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. PROXIMA CENTAURI in Obsid 2388 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. PROXIMA CENTAURI in Obsid 2388 is circled in red on the plot.

Hardness Ratios for PROXIMA CENTAURI, Obsid 2388
Aimpoint	HR₁ = (H-M)/(H+M)	HR₂ = (M-S)/(M+S)	HR₃ = (H-S)/(H+S)
ACIS-S	-0.714	-0.275	-0.827
ACIS-I	-0.678	-0.031	-0.694

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 PROXIMA CENTAURI, Obsid 2388

Aimpoint Quantiles 25 % 25 % Error 50 % 50 % Error 75 % 75 % Error
ACIS-S keV 0.679 0.001 0.840 0.004 1.029 0.006

Q-norm 0.049 0.000 0.070 0.001 0.095 0.001
ACIS-I keV 0.781 0.005 0.927 0.005 1.117 0.007

Q-norm 0.062 0.001 0.081 0.001 0.106 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 PROXIMA CENTAURI, Obsid 2388
Aimpoint	Quantiles	25 %	25 % Error	50 %	50 % Error	75 %	75 % Error
ACIS-S	keV	0.679	0.001	0.840	0.004	1.029	0.006
ACIS-S	Q-norm	0.049	0.000	0.070	0.001	0.095	0.001
ACIS-I	keV	0.781	0.005	0.927	0.005	1.117	0.007
ACIS-I	Q-norm	0.062	0.001	0.081	0.001	0.106	0.001