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             |              CCC  XX   XX    OOO           |
Chandra      |             CC     XX XX    OO OO          | CXC
Electronic   |            CC       XXX    OO   OO         | Number 15
Bulletin     |             CC     XX XX    OO OO          | August
             |              CCC  XX   XX    OOO           | 2002
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Welcome to the Chandra X-ray Center's Electronic News Bulletin Number 15.

CXC Web site: cxc.harvard.edu

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to let us know.  

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Contents:

1. ACIS  Low Energy QE Degradation 

2. First Annual CHANDRA Calibration Workshop 


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Item 1.  ACIS  Low Energy QE Degradation
========================================


Analysis of ACIS Data Affected by the Low Energy QE Degradation

This memo is an update to the report of April 5, 2002 concerning the 
reduction in the ACIS low energy QE.  We summarize the results 
of our investigation into this problem and provide observers with advice 
and new tools to use in their spectral analysis of ACIS data. These provide a
significant improvement in the spectral analysis below 1 keV. The results 
presented here represent the combined efforts of many groups, including, 
the CXC, the IPI teams at PSU and MIT, and Project Science at MSFC. 


http://cxc.harvard.edu/cal/Acis/Cal_prods/qeDeg/index.html

Software to correct for this change in QE is available in
CIAO/Sherpa: http://cxc.harvard.edu/ciao/threads/sherpa_acisabs/
and from the Contributed Software page:
http://asc.harvard.edu/cont-soft/software/ACISABS.1.1.html 


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Item 2. First Annual CHANDRA Calibration Workshop
=================================================


Pileup...CTI...combined with a general rarity of photons... but who
said that X-ray astronomy was going to be easy? With the launch of the
recent generation of X-ray telescopes, we are starting to have
resolution- spatially and spectroscopically- that rivals optical
data. This waveband also affords the possibility of directly studying
some of the most energetic phenomema in the Universe.

As a consequence understanding the performance of the detectors is of
crucial importance. Subtle features of the calibration may mask or
distort important astrophysical phenomena. So please join us at the
first annual CHANDRA Calibration Workshop. Members of the CHANDRA
Science Center Calibration team will be on hand to present their
latest and greatest efforts to characterize the performance of
Advanced CCD Imaging Spectrometer (ACIS), the High Resolution Camera
(HRC), and the Low and High Energy Transmission Gratings (LETG and
HETG). 

The workshop is intended to enhance the diffusion of knowledge about
the performance of the instruments, as well as to encourage the entire
community to contribute to the performance models. There will be poster
presentations, round table discussions as well as sessions of talks
that the community is invited to actively participate in. 

In conjunction with the calibration workshop, the CIAO team is
planning to organize two one-day CIAO tutorials (the day before and
the day after the workshop) intended for intermediate/expert users.
Depending on participant interests and feedback, one or two specific
advanced topics will be discussed in the morning with a hands-on
session following in the afternoon. Participants will be able to work
on either their own or sample CHANDRA data with the presence and
support of members from the CIAO team. Participation is will be
limited (on a firt-come first-served basis) to 24 people per session.

When: The Calibration Workshop will be held on November 6th and 7th,
with the one day CIAO expert tutorials to be held on the 5th and 8th.

Where: The meeting will be held near the CHANDRA OCC, at 1 Hampshire
Street, in close proximity to Harvard-SAO and MIT, and downtown Boston.

Our web page (http://asc.harvard.edu/ccw_02/) will be available in a few
days and will include registration forms and instructions for
submissions of abstracts.



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