NILC PR4 Compton y-map

NILC PR4 Compton y-map

Overview

We provide an updated thermal SZ Compton y-parameter map reconstructed using NILC from the Planck data release 4 (PR4). This product improves upon the 2015 Compton y-parameter map. The data products are described in detail in Chandran et al. (2023).

Data Products

The data products consist of the full-mission PR4 y-map, the half-ring PR4 y-maps, and associated masks. They are available in the Planck Legacy Archive.

Compton y-maps

Figure 1. The PR4 NILC Compton y-map visualized in orthographic projection.

In addition to the full-mission PR4 y-map (Figure 1), maps produced from the two half-ring data splits (HR1 and HR2 y-maps) are provided for noise characterization. The angular resolution of the y-maps is 10 arcmin.

Masks

A small processing mask (NILC-MASK) of sky fraction (fsky) ~ 0.98 is applied to the Planck frequency maps before component separation to avoid ringing effects. A Galactic mask (GAL-MASK) of fsky ~ 0.6 and a point-source mask (PS-MASK) of fsky ~ 0.93 are used for different analyses. Combined, the analysis mask (GAL-MASK + PS-MASK) has an fsky ~ 0.56. The GAL-MASK and NILC-MASK are the same as those used in Planck 2015 results. XXII. The PS-MASK mask is derived from the point-source masks generated by M. López-Caniego for PR4 as a part of the Sevem pipeline.

Maps

Filename = Compton-SZMap-NILC-ymap_2048_PR4.fits
EXTNAME = 'FREQ-MAP' : Data columns
Column Name	Description
FULL	NILC full-mission y-map
HALF_RING 1	NILC half-ring 1 y-map
HALF_RING 2	NILC half-ring 2 y-map
Keyword	Value
COORDSYS	GALACTIC
ORDERING	RING
NSIDE	2048

Masks

Filename = Compton-SZMap-NILC-ymap_2048_PR4_masks.fits
EXTNAME = 'MASKS' : Data columns
Column Name	Description
NILC_MASK	NILC processing mask (fsky=0.98)
GAL_MASK	Galactic mask (fsky =0.60)
PS_MASK	Point-source mask (fsky =0.93)
Keyword	Value
COORDSYS	GALACTIC
ORDERING	RING
NSIDE	2048