J/A+A/592/A48 Annotations to the second Planck cluster catalog (Khatri, 2016)
An alternative validation strategy for the Planck cluster catalog and
y-distortion maps.
Khatri R.
<Astron. Astrophys. 592, A48 (2016)>
=2016A&A...592A..48K 2016A&A...592A..48K (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Molecular clouds
Keywords: cosmic background radiation - cosmology: observations - ISM: clouds -
radio lines: ISM - methods: data analysis -
galaxies: clusters : intracluster medium
Abstract:
We present an all sky map of the y-type distortion calculated from the
full mission Planck HFI (High Frequency Instrument) data using the
recently proposed approach to component separation based on parametric
model fitting and model selection. This simple model selection
approach allows us to distinguish between carbon monoxide (CO) line
emission and y-type distortion, something that is not possible using
the internal linear combination based methods. We create a mask to
cover the regions of significant CO emission relying on the
information in the χ2 map obtained when fitting for the
y-distortion and CO emission to the lowest four HFI channels. We
revisit the second Planck cluster catalog and try to quantify the
quality of the cluster candidates in an approach that is similar in
spirit to Aghanim et al. (2015A&A...580A.138A 2015A&A...580A.138A). We find that at least
93% of the clusters in the cosmology sample are free of CO
contamination. We also find that 59% of unconfirmed candidates may
have significant contamination from molecular clouds. We agree with
Planck Collaboration et al. (2016, A&A, in press., arXiv:1502.01598)
for the worst offenders. We suggest an alternative validation strategy
of measuring and subtracting the CO emission from the Planck cluster
candidates using radio telescopes thus improving the reliability of
the catalog. Our CO mask and annotations to the Planck cluster catalog
identifying cluster candidates with possible CO contamination are made
publicly available.
Description:
We have added additional columns to the second Planck cluster catalog
which quantify the quality of clusters and try to discriminate the
molecular cloud contamination in the catalog. We provide the χ2
for the fits of a parametric model with either Sunyaev-Zeldovich
spectrum or CO-line emission spectrum to the Planck data within
5-arcmin at the position of each cluster. The difference in the
χ2 value can be used to determine whether a candidate is likely
to be a cluster or a molecular cloud and is indicative of the quality
of the cluster candidate.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
catalog.dat 156 1653 Planck cluster catalog with additional columns
(planckclustersR2.0_x3.8.dat)
--------------------------------------------------------------------------------
See also:
VIII/88 : Planck Early Release Compact Source Catalogue (Planck, 2011)
VIII/91 : Planck Catalog of Compact Sources Release 1 (Planck, 2013)
J/A+A/536/A8 : Planck early results. VIII. ESZ sample. (Planck+, 2011)
https://wiki.cosmos.esa.int/planckpla2015/index.php/
Catalogues#Union_catalogue : (Planck collaboration second SZ union catalogue)
Byte-by-byte Description of file: catalog.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 5 I4 --- Seq [1/1653] Serial number in the present
catalogue
7- 10 I4 --- Planck [1/1653] Serial number in original
Planck catalogue (1)
13- 16 A4 --- --- [PSZ2]
18- 30 A13 --- PSZ2 Planck cluster name, GLLL.ll+BB.bb (1)
32- 40 F9.5 deg GLON Galactic longitude (1)
42- 50 F9.5 deg GLAT Galactic latitude (1)
52- 60 F9.5 --- S/N Signal to noise ratio of the
detection (1)
62- 70 F9.5 --- z Redshift of cluster (1)
72- 83 E12.5 10-3arcmin+2 Y Total integrated Comptonization
parameter, mean marginal Y5R500 as
determined by reference pipeline (1)
85- 96 E12.5 10-3arcmin+2 e_Y rms uncertainty on Y (1)
99-101 I3 --- Pvalid [-1/30] Planck validation flag (1) (2)
103-111 F9.3 --- COX2 Chi2 for CO spectrum fit
113-121 F9.3 --- SZX2 Chi2 for SZ spectrum fit
122-131 F10.3 --- COX2-SZX2 Difference between CO and SZ Chi2
133-136 A4 --- LILvalid Validation flag from LIL model
selection algorithm (3)
139 A1 --- FCosmo [F/T] Planck cosmology flag (1) (4)
145-149 F5.3 --- QN [0/1] Planck neural network quality
flag (1) (5)
153-156 A4 --- Qual Good/Bad classification based on QN
--------------------------------------------------------------------------------
Note (1): This field is copied from the original Planck catalogue without
modification. See
https://wiki.cosmos.esa.int/planckpla2015/index.php/Catalogues#Union_catalogue
for details.
Note (2): Summary of the external validation, encoding the most robust external
identification as follows:
10 = ENO follow-up
11 = RTT follow-up
12 = PanSTARRs
13 = RedMAPPer non-blind
14 = SDSS high-z
15 = AMI
16 = WISE
20 = legacy identification from the PSZ1
21 = MCXC
22 = SPT
23 = ACT
24 = RedMAPPer
25 = legacy identification from PSZ1 with externally updated redshift
30 = NED
-1 = no known external counterpart
Note (3): Validation flag from LIL model selection algorithm as follows:
CLG = cluster
IND = indeterminable
MOC = molecular cloud
pCLG = cluster with lower significance of classification than CLG
pMOC = molecular cloud with lower significance of classification than MOC
Note (4): Indicates whether detection is in the cosmology sample (T for True).
Note (5): Neural network quality flag is 1-Qbad, following the definitions in
Aghanim et al. (2015A&A...580A.138A 2015A&A...580A.138A).
--------------------------------------------------------------------------------
Acknowledgements:
Rishi Khatri, khatri(at)theory.tifr.res.in
References:
https://wiki.cosmos.esa.int/planckpla2015/index.php/Catalogues#Union_catalogue
(End) Rishi Khatri [TIFR Mumbai, India], Patricia Vannier [CDS] 31-May-2016