View X-Atlas Observation

Observation ID	Observation Date	Target	Star Name	Object Class	Spectral Type	B-V Magnitude	RA (deg)	DEC (deg)	Exposure (s)
2526	2002-04-24 00:09:36	Tau CMa	HD 50761	Spectroscopic binary	O9II	-0.1550	109.676990	-24.954460	43891.49

Chandra Configuration for the Observation

Zeroth-Order Image

Zeroth-Order Events	Zeroth-Order Count Rate (cts/s)	Pileup
911	0.0208	mild

The zeroth-order image for Tau CMa

Hardness Ratios and Quantiles

Hardness ratios and quantiles are calculated from the predicted ACIS-S or ACIS-I aimpoint spectra, as indicated.

Hardness Ratios
Aimpoint	HR₁ = (H-M)/(H+M)	HR₂ = (M-S)/(M+S)	HR₃ = (H-S)/(H+S)
ACIS-S	-0.800	-0.571	-0.941
ACIS-I	-0.771	-0.333	-0.878

S, M, and H represent the predicted total counts in the following passbands:

S: 0.3-0.9 keV

M: 0.9-1.5 keV

H: 1.5-8.0 keV

Quantiles
Aimpoint	Quantiles	25 %	25 % Error	50 %	50 % Error	75 %	75 % Error
ACIS-S	keV	0.606	0.000	0.723	0.002	0.891	0.007
ACIS-S	Q-norm	0.040	0.000	0.055	0.000	0.077	0.001
ACIS-I	keV	0.664	0.007	0.825	0.007	1.000	0.009
ACIS-I	Q-norm	0.047	0.001	0.068	0.001	0.091	0.001

Normalized quantiles (Q-norm) are defined as:

Q_x = (E_x - E_lo)/(E_hi - E_lo)

Where E_lo = 0.3 keV and E_hi = 8.0 keV.

Hardness Ratio plots and Quantile-based Color-Color Diagrams

X-Atlas Hardness Ratios and Quantiles Listing

Spectral Metrics

A series of line-line, line-continuum, and continuum-continuum ratios calculated from the high-resolution 1^st order MEG or LEG spectrum.

Line-Line Ratios
Ne X / O VIII	Ne2O Error	O VII(i) / O VII(f)	Oif Error	O VII(r) / O VIII	O78 Error	O VIII / Fe XVII	O8Fe Error	Mg XII / Fe XVII	Mg2Fe Error	Si XIV / Fe XVII	Si2Fe Error	S XV / Fe XVII	S2Fe Error
0.0875	0.0849	0.0000	0.0000	0.1425	0.1307	1.8441	0.8734	0.1389	0.1910	0.0000	0.0000	0.0000	0.0000

short line / cont

Line-Continuum & Continuum-Continuum Ratios
sl2c Error	long line / cont	ll2c Error	line / cont	l2c Error	cont long / cont short	cl2cs Error	cont long / cont med	cl2cm Error	cont med / cont short	cm2cs Error
0.2668	0.1465	0.3122	1.7789	0.5858	1.7850	7.2480	1.3468	12.5248	4.0094	1.3736	0.4416

X-Atlas Spectral Metrics Listing

Spectral Fits

Image File Missing: 2T xsmekal zeroth-order fit
Mewe-Kaastra-Liedahl 2-temperature fit of the low-resolution zeroth-order spectrum of Tau CMa.
Warning: The zeroth-order spectrum may be subject to distortions from pileup.

Image File Missing: 2T xsmekal ACIS-S fit
Mewe-Kaastra-Liedahl 2-temperature fit of the predicted low-resolution ACIS-S Aimpoint spectrum of Tau CMa. The predicted spectrum was scaled to 1500 counts.

Image File Missing: 2T xsmekal ACIS-I fit
Mewe-Kaastra-Liedahl 2-temperature fit of the predicted low-resolution ACIS-I Aimpoint spectrum of Tau CMa. The predicted spectrum was scaled to 1500 counts.

Aimpoint	Model	nH (10²²/cm³)	nH error	kT (keV)	kT error	kT2 (keV)	kT2 error	Abundance (solar)	Abundance error	Flux (ergs/cm²/s)	Flux Emission Ratio (kT2/kT1)	Reduced Chi²	DoF
zeroth-order	xswabs*(xsmekal1+xsmekal2)	0.192		0.239		0.239		0.05		9.6407e-13	6.37777	1.20	35
ACIS-S	xswabs*(xsmekal1+xsmekal2)	0.198		1.114		0.192		0.17		1.5367e-13	25.6249	1.08	47
ACIS-I	xswabs*(xsmekal1+xsmekal2)	0.252		5.043		0.189		0.18		3.29235e-13	50.2045	1.46	50

X-Atlas Spectral Fits Listing

HETG Light Curve

GLvary
Odds	8.760
Prob.	1.000
Var. Index	8

HETG light curve for Tau CMa, constructed from all ±1^st, ±2^nd, and ±3^rd order HETG events.

HETG HEG Spectrum

Image File Missing: High-Resolution 1st Order HEG spectrum of obsid 2526

High-Resolution 1st Order HEG Spectrum for Tau CMa

HETG MEG Spectrum

Image File Missing: High-Resolution 1st Order MEG Spectrum of obsid 2526

High-Resolution 1st Order MEG Spectrum for Tau CMa

X-Atlas Data Products

Spectral Data
PHA II	HEG ±1^st Order PHA	HEG ±1^st Order gARF	MEG ±1^st Order PHA	MEG ±1^st Order gARF	[Counts/s/Å] FITS	[Counts/s/Å] text	[ph/s/Å/cm²] FITS	[ph/s/Å/cm²] text

Standard Data Products (Cycle 06)
Aimpoint ARF		Aimpoint RMF
ACIS-S	ACIS-I	ACIS-S	ACIS-I

Retrieve observation data from the Chandra Data Archive: WebChaSeR

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