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. Theta-1 Ori E in Obsid 2567 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. Theta-1 Ori E in Obsid 2567 is circled in red on the plot.

Hardness Ratios for Theta-1 Ori E, Obsid 2567
Aimpoint	HR₁ = (H-M)/(H+M)	HR₂ = (M-S)/(M+S)	HR₃ = (H-S)/(H+S)
ACIS-S	-0.226	-0.032	-0.256
ACIS-I	-0.105	0.216	0.115

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 Theta-1 Ori E, Obsid 2567

Aimpoint Quantiles 25 % 25 % Error 50 % 50 % Error 75 % 75 % Error
ACIS-S keV 0.796 0.009 1.000 0.009 1.451 0.056

Q-norm 0.064 0.001 0.091 0.001 0.149 0.007
ACIS-I keV 0.898 0.012 1.102 0.014 2.037 0.504

Q-norm 0.078 0.002 0.104 0.002 0.226 0.065

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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 Theta-1 Ori E, Obsid 2567
Aimpoint	Quantiles	25 %	25 % Error	50 %	50 % Error	75 %	75 % Error
ACIS-S	keV	0.796	0.009	1.000	0.009	1.451	0.056
ACIS-S	Q-norm	0.064	0.001	0.091	0.001	0.149	0.007
ACIS-I	keV	0.898	0.012	1.102	0.014	2.037	0.504
ACIS-I	Q-norm	0.078	0.002	0.104	0.002	0.226	0.065