View X-Atlas Observation

Observation ID	Observation Date	Target	Star Name	Object Class	Spectral Type	B-V Magnitude	RA (deg)	DEC (deg)	Exposure (s)
1885	2001-09-19 19:36:23	EV LAC	V* EV Lac	Flare Star	M3.5e	1.3600	341.706740	44.333830	100022.96

Chandra Configuration for the Observation

Zeroth-Order Image

Zeroth-Order Events	Zeroth-Order Count Rate (cts/s)	Pileup
17786	0.1778	severe

The zeroth-order image for EV LAC

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	-0.556	-0.139	-0.645
ACIS-I	-0.504	0.101	-0.425

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	0.723	0.000	0.898	7.102	1.117	0.000
ACIS-S	Q-norm	0.055	0.000	0.078	0.922	0.106	0.000
ACIS-I	keV	0.810	0.003	0.986	7.015	1.278	0.003
ACIS-I	Q-norm	0.066	0.000	0.089	0.911	0.127	0.000

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
1.6484	1.1686	0.6797	0.8666	0.2066	0.1883	0.3032	0.1626	0.0500	0.0208	0.1222	0.0696	0.0171	0.0238

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
0.0103	0.0007	0.0108	0.0017	0.0235	0.0021	0.0555	0.0001	0.0562	0.0001	81.4975	0.2808

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 EV LAC.
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 EV LAC. 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 EV LAC. 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		1.994		0.610		0.07		8.76517e-12	1.38257	2.72	257
ACIS-S	xswabs*(xsmekal1+xsmekal2)	0.054		1.237		0.283		0.20		6.77522e-14	1.11713	1.09	61
ACIS-I	xswabs*(xsmekal1+xsmekal2)	0.000		1.283		0.539		0.22		1.07958e-13	0.963106	1.13	60

X-Atlas Spectral Fits Listing

HETG Light Curve

GLvary
Odds	2797.560
Prob.	1.000
Var. Index	10

HETG light curve for EV LAC, 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 1885

High-Resolution 1st Order HEG Spectrum for EV LAC

HETG MEG Spectrum

Image File Missing: High-Resolution 1st Order MEG Spectrum of obsid 1885

High-Resolution 1st Order MEG Spectrum for EV LAC

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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