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ELECTRONIC NEWSLETTER OF THE EUVE OBSERVATORY
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Vol 5, No. 7 19 Jul 1995 ISSN 1065-3597
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Notes from the Editor
=====================
by Brett A. Stroozas, ISO Manager
Welcome to the electronic newsletter for NASA's Extreme Ultraviolet
Explorer (EUVE) satellite, compiled and published monthly by the
Integrated/Intelligent Science Operations (ISO) group at the Center for
EUV Astrophysics (CEA) at the University of California, Berkeley (UCB).
The contents of this issue of the EUVE electronic newsletter are as
follows:
1. EUVE Science News
1.1 Recent Science Highlights
1.2 Release of Cycle 4 NRA
1.3 Abstracts of *Accepted* EUVE Papers
2. Science Operations News
2.1 Integrated/Intelligent Science Operations at CEA
2.2 User's Committee Meeting at GSFC
2.3 Deep Survey Detector Threshold Lowered
2.4 Spiral Dithering Test Results
2.5 Public Data Release for 1 Aug 1995
2.6 On-Line Access to EUVE
3. Educational Outreach Via SOL/SII
4. CEA Test-Bed Awarded CALSPACE Grant
To comment on or make suggestions for the EUVE electronic newsletter,
please send e-mail to ceanews@cea.berkeley.edu (Internet).
The EUVE observatory performed well throughout the month of June,
performing observations of the following guest observer (GO) targets
(alternate name and spectral type information taken from the SIMBAD
or internal CEA databases; "NOIDs" are unidentified objects):
===================================================================
Target Alternate Spectral Observation
Name Name Type GMT Date(s) Notes
===================================================================
Jupiter -------- SolSys 30 May - 06 Jun 1995 ---
HZ 43 WD 1314+293 DAw 06 Jun - 07 Jun 1995 TST
LoTr 5 -------- CSPN 07 Jun - 09 Jun 1995 ---
Moon -------- SolSys 09 Jun - 10 Jun 1995 ---
LoTr 5 -------- CSPN 10 Jun - 16 Jun 1995 ---
Moon -------- SolSys 16 Jun - 16 Jun 1995 ---
LoTr 5 -------- CSPN 16 Jun - 21 Jun 1995 ---
EUVE J1325-115 -------- NOID 21 Jun - 23 Jun 1995 ---
PKS 2005-489 QSO 2005-489 BL-Lac 21 Jun - 23 Jun 1995 RAP
EUVE J2311+006 -------- NOID 23 Jun - 24 Jun 1995 ---
1713+0747 -------- NeutSt 23 Jun - 24 Jun 1995 RAP
HZ Her Her X-1 LMXB 24 Jun - 28 Jun 1995 ---
EUVE_J2041-368 -------- NOID 24 Jun - 28 Jun 1995 RAP
cmaIH2032-358 -------- AGN 24 Jun - 28 Jun 1995 RAP
V818 Sco Sco X-1 LMXB 28 Jun - 30 Jun 1995 ---
EUVE_J2334-472 RE J2334-471 DA 28 Jun - 30 Jun 1995 RAP
EUVE J1533+337 -------- NOID 30 Jun - 30 Jun 1995 ---
EUVE J1201-365 PG 1159-034 DOZ0 30 Jun - 30 Jun 1995 ---
EUVE J1708-111 -------- NOID 30 Jun - 30 Jun 1995 ---
EUVE J1706-763 -------- NOID 30 Jun - 01 Jul 1995 ---
1932+1059 -------- NeutSt 30 Jun - 01 Jul 1995 RAP
===================================================================
Key to Notes:
TST = archimedes spiral "dithering" test
RAP = simultaneous Right Angle Program (RAP) imaging observation
1. EUVE Science News
====================
1.1 Recent Science Highlights
-----------------------------
by Dr. Antonella Fruscione, EUVE Scientist
Drs. K. Werner, S. Dreizler, U. Heber and T. Rauch from Kiel, Bamberg
(Germany) report their recent results in confining the edges of the GW Vir
instability strip.
o The so-called PG1159 stars (from the prototype PG1159-035 or GW Vir)
represent the hottest stage of post Asymptotic Giant Branch stellar
evolution. Surface temperatures reach up to 170000 K. The
photospheres are hydrogen-free and the stars essentially expose the
deep interior of their former Red Giant phase.
o Their evolutionary paths through the Hertzsprung-Russell diagram to the
hot end of the white dwarf cooling sequence leads them through an
instability region in which the stars are performing non-radial
pulsations. These objects hold the key for our understanding of
late stellar evolution because their interior is accessible to
asteroseismologic methods.
o A prerequisite for such investigations are reliable analyses of
photospheric parameters, particularly in order to find the exact
location of the instability strip. Combined campaigns of optical
observations and spectroscopy from space based telescopes (EUVE,
HST, ROSAT) were started for this project. The EUVE satellite turns
out to be particularly useful in determining the surface temperature.
The analysis of a spectrum of the non-pulsator PG1520+525 taken with
EUVE in comparison with HST data of the pulsating prototype
PG1159-035 (GW Vir) locates the blue edge of the instability strip
near T_eff = 140000 K for stars in the respective luminosity range.
1.2 Release of Cycle 4 NRA
--------------------------
by Dr. Ron Oliversen, EUVE Associate Project Scientist (GSFC)
The EUVE Project has released the NASA Research Announcement (NRA)
for the 4th episode Guest Observer Program. Proposals are being solicited
for observations during an 11-month period starting in February 1996.
Proposals are being accepted for using the EUVE spectrometer, the deep-survey
instrument, and the scanning telescopes. The deadline for receipt of
proposals is 6 Oct 1995.
Although the EUVE GO program remains largely unchanged from the 3rd
episode, there the following important modifications that affect the
preparation of the Cycle 4 proposals and how the Project carries out the
programs:
1. Time critical observations are not guaranteed to be observed on the
GO's requested schedule. The scheduling of such observations will
be more constrained than in previous episodes. The response time
for a Target of Opportunity (TOO) may also be affected.
2. The data proprietary period has decreased from 12 months to 6 months.
3. Large Research Programs are being encouraged and will be scheduled
through the end-of-mission (February 1996 to September 1997).
4. GO grant money is available at approximately half the level of support
for previous episodes.
5. No budget page or institutional signature are required to be submitted
at this stage. Once a proposal is accepted those items will be
requested.
The NRA and associated appendices may be obtained via anonymous file
transfer protocol (ftp) from ftp.cea.berkeley.edu (under the directory
/pub/nra95), or hard copies may be requested from the Project Science
Office at euve@stars.gsfc.nasa.gov. Additional information about this
NRA or EUVE may be obtained from Dr. Ron Oliversen, EUVE Associate Project
Scientist (oliversen@stars.gsfc.nasa.gov) or Damian Christian, EUVE
GO Support Scientist (egoinfo@cea.berkeley.edu).
1.3 Abstracts of *Accepted* EUVE Papers
---------------------------------------
Included below are abstracts of EUVE-related papers recently *accepted*
for publication. For those papers authored by CEA scientists, the EUVE
publication numbers are indicated. Unless otherwise noted, researchers may
obtain preprints of CEA papers by sending an e-mail request containing the
publication number(s) of interest to pub@cea.berkeley.edu.
Researchers are encouraged to contribute *accepted* EUVE-related abstracts
for inclusion in future editions of this newsletter; abstracts or preprints
will also be posted under the CEA WWW Home Page. Please send all abstracts
or preprints to archive@cea.berkeley.edu.
--------------------------------------------------------------
The Second EUVE Source Catalog
S. Bowyer, M. Lampton, J. Lewis, X. Wu, P. Jelinsky, R. Lieu,
and R.F. Malina
To appear in Astrophysical Journal Supplement. [CEA publication #649]
We present the Second Catalog of extreme ultraviolet objects
detected by the Extreme Ultraviolet Explorer (EUVE). The data
include (a) all-sky survey detections from the initial six-month
scanner survey phase, (b) additional scanner detections made
subsequently during specially programmed observations designed to
fill in low-exposure sky areas of the initial survey, (c) sources
detected with deep survey telescope observations along the ecliptic,
(d) objects detected by the scanner telescopes during targeted
spectroscopy observations, and (e) other observations. We adopt
an innovative source detection method that separates the usual
likelihood function into two parts: an intensity diagnostic and
a profile diagnostic. These diagnostics allow each candidate
detection to be tested separately for both the signal to noise ratio
and for conformance with the known instrumental point spread function.
We discuss the dependence of the false alarm rate and the survey
completeness on the survey sensitivity threshold. We provide three
lists of the EUV sources detected: the all-sky survey detections,
the deep survey detections, and sources detected during other phases
of the mission. Each list gives positions and intensities in each
waveband. The total number of objects listed is 734. For approximately
65% of these we also provide plausible optical, UV, radio, and/or X-ray
identifications.
--------------------------------------------------------------
Hot White Dwarfs in the Local Interstellar Medium: Hydrogen and Helium
Interstellar Column Densities and Stellar Effective Temperatures from
EUVE Spectroscopy
J. Dupuis, S. Vennes, S. Bowyer, A.K. Pradhan, and P. Thejll
To appear in Astrophysical Journal. [CEA publication #663]
We have obtained extreme ultraviolet (EUV) spectra of the hot DA white
dwarfs Feige 24, G191-B2B, MCT 0455-2812, HZ 43, GD 71, and GD 153 with the
Extreme Ultraviolet Explorer (EUVE) observatory. We use these stars as a
background against which to perform a study of the local interstellar medium
(LISM) absorption. We describe two important instrumental artifacts, fixed
pattern noise and overlapping spectral orders, and we develop a methodology
to explicitly remove these effects. Feige 24, G191-B2B, and MCT 0455-2812
exhibit a rich complex of heavy element transitions in their otherwise
hydrogen-rich photospheres (Z ~= 1E-5), while HZ 43, GD 71, and GD 153 are
consistent with hydrogen atmospheres with a low metallicity (Z <= 1E-7).
The photoionization edge of interstellar He I at 504 A is clearly detected
in the spectra of each of these white dwarfs. We have analyzed the EUV
continuum spectra of these stars with a grid of pure-hydrogen model atmospheres
and, in the case of Feige 24, G191-B2B, and MCT 0455-2812, with a grid of
models incorporating new opacities of C, N, O, and Fe from the Opacity Project.
We obtain new EUV-continuum based estimates of effective temperatures for our
sample stars and, for the three high-metallicity white dwarfs, we establish
the effects of heavy element blanketing on the EUV continuum of these objects
and on the determination of effective temperatures. We find that the ratio
of the neutral column densities of hydrogen and helium in the LISM is similar
(N_HI/H_HeI ~= 14) for five out of six stars in the sample but that Feige 24
may have a substantially different value. The Feige 24 results suggest that
the ionization state in the LISM is inhomogeneous. Our measurements favor a
higher degree of ionization of helium relative to hydrogen and also indicate
that hydrogen in the LISM is predominantly neutral in at least two lines of
sight.
--------------------------------------------------------------
2. Science Operations News
==========================
2.1 Integrated/Intelligent Science Operations at CEA
----------------------------------------------------
by Brett Stroozas, ISO Manager
In response to the reality of reduced operations budgets in the EUVE
Extended Mission, the recent CEA reorganization has produced the
Integrated/Intelligent Science Operations (ISO) group. ISO is responsible
for all aspects of EUVE science operations: observation proposal handling;
instrument health and safety monitoring and commanding; science observation
planning and scheduling; data processing, analysis, and delivery; and
general user support.
The ISO group was organized out of multiple existing independent groups
at CEA, the purpose being to unify and streamline existing EUVE science
operations into a single integrated and intelligent system. Integrated
because it merges the various once-independent operations -- both personnel
and software systems -- into a single cohesive and coordinated unit under a
common management that, due to its minimal structure, fosters communication
and cooperation. Intelligent because it is based upon innovative and
state-of-the-art science operations automation and streamlining techniques
(e.g., a heavy reliance on augmented intelligence software) that minimize the
need for human interaction and promote low-cost mission operations.
In addition to performing the various daily EUVE science operations
functions, ISO members actively work with the Information Systems
Development (ISD) and Test-Bed groups at CEA to investigate, test, and
implement new and innovative applications for the future benefit of EUVE,
for other missions, and for the general public through technology transfer
activities.
2.2 User's Committee Meeting at GSFC
------------------------------------
The EUVE User's Committee (UC), along with members of the EUVE Project
from CEA and GSFC, met at Goddard Space Flight Center (GSFC) on 7 June to
discuss the EUVE extended mission.
On the NASA end, Associate Project Scientist Dr. Ron Oliversen from GSFC
discussed UC personnel changes as well as the progress on the Cycle 4 NRA.
NASA Headquarters representative Dr. Jim Schombert then discussed the NASA
strategic plan and the concentration of its activities into five "strategic
enterprises" -- Mission to Planet Earth, Aeronautics, Human Exploration and
Development of Space, Space Science, and Space Technology. Mr. Hun Tann
from the GSFC Flight Operations Team (FOT) discussed the current spacecraft
status and activities, along with some of the FOT's future automation plans
and transition to single-shift operations. Finally, Mr. Peter Hughes
discussed the EUVE technology program and the flight test-bed for testing
and validating innovative or emerging technologies.
Brett Stroozas (ISO Manager) and Dr. Damian Christian (GO Support Scientist)
then discussed a variety of activities at CEA: an overview of the internal
reorganization, an introduction to ISO, a review of the many ISO activities
during the previous year, and a summary of ISO's future plans.
Last but not least, the UC provided valuable and detailed feedback regarding
the current on-line CEA WWW services and documentation. Many excellent
suggestions were made for adding additional, and reorganizing existing,
material so that CEA would better serve the research community. The UC also
suggested ways in which CEA could improve its communication and data delivery
mechanisms to provide better and faster customer service. Finally, all meeting
participants discussed potential long-term EUVE archive strategies.
Overall, the meeting was quite successful. It provided a forum for all the
relevant parties involved in science operations to personally discuss a wide
variety of issues. The meeting also provided CEA with valuable feedback on
its performance during the year in support of the research community. Many
suggestions were made -- and are being implemented -- for providing better
customer service.
The following table lists the current UC members. For each is given his/her
name, professional affiliation, major area of research, and e-mail address.
---------------------------------------------------------------------------
Member Affiliation Research Area e-mail Address
---------------------------------------------------------------------------
Holberg, Jay U AZ/LPL Chair/WD holberg@vega.lpl.arizona.edu
Brown, Alex U CO Cool Stars ab@echidna.colorado.edu
Bruhweiler, Fred Catholic U LISM/AGN bruhweiler@iue.gsfc.nasa.gov
Doschek, George NRL Sun doschek@11334.dnet.nasa.gov
Dupree, Andrea CfA Cool Stars dupree@cfa.harvard.edu
Hall, Doyle JHU Solar System dthall@pha.jhu.edu
Howell, Steve PSI Int Binary howell@frankenstein.psi.edu
Judge, Phil HAO/NCAR Cool Stars/Sun judge@hao.ucar.edu
Liebert, Jim U AZ WD liebert@as.arizona.edu
Polidan, Ron NASA/GSFC Tech/Int Binary polidan@aesop.gsfc.nasa.gov
Shipman, Harry U DE Education/WD harrys@strauss.udel.edu
---------------------------------------------------------------------------
2.3 Deep Survey Detector Threshold Lowered
------------------------------------------
by Anne Miller, EGO Center Technical Writer
[based on internal CEA memo JVV/EUVE/0053/95]
On 27 July 1995 the lower level data (LLD) threshold of the Deep Survey
detector was decreased from 30 to 20 engineering units in order to increase
detector efficiency in the Deep Survey dead spot [Ed: for more information on
the dead spot see past newsletters -- 3(15), Nov 1993; 4(2), Feb 1994; and
5(3), Mar 1995]. Decreasing the threshold increases efficiency by including
the low-pulse height events from the dead spot, which are above the new lower
threshold. However there is still a serious reduction in gain, by as much as
60%, in the center of the detector. Since events are now telemetered in WSZ
mode, low pulse height events can still be filtered from the data if desired.
2.4 Spiral Dithering Test Results
---------------------------------
by Jean Dupuis, EGO Program Scientist
and Marty Eckert, Engineering Data Analyst
On 6 June scientists began a 30 ksec observation of the hot white dwarf
HZ 43 in order to test a new dithering technique to eliminate the detector
fixed-pattern noise. This new technique, which uses an archimedes spiral
dithering pattern, may replace the current manual random dithering of EUVE
pointing.
During each night time orbit of the test, the spacecraft attitude was
allowed to drift through five complete revolutions of the spiral pattern,
which had an inner radius of 35 arcsec and an outer radius of 2 arc-min. The
signal-to-noise ratios of the resulting HZ 43 spectra were close to the values
expected from Poisson statistics: S/N = 28 vs. 28 for the short-wavelength
spectrometer (SW), 30 vs. 33 for the medium (MW), and 40 v. 48 for the long
(LW). In comparison, the non-dithered spectra of HZ 43 for a similar exposure
time were limited to S/N = ~20 for SW and ~10 for MW and LW. This initial
test of the spiral dithering demonstrates that this technique is effective at
removing the fixed pattern noise. Since it also eliminates the need for
repeated pointing of the instrument, it is expected that the spiral pattern
can be used to decrease the effort required to plan and schedule dithered
observations, while providing equivalent observing efficiency from the
Deep Survey/Spectrometer (DS/S) instruments.
2.5 Public Data Release for 1 Aug 1995
--------------------------------------
by Dr. Nahide Craig, EUVE Science Archive Scientist
The table below lists the GO observations which become public on 1 Aug
1995. For each entry is given the target name, the approximate exposure
time in kiloseconds, the GMT start and end date(s) for the observation, the
spectral type of the target, and the data identification code. All public
data sets may be ordered from the archive via WWW and electronic or postal
mail (see addresses below). Please be sure to include in your order the
DataID(s) of interest.
The data rights policy for GO observations states that GOs have
proprietary rights to the data for one year from the date (s)he receives
it. It is often the case that long observations are broken up over many
months; e.g., an observation approved for 60 ksec may actually be observed
for 10 ksec one month, 20 ksec the next and 30 ksec three months later. In
such cases the one-year proprietary period begins after the GO receives the
final piece of the completed observation.
===============================================================
Target ~Exp Observation Date(s) SpT DataID
Name (ksec) Start End
===============================================================
Data Sets Available 1 Aug 1995:
Mrk 279 196 22 Apr - 29 Apr 1994 AGN go0188
alpha Cen 70 03 Mar - 05 Mar 1995 G2V+K1V go0189 ***
===============================================================
*** = calibration observation
2.6 On-Line Access to EUVE
--------------------------
Listed below are the various methods for on-line access to EUVE:
o CEA World Wide Web (WWW)
open URL http://www.cea.berkeley.edu/
telnet www.cea.berkeley.edu 200 (for those without a WWW browser)
o anonymous FTP
ftp ftp.cea.berkeley.edu
Name: anonymous
Password: type_your_e-mail_address
o anonymous gopher
gopher ftp.cea.berkeley.edu
o EUVE Electronic Newsletters
Past issues -- available via the CEA WWW site
Subscriptions -- mail majordomo@cea.berkeley.edu ("subscribe euvenews")
Post message to all subscribers: mail euvenews@cea.berkeley.edu
o GI Program
Are you interested in finding out about or using EUVE data? Do you
need help in understanding EUVE data sets? Do you need help in using
the available EUVE data analysis software tools? If you answer "yes"
to any of the above, the Guest Investigator (GI) Program at CEA can
help YOU! For further information see the CEA WWW site or contact the
Archive (archive@cea.berkeley.edu).
o Public RAP
The Public Right Angle Program (RAP) is an easy method for researchers
to propose for long-exposure EUVE imaging data. For more information
on the Public RAP and the simple proposal process see the CEA WWW site
or contact the EGO Center (egoinfo@cea.berkeley.edu). Mail all
proposals to euverap@cea.berkeley.edu.
o Contact information for the EUVE Science Archive or GO Center:
Center for EUV Astrophysics
2150 Kittredge St.
Berkeley, CA 94720-5030
Archive EGO Center
510-642-3032 (voice) 510-643-8727 (voice)
510-643-5660 (fax) 510-643-5660 (fax)
archive@cea.berkeley.edu egoinfo@cea.berkeley.edu
3. Educational Outreach Via SOL/SII
===================================
by Robyn Battle, Education Assistant
The Science On-Line Program (SOL) is nearing completion. This program
joined the efforts of CEA, Lawrence Hall of Science, University of California
Museum of Paleontology, Exploratorium, Chicago's Adler Planetarium, and K-12
teachers for the purpose of creating on-line resources that respond to the
needs of 6-12th grade teachers and students. SOL teachers are currently in
the final stages of development on their on-line lessons. These lessons and
activities will be accessible through the Education/SOL section of the CEA
WWW HomePage (http://www.cea.berkeley.edu/).
A meeting was held at CEA to kick off the Science Information
Infrastructure (SII) Program. The SII is a NASA supported collaboration of
science research institutions, science centers, museums, and K-12 teachers.
The SII collaborators will be developing and testing on-line resource units
and classroom activities for K-12 during 1995-1996. These resources are
developed using the WWW and the Internet and will be accessible through the
Education/SII section of the CEA WWW HomePage. This year's SII members are
the following:
o Center for Extreme Ultraviolet Astrophysics
o Exploratorium
o Lawrence Hall of Science
o Smithsonian Astrophysical Observatory
o Boston Museum of Science
o Science Museum of Virginia
o New York Hall of Science
o NCSA and EOSAT
4. CEA Test-Bed Awarded CALSPACE Grant
======================================
by Tom Morgan, EUVE Test-bed Manager
The CEA proposal entitled "Autonomous Prediction for Failures in
Spacecraft: A Space Engineering Solution" was recently approved. The $12k
grant, which was offered through the California Space Institute Mini-Grant
Program (CALSPACE) for 1995-1996, will provide funding for undergraduate
Electrical Engineering and Computer Science students to experience applied
research in the fields of model-based reasoning and artificial intelligence.
Researchers at CEA and NASA's Jet Propulsion Laboratory will provide
mentorship to the students who will be constructing an operational rule-base
in the popular CLIPS environment. The project is characterized by hands-on
collection and trend analysis of EUVE engineering data. The trends are then
represented as rules that allow for automated analysis of EUVE engineering
performance. The specific focus of this project is failure prediction and
advance notification.
---------------------------------------------------------------------------
The EUVE Electronic Newsletter is issued by the Center for Extreme
Ultraviolet Astrophysics, University of California, Berkeley, CA 94720,
USA. The opinions expressed are those of the authors. EUVE Principal
Investigators and Newsletter Publishers: Dr. R.F. Malina and Professor
C.S. Bowyer. EUVE Science and Technology Manager: Dr. C.A. Christian.
ISO Manager and Newsletter Editor: B.A. Stroozas. Funded by NASA contracts
NAS5-30180 and NAS5-29298. Send newsletter correspondence to:
ceanews@cea.berkeley.edu. The EUVE project is managed by NASA's GSFC:
Paul Pashby, GSFC Project Manager; Dr. Yoji Kondo, Project Scientist;
Dr. Ronald Oliversen, Deputy Project Scientist; Mr. Kevin Hartnett,
Project Operations Director. NASA HQ: Dr. Robert Stachnik, Program
Scientist; Dr. G. Riegler, Program Manager. Information on the EUVE
Guest Observer Program is available from: Dr. Y. Kondo, Mail Code 684,
GSFC, Greenbelt, MD 20771 at (301) 286-6247 or e-mail to
euve@stars.span.nasa.gov.
END-----------EUVE------------ELECTRONIC---------------NEWS-------------END
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