ACT (DR6.02) Maps

ACT DR6.02 maps (observation from 2017-2022) with the AdvancedACT camera.

See tables 9, 10 and 11 in Naess et al. 2025 for a detailed description of the files. These maps are released following the IAU polarization convention (POLCCONV='IAU' in FITS header). Baseline software to handle these maps is Pixell (https://github.com/simonsobs/pixell). The maps are divided up into three different types: standard maps, null test maps and coadd maps

*** Standard maps ***

File names are as follows:

act_dr6.02_std_{region}_{time}_{array}_{freq}_4way_{set}_{product}.fits

   region: either AA; DS or DN for daytime observations only; BR, D5 and GC for nighttime only
   time: night or day
   array: pa4, pa5 or pa6
   freq: f090, f150 or f220
   set: set{0-3} or coadd
   product: see below

The map products are

   map: observed I,Q,U Stokes components [uk]
   map_srcfree: observed I,Q,U Stokes components with signal from point sources subtracted [uK]
   ivar: inverse-variance pixel weight [uK^-2]
   xlink: cross-linking information encoded as I,Q,U Stokes components [uK^-2]
   map_healpix: "map" projected to HEALPix [uk]
   map_srcfree_healpix: "map_srcfree" projected to HEALPix [uk]

*** Null test maps ***

File names are as follows:

act_dr6.02_null-{null_type}_{region}_{time}_{array}_{freq}_{nway}_{set}_{product}.fits

where null_type is one of:

   el{1-3}: elevation null test
   pwv{1-2}: PWV null test
   inout{1-2}: Inner-outer null test
   t{1-2}: Time null test

Note that "nway" is given by "2way" for the time null test and "4way" for the other tests.

*** Coadd maps ***

File names are as follows:

{data_type}_coadd_AA_{time}_{freq}_4way_{set}_{product}.fits

Where "data_type" is one of:

   act_dr6.02: coadd of DR6 arrays into single-frequency maps
   act-planck_dr6.02: coadd of DR6 arrays and Planck into single-frequency maps
   act_dr4dr6: coadd of DR4 and DR6 arrays into single-frequency maps
   act-planck_dr4dr6: coadd of DR4, DR6 and Planck arrays into single-frequency maps

Note that the coadd maps are convolved with the coadd_{array}_{freq}_night_beam_tform_jitter_cmb.txt beams, where "array" is "pa5" for the f090 and f150 coadds and "pa4" for the f220 coadd.

Here "time" is given by either "night" for nighttime ACT data only or "daynight" for day and night ACT data

*** Ancillary ***

Two additional files are provided with the maps:

beam_status.txt describes whether the beam passes our beam deformation cuts or not, per TOD. One line per TOD, with columns TOD ID (e.g. 1494463442.1494478197.ar4:f150), start and end unix time (UTC seconds since 1970-01- 01 00:00:00, e.g. 1494463441) for the TOD, and the status. The status is 0 if the beam passes the cuts and 1 if it fails.

srcsamp_mask.fits is a mask that is one in high-contrast areas where special model error mitigation was used.