View X-Atlas Observation

Observation ID	Observation Date	Target	Star Name	Object Class	Spectral Type	B-V Magnitude	RA (deg)	DEC (deg)	Exposure (s)
1904	2001-03-27 06:23:50	CH CYG	HD 182917	Symbiotic Star	M7IIIv	1.3200	291.137940	50.241340	47079.37

Chandra Configuration for the Observation

Zeroth-Order Image

Zeroth-Order Events	Zeroth-Order Count Rate (cts/s)	Pileup
998	0.0212	mild

The zeroth-order image for CH CYG

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	0.117	-0.656	-0.584
ACIS-I	0.306	-0.434	-0.147

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	0.002	0.723	0.007	1.029	0.017
ACIS-S	Q-norm	0.040	0.000	0.055	0.001	0.095	0.002
ACIS-I	keV	0.679	0.007	0.942	0.013	4.898	0.093
ACIS-I	Q-norm	0.049	0.001	0.083	0.002	0.597	0.012

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
0.4142	1.7438	0.4681	2.2685	0.8361	3.3619	1.1993	4.3246	0.2305	1.1696	0.3204	1.3208	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
0.2501	0.1358	0.4711	2.0113	0.7267	2.0159	10.1755	2.3010	59.8836	79.3055	0.2047	0.2711

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 CH CYG.
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 CH CYG. 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 CH CYG. 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)	0.000		12.110		0.011		131.60		6.04648e-13	0	13.63	46
ACIS-S	xswabs*(xsmekal1+xsmekal2)	0.010		30.000		0.216		0.83		1.61246e-13	5.18775	5.68	55
ACIS-I	xswabs*(xsmekal1+xsmekal2)	0.010		30.000		0.212		0.11		4.09987e-13	8.30547	7.36	74

X-Atlas Spectral Fits Listing

HETG Light Curve

GLvary
Odds	388.458
Prob.	1.000
Var. Index	10

HETG light curve for CH CYG, 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 1904

High-Resolution 1st Order HEG Spectrum for CH CYG

HETG MEG Spectrum

Image File Missing: High-Resolution 1st Order MEG Spectrum of obsid 1904

High-Resolution 1st Order MEG Spectrum for CH CYG

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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