Target Preview

Observation ID Observation Date Target Star Name Object Class Spectral Type B-V Magnitude RA (deg) DEC (deg) Exposure (s)
4509 2004-03-09 01:48:47 Spica (Alpha Vir) Alpha Vir Variable Star of beta Cep type B1III-IV+... -0.1300 201.298230 -11.161410 89040.42

Chandra Configuration for the Observation

Zeroth-Order Image

Image File Missing: Snapshot of the Zeroth-Order Image
Zeroth-Order Events Zeroth-Order Count Rate (cts/s) Pileup
5327 0.0598 severe
The zeroth-order image for Spica (Alpha Vir)

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 -0.802 -0.737 -0.967
ACIS-I -0.755 -0.498 -0.910
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 0.504 0.001 0.621 0.006 0.796 0.005
Q-norm 0.026 0.000 0.042 0.001 0.064 0.001
ACIS-I keV 0.606 0.004 0.767 0.006 0.927 0.006
Q-norm 0.040 0.000 0.061 0.001 0.081 0.001
Normalized quantiles (Q-norm) are defined as:
Qx = (Ex - Elo)/(Ehi - Elo)
Where Elo = 0.3 keV and Ehi = 8.0 keV.
Hardness Ratio plots and Quantile-based Color-Color DiagramsX-Atlas Hardness Ratios and Quantiles Listing

Spectral Metrics

A series of line-line, line-continuum, and continuum-continuum ratios calculated from the high-resolution 1st 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
0.1684 0.1809 14.8473 38.7902 0.9097 0.7240 0.5790 0.3531 0.0051 0.0337 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
0.0580 0.0000 0.7220 0.0000 0.7889 0.0000 17.6508 0.0000 17.6508 3.0841 0.0000 0.0000
X-Atlas Spectral Metrics Listing

Spectral Fits

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
X-Atlas Spectral Fits Listing

LETG Light Curve

Image File Missing: LETG Light Curve
GLvary
Odds-0.442
Prob.0.265
Var. Index0
LETG light curve for Spica (Alpha Vir), constructed from all ±1st, ±2nd, and ±3rd order LETG events.

LETG LEG Spectrum

Image File Missing: High-Resolution 1st Order LEG spectrum of obsid 4509
High-Resolution 1st Order LEG Spectrum for Spica (Alpha Vir)

X-Atlas Data Products

Spectral Data
PHA II LEG ±1st Order PHA LEG ±1st 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 ARFAimpoint RMF
ACIS-SACIS-IACIS-SACIS-I
Retrieve observation data from the Chandra Data Archive: WebChaSeR
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