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. ALPHA CEN in Obsid 29 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. ALPHA CEN in Obsid 29 is circled in red on the plot.

Hardness Ratios for ALPHA CEN, Obsid 29
Aimpoint	HR₁ = (H-M)/(H+M)	HR₂ = (M-S)/(M+S)	HR₃ = (H-S)/(H+S)
ACIS-S	0.498	-0.656	-0.234
ACIS-I	0.563	-0.257	0.358

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 ALPHA CEN, Obsid 29

Aimpoint Quantiles 25 % 25 % Error 50 % 50 % Error 75 % 75 % Error
ACIS-S keV 0.548 0.002 0.810 0.007 2.489 0.022

Q-norm 0.032 0.000 0.066 0.001 0.284 0.003
ACIS-I keV 0.854 0.010 2.022 0.068 3.409 0.031

Q-norm 0.072 0.001 0.224 0.009 0.404 0.004

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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 ALPHA CEN, Obsid 29
Aimpoint	Quantiles	25 %	25 % Error	50 %	50 % Error	75 %	75 % Error
ACIS-S	keV	0.548	0.002	0.810	0.007	2.489	0.022
ACIS-S	Q-norm	0.032	0.000	0.066	0.001	0.284	0.003
ACIS-I	keV	0.854	0.010	2.022	0.068	3.409	0.031
ACIS-I	Q-norm	0.072	0.001	0.224	0.009	0.404	0.004