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 3 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 3 is circled in red on the plot.

Hardness Ratios for Theta-1 Ori E, Obsid 3
Aimpoint	HR₁ = (H-M)/(H+M)	HR₂ = (M-S)/(M+S)	HR₃ = (H-S)/(H+S)
ACIS-S	-0.121	0.381	0.273
ACIS-I	-0.046	0.556	0.524

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 3

Aimpoint Quantiles 25 % 25 % Error 50 % 50 % Error 75 % 75 % Error
ACIS-S keV 0.942 0.007 1.205 0.010 1.847 0.020

Q-norm 0.083 0.001 0.117 0.001 0.201 0.003
ACIS-I keV 1.015 0.005 1.351 0.011 2.008 0.022

Q-norm 0.093 0.001 0.136 0.001 0.222 0.003

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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 3
Aimpoint	Quantiles	25 %	25 % Error	50 %	50 % Error	75 %	75 % Error
ACIS-S	keV	0.942	0.007	1.205	0.010	1.847	0.020
ACIS-S	Q-norm	0.083	0.001	0.117	0.001	0.201	0.003
ACIS-I	keV	1.015	0.005	1.351	0.011	2.008	0.022
ACIS-I	Q-norm	0.093	0.001	0.136	0.001	0.222	0.003