S4 Inflation Chapter Plot Suggestions, v2

2015-07-07  (Victor Buza)

This is a follow-up posting on this, showing "$$\sigma_r$$ vs Effort" and "$$\sigma_r$$ vs $$f_{sky}$$," plots, as well as a few versions of the "$$C_l^{BB}$$" plot. Aside from stylistic updates, there are two main changes from the last posting:

• First, even though the current optimization prefers f_sky=1% as the minimum for the r=0 case, perhaps in reality we’d like to do something slightly larger. We’re proposing to switch to f_sky=3% as the default scenario. One consequence of this would be reducing the delensing level from 95% power to 90% (i.e. go from 5% residual lensing power, to 10%). This is what's currently in the Science Book.
• Looking at models of interest on the r-ns plots, and through the text, it seems that r=0.003 is perhaps a better choice for the $$r>0$$ model. There is a class of models at that level, and it is possibly the lowest r we could sensibly detect. This is not yet in the Science Book, but is presented below.

1. $$C_l^{BB}$$ plot -- bin-by-bin forecasted tensor constraints

Figure 1:

Bin-by-bin forecasted tensor constraints for r=0.01 and r=0.003, $$f_{sky} = 0.03$$, and the default detector effort ($$10^{6}$$ detector years). Vertical error bars denote 68% credible intervals, with the point marking the model expectation value. If the 68% interval includes zero, we indicate the 95% upper limit with a downward triangle. Horizontal error bars denote bin widths calculated from bandpower window functions. Primordial B-mode spectra are shown for several representative values of the tensor-to-scalar ratio. The solid green line shows the $$\Lambda CDM$$ expectation for the B modes induced by gravitational lensing of E modes, with the dashed line showing $$1/10$$ of the lensing power. The solid blue and red lines show the dust and synchrotron (current upper limit) model assumed in the forecasting, at the foreground minimum of $$95 GHz$$. The levels of dust and synchrotron are equal to the ones reported in BK14.

• Default: Current version in the Science Book
• + BK14: adds CMB component BK14 bandpowers.
• + r=0.05: adds an r=0.05 theory line as well as a r=0.05 + lensing theory line
• + E modes: adds the E-mode theory line, and increases the dynamic range

2. "$$\sigma_r$$ vs Effort" and "$$\sigma_r$$ vs $$f_{sky}$$"

Figure 2:

Equivalent to Figure 3 of the previous posting, except now the "$$\sigma_r$$ vs effort" plot is made for a default $$f_{sky}=0.03$$.

It's important to keep in mind that there are a number of effects that penalize large $$f_{sky}$$ that are not included in this analysis:

• First, the foreground treatment currently assumes equal foreground amplitudes even as we increase the sky area, whereas we know that above $$f_{sky}$$ of 0.1 the foregrounds will get brighter.
• The treatment also assumes single fits for foreground parameters over the entire survey, more realistic treatment would refit the foreground parameters for smaller subregions and that will reduce the sensitivities at larger $$f_{sky}$$.
• Similarly, no systematic penalty or unmodeled foregrounds penalty is imposed, and that will introduce uncertainties in the fractional residual power levels that are worse for lower map signal to noise of the large $$f_{sky}$$ cases.