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. Tau CMa in Obsid 2525 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. Tau CMa in Obsid 2525 is circled in red on the plot.

Hardness Ratios for Tau CMa, Obsid 2525
Aimpoint	HR₁ = (H-M)/(H+M)	HR₂ = (M-S)/(M+S)	HR₃ = (H-S)/(H+S)
ACIS-S	-0.797	-0.506	-0.929
ACIS-I	-0.753	-0.285	-0.855

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 Tau CMa, Obsid 2525

Aimpoint Quantiles 25 % 25 % Error 50 % 50 % Error 75 % 75 % Error
ACIS-S keV 0.635 0.003 0.752 0.007 0.913 0.005

Q-norm 0.044 0.000 0.059 0.001 0.080 0.001
ACIS-I keV 0.694 0.007 0.854 0.007 1.000 0.007

Q-norm 0.051 0.001 0.072 0.001 0.091 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 Tau CMa, Obsid 2525
Aimpoint	Quantiles	25 %	25 % Error	50 %	50 % Error	75 %	75 % Error
ACIS-S	keV	0.635	0.003	0.752	0.007	0.913	0.005
ACIS-S	Q-norm	0.044	0.000	0.059	0.001	0.080	0.001
ACIS-I	keV	0.694	0.007	0.854	0.007	1.000	0.007
ACIS-I	Q-norm	0.051	0.001	0.072	0.001	0.091	0.001