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ELECTRONIC NEWSLETTER OF THE EUVE OBSERVATORY
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Vol 6, No. 5 31 May 1996 ISSN 1065-3597
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(C) 1996, Regents of the University of California
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Sender: ceanews@cea.berkeley.edu
Precedence: bulk
Reply-To: ceanews-owner@cea.berkeley.edu
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
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 EUVE Science Highlights
1.2 Abstracts of Recently *Accepted* EUVE Papers
2. EUVE Science Operations News
2.1 Goals/Status for the "Outsourced" EUVE Mission
2.2 Public Data Release for 1 Jun 1996
2.3 On-Line Access to EUVE
3. SelMon Test-Bed Experiment to Begin at GSFC
To comment on or make suggestions for the EUVE electronic newsletter,
please send e-mail to archive@cea.berkeley.edu (Internet).
The EUVE observatory performed well throughout the month of Apr
1996, conducting 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
===================================================================
RE J1746-703 EUVE J1746-706 NOID 27 Mar - 05 Apr 1996 ---
3C 273 PKS 1226+02 QSO 27 Mar - 05 Apr 1996 RAP
1219+044 -------- AGN 27 Mar - 05 Apr 1996 RAP
1227+024 -------- AGN 27 Mar - 05 Apr 1996 RAP
EUVE J0729-388 -------- NOID 05 Apr - 11 Apr 1996 ---
ALEXIS Transient -------- NOID 11 Apr - 11 Apr 1996 TOO
EUVE J0729-388 -------- NOID 11 Apr - 14 Apr 1996 ---
Jupiter -------- SolSys 14 Apr - 17 Apr 1996 ---
Mkn 421 UGC 6132 BLLac 17 Apr - 30 Apr 1996 ---
EUVE J1429-38.0 -------- NOID 17 Apr - 30 Apr 1996 RAP
EUVE J1434-36.3 -------- NOID 17 Apr - 30 Apr 1996 RAP
V824 Ara HD 155555 K1Vp 30 Apr - 03 May 1996 ---
===================================================================
Key to Notes:
RAP = simultaneous Right Angle Program imaging observation
TOO = Target of Opportunity
1. EUVE Science News
====================
1.1 Recent EUVE Science Highlights
----------------------------------
by Dr. Pierre Chayer, EUVE/CEA Scientist
*** EUVE Observations of the Bright Comet B2 1996 (Hyakutake) ***
Comet B2 1996 (Hyakutake), first detected January 30th by Yuji
Hyakutake in Japan, was observed by EUVE from 21-25 Mar 1996. The
EUVE operations team successfully programmed the satellite to track
the fast-moving comet at the time of its nearest approach to the
Earth. Concurrent with the 82 ksec spectrometer observation, an image
of the comet was obtained with the Deep Survey imaging telescope using
the Lexan filter (70-190 A). If detected, spectral resonance lines of
helium and neon, which are only visible in the EUV spectrum, can
provide important clues to our understanding of the formation of
comets and of the solar system. These comet observations are being
analyzed by Dr. Michael Mumma.
1.2 Abstracts of Recently *Accepted* EUVE Papers
------------------------------------------------
Included below are abstracts of EUVE-related papers recently
*accepted* for publication. For those papers authored by CEA
personnel, the CEA publication numbers are indicated. Unless
otherwise noted, researchers may obtain preprints of the 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 CALIBRATION OF THE EUVE SPECTROMETERS, I. WAVELENGTH CALIBRATION
AND RESOLUTION
M. Abbott, W. Boyd, P. Jelinsky, C. Christian, A. Miller-Bagwell, M.
Lampton, R.F. Malina., and J.V. Vallerga
To appear in The Astrophysical Journal (Supplement). [CEA publication
#729]
We describe the wavelength calibration of the Extreme Ultraviolet
Explorer (EUVE) spectrometers and measurements of the spectrometers'
resolution. The three spectrometers operate in the wavelength range
from 70 to 760 A with a resolving power of ~300. We present the
equations required to map each detected photon to a wavelength and
imaging angle. The equations depend on the position of the source on
the sky, the orientation of the spacecraft when the photon arrives,
and the position on the EUVE detectors where the photon arrives.
These equations were determined using a ray-traced model of the EUVE
spectrometers along with measurements of emission lines and continua
obtained both in prelaunch laboratory calibration and from
observations of stellar sources while in orbit.
We describe the procedures used to apply the equations in this
paper to actual spectrometer data. We also discuss the implications
of the results of this calibration for the analysis of the spectral
images and suggest aperture sizes for spectral extraction.
With this calibration, we can remap detected photons with rms
errors of 0.22 resolution elements (0.11 A) in the short wavelength
(SW) spectrometer, 0.13 elements (0.13 A) in the medium wavelength
(MW) spectrometer, and 0.13 elements (0.25 A) in the long wavelength
(LW) spectrometer. The imaging angles for any one observation have
rms errors of 4.8" (1.1 pixel) in the SW spectrometer, 3.3" (0.7
pixel) in the MW spectrometer, and 2.9" (0.6 pixel) in the LW
spectrometer.
--------------------------------------------------------------
DISCOVERY OF A WHITE DWARF COMPANION (MS0354.6-3650 = EUVE J0356-366)
TO A G2V STAR
D.J. Christian, S. Vennes, J.R. Thorstensen, and M. Mathioudakis
To appear in The Astronomical Journal. [CEA publication #735]
We present X-ray, ultraviolet, and optical observations of the
mysterious EUV/soft X-ray source EUVE J0356-366 (= MS0354.6-3650).
Initial Einstein observations identified this source with a cluster of
galaxies, but the relatively high source count rate in the Extreme
Ultraviolet Explorer (EUVE) 100 A band and the lack of variability
hinted that EUVE J0356-366 might be a white dwarf; the UK Schmidt
plate of the field surrounding this object found a 12.45 magnitude G2V
star that could hide a compact companion. This hypothesis was
confirmed in an IUE ultraviolet spectrum that shows the definite
signature of a hydrogen-rich white dwarf (DA). A model atmosphere
analysis shows that the DA star is hot (T_eff >= 52,000 K) and may
have a low abundance of heavy elements. We show that the G2V star and
the DA star form a physical pair at a distance of 400 pc and therefore
add to the list of white dwarf plus luminous main sequence star
binaries discovered in EUV surveys.
--------------------------------------------------------------
AN EPHEMERIS FOR THE PRE-CATACLYSMIC BINARY EUVE J0720-317
S. Vennes and J.R. Thorstensen
To appear in The Astronomical Journal. [CEA publication #737]
We present H-alpha radial velocities and equivalent widths of the
hot white dwarf plus red dwarf binary EUVE J0720-317, which cover a
621 day baseline without cycle-count ambiguities and define an orbital
period of 1.26245 +/- 0.00004 d. The equivalent width variation lags
the radial velocity by 0.21 +/- 0.02, consistent with an expected
0.25-cycle offset if the emission arises entirely from reprocessing of
the white dwarf's EUV radiation in the red dwarf upper atmosphere.
Moreover, using our new ephemeris we show that photometric variations
reported in the literature are strictly in phase with the Balmer line
strength variations, providing further support for the
EUV-illumination model. We present revised estimates of the component
masses and discuss the binary evolutionary status.
--------------------------------------------------------------
EUVE PHOTOMETRIC ECLIPSE OBSERVATIONS OF AR LACERTAE
D. Christian, J.J. Drake, R.J. Patterer, P.W. Vedder, and S. Bowyer
To appear in The Astronomical Journal. [CEA publication #740]
We report on observations of the eclipsing RS CVn system AR Lac
with the Extreme Ultraviolet Explorer (EUVE) scanning and deep survey
(DS) telescopes. This system consists of a G2IV star and a K0IV star
separated by 9.2 R_solar with an orbital period of about 1.98 days.
The scanner observations consisted of a single pointing over a period
of 25 hours, providing some coverage of both primary and secondary
eclipses and subsequent scanning during the all-sky survey. During
the pointed observation AR Lac was detected in the EUVE Lexan/boron
(Lexan/B, 50-180 A) and Al/Ti/C (160-240 A) bands at average count
rates of 0.12 and 0.016 count/s, respectively. During primary
eclipse, the Lexan/B count rate was at about one-third of its
subsequent value at quadrature, suggesting that, in the case of a
compact and relatively homogeneous corona, a minimum of 60-70% of the
extreme ultraviolet (EUV) emission originates on the G star. There was
no detectable modulation corresponding to secondary eclipse in either
Lexan/B or Al/Ti/C bands. Data taken several months later during the
EUVE all-sky survey yield the same Lexan/B count rate as the pointed
data but only an upper limit in the Al/Ti/C bandpass. AR Lac was
observed again with the DS as part of a Guest Observer pointed
observation. This single pointing lasted slightly more than 3 days
and included both primary and secondary eclipses. AR Lac was detected
in the DS Lexan/B band with an average count rate of 0.31 count/s.
The primary eclipse is easily visible as a ~40% decrease in intensity.
A dip in the lightcurve is present at the time of secondary eclipse
but is not readily discernible from the average level of variability.
A flare corresponding to a factor of two increase over the quiescent
emission count rate was observed during the next expected secondary
eclipse. We have performed an elementary emission measure analysis
and compared isothermal models that fit the EUVE data to earlier
EINSTEIN, EXOSAT, ASCA and ROSAT two-temperature models culled from
the literature. In general, the EUVE data indicate very similar
emission measures to those derived in previous work, indicating that
the corona of AR Lac does not vary in average X-ray or EUV luminosity
over periods of years up to a decade. Assuming an isothermal model
with T ~ 1E+07 K, as indicated by the emission measure analysis, the
total Lexan/B count rate at quadrature implies an EUV luminosity of
1.1E+30 erg/s in the 50-180 A bandpass.
--------------------------------------------------------------
2. EUVE Science Operations News
===============================
2.1 Goals/Status for the "Outsourced" EUVE Mission
--------------------------------------------------
by Dr. Roger Malina, CEA Director
As reported in a previous edition of the newsletter, NASA has made
a decision to outsource operations of the EUVE satellite to CEA at
UCB. In making this decision, Dr. Wes Huntress situated it within the
NASA Zero-Base Review of 1995 that stated "the guideline to NASA
centers that outsourcing and commercial services shall be maximized".
Discussions with Dr. Joseph Rothenberg, Director of GSFC, confirms
that it is GSFC's plan to outsource operations of most small
satellites such as EUVE and that discussions are already under way on
outsourcing of other GSFC missions.
Subsequent to the outsourcing decision, the following specific
policy goals for the outsourcing were established by the EUVE Program
Manager, Dr. Guenter Riegler, in cooperation with Dr. Rothenberg and
UCB:
(1) EUVE mission operations should transition to a location at or
near the UCB campus in order to enable student participation and
to approximate the likely setting for future university-run
mission operations models.
(2) After transition of mission technical and operations knowledge
and establishment of a robust core operations capability, an
education component should be attached to EUVE mission operations
in order to foster science and engineering training and outreach.
(3) Technology innovation, testbedding, and dissemination shall
continue to be an important objective for the EUVE program. The
focal point at GSFC will continue to be Dr. Peter Hughes, who
will keep the UCB team informed of technology advancements within
NASA and will assist in disseminating technical and operations
developments generated within the EUVE team.
(4) After successful completion of the outsourcing transition,
leadership and responsibility for the continued operation of EUVE
shall transfer from NASA to UCB.
We are currently working to establish detailed plans to allow us to
meet these goals.
The UCB proposal to NASA for the EUVE outsourcing contemplates the
establishment of an EUVE Advisory Board that would oversee policy
aspects of the EUVE operations and ensure that the interests of the
user communities are being met in the operations of the EUVE mission.
This Advisory Board is in the process of being established.
The outsourcing schedule is a tight one, with the first phase of
transfer occurring on 16 Jul with a contract in place with an
Industrial Partner for the EUVE outsourced operations. During the
transition there may be small impacts on the EUVE science plan; guest
observers with any concerns about any impact on their science
observations should feel free to contact me at
rmalina@cea.berkeley.edu.
2.2 Public Data Release for 1 Jun 1996
--------------------------------------
by Dr. Nahide Craig, EUVE User Support Scientist
The table below lists the GO observations that become public on 1
Jun 1996. For each entry is given the target name, the approximate
exposure time in ksec, 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 can 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.
Processed data sets are shipped on 8mm tape (or, if requested, on
CD-ROM) via postal mail.
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 is sent the final piece of the completed
observation.
===============================================================
Target ~Exp Observation Date(s) SpT DataID
Name (ksec) Start End
===============================================================
Data Sets Available 1 Jun 1996:
VW Cep 100 30 Jan - 02 Feb 1995 K0Vvar go0293
VW Cep 41 02 Feb - 04 Feb 1995 K0Vvar go0294
kappa Cet 100 13 Oct - 17 Oct 1994 G5Vvar go0295
kappa Cet 41 17 Oct - 18 Oct 1994 G5Vvar go0296
EUVE J0715-704 100 09 Feb - 12 Feb 1995 DA go0297
EUVE J0715-704 1 12 Feb - 12 Feb 1995 DA go0298
DH Leo 100 12 Feb - 16 Feb 1995 K0V go0299
DH Leo 100 16 Feb - 19 Feb 1995 KOV go0300
DH Leo 21 19 Feb - 20 Feb 1995 KOV go0301
HZ 43 33 07 Feb - 09 Feb 1995 DAw go0302
Jupiter 56 07 May - 09 May 1994 SolSys go0303 *
Jupiter 82 19 Mar - 22 Mar 1995 SolSys go0304
AM Her 100 08 Mar - 12 Mar 1995 CV:AM go0305
AM Her 28 12 Mar - 13 Mar 1995 CV:AM go0306
GJ 411 100 22 Mar - 26 Mar 1995 M2V go0307
GJ 411 100 26 Mar - 29 Mar 1995 M2V go0308
GJ 411 100 29 Mar - 02 Apr 1995 M2V go0309
GJ 411 71 02 Apr - 04 Apr 1995 M2V go0310
alpha Col 89 05 Mar - 08 Mar 1995 B7IVe go0311
EUVE J1126+186 100 13 Mar - 16 Mar 1995 DAw go0312
EUVE J1126+186 81 16 Mar - 19 Mar 1995 DAw go0313
UZ For 90 18 Nov - 22 Nov 1993 CV:AM go0314
UZ For 107 15 Nov - 19 Nov 1995 CV:AM go0315
RE 1149+28 100 26 Dec 29 Dec 1994 CV:AM go0316
RE 1149+28 100 29 Dec - 02 Jan 1994 CV:AM go0317
RE 1149+28 33 02 Jan - 03 Jan 1995 CV:AM go0318
3c273 46 03 Jan - 06 Feb 1995 QSO go0319
* This Jupiter observation was conducted as a calibration/engineering
test.
===============================================================
2.3 On-Line Access to EUVE
--------------------------
Listed below are the various methods for on-line access to EUVE:
o CEA World Wide Web (WWW)
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_full_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 more information see the CEA
WWW site or contact the Archive (archive@cea.berkeley.edu).
o Public RAP
The Public Right Angle Program (RAP) is a simple and 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 EGO Center:
Center for EUV Astrophysics
2150 Kittredge St.
Berkeley, CA 94720-5030
510-642-3032 (voice)
510-643-5660 (fax)
archive@cea.berkeley.edu
egoinfo@cea.berkeley.edu
3. SelMon Test-Bed Experiment to Begin at GSFC
==============================================
by Tom Morgan, Applied Research Technology Manager
The Center for EUV Astrophysics shipped the Selective Monitor
(SelMon) workstation and software to the EUVE Control Center at GSFC
on 8 May 1996. The SelMon software application is being developed at
NASA's Jet Propulsion Laboratory (JPL) by Drs. Richard Doyle and
Dennis Decoste, both members of JPL's Artificial Intelligence group.
SelMon will be part of an experiment funded by NASA Headquarters
and the GSFC Flight Testbed for Innovative Mission Operations
(FTB-IMO). SelMon will be incorporated into the control center
architecture to receive real-time health and safety data from the EUVE
spacecraft.
Results from the SelMon experiment will indicate if satellite
health and safety monitoring and component trending can be performed
without traditional apriori construction of limits and thresholds.
SelMon is expected to monitor the health and safety of the satellite
more precisely than the traditional methods that use simple limit
checking. The SelMon application utilizes a "learning engine" and
historical health and safety data to characterize nominal component
behavior signatures. Significant deviations from nominal behavior
signatures will activate alarms and alert EUVE operators.
The SelMon application created for EUVE is being studied by other
NASA missions. The Hubble Space Telescope ground systems reengineering
team, Vision 2000, was given a demonstration of the EUVE SelMon
workstation in late May. The experiment will provide insight into the
potential for plug-and-play "black-box" learning systems to replace
traditional knowledge engineered rule bases.
---------------------------------------------------------------------------
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 S. Bowyer. Newsletter Editor: B.A. Stroozas. Funded
by NASA contract NAS5-29298. Send newsletter correspondence to
archive@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, Mission
Director. NASA HQ: Dr. G. Riegler, Program Manager. Information on
the EUVE GO 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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