1. ACIS Calibration: Recent Updates, Planned Updates ... · E0102: Gratuitous Pretty Pictures of...

Chandra X-Ray Observatory CXC

Paul Plucinsky EPIC Cal April 20071

1.1. ACIS Calibration:ACIS Calibration: Recent Updates, Recent Updates,

Planned Updates, &Planned Updates, & Future IssuesFuture Issues

2.2. E0102: Joint Fits with ACIS S3, E0102: Joint Fits with ACIS S3,

MOS1/2 & MOS1/2 & pnpn

Paul Plucinsky, Joseph Paul Plucinsky, Joseph DePasqualeDePasquale,, & &

Steve SnowdenSteve Snowden



1. Recent Updates to the ACIS Calibration1. Recent Updates to the ACIS Calibration

• BI CCD CTI correction for -120 C (S3 & S1), need to have CIAO

3.4 also to apply the correction, BI CTI correction is now part of the

standard data processing

• Effective area correction around the Si K edge, ~4 % at 1.8 keV

• FI CCD ``dead area’’ correction to account for the area lost on

average in each frame to cosmic rays, 2.5-4.0% as a function of row

CALDB 3.3.0 released on 15 December 2006



Planned Update: CTI Correction for Graded Mode for FI Planned Update: CTI Correction for Graded Mode for FI CCDsCCDs

• Faint mode CTI correction adjusts the PH of each pixel in the 3x3

event island

• In Graded mode, only have x, y position of event, grade, and

summed PH

• Use grade and summed PH to determine the most likely charge

distribution based on ``average’’ images

• Use this information in an Graded mode CTI correction

Mn-K flight grade 8 (left split) for S2

Bottom 256 rows Top 256 rows

Vikhlinin (SAO)



Map ofMap of Good and Bad Grades Good and Bad Grades

Vikhlinin (SAO)

33 of 256 flight

grades are included

in the ASCA

G02346 grades

Create average

images for each

of these 33

grades for

multiple energies



Comparison of Graded Mode and Faint Mode CTI CorrectionComparison of Graded Mode and Faint Mode CTI Correction

Posson-

Brown

(SAO)

Graded mode

CTI correction

provides most

of the benefit

of the Faint

mode correction

For FI

CCDs only !



Continuous Clocking Mode Calibration Continuous Clocking Mode Calibration

Edgar (SAO)

In CC mode:

- row-to-row transfer

time is different so the

effects of CTI are

different

-- don’t know the y

position of the events,

but for some

observations you know

the y position of the

source

External Calibration Source: No CTI correction applied



Update on Contaminant BuildupUpdate on Contaminant Buildup

Data:

Grant (MIT)

Model:

O’Dell &

Tennant

(MSFC)



Optical DepthOptical Depth ComparisonComparison

C-K Marshall (MIT)

inferred optical

depth at 700 eV

ECS Grant (MIT)

Mn L

E0102 DePasquale

(SAO) OVIII Ly-a



Future Issues: Focal Plane Operating TemperatureFuture Issues: Focal Plane Operating Temperature

• current operating temperature is -119.7 C

• as the mission has progressed, the frequency and magnitude of

deviations from the desired temperature have increased

• it might become necessary to operate at a higher temperature, significant

impact for the FI CCDs



2. E0102: Gratuitous Pretty Pictures of E01022. E0102: Gratuitous Pretty Pictures of E0102

S3 Summed Data ~100 S3 Summed Data ~100 ksks RGS Spectrum (Pollock 2006)RGS Spectrum (Pollock 2006)

Objective:Objective: develop a spectral model which can be used by RGS, HETG,

EPIC & ACIS, etc.



Application of RGS Spectral ModelApplication of RGS Spectral Model Dewey (MIT)

Use RGS

spectral model

Construct a

spatial model

Compare

simulation to

data

Bright lines

agree well



MEG minus

1st order

Simulation

Comparison

KS test

OVIII OVIINeIXNeXMgXI



MEG plus

1st order

Simulation

Comparison

KS test

MgXI NeX NeIX OVIII OVII



Joint Fit with Pollock Model to ACIS S3, MOS1/2 & Joint Fit with Pollock Model to ACIS S3, MOS1/2 & pnpn

SAS 7.0, latest CCF

Many thanks

Steve !!

No fit, adopt

Pollock

RGS model

Brems kT = 0.36

keV

CCD spectra prefer

a harder continuum

NH=5.36e20

Line Es and

widths frozen,

Norms free



Joint Fit with Pollock Model to ACIS S3, MOS1/2 & Joint Fit with Pollock Model to ACIS S3, MOS1/2 & pnpn

Fit, Brems

kT =0.60 keV

NH=5.36e20

Line Es &

widths

frozen,

norms free



Individual Fit with Pollock Model to ACIS S3Individual Fit with Pollock Model to ACIS S3

Fit, Brems

kT =0.60 keV

NH=5.36e20

Line Es &

widths

frozen,

norms free



Individual Fit with Pollock Model toIndividual Fit with Pollock Model to MOS1MOS1

Fit, Brems

kT =0.60 keV

NH=5.36e20

Line Es &

widths

frozen,

norms free



Individual Fit with Pollock Model toIndividual Fit with Pollock Model to MOS1: MOS1: Ne Ne lines freelines free

Fit, Brems

kT =0.65 keV

NH=5.36e20

Ne Line Es

free,

widths

frozen,

norms free



Individual Fit with Pollock Model to Individual Fit with Pollock Model to pnpn

Fit, Brems

kT =0.40 keV

NH=5.36e20

Line Es

frozen,

widths

frozen,

norms free



Where Do We Go From Here ?Where Do We Go From Here ?

• Dewey analysis needs to be updated with latest response files for

HRMA/ACIS/HETG

• Line-based analysis needs to be updated with the latest response

files for HRMA/HETG/ACIS

• RGS data need to be re-analyzed with new background model for

RGS

• RGS and HETG teams agree on a model well before the IACHEC

meeting in California

• ACIS, MOS, and pn use the new model to fit the CCD spectra



LetLet’’s Agree on a Model !!!!!!!s Agree on a Model !!!!!!!

Purpose: to improve the low-energy response model of ACIS, MOS

and pn CCD instruments

1) RGS and HETG agree on flux of bright lines

2) RGS and HETG compromise on existence of weak lines

3) RGS and HETG agree on widths for the lines

4) Select a continuum model and absorption

5) HETG team must analyze second epoch observations of E0102

6) Fit ACIS, MOS, and pn with the same model

1. ACIS Calibration: Recent Updates, Planned Updates ... · E0102: Gratuitous Pretty Pictures of...

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