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. V987 TAU = HDE 283572 in Obsid 3756 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. V987 TAU = HDE 283572 in Obsid 3756 is circled in red on the plot.

Hardness Ratios for V987 TAU = HDE 283572, Obsid 3756
Aimpoint	HR₁ = (H-M)/(H+M)	HR₂ = (M-S)/(M+S)	HR₃ = (H-S)/(H+S)
ACIS-S	-0.426	0.190	-0.257
ACIS-I	-0.371	0.388	0.019

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 V987 TAU = HDE 283572, Obsid 3756

Aimpoint Quantiles 25 % 25 % Error 50 % 50 % Error 75 % 75 % Error
ACIS-S keV 0.840 0.000 1.029 0.001 1.365 0.006

Q-norm 0.070 0.000 0.095 0.000 0.138 0.001
ACIS-I keV 0.913 0.007 1.102 0.006 1.482 0.006

Q-norm 0.080 0.001 0.104 0.001 0.153 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 V987 TAU = HDE 283572, Obsid 3756
Aimpoint	Quantiles	25 %	25 % Error	50 %	50 % Error	75 %	75 % Error
ACIS-S	keV	0.840	0.000	1.029	0.001	1.365	0.006
ACIS-S	Q-norm	0.070	0.000	0.095	0.000	0.138	0.001
ACIS-I	keV	0.913	0.007	1.102	0.006	1.482	0.006
ACIS-I	Q-norm	0.080	0.001	0.104	0.001	0.153	0.001