, M, Toffolati, L, Tomasi, M, Tristram, M, Trombetti, T, Valiviita, J, Van Tent, F, Vielva, P, Bond, JR, Villa, F, Vittorio, N, Wandelt, BD, Wehus, IK, White, M, Zacchei, A, Zonca, A, Borrill, J, Bouchet, FR, Burigana, C, Calabrese, E, Cardoso, J-F, Challinor, A, Chiang, HC, Colombo, LPL, Combet, C, Crill, BP, Curto, A, Cuttaia, F, De Bernardis, P, De Rosa, A, De Zotti, G, Delabrouille, J, Di Valentino, E, Dickinson, C, Diego, JM, Dore, O, Ducout, A, Dupac, X, Dusini, S, Efstathiou, G, Elsner, F, Ensslin, TA, Eriksen, HK
Other Authors: Science and Technology Facilities Council (STFC), Science and Technology Facilities Council
Format: Article in Journal/Newspaper
Language:English
Published: EDP Sciences 2017
Subjects:
Online Access:http://hdl.handle.net/10044/1/55072
https://doi.org/10.1051/0004-6361/201629504
id ftimperialcol:oai:spiral.imperial.ac.uk:10044/1/55072
record_format openpolar
institution Open Polar
collection Imperial College London: Spiral
op_collection_id ftimperialcol
language English
topic Science & Technology
Physical Sciences
Astronomy & Astrophysics
cosmology: observations
cosmic background radiation
cosmological parameters
cosmology: theory
PROBE WMAP OBSERVATIONS
CMB ANISOTROPIES
APPROXIMATION
RADIATION
UNIVERSE
MAPS
0201 Astronomical And Space Sciences
spellingShingle Science & Technology
Physical Sciences
Astronomy & Astrophysics
cosmology: observations
cosmic background radiation
cosmological parameters
cosmology: theory
PROBE WMAP OBSERVATIONS
CMB ANISOTROPIES
APPROXIMATION
RADIATION
UNIVERSE
MAPS
0201 Astronomical And Space Sciences
Aghanim, N
Akrami, Y
Ashdown, M
Aumont, J
Baccigalupi, C
Ballardini, M
Banday, AJ
Barreiro, RB
Bartolo, N
Basak, S
Benabed, K
Fantaye, Y
Finelli, F
Forastieri, F
Frailis, M
Franceschi, E
Frolov, A
Galeotta, S
Galli, S
Ganga, K
Genova-Santos, RT
Mennella, A
Gerbino, M
Gonzalez-Nuevo, J
Gorski, KM
Gratton, S
Gruppuso, A
Gudmundsson, JE
Herranz, D
Hivon, E
Huang, Z
Jaffe, AH
Migliaccio, M
Jones, WC
Keihanen, E
Keskitalo, R
Kiiveri, K
Kim, J
Kisner, TS
Knox, L
Krachmalnicoff, N
Kunz, M
Kurki-Suonio, H
Millea, M
Lagache, G
Lamarre, J-M
Lasenby, A
Lattanzi, M
Lawrence, CR
Le Jeune, M
Levrier, F
Lewis, A
Liguori, M
Lilje, PB
Miville-Deschenes, M-A
Lilley, M
Lindholm, V
Lopez-Caniego, M
Lubin, PM
Ma, Y-Z
Macias-Perez, JF
Maggio, G
Maino, D
Mandolesi, N
Mangilli, A
Molinari, D
Maris, M
Martin, PG
Martinez-Gonzalez, E
Matarrese, S
Mauri, N
McEwen, JD
Meinhold, PR
Moneti, A
Montier, L
Morgante, G
Moss, A
Narimani, A
Bersanelli, M
Natoli, P
Oxborrow, CA
Pagano, L
Paoletti, D
Partridge, B
Patanchon, G
Patrizii, L
Pettorino, V
Piacentini, F
Polastri, L
Bielewicz, P
Polenta, G
Puget, J-L
Rachen, JP
Racine, B
Reinecke, M
Remazeilles, M
Renzi, A
Rocha, G
Rossetti, M
Roudier, G
Bonaldi, A
Rubino-Martin, JA
Ruiz-Granados, B
Salvati, L
Sandri, M
Savelainen, M
Scott, D
Sirignano, C
Sirri, G
Stanco, L
Suur-Uski, A-S
Bonavera, L
Tauber, JA
Tavagnacco, D
Tenti, M
Toffolati, L
Tomasi, M
Tristram, M
Trombetti, T
Valiviita, J
Van Tent, F
Vielva, P
Bond, JR
Villa, F
Vittorio, N
Wandelt, BD
Wehus, IK
White, M
Zacchei, A
Zonca, A
Borrill, J
Bouchet, FR
Burigana, C
Calabrese, E
Cardoso, J-F
Challinor, A
Chiang, HC
Colombo, LPL
Combet, C
Crill, BP
Curto, A
Cuttaia, F
De Bernardis, P
De Rosa, A
De Zotti, G
Delabrouille, J
Di Valentino, E
Dickinson, C
Diego, JM
Dore, O
Ducout, A
Dupac, X
Dusini, S
Efstathiou, G
Elsner, F
Ensslin, TA
Eriksen, HK
Planck intermediate results LI. Features in the cosmic microwave background temperature power spectrum and shifts in cosmological parameters
topic_facet Science & Technology
Physical Sciences
Astronomy & Astrophysics
cosmology: observations
cosmic background radiation
cosmological parameters
cosmology: theory
PROBE WMAP OBSERVATIONS
CMB ANISOTROPIES
APPROXIMATION
RADIATION
UNIVERSE
MAPS
0201 Astronomical And Space Sciences
description The six parameters of the standard ΛCDM model have best-fit values derived from the Planck temperature power spectrum that are shifted somewhat from the best-fit values derived from WMAP data. These shifts are driven by features in the Planck temperature power spectrum at angular scales that had never before been measured to cosmic-variance level precision. We have investigated these shifts to determine whether they are within the range of expectation and to understand their origin in the data. Taking our parameter set to be the optical depth of the reionized intergalactic medium τ, the baryon density ωb, the matter density ωm, the angular size of the sound horizon θ∗, the spectral index of the primordial power spectrum, ns , and Ase −2τ (where As is the amplitude of the primordial power spectrum), we have examined the change in best-fit values between a WMAP-like large angular-scale data set (with multipole moment ` < 800 in the Planck temperature power spectrum) and an all angularscale data set (` < 2500 Planck temperature power spectrum), each with a prior on τ of 0.07 ± 0.02. We find that the shifts, in units of the 1σ expected dispersion for each parameter, are {∆τ, ∆Ase −2τ , ∆ns , ∆ωm, ∆ωb, ∆θ∗} = {−1.7, −2.2, 1.2, −2.0, 1.1, 0.9}, with a χ 2 value of 8.0. We find that this χ 2 value is exceeded in 15% of our simulated data sets, and that a parameter deviates by more than 2.2σ in 9% of simulated data sets, meaning that the shifts are not unusually large. Comparing ` < 800 instead to ` > 800, or splitting at a different multipole, yields similar results. We examined the ` < 800 model residuals in the ` > 800 power spectrum data and find that the features there that drive these shifts are a set of oscillations across a broad range of angular scales. Although they partly appear similar to the effects of enhanced gravitational lensing, the shifts in ΛCDM parameters that arise in response to these features correspond to model spectrum changes that are predominantly due to non-lensing effects; the only exception is τ, which, at fixed Ase −2τ , affects the ` > 800 temperature power spectrum solely through the associated change in As and the impact of that on the lensing potential power spectrum. We also ask, “what is it about the power spectrum at ` < 800 that leads to somewhat different best-fit parameters than come from the full ` range?” We find that if we discard the data at ` < 30, where there is a roughly 2σ downward fluctuation in power relative to the model that best fits the full ` range, the ` < 800 best-fit parameters shift significantly towards the ` < 2500 best-fit parameters. In contrast, including ` < 30, this previously noted “low-` deficit” drives ns up and impacts parameters correlated with ns , such as ωm and H0. As expected, the ` < 30 data have a much greater impact on the ` < 800 best fit than on the ` < 2500 best fit. So although the shifts are not very significant, we find that they can be understood through the combined effects of an oscillatory-like set of high-` residuals and the deficit in low-` power, excursions consistent with sample variance that happen to map onto changes in cosmological parameters. Finally, we examine agreement between Planck T T data and two other CMB data sets, namely the Planck lensing reconstruction and the T T power spectrum measured by the South Pole Telescope, again finding a lack of convincing evidence of any significant deviations in parameters, suggesting that current CMB data sets give an internally consistent picture of the ΛCDM model.
author2 Science and Technology Facilities Council (STFC)
Science and Technology Facilities Council (STFC)
Science and Technology Facilities Council (STFC)
Science and Technology Facilities Council
Science and Technology Facilities Council (STFC)
format Article in Journal/Newspaper
author Aghanim, N
Akrami, Y
Ashdown, M
Aumont, J
Baccigalupi, C
Ballardini, M
Banday, AJ
Barreiro, RB
Bartolo, N
Basak, S
Benabed, K
Fantaye, Y
Finelli, F
Forastieri, F
Frailis, M
Franceschi, E
Frolov, A
Galeotta, S
Galli, S
Ganga, K
Genova-Santos, RT
Mennella, A
Gerbino, M
Gonzalez-Nuevo, J
Gorski, KM
Gratton, S
Gruppuso, A
Gudmundsson, JE
Herranz, D
Hivon, E
Huang, Z
Jaffe, AH
Migliaccio, M
Jones, WC
Keihanen, E
Keskitalo, R
Kiiveri, K
Kim, J
Kisner, TS
Knox, L
Krachmalnicoff, N
Kunz, M
Kurki-Suonio, H
Millea, M
Lagache, G
Lamarre, J-M
Lasenby, A
Lattanzi, M
Lawrence, CR
Le Jeune, M
Levrier, F
Lewis, A
Liguori, M
Lilje, PB
Miville-Deschenes, M-A
Lilley, M
Lindholm, V
Lopez-Caniego, M
Lubin, PM
Ma, Y-Z
Macias-Perez, JF
Maggio, G
Maino, D
Mandolesi, N
Mangilli, A
Molinari, D
Maris, M
Martin, PG
Martinez-Gonzalez, E
Matarrese, S
Mauri, N
McEwen, JD
Meinhold, PR
Moneti, A
Montier, L
Morgante, G
Moss, A
Narimani, A
Bersanelli, M
Natoli, P
Oxborrow, CA
Pagano, L
Paoletti, D
Partridge, B
Patanchon, G
Patrizii, L
Pettorino, V
Piacentini, F
Polastri, L
Bielewicz, P
Polenta, G
Puget, J-L
Rachen, JP
Racine, B
Reinecke, M
Remazeilles, M
Renzi, A
Rocha, G
Rossetti, M
Roudier, G
Bonaldi, A
Rubino-Martin, JA
Ruiz-Granados, B
Salvati, L
Sandri, M
Savelainen, M
Scott, D
Sirignano, C
Sirri, G
Stanco, L
Suur-Uski, A-S
Bonavera, L
Tauber, JA
Tavagnacco, D
Tenti, M
Toffolati, L
Tomasi, M
Tristram, M
Trombetti, T
Valiviita, J
Van Tent, F
Vielva, P
Bond, JR
Villa, F
Vittorio, N
Wandelt, BD
Wehus, IK
White, M
Zacchei, A
Zonca, A
Borrill, J
Bouchet, FR
Burigana, C
Calabrese, E
Cardoso, J-F
Challinor, A
Chiang, HC
Colombo, LPL
Combet, C
Crill, BP
Curto, A
Cuttaia, F
De Bernardis, P
De Rosa, A
De Zotti, G
Delabrouille, J
Di Valentino, E
Dickinson, C
Diego, JM
Dore, O
Ducout, A
Dupac, X
Dusini, S
Efstathiou, G
Elsner, F
Ensslin, TA
Eriksen, HK
author_facet Aghanim, N
Akrami, Y
Ashdown, M
Aumont, J
Baccigalupi, C
Ballardini, M
Banday, AJ
Barreiro, RB
Bartolo, N
Basak, S
Benabed, K
Fantaye, Y
Finelli, F
Forastieri, F
Frailis, M
Franceschi, E
Frolov, A
Galeotta, S
Galli, S
Ganga, K
Genova-Santos, RT
Mennella, A
Gerbino, M
Gonzalez-Nuevo, J
Gorski, KM
Gratton, S
Gruppuso, A
Gudmundsson, JE
Herranz, D
Hivon, E
Huang, Z
Jaffe, AH
Migliaccio, M
Jones, WC
Keihanen, E
Keskitalo, R
Kiiveri, K
Kim, J
Kisner, TS
Knox, L
Krachmalnicoff, N
Kunz, M
Kurki-Suonio, H
Millea, M
Lagache, G
Lamarre, J-M
Lasenby, A
Lattanzi, M
Lawrence, CR
Le Jeune, M
Levrier, F
Lewis, A
Liguori, M
Lilje, PB
Miville-Deschenes, M-A
Lilley, M
Lindholm, V
Lopez-Caniego, M
Lubin, PM
Ma, Y-Z
Macias-Perez, JF
Maggio, G
Maino, D
Mandolesi, N
Mangilli, A
Molinari, D
Maris, M
Martin, PG
Martinez-Gonzalez, E
Matarrese, S
Mauri, N
McEwen, JD
Meinhold, PR
Moneti, A
Montier, L
Morgante, G
Moss, A
Narimani, A
Bersanelli, M
Natoli, P
Oxborrow, CA
Pagano, L
Paoletti, D
Partridge, B
Patanchon, G
Patrizii, L
Pettorino, V
Piacentini, F
Polastri, L
Bielewicz, P
Polenta, G
Puget, J-L
Rachen, JP
Racine, B
Reinecke, M
Remazeilles, M
Renzi, A
Rocha, G
Rossetti, M
Roudier, G
Bonaldi, A
Rubino-Martin, JA
Ruiz-Granados, B
Salvati, L
Sandri, M
Savelainen, M
Scott, D
Sirignano, C
Sirri, G
Stanco, L
Suur-Uski, A-S
Bonavera, L
Tauber, JA
Tavagnacco, D
Tenti, M
Toffolati, L
Tomasi, M
Tristram, M
Trombetti, T
Valiviita, J
Van Tent, F
Vielva, P
Bond, JR
Villa, F
Vittorio, N
Wandelt, BD
Wehus, IK
White, M
Zacchei, A
Zonca, A
Borrill, J
Bouchet, FR
Burigana, C
Calabrese, E
Cardoso, J-F
Challinor, A
Chiang, HC
Colombo, LPL
Combet, C
Crill, BP
Curto, A
Cuttaia, F
De Bernardis, P
De Rosa, A
De Zotti, G
Delabrouille, J
Di Valentino, E
Dickinson, C
Diego, JM
Dore, O
Ducout, A
Dupac, X
Dusini, S
Efstathiou, G
Elsner, F
Ensslin, TA
Eriksen, HK
author_sort Aghanim, N
title Planck intermediate results LI. Features in the cosmic microwave background temperature power spectrum and shifts in cosmological parameters
title_short Planck intermediate results LI. Features in the cosmic microwave background temperature power spectrum and shifts in cosmological parameters
title_full Planck intermediate results LI. Features in the cosmic microwave background temperature power spectrum and shifts in cosmological parameters
title_fullStr Planck intermediate results LI. Features in the cosmic microwave background temperature power spectrum and shifts in cosmological parameters
title_full_unstemmed Planck intermediate results LI. Features in the cosmic microwave background temperature power spectrum and shifts in cosmological parameters
title_sort planck intermediate results li. features in the cosmic microwave background temperature power spectrum and shifts in cosmological parameters
publisher EDP Sciences
publishDate 2017
url http://hdl.handle.net/10044/1/55072
https://doi.org/10.1051/0004-6361/201629504
geographic South Pole
geographic_facet South Pole
genre South pole
genre_facet South pole
op_relation Astronomy and Astrophysics
op_rights © ESO 2017
op_doi https://doi.org/10.1051/0004-6361/201629504
container_title Astronomy & Astrophysics
container_volume 607
container_start_page A95
_version_ 1766203022898102272
spelling ftimperialcol:oai:spiral.imperial.ac.uk:10044/1/55072 2023-05-15T18:23:26+02:00 Planck intermediate results LI. Features in the cosmic microwave background temperature power spectrum and shifts in cosmological parameters Aghanim, N Akrami, Y Ashdown, M Aumont, J Baccigalupi, C Ballardini, M Banday, AJ Barreiro, RB Bartolo, N Basak, S Benabed, K Fantaye, Y Finelli, F Forastieri, F Frailis, M Franceschi, E Frolov, A Galeotta, S Galli, S Ganga, K Genova-Santos, RT Mennella, A Gerbino, M Gonzalez-Nuevo, J Gorski, KM Gratton, S Gruppuso, A Gudmundsson, JE Herranz, D Hivon, E Huang, Z Jaffe, AH Migliaccio, M Jones, WC Keihanen, E Keskitalo, R Kiiveri, K Kim, J Kisner, TS Knox, L Krachmalnicoff, N Kunz, M Kurki-Suonio, H Millea, M Lagache, G Lamarre, J-M Lasenby, A Lattanzi, M Lawrence, CR Le Jeune, M Levrier, F Lewis, A Liguori, M Lilje, PB Miville-Deschenes, M-A Lilley, M Lindholm, V Lopez-Caniego, M Lubin, PM Ma, Y-Z Macias-Perez, JF Maggio, G Maino, D Mandolesi, N Mangilli, A Molinari, D Maris, M Martin, PG Martinez-Gonzalez, E Matarrese, S Mauri, N McEwen, JD Meinhold, PR Moneti, A Montier, L Morgante, G Moss, A Narimani, A Bersanelli, M Natoli, P Oxborrow, CA Pagano, L Paoletti, D Partridge, B Patanchon, G Patrizii, L Pettorino, V Piacentini, F Polastri, L Bielewicz, P Polenta, G Puget, J-L Rachen, JP Racine, B Reinecke, M Remazeilles, M Renzi, A Rocha, G Rossetti, M Roudier, G Bonaldi, A Rubino-Martin, JA Ruiz-Granados, B Salvati, L Sandri, M Savelainen, M Scott, D Sirignano, C Sirri, G Stanco, L Suur-Uski, A-S Bonavera, L Tauber, JA Tavagnacco, D Tenti, M Toffolati, L Tomasi, M Tristram, M Trombetti, T Valiviita, J Van Tent, F Vielva, P Bond, JR Villa, F Vittorio, N Wandelt, BD Wehus, IK White, M Zacchei, A Zonca, A Borrill, J Bouchet, FR Burigana, C Calabrese, E Cardoso, J-F Challinor, A Chiang, HC Colombo, LPL Combet, C Crill, BP Curto, A Cuttaia, F De Bernardis, P De Rosa, A De Zotti, G Delabrouille, J Di Valentino, E Dickinson, C Diego, JM Dore, O Ducout, A Dupac, X Dusini, S Efstathiou, G Elsner, F Ensslin, TA Eriksen, HK Science and Technology Facilities Council (STFC) Science and Technology Facilities Council (STFC) Science and Technology Facilities Council (STFC) Science and Technology Facilities Council Science and Technology Facilities Council (STFC) 2017-09-10 http://hdl.handle.net/10044/1/55072 https://doi.org/10.1051/0004-6361/201629504 English eng EDP Sciences Astronomy and Astrophysics © ESO 2017 Science & Technology Physical Sciences Astronomy & Astrophysics cosmology: observations cosmic background radiation cosmological parameters cosmology: theory PROBE WMAP OBSERVATIONS CMB ANISOTROPIES APPROXIMATION RADIATION UNIVERSE MAPS 0201 Astronomical And Space Sciences Journal Article 2017 ftimperialcol https://doi.org/10.1051/0004-6361/201629504 2018-09-16T06:01:13Z The six parameters of the standard ΛCDM model have best-fit values derived from the Planck temperature power spectrum that are shifted somewhat from the best-fit values derived from WMAP data. These shifts are driven by features in the Planck temperature power spectrum at angular scales that had never before been measured to cosmic-variance level precision. We have investigated these shifts to determine whether they are within the range of expectation and to understand their origin in the data. Taking our parameter set to be the optical depth of the reionized intergalactic medium τ, the baryon density ωb, the matter density ωm, the angular size of the sound horizon θ∗, the spectral index of the primordial power spectrum, ns , and Ase −2τ (where As is the amplitude of the primordial power spectrum), we have examined the change in best-fit values between a WMAP-like large angular-scale data set (with multipole moment ` < 800 in the Planck temperature power spectrum) and an all angularscale data set (` < 2500 Planck temperature power spectrum), each with a prior on τ of 0.07 ± 0.02. We find that the shifts, in units of the 1σ expected dispersion for each parameter, are {∆τ, ∆Ase −2τ , ∆ns , ∆ωm, ∆ωb, ∆θ∗} = {−1.7, −2.2, 1.2, −2.0, 1.1, 0.9}, with a χ 2 value of 8.0. We find that this χ 2 value is exceeded in 15% of our simulated data sets, and that a parameter deviates by more than 2.2σ in 9% of simulated data sets, meaning that the shifts are not unusually large. Comparing ` < 800 instead to ` > 800, or splitting at a different multipole, yields similar results. We examined the ` < 800 model residuals in the ` > 800 power spectrum data and find that the features there that drive these shifts are a set of oscillations across a broad range of angular scales. Although they partly appear similar to the effects of enhanced gravitational lensing, the shifts in ΛCDM parameters that arise in response to these features correspond to model spectrum changes that are predominantly due to non-lensing effects; the only exception is τ, which, at fixed Ase −2τ , affects the ` > 800 temperature power spectrum solely through the associated change in As and the impact of that on the lensing potential power spectrum. We also ask, “what is it about the power spectrum at ` < 800 that leads to somewhat different best-fit parameters than come from the full ` range?” We find that if we discard the data at ` < 30, where there is a roughly 2σ downward fluctuation in power relative to the model that best fits the full ` range, the ` < 800 best-fit parameters shift significantly towards the ` < 2500 best-fit parameters. In contrast, including ` < 30, this previously noted “low-` deficit” drives ns up and impacts parameters correlated with ns , such as ωm and H0. As expected, the ` < 30 data have a much greater impact on the ` < 800 best fit than on the ` < 2500 best fit. So although the shifts are not very significant, we find that they can be understood through the combined effects of an oscillatory-like set of high-` residuals and the deficit in low-` power, excursions consistent with sample variance that happen to map onto changes in cosmological parameters. Finally, we examine agreement between Planck T T data and two other CMB data sets, namely the Planck lensing reconstruction and the T T power spectrum measured by the South Pole Telescope, again finding a lack of convincing evidence of any significant deviations in parameters, suggesting that current CMB data sets give an internally consistent picture of the ΛCDM model. Article in Journal/Newspaper South pole Imperial College London: Spiral South Pole Astronomy & Astrophysics 607 A95