BPWFs

The figure below shows each of the bandpower window functions, with the nine “science” bandpowers colored and labeled. The first bandpower bin (which we discard) and the higher bins are colored in light grey. The black ‘x’s indicate the weighted band centers.

Beam widths are in arcmins and correspond to 20GHz (on LAT), 30/40GHz, 85/145GHz, 95/155GHz, and 220/270GHz.

A previous post showing CMB-S4 BPWFs is 20181127_bpwf_DC4. The difference in slope across the lowest few bins appears to be due to bug fix by Justin which is described in 20181208_cmbs4_cl2bandpowers. (Note that this last post is not linked from the index page.)

This posting is after a tweak to the apodization mask to improve E/B purity as described in this post.

Real maps built from filtered time-ordered-data have the lowest multipoles suppressed by this filtering, To approximate this effect the S4 sim maps have been generated with \(\ell<30\) \(a_{lm}\)'s set to zero. For the 06 set we now include this insensitivity to low \(\ell\) in the BPWF's. (In previous work it was included by cutting off the theory spectra before multiplying by the BPWF's.) Clearly in a real filtered map there is a roll off to low \(\ell\) rather than a hard cut.

[For those with access to BK logbook 20200421_bk18mm_bpwf is most recent analgous posting. Also see this posting 20200617_healpix_output_ii]

For comparison the 04 BPWFs are re-plotted here in the same format.