X-ray Hardness and Quantiles

Hardness ratios calculated from the predicted ACIS-S Aimpoint spectra of selected X-Atlas targets (× = hot star; ◊ = cool star). S, M, and H are the total predicted counts in the passbands listed on the plot. AR LAC-3 LAST QUAD (1) in Obsid 8 is circled in red on the plot.

Hardness ratios calculated from the predicted ACIS-I Aimpoint spectra of selected X-Atlas targets (× = hot star; ◊ = cool star). S, M, and H are the total predicted counts in the passbands listed on the plot. AR LAC-3 LAST QUAD (1) in Obsid 8 is circled in red on the plot.

Hardness Ratios for AR LAC-3 LAST QUAD (1), Obsid 8
Aimpoint	HR₁ = (H-M)/(H+M)	HR₂ = (M-S)/(M+S)	HR₃ = (H-S)/(H+S)
ACIS-S	-0.341	0.143	-0.209
ACIS-I	-0.282	0.365	0.092

X-ray Quantiles

Quantile-based color-color diagram: (m = Q₅₀ = (E₅₀ - E_lo)/(E_hi - E_lo)). E_lo = 0.3 keV; E_hi = 8.0 keV

View complete listing of X-Atlas Spectral Metrics (Hardness, Quantiles).

Quantiles for AR LAC-3 LAST QUAD (1), Obsid 8

Aimpoint Quantiles 25 % 25 % Error 50 % 50 % Error 75 % 75 % Error
ACIS-S keV 0.825 0.001 1.044 0.000 1.424 0.007

Q-norm 0.068 0.000 0.097 0.000 0.146 0.001
ACIS-I keV 0.927 0.001 1.146 0.004 1.555 0.007

Q-norm 0.081 0.000 0.110 0.001 0.163 0.001

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ACIS-S hot stars JPG Postscript	ACIS-S cool stars JPG Postscript
ACIS-I hot stars JPG Postscript	ACIS-I cool stars JPG Postscript

Quantiles for AR LAC-3 LAST QUAD (1), Obsid 8
Aimpoint	Quantiles	25 %	25 % Error	50 %	50 % Error	75 %	75 % Error
ACIS-S	keV	0.825	0.001	1.044	0.000	1.424	0.007
ACIS-S	Q-norm	0.068	0.000	0.097	0.000	0.146	0.001
ACIS-I	keV	0.927	0.001	1.146	0.004	1.555	0.007
ACIS-I	Q-norm	0.081	0.000	0.110	0.001	0.163	0.001