ACT (AdvACT) Bridge Maps

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This data release provides Compton-y maps of the Abell 399 – Abell 401 system made by internal linear combination (ILC) of maps from ACT and Planck: from ACT, f090, f150 and f220 maps including data from 2008 to 2019; from Planck, the 100, 143, 217, 353 and 545 GHz maps.

The map-making procedure is described in Hincks et al. (2022; arXiv:2107.04611) with further details in Madhavacheril et al. (2019; 1911.05717). Please cite Hincks et al. when using this map.

Data maps
There are two maps in this release:

Map (1): act_planck_sr_br_1.0_s19_y_map.fits
Map (2): act_planck_sr_br_1.0_s19_y_map_dust_deprojected.fits

Map (1) is the result of the standard ILC using the thermal Sunyaev-Zeldovich spectrum to produce a Compton-y map. Map (2) additionally removes a dust-like component by requiring that a 24 K modified blackbody spectrum with spectral index of 1.2 be de-projected in the ILC. Map (2) has lower resolution (see below) and is ~20% noisier.

The maps use the CAR (plate carée) projection with 0.5 arcmin pixels. The pixel values give the Compton-y parameter (which is unitless).

Effective Beams
The beam transfer functions of these maps are Gaussians, with FWHM as follows:

Map (1): 1.65 arcmin
Map (2): 2.20 arcmin

Hincks et al. (2022) also included maps of the A399–401 bridge from the MUSTANG-2 instrument on the Green Bank Telescope. Those maps will posted on the Harvard Dataverse and a link will be added here when available.

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