Astronomy & Astrophysics
manuscript no. PlanckMission2013
c
©
ESO 2014
June 6, 2014
Planck
2013 results. I. Overview of products and scientific results
Planck Collaboration: P. A. R. Ade
116
, N. Aghanim
79
, M. I. R. Alves
79
, C. Armitage-Caplan
122
, M. Arnaud
96
, M. Ashdown
93
,
8
,
F. Atrio-Barandela
23
, J. Aumont
79
, H. Aussel
96
, C. Baccigalupi
114
, A. J. Banday
128
,
13
, R. B. Barreiro
89
, R. Barrena
88
, M. Bartelmann
126
,
103
,
J. G. Bartlett
1
,
91
, N. Bartolo
43
, S. Basak
114
, E. Battaner
131
, R. Battye
92
, K. Benabed
80
,
125
, A. Beno
ˆ
ıt
77
, A. Benoit-L
́
evy
32
,
80
,
125
, J.-P. Bernard
128
,
13
,
M. Bersanelli
47
,
68
, B. Bertincourt
79
, M. Bethermin
96
, P. Bielewicz
128
,
13
,
114
, I. Bikmaev
27
,
3
, A. Blanchard
128
, J. Bobin
96
, J. J. Bock
91
,
14
,
H. B
̈
ohringer
104
, A. Bonaldi
92
, L. Bonavera
89
, J. R. Bond
11
, J. Borrill
18
,
119
, F. R. Bouchet
80
,
125
, F. Boulanger
79
, H. Bourdin
49
, J. W. Bowyer
75
,
M. Bridges
93
,
8
,
85
, M. L. Brown
92
, M. Bucher
1
, R. Burenin
118
,
107
, C. Burigana
67
,
45
, R. C. Butler
67
, E. Calabrese
122
, B. Cappellini
68
,
J.-F. Cardoso
97
,
1
,
80
, R. Carr
54
, P. Carvalho
8
, M. Casale
54
, G. Castex
1
, A. Catalano
98
,
95
, A. Challinor
85
,
93
,
15
, A. Chamballu
96
,
20
,
79
, R.-R. Chary
76
,
X. Chen
76
, H. C. Chiang
37
,
9
, L.-Y Chiang
84
, G. Chon
104
, P. R. Christensen
110
,
51
, E. Churazov
103
,
118
, S. Church
121
, M. Clemens
63
,
D. L. Clements
75
, S. Colombi
80
,
125
, L. P. L. Colombo
31
,
91
, C. Combet
98
, B. Comis
98
, F. Couchot
94
, A. Coulais
95
, B. P. Crill
91
,
111
, M. Cruz
25
,
A. Curto
8
,
89
, F. Cuttaia
67
, A. Da Silva
16
, H. Dahle
87
, L. Danese
114
, R. D. Davies
92
, R. J. Davis
92
, P. de Bernardis
46
, A. de Rosa
67
, G. de Zotti
63
,
114
,
T. D
́
echelette
80
, J. Delabrouille
1
, J.-M. Delouis
80
,
125
, J. D
́
emocl
`
es
96
, F.-X. D
́
esert
72
, J. Dick
114
, C. Dickinson
92
, J. M. Diego
89
, K. Dolag
130
,
103
,
H. Dole
79
,
78
, S. Donzelli
68
, O. Dor
́
e
91
,
14
, M. Douspis
79
, A. Ducout
80
, J. Dunkley
122
, X. Dupac
55
, G. Efstathiou
85
, F. Elsner
80
,
125
, T. A. Enßlin
103
,
H. K. Eriksen
87
, O. Fabre
80
, E. Falgarone
95
, M. C. Falvella
6
, Y. Fantaye
87
, J. Fergusson
15
, C. Filliard
94
, F. Finelli
67
,
69
, I. Flores-Cacho
13
,
128
,
S. Foley
56
, O. Forni
128
,
13
, P. Fosalba
81
, M. Frailis
65
, A. A. Fraisse
37
, E. Franceschi
67
, M. Freschi
55
, S. Fromenteau
1
,
79
, M. Frommert
22
,
T. C. Gaier
91
, S. Galeotta
65
, J. Gallegos
55
, S. Galli
80
, B. Gandolfo
56
, K. Ganga
1
, C. Gauthier
1
,
101
, R. T. G
́
enova-Santos
88
, T. Ghosh
79
,
M. Giard
128
,
13
, G. Giardino
57
, M. Gilfanov
103
,
118
, D. Girard
98
, Y. Giraud-H
́
eraud
1
, E. Gjerløw
87
, J. Gonz
́
alez-Nuevo
89
,
114
, K. M. G
́
orski
91
,
132
,
S. Gratton
93
,
85
, A. Gregorio
48
,
65
, A. Gruppuso
67
, J. E. Gudmundsson
37
, J. Haissinski
94
, J. Hamann
124
, F. K. Hansen
87
, M. Hansen
110
,
D. Hanson
105
,
91
,
11
, D. L. Harrison
85
,
93
, A. Heavens
75
, G. Helou
14
, A. Hempel
88
,
52
, S. Henrot-Versill
́
e
94
, C. Hern
́
andez-Monteagudo
17
,
103
,
D. Herranz
89
, S. R. Hildebrandt
14
, E. Hivon
80
,
125
, S. Ho
34
, M. Hobson
8
, W. A. Holmes
91
, A. Hornstrup
21
, Z. Hou
40
, W. Hovest
103
, G. Huey
42
,
K. M. Hu
ff
enberger
35
, G. Hurier
79
,
98
, S. Ili
́
c
79
, A. H. Ja
ff
e
75
, T. R. Ja
ff
e
128
,
13
, J. Jasche
80
, J. Jewell
91
, W. C. Jones
37
, M. Juvela
36
, P. Kalberla
7
,
P. Kangaslahti
91
, E. Keih
̈
anen
36
, J. Kerp
7
, R. Keskitalo
29
,
18
, I. Khamitov
123
,
27
, K. Kiiveri
36
,
61
, J. Kim
110
, T. S. Kisner
100
, R. Kneissl
53
,
10
,
J. Knoche
103
, L. Knox
40
, M. Kunz
22
,
79
,
4
, H. Kurki-Suonio
36
,
61
, F. Lacasa
79
, G. Lagache
79
, A. L
̈
ahteenm
̈
aki
2
,
61
, J.-M. Lamarre
95
, M. Langer
79
,
A. Lasenby
8
,
93
, M. Lattanzi
45
, R. J. Laureijs
57
, A. Lavabre
94
, C. R. Lawrence
91
, M. Le Jeune
1
, S. Leach
114
, J. P. Leahy
92
, R. Leonardi
55
,
J. Le
́
on-Tavares
58
,
2
, C. Leroy
79
,
128
,
13
, J. Lesgourgues
124
,
113
, A. Lewis
33
, C. Li
102
,
103
, A. Liddle
115
,
33
, M. Liguori
43
, P. B. Lilje
87
,
M. Linden-Vørnle
21
, V. Lindholm
36
,
61
, M. L
́
opez-Caniego
89
, S. Lowe
92
, P. M. Lubin
41
, J. F. Mac
́
ıas-P
́
erez
98
, C. J. MacTavish
93
, B. Ma
ff
ei
92
,
G. Maggio
65
, D. Maino
47
,
68
, N. Mandolesi
67
,
6
,
45
, A. Mangilli
80
, A. Marcos-Caballero
89
, D. Marinucci
50
, M. Maris
65
, F. Marleau
83
,
D. J. Marshall
96
, P. G. Martin
11
, E. Mart
́
ınez-Gonz
́
alez
89
, S. Masi
46
, M. Massardi
66
, S. Matarrese
43
, T. Matsumura
14
, F. Matthai
103
, L. Maurin
1
,
P. Mazzotta
49
, A. McDonald
56
, J. D. McEwen
32
,
108
, P. McGehee
76
, S. Mei
59
,
127
,
14
, P. R. Meinhold
41
, A. Melchiorri
46
,
70
, J.-B. Melin
20
,
L. Mendes
55
, E. Menegoni
46
, A. Mennella
47
,
68
, M. Migliaccio
85
,
93
, K. Mikkelsen
87
, M. Millea
40
, R. Miniscalco
56
, S. Mitra
74
,
91
,
M.-A. Miville-Desch
ˆ
enes
79
,
11
, D. Molinari
44
,
67
, A. Moneti
80
, L. Montier
128
,
13
, G. Morgante
67
, N. Morisset
73
, D. Mortlock
75
, A. Moss
117
,
D. Munshi
116
, J. A. Murphy
109
, P. Naselsky
110
,
51
, F. Nati
46
, P. Natoli
45
,
5
,
67
, M. Negrello
63
, N. P. H. Nesvadba
79
, C. B. Netterfield
26
,
H. U. Nørgaard-Nielsen
21
, C. North
116
, F. Noviello
92
, D. Novikov
75
, I. Novikov
110
, I. J. O’Dwyer
91
, F. Orieux
80
, S. Osborne
121
, C. O’Sullivan
109
,
C. A. Oxborrow
21
, F. Paci
114
, L. Pagano
46
,
70
, F. Pajot
79
, R. Paladini
76
, S. Pandolfi
49
, D. Paoletti
67
,
69
, B. Partridge
60
, F. Pasian
65
, G. Patanchon
1
,
P. Paykari
96
, D. Pearson
91
, T. J. Pearson
14
,
76
, M. Peel
92
, H. V. Peiris
32
, O. Perdereau
94
, L. Perotto
98
, F. Perrotta
114
, V. Pettorino
22
, F. Piacentini
46
,
M. Piat
1
, E. Pierpaoli
31
, D. Pietrobon
91
, S. Plaszczynski
94
, P. Platania
90
, D. Pogosyan
38
, E. Pointecouteau
128
,
13
, G. Polenta
5
,
64
, N. Ponthieu
79
,
72
,
L. Popa
82
, T. Poutanen
61
,
36
,
2
, G. W. Pratt
96
, G. Pr
́
ezeau
14
,
91
, S. Prunet
80
,
125
, J.-L. Puget
79
, A. R. Pullen
91
, J. P. Rachen
28
,
103
, B. Racine
1
,
A. Rahlin
37
, C. R
̈
ath
104
, W. T. Reach
129
, R. Rebolo
88
,
19
,
52
, M. Reinecke
103
, M. Remazeilles
92
,
79
,
1
, C. Renault
98
, A. Renzi
114
, A. Riazuelo
80
,
125
,
S. Ricciardi
67
, T. Riller
103
, C. Ringeval
86
,
80
,
125
, I. Ristorcelli
128
,
13
, G. Robbers
103
, G. Rocha
91
,
14
, M. Roman
1
, C. Rosset
1
, M. Rossetti
47
,
68
,
G. Roudier
1
,
95
,
91
, M. Rowan-Robinson
75
, J. A. Rubi
̃
no-Mart
́
ın
88
,
52
, B. Ruiz-Granados
131
, B. Rusholme
76
, E. Salerno
12
, M. Sandri
67
,
L. Sanselme
98
, D. Santos
98
, M. Savelainen
36
,
61
, G. Savini
112
, B. M. Schaefer
126
, F. Schiavon
67
, D. Scott
30
, M. D. Sei
ff
ert
91
,
14
, P. Serra
79
,
E. P. S. Shellard
15
, K. Smith
37
, G. F. Smoot
39
,
100
,
1
, T. Souradeep
74
, L. D. Spencer
116
, J.-L. Starck
96
, V. Stolyarov
8
,
93
,
120
, R. Stompor
1
,
R. Sudiwala
116
, R. Sunyaev
103
,
118
, F. Sureau
96
, P. Sutter
80
, D. Sutton
85
,
93
, A.-S. Suur-Uski
36
,
61
, J.-F. Sygnet
80
, J. A. Tauber
57
, D. Tavagnacco
65
,
48
,
D. Taylor
54
, L. Terenzi
67
, D. Texier
54
, L. To
ff
olatti
24
,
89
, M. Tomasi
68
, J.-P. Torre
79
, M. Tristram
94
, M. Tucci
22
,
94
, J. Tuovinen
106
, M. T
̈
urler
73
,
M. Tuttlebee
56
, G. Umana
62
, L. Valenziano
67
, J. Valiviita
61
,
36
,
87
, B. Van Tent
99
, J. Varis
106
, L. Vibert
79
, M. Viel
65
,
71
, P. Vielva
89
, F. Villa
67
,
N. Vittorio
49
, L. A. Wade
91
, B. D. Wandelt
80
,
125
,
42
, C. Watson
56
, R. Watson
92
, I. K. Wehus
91
, N. Welikala
1
, J. Weller
130
, M. White
39
,
S. D. M. White
103
, A. Wilkinson
92
, B. Winkel
7
, J.-Q. Xia
114
, D. Yvon
20
, A. Zacchei
65
, J. P. Zibin
30
, and A. Zonca
41
(A
ffi
liations can be found after the references)
Received XX, 2012; accepted XX, 2013
ABSTRACT
The European Space Agency’s
Planck
satellite, dedicated to studying the early Universe and its subsequent evolution, was launched 14 May
2009 and has been scanning the microwave and submillimetre sky continuously since 12 August 2009. In March 2013, ESA and the
Planck
Collaboration released the initial cosmology products based on the the first 15.5 months of
Planck
data, along with a set of scientific and technical
papers and a web-based explanatory supplement. This paper gives an overview of the mission and its performance, the processing, analysis, and
characteristics of the data, the scientific results, and the science data products and papers in the release. The science products include maps of
the cosmic microwave background (CMB) and di
ff
use extragalactic foregrounds, a catalogue of compact Galactic and extragalactic sources, and
a list of sources detected through the Sunyaev-Zeldovich e
ff
ect. The likelihood code used to assess cosmological models against the
Planck
data
and a lensing likelihood are described. Scientific results include robust support for the standard six-parameter
Λ
CDM model of cosmology and
improved measurements of its parameters, including a highly significant deviation from scale invariance of the primordial power spectrum. The
Planck
values for these parameters and others derived from them are significantly di
ff
erent from those previously determined. Several large-scale
anomalies in the temperature distribution of the CMB, first detected by
WMAP
, are confirmed with higher confidence.
Planck
sets new limits on
the number and mass of neutrinos, and has measured gravitational lensing of CMB anisotropies at greater than 25
σ
.
Planck
finds no evidence
for non-Gaussianity in the CMB.
Planck
’s results agree well with results from the measurements of baryon acoustic oscillations.
Planck
finds a
lower Hubble constant than found in some more local measures. Some tension is also present between the amplitude of matter fluctuations (
σ
8
)
derived from CMB data and that derived from Sunyaev-Zeldovich data. The
Planck
and
WMAP
power spectra are o
ff
set from each other by an
average level of about 2% around the first acoustic peak. Analysis of
Planck
polarization data is not yet mature, therefore polarization results are
not released, although the robust detection of
E
-mode polarization around CMB hot and cold spots is shown graphically.
Key words.
Cosmology: observations — Cosmic background radiation — Surveys — Space vehicles: instruments — Instrumentation: detectors
1
arXiv:1303.5062v2 [astro-ph.CO] 5 Jun 2014
1. Introduction
The
Planck
satellite
1
(Tauber et al. 2010a; Planck Collaboration
I 2011) was launched on 14 May 2009 and observed the sky
stably and continuously from 12 August 2009 to 23 October
2013.
Planck
’s scientific payload comprised an array of 74 de-
tectors sensitive to frequencies between 25 and 1000 GHz, which
scanned the sky with angular resolution between 33
′
and 5
′
.
The detectors of the Low Frequency Instrument (LFI; Bersanelli
et al. 2010; Mennella et al. 2011) are pseudo-correlation ra-
diometers, covering bands centred at 30, 44, and 70 GHz. The
detectors of the High Frequency Instrument (HFI; Lamarre et al.
2010; Planck HFI Core Team 2011a) are bolometers, covering
bands centred at 100, 143, 217, 353, 545, and 857 GHz.
Planck
images the whole sky twice in one year, with a combination of
sensitivity, angular resolution, and frequency coverage never be-
fore achieved.
Planck
, its payload, and its performance as pre-
dicted at the time of launch are described in 13 papers included
in a special issue of Astronomy & Astrophysics (Volume 520).
The main objective of
Planck
, defined in 1995, is to mea-
sure the spatial anisotropies in the temperature of the cos-
mic microwave background (CMB), with an accuracy set by
fundamental astrophysical limits, thereby extracting essentially
all the cosmological information embedded in the temperature
anisotropies of the CMB.
Planck
was also designed to measure
to high accuracy the CMB polarization anisotropies, which en-
code not only a wealth of cosmological information, but also
provide a unique probe of the early history of the Universe dur-
ing the time when the first stars and galaxies formed. Finally,
Planck
produces a wealth of information on the properties of ex-
tragalactic sources and on the dust and gas in the Milky Way
(see Fig. 1). The scientific objectives of
Planck
are described in
detail in Planck Collaboration (2005). With the results presented
here and in a series of accompanying papers (see Fig. 2),
Planck
has already achieved many of its planned science goals.
This paper presents an overview of the
Planck
mission, and
the main data products and scientific results of
Planck
’s second
release
2
, based on data acquired in the period 12 August 2009 to
28 November 2010.
1.1. Overview of 2013 science results
Cosmology
—A major goal of
Planck
is to measure the key cos-
mological parameters describing our Universe.
Planck
’s com-
bination of sensitivity, angular resolution, and frequency cov-
erage enables it to measure anisotropies on intermediate and
small angular scales over the whole sky much more accurately
than previous experiments. This leads to improved constraints
on individual parameters, the breaking of degeneracies between
1
Planck
(http:
//
www.esa.int
/
Planck
) is a project of the European
Space Agency (ESA) with instruments provided by two scientific con-
sortia funded by ESA member states (in particular the lead countries,
France and Italy) with contributions from NASA (USA), and telescope
reflectors provided in a collaboration between ESA and a scientific con-
sortium led and funded by Denmark.
2
In January of 2011, ESA and the
Planck
Collaboration released
to the public a first set of scientific data, the Early Release Compact
Source Catalogue (ERCSC), a list of unresolved and compact sources
extracted from the first complete all-sky survey carried out by
Planck
(Planck Collaboration VII 2011). At the same time, initial scientific re-
sults related to astrophysical foregrounds were published in a special
issue of Astronomy and Astrophysics (Vol 520, 2011). Since then, 12
“Intermediate” papers have been submitted for publication to A&A con-
taining further astrophysical investigations by the Collaboration.
combinations of other parameters, and less reliance on supple-
mentary astrophysical data than previous CMB experiments.
Cosmological parameters are presented and discussed in Sect. 9
and in Planck Collaboration XVI (2014).
The Universe observed by
Planck
is well-fit by a six-
parameter, vacuum-dominated, cold dark matter (
Λ
CDM)
model, and we provide strong constraints on deviations from this
model. The values of key parameters in this model are summa-
rized in Table 10. In some cases we find significant changes com-
pared to previous measurements, as discussed in detail in Planck
Collaboration XVI (2014).
With the
Planck
data, we: (a) firmly establish deviation from
scale invariance of the primordial matter perturbations, a key
indicator of cosmic inflation; (b) detect with high significance
lensing of the CMB by intervening matter, providing evidence
for dark energy from the CMB alone; (c) find no evidence for
significant deviations from Gaussianity in the statistics of CMB
anisotropies; (d) find a deficit of power on large angular scales
with respect to our best-fit model; (e) confirm the anomalies at
large angular scales first detected by
WMAP
; and (f) establish
the number of neutrino species to be consistent with three.
The
Planck
data are in remarkable accord with a flat
Λ
CDM
model; however, there are tantalizing hints of tensions both inter-
nal to the
Planck
data and with other data sets. From the CMB,
Planck
determines a lower value of the Hubble constant than
some more local measures, and a higher value for the ampli-
tude of matter fluctuations (
σ
8
) than that derived from Sunyaev-
Zeldovich data. While such tensions are model-dependent, none
of the extensions of the six-parameter
Λ
CDM cosmology that
we explored resolves them. More data and further analysis may
shed light on such tensions. Along these lines, we expect sig-
nificant improvement in data quality and the level of systematic
error control, plus the addition of polarization data, from
Planck
in 2014.
A more extensive summary of cosmology results is given in
Sect. 9.
Foregrounds
—The astrophysical foregrounds measured by
Planck
to be separated from the CMB are interesting in their
own right. Compact and point-like sources consist mainly of
extragalactic infrared and radio sources, and are released in
the
Planck
Catalogue of Compact Sources (PCCS; Planck
Collaboration XXVIII 2014). An all-sky catalogue of sources
detected via the Sunyaev-Zeldovich (SZ) e
ff
ect, which will be-
come a reference for studies of SZ-detected galaxy clusters, is
given in Planck Collaboration XXIX (2014).
Seven types of unresolved foregrounds must be removed or
controlled for CMB analysis: thermal dust emission; anomalous
microwave emission (likely due to tiny spinning dust grains); CO
rotational emission lines (significant in at least three HFI bands);
free-free emission; synchrotron emission; the clustered cosmic
infrared background (CIB); and SZ secondary CMB distortions.
For cosmological purposes, we achieve robust separation of the
CMB from foregrounds using only
Planck
data with multiple in-
dependent methods. We release maps of: thermal dust
+
fluctua-
tions of the cosmic infrared background; integrated emission of
carbon monoxide; and synchrotron
+
free-free
+
spinning dust
emission. These maps provide a rich source for studies of the
interstellar medium. Other maps are released that use ancillary
data in addition to the
Planck
data to achieve more physically
meaningful analysis.
These foreground products are described in Sect. 8.
Planck Collaboration: The
Planck
mission
Fig. 1.
Composite, multi-frequency, full-sky image released by
Planck
in 2010. Made from the first nine months of the data, it
illustrates artistically the multitude of Galactic, extragalactic, and cosmological components of the radiation detected by its payload.
Unless otherwise specified, all full-sky images in this paper are Mollweide projections in Galactic coordinates, pixelised according
to the
HEALPix
(G
́
orski et al. 2005) scheme.
1.2. Features of the Planck mission
Planck
has an unprecedented combination of sensitivity, angu-
lar resolution, and frequency coverage. For example, the
Planck
detector array at 143 GHz has instantaneous sensitivity and an-
gular resolution 25 and three times better, respectively, than
the
WMAP
V band (Bennett et al. 2003; Hinshaw et al. 2013).
Considering the final mission durations (nine years for
WMAP
,
29 months for
Planck
HFI, and 50 months for
Planck
LFI),
the white noise at map level, for example, is 12 times lower at
143 GHz for the same resolution. In harmonic space, the noise
level in the
Planck
power spectra is two orders of magnitude
lower than in those of
WMAP
at angular scales where beams are
unimportant (
` <
700 for
WMAP
and 2500 for
Planck
).
Planck
measures 2.6 times as many independent multipoles as
WMAP
,
corresponding to 6.8 times as many independent modes (
`,
m
)
when comparing the same leading CMB channels for the two
missions. This increase in angular resolution and sensitivity re-
sults in a large gain for analysis of CMB non-Gaussianity and
cosmological parameters. In addition,
Planck
has a large over-
lap in
`
with the high resolution ground-based experiments ACT
(Sievers et al. 2013) and SPT (Keisler et al. 2011). The noise
spectra of SPT and
Planck
cross at
`
∼
2000, allowing an excel-
lent check of the relative calibrations and transfer functions.
Increased sensitivity places
Planck
in a new situation. Earlier
satellite experiments (
COBE
/
DMR, Smoot et al. 1992;
WMAP
,
Bennett et al. 2013) were limited by detector noise more than
systematic e
ff
ects and foregrounds. Ground-based and balloon-
borne experiments ongoing or under development (e.g., ACT,
Kosowsky 2003; SPT, Ruhl et al. 2004; SPIDER, Fraisse et al.
2011; and EBEX, Reichborn-Kjennerud et al. 2010), have far
larger numbers of detectors and higher angular resolution than
Planck
, but can survey only a fraction of the sky over a lim-
ited frequency range. They are therefore sensitive to fore-
grounds and limited to analysing only the cleanest regions of the
sky. Considering the impact of cosmic variance, Galactic fore-
grounds are not a serious limitation for CMB temperature-based
cosmology at the largest spatial scales over a limited part (
<
0
.
5)
of the sky. Di
ff
use Galactic emission components have steep fre-
quency and angular spectra, and are very bright at frequencies
below 70 and above 100 GHz at low spatial frequencies. At in-
termediate and small angular scales, extragalactic foregrounds,
such as unresolved compact sources, the SZ e
ff
ect from unre-
solved galaxy clusters and di
ff
use hot gas, and the correlated
CIB, become important and cannot be ignored when carrying
out CMB cosmology studies.
Planck
’s all-sky, wide-frequency
coverage is key, allowing it to measure these foregrounds and
remove them to below intrinsic detector noise levels, helped by
higher resolution experiments in characterizing the statistics of
discrete foregrounds.
When detector noise is very low, systematic e
ff
ects that arise
from the instrument, telescope, scanning strategy, or calibration
approach may dominate over noise in specific spatial or fre-
quency ranges. The analysis of redundancy is the main tool used
by
Planck
to understand and quantify the e
ff
ect of systematics.
Redundancy on short timescales comes from the scanning strat-
egy (Sect. 4.1), which has particular advantages in this respect,
especially for the largest scales. When first designed, this strat-
egy was considered ambitious because it required low 1
/
f
noise
near 0.0167 Hz (the spin frequency) and very stable instruments
over the whole mission. Redundancy on long timescales comes
in two versions: 1)
Planck
scans approximately the same circle
on the sky every six months, alternating in the direction of the
scan; and 2)
Planck
scans exactly (within arcminutes) the same
circle on the sky every one year. The ability to compare maps
made in individual all-sky “Surveys” (covering approximately
six month intervals, see Sect. 4.1 and Table 1) and year-by-year
is invaluable in identifying specific systematic e
ff
ects and cali-
bration errors. Although
Planck
was designed to cover the whole
3
Planck Collaboration: The
Planck
mission
sky twice over, its superb in-flight performance has enabled it to
complete nearly five full-sky maps with the HFI instrument, and
more than eight with the LFI instrument. The redundancy pro-
vided by such a large number of Surveys is a major asset for
Planck
, allowing tests of the overall stability of the instruments
over the mission and sensitive measurements of systematic resid-
uals on the sky.
Redundancy of a di
ff
erent sort is provided by multiple de-
tectors within frequency bands. HFI includes four independent
pairs of polarization-sensitive detectors in each channel from
100 to 353 GHz, in addition to the four total intensity (spi-
der web) detectors at all frequencies except 100 GHz. LFI in-
cludes six independent pairs of polarization-sensitive detectors
at 70 GHz, with three at 44 GHz and two at 30 GHz. The di
ff
erent
technologies used in the two instruments provide an additional
powerful tool to identify and remove systematic e
ff
ects.
Overall, the combination of scanning strategy and instru-
mental redundancy has allowed identification and removal of
most systematic e
ff
ects a
ff
ecting CMB temperature measure-
ments. This can be seen in the fact that additional Surveys have
led to significant improvements, at a rate greater than the square
root of the integration time, in the signal-to-noise ratio (SNR)
achieved in the combined maps. Given that the two instruments
have achieved their expected intrinsic sensitivity, and that most
systematics have been brought below the noise (detector or cos-
mic variance) for intensity, it is a fact that cosmological results
derived from the
Planck
temperature data are already being lim-
ited by the foregrounds, fulfilling one of the main objectives of
the mission.
1.3. Status of Planck polarization measurements
The situation for CMB polarization, whose amplitude is typi-
cally 4 % of intensity, is less mature. At present,
Planck
’s sen-
sitivity to the CMB polarization power spectrum at low mul-
tipoles (
` <
20) is significantly limited by residual systemat-
ics. These are of a di
ff
erent nature than those of temperature
because polarization measurement with
Planck
requires di
ff
er-
encing between detector pairs. Furthermore, the component sep-
aration problem is di
ff
erent, on the one hand simpler because
only three polarized foregrounds have been identified so far (dif-
fuse synchrotron and thermal dust emission, and radio sources),
on the other hand more complicated because the di
ff
use fore-
grounds are more highly polarized than the CMB, and therefore
more dominant over a larger fraction of the sky. Moreover, no ex-
ternal templates exist for the polarized foregrounds. These fac-
tors are currently restricting
Planck
’s ability to meet its most
ambitious goals, e.g., to measure or set stringent upper limits
on cosmological
B
-mode amplitudes. Although this situation is
being improved at the present time, the possibility remains that
these e
ff
ects will be the final limitation for cosmology using the
polarized
Planck
data. The situation is much better at high mul-
tipoles, where the polarization data are already close to being
limited by intrinsic detector noise.
These considerations have led to the strategy adopted by the
Planck
Collaboration for the 2013 release of using only
Planck
temperature data for scientific results. To reduce the uncertainty
on the reionization optical depth,
τ
, we sometimes supplement
the
Planck
temperature data with the
WMAP
low-
`
polarization
likelihood (the data designation in such cases includes “WP”).
And we give two examples of polarization data at higher multi-
poles to demonstrate the quality already achieved. The first ex-
ample shows that the measured high-
`
EE
spectrum agrees ex-
tremely well with that expected from the best-fit model derived
from temperature data alone (Planck Collaboration XVI 2014).
The second uses stacking techniques on the peaks and troughs
of the CMB intensity (Sect. 9.3), giving a direct and spectacu-
lar visualization of the
E
-mode polarization induced by matter
oscillating in the potential well of dark matter at recombination.
Cosmological analysis using the full 29- and 50-month data
sets, including polarization, will be published with the second
major release of data in 2014. Scientific investigations of di
ff
use
Galactic polarized emissions at frequencies and angular scales
where the polarized emission is strong compared to residual sys-
tematics will be released in the coming months (see Sect. 8.2.3
for a description). The sensitivity and accuracy of
Planck
’s po-
larized maps is already well beyond that of any previous survey
in this frequency range.
2. Data products in the 2013 release
The 2013 distribution of released products (hereafter the “2013
products”), which can be freely accessed via the
Planck
Legacy
Archive interface
3
, is based on data acquired by
Planck
dur-
ing the “nominal mission”, defined as 12 August 2009 to
28 November 2010, and comprises:
–
Maps of the sky at nine frequencies (Sect. 6).
–
Additional products that serve to quantify the characteristics
of the maps to a level adequate for the science results being
presented, such as noise maps, masks, and instrument char-
acteristics.
–
Four high-resolution maps of the CMB sky and accompa-
nying characterization products (Sect. 7.1). Non-Gaussianity
results are based on one of the maps; the others demonstrate
the robustness of the results and their insensitivity to di
ff
er-
ent methods of analysis.
–
A low-resolution CMB map (Sect. 7.1) used in the low
`
likelihood code, with an associated set of foreground maps
produced in the process of separating the low-resolution
CMB from foregrounds, with accompanying characteriza-
tion products.
–
Maps of foreground components at high resolution, includ-
ing: thermal dust
+
residual CIB; CO; synchrotron
+
free-
free
+
spinning dust emission; and maps of dust temperature
and opacity (Sect. 8).
–
A likelihood code and data package used for testing cosmo-
logical models against the
Planck
data, including both the
CMB (Sect. 7.3.1) and CMB lensing (Sect. 7.3.2) . The CMB
part is based at
` <
50 on the low-resolution CMB map just
described and on the
WMAP
-9 polarized likelihood (to re-
duce the uncertainty in
τ
), and at
`
≥
50 on cross-power
spectra of individual detector sets. The lensing part is based
on the 143 and 217 GHz maps.
–
The
Planck
Catalogue of Compact Sources (PCCS,
Sect. 8.1), comprising lists of compact sources over the en-
tire sky at the nine
Planck
frequencies. The PCCS super-
sedes the previous Early Release Compact Source Catalogue
(Planck Collaboration XIV 2011).
–
The
Planck
Catalogue of Sunyaev-Zeldovich Sources (PSZ,
Sect. 8.1.2), comprising a list of sources detected by their
SZ distortion of the CMB spectrum. The PSZ supersedes
the previous Early Sunyaev-Zeldovich Catalogue (Planck
Collaboration XXIX 2014).
3
http://archives.esac.esa.int/pla2
4
Planck Collaboration: The
Planck
mission
3. Papers accompanying the 2013 release
The characteristics, processing, and analysis of the
Planck
data
as well as a number of scientific results are described in a series
of papers released simultaneously with the data. The titles of the
papers begin with “
Planck
2013 results.”, followed by the spe-
cific titles below. Figure 2 gives a graphical view of the papers,
divided into product, processing, and scientific result categories.
I. Overview of products and results (
this paper
)
II. Low Frequency Instrument data processing
III. LFI systematic uncertainties
IV. LFI beams and window functions
V. LFI calibration
VI. High Frequency Instrument data processing
VII. HFI time response and beams
VIII. HFI photometric calibration and mapmaking
IX. HFI spectral response
X. HFI energetic particle e
ff
ects: characterization, removal, and
simulation
XI. All-sky model of dust emission based on Planck data
XII. Di
ff
use component separation
XIII. Galactic CO emission
XIV. Zodiacal emission
XV. CMB power spectra and likelihood
XVI. Cosmological parameters
XVII. Gravitational lensing by large-scale structure
XVIII. The gravitational lensing-infrared background
correlation
XIX. The integrated Sachs-Wolfe e
ff
ect
XX. Cosmology from Sunyaev-Zeldovich cluster counts
XXI. Cosmology with the all-sky Compton-parameter power
spectrum
XXII. Constraints on inflation
XXIII. Isotropy and statistics of the CMB
XXIV. Constraints on primordial non-Gaussianity
XXV. Searches for cosmic strings and other topological defects
XXVI. Background geometry and topology of the Universe
XXVII. Doppler boosting of the CMB: Eppur si muove
XXVIII. The
Planck
Catalogue of Compact Sources
XXIX. The
Planck
catalogue of Sunyaev-Zeldovich sources
XXX. Cosmic infrared background measurements and
implications for star formation
XXXI. Consistency of the
Planck
data
In the next few months additional papers will be released
concentrating on Galactic foregrounds in both temperature and
polarization.
This paper contains an overview of the main aspects of the
Planck
project that have contributed to the 2013 release, and
points to the papers (Fig. 2) that contain full descriptions. It pro-
ceeds as follows:
–
Section 4 summarizes the operations of
Planck
and the per-
formance of the spacecraft and instruments.
–
Sections 5 and 6 describe the processing steps carried out in
the generation of the nine
Planck
frequency maps and their
characteristics.
–
Section 7 describes the
Planck
2013 products related to the
Cosmic Microwave Background, namely the CMB maps, the
lensing products, and the likelihood code.
–
Section 8 describes the
Planck
2013 astrophysical products,
namely catalogues of compact sources and maps of di
ff
use
foreground emission.
–
Section 9 describes the main cosmological science results
based on the 2013 CMB products.
–
Section 10 concludes with a summary and a look towards the
next generation of
Planck
products.
4. The
Planck
mission
Planck
was launched from Kourou, French Guiana, on 14 May
2009 on an Ariane 5 ECA rocket, together with the
Herschel
Space Observatory. After separation from the rocket and from
Herschel
,
Planck
followed a trajectory to the
L
2
point of the
Sun-Earth system. It was injected into a 6-month Lissajous orbit
around
L
2
in early July 2009 (Fig. 3). Small manoeuvres are
required at approximately monthly intervals (totalling around
1 m s
−
1
per year) to keep
Planck
from drifting away from
L
2
.
The first three months of operations focused on commission-
ing (during which
Planck
cooled down to the operating tem-
peratures of the coolers and the instruments), calibration, and
performance verification. Routine operations and science obser-
vations began 12 August 2009. Detailed information about the
first phases of operations may be found in Planck Collaboration
I (2011) and Planck Collaboration (2013).
4.1. Scanning strategy
Planck
spins at 1 rpm about the symmetry axis of the spacecraft.
The spin axis follows a cycloidal path across the sky in step-
wise displacements of 2
′
(Fig. 4). To maintain a steady advance
of the projected position of the spin axis along the ecliptic plane,
the time interval between two manoeuvres varies between 2360 s
and 3904 s. Details of the scanning strategy are given in Tauber
et al. (2010a) and Planck Collaboration I (2011).
The fraction of time used by the manoeuvres themselves
(typical duration of five minutes) varies between 6 % and 12 %,
depending on the phase of the cycloid. At present, the recon-
structed position of the spin axis during manoeuvres has not
been determined accurately enough for scientific work (but see
Sect. 4.5), and the data taken during manoeuvres are not used
in the analysis. Over the nominal mission, the total reduction of
scientific data due to manoeuvres was 9.2 %.
The boresight of the telescope is 85
◦
from the spin axis. As
Planck
spins, the instrument beams cover nearly great circles in
the sky. The spin axis remains fixed (except for a small drift due
to Solar radiation pressure) for between 39 and 65 spins (corre-
sponding to the dwell times given above), depending on which
part of the cycloid
Planck
is in. To high accuracy, any one beam
covers precisely the same sky between 39 and 65 times. The set
of observations made during a period of fixed spin axis point-
ing is often referred to as a “ring.” This redundancy plays a key
role in the analysis of the data, as will be seen below, and is an
important feature of the scan strategy.
As the Earth and
Planck
orbit the Sun, the nearly-great cir-
cles that are observed rotate about the ecliptic poles. The ampli-
tude of the spin-axis cycloid is chosen so that all beams of both
instruments cover the entire sky in one year. In e
ff
ect,
Planck
tilts
to cover first one Ecliptic pole, then tilts the other way to cover
the other pole six months later. If the spin axis stayed exactly
5
Planck Collaboration: The
Planck
mission
HFI Processing
LFI Processing
LFI Beams &
window functs
LFI Calibration
LFI Systematics
HFI Calibration
Component
Separation
Overview of
products & results
Frequency Maps
Component Maps
Power Spectra
Parameters
Power Spectra
& Likelihood
Cosmological
Parameters
Catalogue of
compact sources
Lensing by
LSS
Catalogue of
SZ sources
Galactic CO
Consistency of
the Data
HFI Time Response
& Beams
HFI Spectral
Response
HFI Energetic
particle effects
Zodiacal
Emission
II
XIII
VI
XXXI
XII
XV
XXVIII
XXIX
XVI
XVII
XIV
X
IX
VII
IV
V
VIII
III
I
Lensing-IR
background
correlation
XVIII
Integrated
Sachs-Wolfe
effect
XIX
Cosmology from
SZ counts
XX
Compton para-
meter power
spectrum
XXi
Constraints on
inflation
XXII
Isotropy &
statistics of
the CMB
Primordial
non-Gaussianity
XXIII
XXIV
Strings &
other defects
XXV
Background
geometry &
topology
XXVi
Doppler boost-
ing of the
CMB
XXVii
All-sky model
of thermal dust
XI
Cosmic
Infrared
Background
XXX
Fig. 2.
Planck
papers published simultaneously with the release of the 2013 products. The title of each paper is abbreviated. The
roman numerals correspond to the sequence number assigned to each of the papers in the series; references include this number.
Green boxes refer to papers describing aspects of data processing and the 2013
Planck
products. Blue boxes refer to papers mainly
dedicated to scientific analysis of the products. Pink boxes describe specific 2013
Planck
products.
on the ecliptic plane, the telescope boresight were perpendicu-
lar to the spin axis, the Earth were in a precisely circular orbit,
and
Planck
had only one detector with a beam aligned precisely
with the telescope boresight, that beam would cover the full sky
in six months. In the next six months, it would cover the same
sky, but with the opposite sense of rotation on a given great cir-
cle. However, since the spin axis is steered in a cycloid, the tele-
scope is 85
◦
to the spin axis, the focal plane is several degrees
wide, and the Earth’s orbit is slightly elliptical, the symmetry
of the scanning is (slightly) broken. Thus the
Planck
beams scan
the entire sky exactly twice in one year, but scan only 93 % of the
sky in six months. For convenience, we call an approximately six
month period one “survey”, and use that term as an inexact short-
hand for one coverage of the sky. Nine numbered “Surveys” are
defined precisely in Table 1. It is important to remember that as
long as the phase of the cycloid remains constant, one year cor-
6
Planck Collaboration: The
Planck
mission
Fig. 3.
The trajectory of
Planck
from launch until 13 January 2012, in Earth-centred rotating coordinates (
X
is in the Sun-Earth
direction;
Z
points to the north ecliptic pole). Symbols indicate the start of routine operations (circle), the end of the nominal mission
(triangle), and the end of HFI data acquisition (diamond). The orbital periodicity is 6 months. The distance from the Earth-Moon
barycentre is shown in the bottom right panel, together with Survey boundaries.
responds to exactly two coverages of the sky, while one Survey
has an exact meaning only as defined in Table 1. Null tests be-
tween 1-year periods with the same cycloid phase are extremely
powerful. Null tests between Surveys are also useful for many
types of tests, particularly in revealing di
ff
erences due to beam
orientation.
4.2. Routine operations
Routine operations started on 12 August 2009. The beginning
and end dates of each Survey are listed in Table 1, which also
shows the fraction of the sky covered by all frequencies. The
fourth Survey was shortened somewhat so that the slightly dif-
ferent scanning strategy adopted for Surveys 5–8 (see below)
could be started before the Crab Nebula, an important polariza-
tion calibration source, was observed. The coverage of the fifth
Survey is smaller than the others because several weeks of in-
tegration time were dedicated to “deep rings” (defined below)
covering sources of special importance.
During routine scanning, the
Planck
instruments naturally
observe objects of special interest for calibration. These include
Mars, Jupiter, Saturn, Uranus, Neptune, and the Crab Nebula.
Di
ff
erent types of observations of these objects were performed:
–
Normal scans on Solar System objects and the Crab Nebula.
The complete list of observing dates for these objects can be
found in Planck Collaboration (2013).
–
“Deep rings.” These special scans are performed on obser-
vations of Jupiter and the Crab Nebula from January 2012
onward. They comprise deeply and finely sampled (step size
0.
′
5) observations with the spin axis along the Ecliptic plane,
lasting typically two to three weeks. Since the Crab is crucial
for calibration of both instruments, the average longitudinal
speed of the pointing steps was increased before scanning
the Crab, to improve operational margins and ease recovery
in case of problems.
–
“Drift scans.” These special observations are performed on
Mars, making use of its proper motion. They allow finely-
sampled measurements of the beams, particularly for HFI.
The rarity of Mars observations during the mission gives
them high priority.
The cycloid phase was shifted by 90
◦
for Surveys 5–8 to op-
timize the range of polarization angles on key sources in the
combination of Surveys 1–8, thereby helping in the treatment
of systematic e
ff
ects and improving polarization calibration.
As stated in Sect. 2, the 2013 products are based on the
15.5-month nominal mission, and include data acquired during
Surveys 1, 2, and part of 3.
7
Planck Collaboration: The
Planck
mission
Fig. 4.
Top two panels
: the path of the spin axis of
Planck
(in ecliptic longitude and latitude) over the period 12 August 2009 (91
days after launch) to 13 January 2012, the “0.1-K mission” period (Table 1).
Bottom panel
: the evolution of the dwell time during the
same period. Intervals of acceleration
/
deceleration (e.g., around observations of the Crab) are clearly visible as symmetric temporary
increases and reductions of dwell time. Survey boundaries are indicated by vertical dashed lines in the upper plot. The change in
cycloid phase is clearly visible at operational day (OD) 807. The disturbances around OD 950 are due to the “spin-up campaign”.
Table 1.
Planck
Surveys (defined in Sect. 4.1). Times are UT.
Survey
Instrument
Beginning
End
Coverage
a
1 . . . . . . . . . . . . . . . . . .
LFI & HFI
12 Aug 2009 (14:16:51)
02 Feb 2010 (20:51:04)
93.1 %
2 . . . . . . . . . . . . . . . . . .
LFI & HFI
02 Feb 2010 (20:54:43)
12 Aug 2010 (19:27:20)
93.1 %
3 . . . . . . . . . . . . . . . . . .
LFI & HFI
12 Aug 2010 (19:30:44)
08 Feb 2011 (20:55:55)
93.1 %
4 . . . . . . . . . . . . . . . . . .
LFI & HFI
08 Feb 2011 (20:59:10)
29 Jul 2011 (17:13:32)
86.6 %
5 . . . . . . . . . . . . . . . . . .
LFI & HFI
29 Jul 2011 (18:04:49)
01 Feb 2012 (05:25:59)
80.1 %
6 . . . . . . . . . . . . . . . . . .
LFI
01 Feb 2012 (05:26:29)
03 Aug 2012 (16:48:51)
79.2 %
7 . . . . . . . . . . . . . . . . . .
LFI
03 Aug 2012 (16:48:53)
31 Jan 2013 (10:32:08)
73.7 %
8 . . . . . . . . . . . . . . . . . .
LFI
31 Jan 2013 (10:32:10)
03 Aug 2013 (21:53:37)
70.6 %
9 . . . . . . . . . . . . . . . . . .
LFI
03 Aug 2013 (21:53:39)
03 Oct 2013 (21:13:38)
21.2 %
“Nominal mission” . . . . .
LFI & HFI
12 Aug 2009 (14:16:51)
28 Nov 2010 (12:00:53)
...
“0.1-K mission” . . . . . . .
LFI & HFI
12 Aug 2009 (14:16:51)
13 Jan 2012 (14:54:07)
...
a
Fraction of sky covered by all frequencies
The scientific lifetime of the HFI bolometers ended on
13 January 2012 when the supply of
3
He needed to cool them
to 0.1 K ran out. LFI continued to operate and acquire sci-
entific data through 3 October 2013.
Planck
operations ended
23 October 2013. Data from the remaining part of Survey 3,
Surveys 4 and 5 (both LFI and HFI), and Surveys 6–9 (LFI only)
will be released in 2014.
Routine operations were significantly modified twice more:
–
The sorption cooler switchover from the nominal to the re-
dundant unit took place on 11 August 2010, leading to an
interruption of acquisition of useful scientific data for about
8