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Table 1

Summary wavelength dependence of dips.

Parametera 2016 Jan. 18 2016 Jan. 20

s 13 0.994 ± 0.007 0.988 ± 0.007
s 14 1.013 ± 0.011 0.983 ± 0.010
s 24 1.010 ± 0.009 1.000 ± 0.010

smn 1.006 ± 0.010 0.990 ± 0.009
std. dev. smn 0.010 ± 0.006 0.009 ± 0.005

δ s 13 −0.006 ± 0.007 −0.012 ± 0.007
δ s 14 + 0.013 ± 0.011 −0.017 ± 0.010
δ s 24 + 0.010 ± 0.009 + 0.000 ± 0.010

δsmn 0.006 ± 0.010 −0.010 ± 0.009
std. dev. δsmn 0.010 ± 0.006 0.009 ± 0.005

ln(λ3/λ1) 0.296 0.296
ln(λ4/λ1) 0.466 0.466
ln(λ4/λ2) 0.304 0.304

⟨ ln(λn/λm) ⟩ 0.354 0.354

α 13 −0.020 ± 0.024 −0.040 ± 0.024
α 14 + 0.027 ± 0.024 −0.038 ± 0.021
α 24 + 0.033 ± 0.030 + 0.001 ± 0.033

α b −0.013 ± 0.027 c + 0.026 ± 0.032 c
2-σ limit on | α | 0.06 0.06

Notes.

(a)

The value smn is the slope of the Dm vs. Dn curve. The uncertainties given are those that adjust to be equal to unity. δsmnsmn − 1. The four centers of the wavebands are λ1 = 0.528 nm; λ2 = 0.620 nm; λ3 = 0.709 nm; and λ4 = 0.840 nm. The values αmn are the Ångström exponents computed for each of three combinations of wavebands, and α is the mean of the three values of Ångström exponent computed by minimizing χ2.

(b)

The uncertainties in α are based on the rms scatter among the different results for αmn rather than on the formal statistical uncertainty.

(c)

If we also allow for an additive constant in Eq. (4) as a free parameter, i.e., to determine the flux = 1 level empirically, we find that these uncertainties would increase by ~50%.

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