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Current Status of the Blank Field Templates for the PN Timing Mode
Benjamin Muck1 Ё M. Guainazzi2 , E. Kendziorra1 , C. Tenzer
1

1

Institute for Astronomy and Astrophysics & Kepler Center for Astro and Particle Physics, University of Tubingen Ё 2 ESAC - ESA

EPIC - CAL 25th March 2014

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Outline

1

Why do we need a PN TM background template? How can we get a Blank Field? A gauge for the background Testing Summary and Outlook

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3

4

5

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Why do we need a PN TM background template?

Reminder: Background for PN TM Observations

Problems most counts in the central region also source photons at the border of the ccd no "blank" region to extract background

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Why do we need a PN TM background template?

Reminder: Background for PN TM Observations

Solution examine all observations performed in Timing Mode ( > 200 public available) check for "Blank Fields" ( 60 ) check if they are really blank

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How can we get a Blank Field?

Check if They are Really Blank
Blank Field check Count rate of 3 detector parts in 3 0.5 2.0 5.0 energy ranges: ­ 2.0 keV ­ 5.0 keV ­ 10.0 keV

compare the count rate ratios of the three regions get the expected ratio with help of the effective area

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How can we get a Blank Field?

Check if They are Really Blank
Blank Field check checked PI over RawX plots checked light curves for periodic signals checked light curves above 10 keV checked general spectral shape checked (if available) MOS data subtract contaminating sources no significant change (< 10%)

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A gauge for the background

We Need a Gauge for the Background

Idea check different parameters to find a gauge which Blank Field template we have to use independent measure for the background check for dependence of the blank fields on the parameters

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A gauge for the background

A gauge for the background ­ Galactic coordinates

3.5

3.5

Hardness Ratio Cts(4-8 keV)/Cts(1.5-2.5 keV)

3.0 2.5 2.0 1.5 1.0 0.5

Hardness Ratio Cts(4-8 keV)/Cts(1.5-2.5 keV)
-50 0 50

3.0 2.5 2.0 1.5 1.0 0.5 0

The galactic latitude

50

100

The galactic longitude

150

200

250

300

350

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A gauge for the background

A gauge for the background ­ Time
3.5

Hardness Ratio Cts(4-8 keV)/Cts(1.5-2.5 keV)

3.0 2.5 2.0 1.5 1.0 0.5 0.5

1.0

1.5

2.0

TIME in MDJ

2.5

3.0

3.5

4.0

4.5 1e8

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A gauge for the background

A gauge for the background ­ RGS Bkg count rate
3.5

Hardness Ratio Cts(4-8 keV)/Cts(1.5-2.5 keV)

3.0 2.5 2.0 1.5 1.0 0.5 0.0

0.2

0.4

RGS Bkg count rate
PN TM Blank Field

0.6

0.8

1.0

1.2

1.4

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A gauge for the background

The Blank Fields - RGS Dependence
the RGS background count rate is taken from the RGS CCD 9 the RGS Bkg CR is divided into 4 CR intervals [cts/s]: 0.03 ­ 0.05 0.05 ­ 0.07 0.07 ­ 0.20 0.20 ­ 0.40 Spectrum gets harder for higher RGS Bkg count rates

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A gauge for the background

The Blank Fields - RGS Dependence

the RGS background count rate is taken from the RGS CCD 9 the RGS Bkg CR is divided into 4 CR intervals [cts/s]: 0.03 ­ 0.05 0.05 ­ 0.07 0.07 ­ 0.20 0.20 ­ 0.40

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Testing

Testing

Two test samples weak sources MG highly obscured sources First Test only for two observations of the obscured sample a BF close in position or comparable RGS background count rate could be found no unique selection criterion

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Testing

Testing
Merged Blank Field Event List merged all blank fields in one event list select blank field according to the count rate in the 10­12 kev range Time-independent use average count rate of the observation CRsrc /2 < CR
bf

< 2 в CR

src

Time-dependent divide observation in 5000 s parts redefine count rate region CRsrc /3 < CR
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Testing

Testing

Blank field is normalized to the count rate in the 10­12 keV range

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Testing

Testing

Blank field is normalized to the count rate in the 12­15 keV range

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Summary and Outlook

Summary & Outlook
Summary scanned whole dataset of Timing Mode observations checked if they are really blank found source contamination and subtracted it created a merged blank field event list select blank field according to the count rate in the 10­12 keV range normalize to the 10­12 keV range or 12­15 keV range first tests look promising Outlook tests will be finalized at the ESAC script will be provided to the users
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