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ELECTRONIC NEWSLETTER OF THE EUVE OBSERVATORY
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Vol. 7, No. 8 31 August 1997 ISSN 1065-3597
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(C) 1997, Regents of the University of California
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Notes from the Editor
=====================
by Brett A. Stroozas, EUVE Mission/Flight Director
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 EUVE Science Program Management Changes
1.2 EUVE Detects ALEXIS "Bastille Day" Transient
1.3 Public GO/RAP Data Release for 1 Sep 1997
1.4 Abstracts of Recently *Accepted* EUVE Papers
2. EUVE Satellite Mission Operations News
2.1 Observation of P/Encke a Major Challenge
2.2 FOT Successfully Implements Payload ATCs
2.3 On-Line Access to EUVE
3. EUVE Outsourced Extended Mission Status Report
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 July
1997, completing and/or beginning observations of the following Guest
Observer (GO) and Right-Angle Program (RAP) targets. For each target
is listed its name, its spectral type (generally from the SIMBAD
database), the observation start day/time (day-of-year:hours:minutes),
name of Principal Investigator (PI), observation type/priority, and
any relevant notes:
=======================================================================
Target SpT GMT Start PI T Notes(*)
=======================================================================
RXJ 1856.5-3754 NeutSt 181:22:25 (30 Jun) Walter 1 EGO
AR Lac RSCVn 184:13:30 (03 Jul) White 1 EGO,CO1
P/Encke Comet 187:09:28 (06 Jul) Lisse 1 EGO,CO2,SCA,TCO
RXJ 1856.5-3754 NeutSt 190:00:28 (09 Jul) Walter 1 EGO
P/Encke Comet 190:09:56 (09 Jul) Lisse 1 EGO,CO2,SCA,TCO
RXJ 1856.5-3754 NeutSt 190:14:40 (09 Jul) Walter 1 EGO
P/Encke Comet 191:11:10 (10 Jul) Lisse 1 EGO,CO2,SCA,TCO
RXJ 1856.5-3754 NeutSt 191:15:54 (10 Jul) Walter 1 EGO
P/Encke Comet 192:10:49 (11 Jul) Lisse 1 EGO,CO2,SCA,TCO
RXJ 1856.5-3754 NeutSt 192:15:33 (11 Jul) Walter 1 EGO
P/Encke Comet 193:10:29 (12 Jul) Lisse 1 EGO,CO2,SCA,TCO
RXJ 1856.5-3754 NeutSt 193:15:13 (12 Jul) Walter 1 EGO
P/Encke Comet 194:10:09 (13 Jul) Lisse 1 EGO,CO2,SCA,TCO
RXJ 1856.5-3754 NeutSt 194:14:53 (13 Jul) Walter 1 EGO
P/Encke Comet 195:09:48 (14 Jul) Lisse 1 EGO,CO2,SCA,TCO
RXJ 1856.5-3754 NeutSt 195:14:32 (14 Jul) Walter 1 EGO
ALEXIS Trans NOID 195:17:47 (14 Jul) Bloch 1 EGO,TOO,MU3
RXJ 1856.5-3754 NeutSt 195:22:31 (14 Jul) Walter 1 EGO
P/Encke Comet 196:11:03 (15 Jul) Lisse 1 EGO,CO2,SCA,TCO
RXJ 1856.5-3754 NeutSt 196:14:53 (15 Jul) Walter 1 EGO
QS Tel CV:AM 197:01:20 (16 Jul) Rosen 1 EGO
EUVE J1759+428 NOID 197:01:20 (16 Jul) Lampton 3 RAP
RXJ 1856.5-3754 NeutSt 197:21:45 (16 Jul) Walter 1 EGO
P/Encke Comet 198:10:22 (17 Jul) Lisse 1 EGO,CO2,SCA,TCO
RXJ 1856.5-3754 NeutSt 198:15:05 (17 Jul) Walter 1 EGO
P/Encke Comet 199:10:02 (18 Jul) Lisse 1 EGO,CO2,SCA,TCO
RXJ 1856.5-3754 NeutSt 199:14:45 (18 Jul) Walter 1 EGO
P/Encke Comet 200:09:42 (19 Jul) Lisse 1 EGO,CO2,SCA,TCO
EUVE J2249+585 WD:DA 200:14:25 (19 Jul) Chayer 1 EGO,SPI
P/Encke Comet 201:09:22 (20 Jul) Lisse 1 EGO,CO2,SCA,TCO
EUVE J2249+585 WD:DA 201:14:05 (20 Jul) Chayer 1 EGO,SPI
Survey ENG 205:23:53 (24 Jul) ------ - CAL,CFG
Her X-1 LMXB 206:04:30 (25 Jul) Leahy 1 EGO,CON,MU8,TCO
EUVE J2041-368 NOID 206:04:30 (25 Jul) Dupuis 3 RAP
cmaIH2032-358 AGN 206:04:30 (25 Jul) Fruscione 3 RAP
EUVE J2249+585 WD:DA 210:12:43 (29 Jul) Chayer 1 EGO,SPI
lambda And RSCVn 211:07:30 (30 Jul) Dupree 1 EGO,CON
=======================================================================
(*) Key to Notes:
CAL = Science calibration observation
CFG = Special configuration of science payload instruments
CO1 = Observation coordinated with the Galileo satellite
CO2 = Observation coordinated with the ROSAT and XTE
satellites and with ground observatories
CON = Contiguous observation
EGO = EUVE Guest Observer observation
MU3 = Multiple pointings (3) required for this observation
MU8 = Multiple pointings (8) required for this "nodded" (up
and down) dithered observation
RAP = Right-Angle Program observation
SCA = Scanner imaging observation
SPI = Spiral-dithered observation
TCO = Time-critical observation
TOO = Target of Opportunity
1. EUVE Science News
====================
1.1 EUVE Science Program Management Changes
-------------------------------------------
by Dr. Roger Malina, EUVE Observatory Director
Along with the technical aspects of the outsourcing, the evolution
of the EUVE Project's science management structure has also progressed
over the last year. The EUVE Science Advisory Board (ESAB) is now
well established, and continues to review and refine science program
operations strategies through regular bi-monthly meetings. The
following are some of the recent highlights and/or changes:
o Annual ESAB Meeting at CEA -- The members of the ESAB will meet
with the EUVE Project at CEA on 1-2 October to review science
program operations and plans for the upcoming year. If you have
questions or issues that you would like to have discussed at this
meeting, please send them to the ESAB Chair, Professor Steve Howell
(University of WY; showell@kaya.uwyo.edu). The other members of
the ESAB are Dr. Andrea Dupree (Harvard Smithsonian Center for
Astrophysics), Dr. Jim Liebert (University of AZ), and Professor
Chris Mckee (University of CA, Berkeley).
o ESAB Charter -- A Charter for the ESAB has been written and is
available on the EUVE WWW site at:
http://www.cea.berkeley.edu/~science/html/sci_esab_esab.html
The Charter outlines the rules governing the functioning of the
ESAB (information on the ESAB members and how to contact them is
also available in an Appendix). The Charter contains various
policy guidelines that are used to govern operation of the EUVE
observatory, including the following: roles and responsibilities of
the EUVE Observatory Director (and his Deputy), conflict of
interest policies and procedures, observation selection parameters,
data rights, TOO policies, and GO and RAP policies and procedures.
o RAP Data Proprietary Period -- In order to streamline the
processing of RAP observations and to support rapid utilization of
the data, RAP observations conducted as of 15 March 1997 no longer
have any associated proprietary data period. CEA will, however,
continue to notify RAP PIs when their targets have been scheduled,
and to process and deliver to those PIs their associated RAP data.
o RAP Data Processing -- Processing of RAP observations since March
1997 continues to be delayed due to processing queue priorities
associated with the generation of the permanent EUVE archive. RAP
processing is expected to resume as soon as resources allow.
Observers with a critical need for their RAP data should contact
egoinfo@cea.berkeley.edu with a justified request for special
processing.
o TOO Bumping Priorities -- The EUVE program has established the
following "bumping priority" for TOOs in order to minimize their
impact on coordinated and time-critical observations (observation
categories are listed from highest priority and least likely to be
interrupted, to lowest priority and most likely to be interrupted):
1. Type 1 pre-approved TOO in progress
2. Director's Discretionary Time (DDT) TOO in progress
3. Type 1 coordinated observation
4. DDT coordinated observation
5. Type 2 coordinated observation
6. Type 1 time-critical observation
7. DDT time-critical observation
8. Type 1 contiguous observation
9. DDT contiguous observation
10. Type 1 ordinary observation
11. DDT ordinary observation
12. Type 2 time-critical observation
13. Type 2 contiguous observation
14. Type 2 ordinary observation
15. Calibration observation
16. Testbed experiment
17. Engineering test
1.2 EUVE Detects ALEXIS "Bastille Day" Transient
------------------------------------------------
by Brett A. Stroozas, EUVE Mission/Flight Director
Since its launch on 25 April 1993, the ALEXIS satellite has been
detecting transient EUV sources (see the ALEXIS WWW site at
http://nis-www.lanl.gov/nis-projects/alexis for the mission's
objectives and other related information). The rapid fall-off of the
intensity of these detections make these transients especially
interesting to scientists. Since early 1996, in support of an
approved EUVE GO proposal from the ALEXIS team, the EUVE Project has
carried out TOOs to ALEXIS transient detections; the ALEXIS team has
called five EUVE TOOs so far this year. Unfortunately, EUVE TOO
response has never been rapid enough to detect the ALEXIS transient.
This situation changed, however, on 14 July with the EUVE detection of
the so-called ALEXIS "Bastille Day" Transient.
During the observation of this transient on 14 July EUVE detected a
weak but highly significant source very near the ALEXIS source
position. Various sanity checks were conducted to verify that the
source was real. Everyone is very excited about this EUVE detection
and the nature of the underlying source. The ALEXIS team is currently
conducting follow-up analysis and additional ground-based
observations. Further information on the EUVE detection of this
transient is available on the WWW at
http://nis-www.lanl.gov/~ddupre/alexis/TOO_7-14-97.html
Rapid response time is critical in order to catch these transients
in action. EUVE's TOO response to the Bastille Day Transient was the
Project's fastest ever. At 8:38am Pacific time on that day the EUVE
Flight Operations Team (FOT) received preliminary notification of a
possible EUVE TOO opportunity from the ALEXIS team, who formally
called an EUVE TOO at 9:39am. By 10:30am the EUVE FOT had completed
all the necessary planning and scheduling activities, and had uploaded
the relevant information to the EUVE spacecraft. The observation of
the ALEXIS transient began just minutes later, at 10:47am. This rapid
TOO response -- 2 hours and nine minutes between the preliminary
notification to "first light" (and only one hour and eight minutes
after the TOO was formally called) -- was a new record for the EUVE
FOT.
Historically, the typical EUVE TOO response time was ~8 hours,
which is comparable with that of other satellites. Late last year CEA
worked with the pre-outsourced FOT at GSFC to cut EUVE TOO response in
half to ~4 hours (note that due to budgetary considerations TOOs are
restricted to the staffed day shift). Since completion of the
outsourcing and the integration of payload and spacecraft operations
at UCB, CEA has been able to further cut this response nearly in half
once again to the current average of ~2.5 hours. Although we know of
no published survey of satellite TOO response times, those of the EUVE
Project would surely be near -- if not at -- the top.
1.3 Public GO/RAP Data Release for 1 Sep 1997
---------------------------------------------
by Dr. Nahide Craig, EUVE User Support Scientist
The table below lists the GO/RAP observations that become public on
1 Sep 1997. For each observation is given the target name, the
approximate exposure time in ksec, the GMT start/end dates, the
target's spectral type, and the assigned data identification code (GO
and RAP data are marked accordingly). All public data sets can be
ordered from the EUVE Science 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 via postal
mail on 8mm tape or (if requested) on CD-ROM.
The data rights policies for observations state that Principal
Investigators (PIs) have proprietary rights to their data for a given
period of time 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 proprietary period begins after the PI is sent the final
piece of the completed observation; note that, per the new ESAB
policy, RAP targets observed as of 15 Mar 1997 do *not* have
associated proprietary periods. See the UCB/CEA WWW site (address
below) for a complete list of publicly available EUVE data products.
===============================================================
Target ~Exp GMT Observation Dates SpT DataID
Name (ksec) Start End
===============================================================
GO DATA SETS AVAILABLE 1 SEP 1997:
----- Cycle 4 Observations -----
EUVE J2206+63.7 25 08 Dec - 09 Dec 1996 NOID go0582
2EUVE J0908+32.6 25 09 Dec - 10 Dec 1996 NOID go0583
NGC 4051 80 11 Dec - 14 Dec 1996 AGN:Sy1 go0584
PC 0025+0447 17 22 Dec - 23 Dec 1996 M go0585
PC 0025+0447 63 25 Dec - 27 Dec 1996 M go0586
ACO 1795 106 03 Feb - 07 Feb 1997 ClGal go0587
HU Aqr 144 23 Oct - 28 Oct 1996 CV go0588
NGC 246 100 28 Oct - 31 Oct 1996 PlanNeb go0589
----- Cycle 3 Observations -----
QQ Vul 144 11 Aug - 16 Aug 1996 XRB go0590 **
QQ Vul 144 16 Aug - 21 Aug 1996 XRB go0591 **
** --> Scanner observation
RAP DATA SETS AVAILABLE 1 SEP 1997
EUVE J0249+099 25 09 Dec - 10 Dec 1996 NOID rap0124
EUVE J0642-046 82 23 Jan - 26 Jan 1997 NOID rap0125
CN Leo 110 26 Jan - 29 Jan 1997 M6V:e rap0126
================================================================
1.4 Abstracts of Recently *Accepted* EUVE Papers
------------------------------------------------
by Brett A. Stroozas, EUVE Mission/Flight Director
Included below are abstracts of EUVE-related papers recently
*accepted* for publication. For those papers authored by UCB/CEA
personnel, the UCB/CEA publication numbers are indicated. Unless
otherwise noted, researchers may obtain preprints of the UCB/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 and for
posting under the UCB/CEA/EUVE WWW site. Please send all abstracts to
archive@cea.berkeley.edu.
--------------------------------------------------------------
THE EUV TRANSIENT RE J1255+266
J.J.Drake, A. Fruscione, M.G. Hoare, and P. Callanan
To appear in Astrophysical Journal.
We report on the analysis of a deep Extreme Ultraviolet Explorer
(EUVE) observation made with the Deep Survey and Spectrometer
telescope which included in the field the remarkable bright extreme
ultraviolet (EUV) transient source RE J1255+266 discovered in 1994
June by the ROSAT Wide Field Camera (WFC). A careful analysis of the
resulting Deep Survey (DS) Lexan/B (67-178 A) image, whose aggregated
exposure time is 137 ks, has not revealed any trace of the source, but
has yielded a quite stringent formal upper limit on the quiescent EUVE
DS count rate of 0.003 count/s (3 sigma), and a "visual" upper limit
of 0.002 count/s. An analysis based on black body spectra, pure
hydrogen DA white dwarf models, and optically thin plasma model
spectra has provided constraints on the source counterpart. The
observed count rate upper limit is consistent with the optical
identification proposed by Watson et al. in which a DA white dwarf is
the primary component of a CV-like system involving a very low mass M
dwarf secondary star. Our upper limit to the EUVE DS count rate, when
compared with the count rate observed with the ROSAT WFC at the peak
of the outburst, implies a brightening of the EUV source flux relative
to quiescence by a factor >54000.
--------------------------------------------------------------
2. EUVE Satellite Mission Operations News
=========================================
by Brett A. Stroozas, EUVE Mission/Flight Director
The month of July was, once again, a very busy one for EUVE mission
operations. The Observatory conducted observations of twelve separate
targets -- eight GO and three RAP targets, and one engineering test.
These targets included an ALEXIS TOO (described above), coordinated
observations of AR Lac (with the Galileo satellite) and Comet P/Encke
(see below), and a "nodded" dithered multi-pointing observation of Her
X-1. The observation of Comet P/Encke posed a special challenge and
is discussed below. Another topic that warrants special discussion is
the (final!) successful implementation of payload absolute time
commands (ATCs).
2.1 Observation of P/Encke a Major Challenge
--------------------------------------------
During the period of 6-20 July the EUVE Observatory conducted
observations of the periodic comet P/Encke. The science goals of this
observation dictated that it be conducted with the scanning imaging
telescopes instead of the primary GO instrument, the deep/survey
spectrometer telescope. The observation was also time-critical, being
coordinated with the ROSAT and XTE satellites as well as with various
ground-based observatories. P/Encke, a moving target, required ~80
separate and individual pointings, and was conducted as one 3-day
continuous observation followed by brief monitoring observations (~3
orbits each) almost every day over the course of the subsequent two
weeks.
These various constraints, when interspersed and juggled with the
other observations conducted during this same time period, made this
observation a major challenge for the UCB FOT to plan, schedule, and
implement. The FOT, however, successfully pulled it off without any
major problems.
2.2 FOT Successfully Implements Payload ATCs
--------------------------------------------
In last month's newsletter (Vol. 7, No.7; Section 2.3) we discussed
the 26 June reset of the payload command, data, and power (CDP) unit,
which was the result of the on-board execution of a "bad" payload ATC
load; this, in turn, was a result of a bug in some ground software
that has since been patched. During the month of July the FOT used
this patched software to generate and remotely test payload ATC
execution using the Explorer Platform (EP) spacecraft simulator (with
its attached payload CDP) at GSFC. These tests were a qualified
success, although the simulator setup provided only limited visibility
into the flight EP/CDP interface.
To allow engineers to properly verify ATC execution, the FOT then
conducted a follow-on "operational test" that consisted of dumping the
payload RAM via ATC during a realtime contact with the satellite.
This test was a complete success. The FOT subsequently used payload
ATCs to reconfigure for the Her X-1 observation that started later
that day, and we plan to use them on an ongoing basis from now on.
This final successful implementation of payload ATCs is *long*
overdue -- literally by years! On multiple occasions in the past CEA
had attempted to implement payload ATCs. The major hurdle was always
the complications of implementing payload ATC software at CEA with the
relevant interfaces with the FOT and systems at GSFC. Since all
spacecraft operations are now conducted at UCB, there is no need for
such interface software and the problem was significantly simplified
-- a very valuable lesson learned!
2.3 On-Line Access to EUVE
--------------------------
Listed below are the various methods for on-line access to EUVE:
o UCB/CEA WWW URL: http://www.cea.berkeley.edu/
o anonymous FTP: ftp.cea.berkeley.edu
o EUVE Electronic Newsletters
Past issues -- available via the UCB/CEA WWW site
Subscriptions -- mail majordomo@cea.berkeley.edu ("subscribe
euvenews")
Post message (moderated) 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 UCB/CEA can help YOU! For more information see the
UCB/CEA WWW site or contact the EUVE Science Archive
(archive@cea.berkeley.edu).
o Public RAP
The Public 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 UCB/CEA WWW site (address below) 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. EUVE Outsourced Extended Mission Status Report
=================================================
by Brett Stroozas, EUVE Mission/Flight Director
Work continues to clean up the remaining open issues from the
outsourcing of EUVE Explorer Platform (EP) spacecraft operations from
GSFC to UCB/CEA. The following paragraphs describe some of the
outsourcing highlights from July 1997.
On 3 July UCB received from GSFC a new software release (v4.4a) for
the Transportable Payload Operations Control Center (TPOCC) that is
used to command and control the spacecraft. The FOT installed this
release on the backup TPOCC equipment "string" at CEA, and is
conducting full operational testing. In general, v4.4a is running
well; it includes a number of improvements over the previous release
(v4.3), the most notable one being a significant improvement (>5x) in
the speed of TPOCC's command processing. A number of minor issues and
a few major ones remain open. The UCB FOT and the GSFC TPOCC
development team continue to work together to resolve and test these
issues for the final GSFC-funded EUVE-specific TPOCC release (v4.4b)
that is scheduled for later this year. During the last year the
GSFC's development team has done an outstanding job in support of
TPOCC for UCB and the outsourced EUVE mission -- we owe them our
thanks!
Also, on 15 July UCB received from GSFC a new software release
(v5.1) for the Generic Trend Analysis System (GTAS). This system
works with TPOCC to provide a trend analysis tool for use by
spacecraft engineers. The FOT immediately installed the new GTAS
release and is using it in operations.
--------------------------------------------------------------------------
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. Roger F.
Malina and Professor Stuart Bowyer. EUVE Newsletter Editor: Brett
Stroozas. Funded by NASA/UCB Cooperative Agreement NCC5-138. Send
newsletter correspondence to ceanews@cea.berkeley.edu.
The EUVE project is managed for NASA by UCB: Dr. Roger F. Malina,
EUVE Observatory Director; Dr. John Vallerga, EUVE Observatory
Deputy Director; Dr. Mike Gunter, EUVE Project Manager; Mr. Brett
Stroozas, EUVE Mission/Flight Director; Mr. Rob Nevitt, EUVE
Operations Manager. NASA HQ: Dr. Guenter Riegler, Program Manager.
EUVE Science Advisory Board: Dr. Steve Howell (Chair).
END-----------EUVE------------ELECTRONIC---------------NEWS-------------END
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