Документ взят из кэша поисковой машины. Адрес оригинального документа : http://xmm.vilspa.esa.es/calibration/documentation/epic_cal_meetings/200904/marshall_ChandraEAandCrossCal.pdf
Дата изменения: Tue May 13 17:47:04 2014
Дата индексирования: Wed Apr 13 13:45:12 2016
Кодировка:
CHANDRA HRMA EFFECTIVE AREA
Herman L. Marshall (MIT CXC)


CHANDRA HRMA EFFECTIVE AREA
Herman L. Marshall (MIT CXC)


CHANDRA EFFECTIVE AREA ISSUES
HRMA overlayer (with L. David, D. Jerius, etc.)
First found using gratings due to Ir-M edge Also manifested at high energies Contradictory ground cal data delayed modeling effort A new model was picked in late 2008, now in caldb

ACIS contaminant (with A. Vikhlinin)
First found using gratings: spectral model Found to be variable using clusters: temporal model Tracked using ECS, spatial-spectral-temporal model in 2004 Now: temporal model wrong, ACIS-I ACIS-S

ACIS low E gain sag causes order sorting losses
Apr. 1, 2009
2

HLM-- Chandra Effective Area


HRMA AREA MODEL, REVISED
Motivation:
No overlayer during ground cal (XRCF) Grating XRCF data shows overlayer Cluster kT values disagreed with XMM pn and MOS

Pure overlayer models don't fit XRCF data 10 models tried None were perfect Few are very bad One picked: F
Apr. 1, 2009
3

HLM-- Chandra Effective Area


C O M PA R E T O X M M : FLUXES

Apr. 1, 2009

4

HLM-- Chandra Effective Area


C O M PA R E T O X M M : T E M P E R AT U R E S

Apr. 1, 2009

5

HLM-- Chandra Effective Area


C O M PA R E T O X M M : T E M P E R AT U R E S

Apr. 1, 2009

5

HLM-- Chandra Effective Area


C O M PA R E T O X M M : T E M P E R AT U R E S

Apr. 1, 2009

5

HLM-- Chandra Effective Area


R E L AT E D H E T G S ADJUSTMENT
HEG and MEG didn't agree Ratio depends on HRMA model Milder fixes for models d-g HEG/MEG =1 to < ± 3%
Apr. 1, 2009
6

HLM-- Chandra Effective Area


A C I S C O N TA M I N A N T: TWO PROBLEMS
Apparent increase in optical depth at 700 eV C-K edge measurements disagree worse than before

row 165

full-chip data

Apr. 1, 2009

7

HLM-- Chandra Effective Area


PROPOSED C O N TA M I N A N T M O D E L
Model excess opacity Two layers
elements (C, F, O, H) fluffium

Apr. 1, 2009

8

HLM-- Chandra Effective Area


SPECTRAL MODEL OF T H E O B F C O N TA M I N A N T
Elemental portion
Mostly C Fixed F:C, O:C, H:C Depth(t) is double exponential

Fluffium
Ad hoc spectrum Depth(t) is single exponential

Same spatial model
Apr. 1, 2009
9

HLM-- Chandra Effective Area


S PAT I A L R E A N A LY S I S
Optical depth is increasing, not asymptotic ACIS-I differs from ACIS-S Mn-L complex is weakening
Apr. 1, 2009 HLM-- Chandra Effective Area

readout

center

10


DECLINING MN-L&F-K

2000.2

2005.0

2007.5
Apr. 1, 2009
11

2009.0
HLM-- Chandra Effective Area


ACIS-I IS DIFFERENT
Preliminary results indicate asymptotic at center, increasing at edge Source is VERY weak

2000.2

2009.0 Apr. 1, 2009 HLM-- Chandra Effective Area

12


ANOTHER C O M P L I C AT I O N
PH selection is incomplete Results from gain errors May vary by observation

Apr. 1, 2009

13

HLM-- Chandra Effective Area


A C I S - S 1 G A I N V. E N E R G Y H A S O D D B E H AV I O R

Apr. 1, 2009

14

HLM-- Chandra Effective Area


A C I S - S 1 G A I N V. E N E R G Y H A S O D D B E H AV I O R

Apr. 1, 2009

14

HLM-- Chandra Effective Area


F L U X C O M PA R I S O N

(courtesy Michael Smith) Apr. 1, 2009
15

HLM-- Chandra Effective Area


F L U X C O M PA R I S O N

(courtesy Michael Smith) Apr. 1, 2009
15

HLM-- Chandra Effective Area


S U M M A RY
HRMA overlayer
A new model was picked in late 2008, now in caldb Corresponding changes to HETGS efficiencies released

ACIS contaminant
Work on spatial-temporal model continues Releasing a new model in April or May 2009

ACIS low E gain sag causes order sorting losses
Requires study

Comparisons to XMM still show systematic differences
Apr. 1, 2009
16

HLM-- Chandra Effective Area