EEEEEEEEEEE U U V V EEEEEEEEEEE
E U U V V E
E U U V V E
EEEEEEE U U V V EEEEEEE
E U U V V E
E U U V V E
EEEEEEEEEEE UUUUU V EEEEEEEEEEE
---------------------------------------------------------------------------
ELECTRONIC NEWSLETTER OF THE EUVE OBSERVATORY
---------------------------------------------------------------------------
Vol 4, No. 3 09 March 1994 ISSN 1065-3597
---------------------------------------------------------------------------
Notes from the Editor
=====================
by Brett A. Stroozas, Data Analysis Support Staff (DASS)
and Archive Manager
Welcome to the electronic newsletter for NASA's Extreme Ultraviolet
Explorer satellite (EUVE), which is compiled and published monthly by the
EUVE Public Science Archive group at the Center for EUV Astrophysics (CEA)
in Berkeley, CA. The EUVE observatory continued to perform extremely well
throughout the month of February, completing observations of the following
Guest Observer (GO) targets: PSR0437-37, DK UMa, Vela, PG1520+525, Ca-
pella, sigma CrB, WD1057+719, and AG Dra.
The contents of this issue of the EUVE electronic newsletter are as
follows:
1. GO Data Releases
2. EUVE User's Committee Meeting Notes
3. Abstracts of Recently *Accepted* EUVE Papers
4. EUVE Session at the RAS/EAS94 Meeting
5. "Space News" Highlights EUVE Innovation in Science Operations
6. SOMOWG Meeting Notes
7. Notes from the EUVE Public Science Archive
8. "egi" Notes for GOs
9. CEA Job Listings
To comment on, make suggestions for, or request subscriptions to the EUVE
electronic newsletter, send e-mail to ceanews@cea.berkeley.edu (Internet).
1. GO Data Releases
===================
1.1 GO Data Rights to Expire Starting in April, 1994
----------------------------------------------------
by Dr. Harry Shipman, EUVE User's Committee Chairman
For at least a decade it has been an astronomical tradition that GOs
have proprietary rights to their data for a year after receiving it. The
first data tapes for the EUVE Guest Observer (EGO) program were distribu-
ted in April, 1993 and so these data will begin to become public in April,
1994. Once GO data rights expire, the EUVE Public Science Archive will
distribute data for those publicly available targets to anyone requesting
them.
As you may know, it is critical in the current funding climate to dem-
onstrate that missions like EUVE continue to be scientifically productive.
Some of us may have had contact with a more sedate, slower-paced astron-
omical world inhabited by gentlemen astronomers (they were almost all men
in those days), each having drawers and closets full of data from which
nuggets of insight would occasionally emerge. This era is past. Many
people who have a great deal to say about the future of space science in
general -- and EUVE in particular -- are beginning to ask for results.
And so I encourage you to continue to produce and publish good science
from EUVE -- there are a lot of great insights which are coming about and
the world needs to know about them.
1.2 Distribution of Archival GO Data Sets
-----------------------------------------
by Brett A. Stroozas, DASS/Archive Manager
As proprietary data rights begin to expire for GOs in April, the EUVE
Public Science Archive is working with the EGO Center to make the relevant
full data sets publicly available to the astronomical community. The ten-
tative plan is to release data sets on the first of the month following the
month in which the data was delivered to the GO (and a year later, of
course). The Archive group is currently working with the EGO Center and
with Deputy Project Scientist Dr. Ron Oliversen to define the schedule
for upcoming data releases, particularly those to go public within the next
few months. This list will be publicized soon (e.g. via the newsletter).
In order to receive EUVE archival GO data sets, interested parties will
be required to register their order with the Archive group in order to help
us track data distribution. The primary mechanism for registration and or-
der of data sets will be via Mosaic; order forms are currently under de-
velopment.
As a final reminder, thirteen full GO data sets have already been pub-
licly released. These observations are listed in the following table; the
Notes column indicates whether the observations are available on 8mm tape
(TAR format) and/or on CD-ROM (see section 6.1 below for ordering instruc-
tions):
Target Observation Exposure
Name Dates Time Notes
------------ -------------- -------- ---------
AT Mic 01-03 Jul 1992 ~39 ksec tape/cdrom1.1
AU Mic 14-17 Jul 1992 ~80 ksec tape
Capella 10-13 Dec 1992 ~80 ksec tape/cdrom2.1b
Feige 24 18-20 Nov 1992 ~58 ksec tape/cdrom2.1a
G191-B2B 13-15 Dec 1992 ~49 ksec tape/cdrom2.1a
HR1099 22-25 Oct 1992 ~79 ksec tape/cdrom2.1c
Moon 10 Dec 1992 ~1.7 ksec tape/cdrom2.1c
PKS2155-304 21-22 Jul 1992 ~35 ksec tape/cdrom2.1c
Procyon 11-15 Jan 1993 ~80 ksec tape/cdrom2.1b
RE1938-461 08-09 Jul 1992 ~39 ksec tape/cdrom2.1c
WD0549+158 10-11 Jan 1993 ~49 ksec tape/cdrom2.1a
WD1620-391 23-25 Jun 1992 ~39 ksec tape/cdrom2.1c
WD1845+019 28-29 Jun 1992 ~39 ksec tape/cdrom2.1a
2. EUVE User's Committee Meeting Notes
======================================
2.1 Next User's Committee Meeting
---------------------------------
by Anne Miller, EGO Technical Writer
The next meeting of the EUVE User's Committee will be held in early May
at NASA's Goddard Space Flight Center (GSFC). The User's Committee is the
liaison between the astronomical community and NASA. A well-focussed sci-
entific program with strong community support will be vital to any contin-
uation or extension of the EUVE mission. If you have input or would like
more information, please contact the User Committee Chairman, Dr. Harry
Shipman, at harrys@strauss.udel.edu (Tel: 302-831-2986) or Deputy Project
Scientist Dr. Ron Oliversen at oliversen@stars.span.nasa.gov (Tel:
301-286-6290).
2.2 Summary of EUVE User's Committee Meeting at Recent AAS
----------------------------------------------------------
by Dr. Harry Shipman, EUVE User's Committee Chairman
The EUVE project attracted considerable attention at the January, 1994
meeting of the American Astronomical Society (AAS) in Washington, D.C.
As you may recall, we presented our EUVE extended mission plans during a
lunch-time meeting for anyone interested. In retrospect, we scheduled a
meeting room which was far too small; crowds overflowed out into the hall
and beyond as hundreds of astronomers were eagerly interested in our plans!
EUVE users have presented over a dozen worthwhile candidate key projects
for an extended mission, and some choices will have to be made; if EUVE
were to do all of these key projects and nothing else, NASA would have to
keep the spacecraft operating for ten years! And at the moment, we do
visualize that a considerable part of an extended mission -- perhaps half
-- will be devoted to smaller GO science projects. The current GO program
has produced a large number of good results in the short time since its
inception, and I think that most of us don't want key projects to com-
pletely shut out GO science.
3. Abstracts of Recently *Accepted* EUVE Papers
===============================================
Included below are abstracts of EUVE-related papers recently *accepted*
for publication in refereed journals. GOs are encouraged to contribute
*accepted* abstracts for inclusion in future editions of this newsletter
and for posting under the EGO Center Mosaic "Home Page". All abstracts
should be sent to egoinfo@cea.berkeley.edu.
--------------------------------------------------------------
LIMITS ON THE HYDROGEN LAYER MASS AND CONSEQUENT HELIUM OPACITY IN HOT DA
WHITE DWARF ATMOSPHERES
M.A. Barstow (U of Leicester), J.B. Holberg (U of AZ) and D. Koester
(U at Kiel, FRG)
to be published in Monthly Notices of the Royal Astronomical Society
The results of the ROSAT sky survey of hot H-rich DA white dwarfs
demonstrated that, at temperatures above ~40,000 K, most stars contain
significant quantities of heavy elements in their atmospheres. Conversely,
below 40,000K most DA white dwarfs appear to have pure H envelopes with,
at most, only small traces of any other material. However, ROSAT was
unable to exclude a contribution from He to the total photospheric opacity
present in these stars. Consequently, the role of He in hot DA white
dwarfs remains uncertain. New spectroscopic observations made by the
Extreme Ultraviolet Explorer (EUVE) satellite promise to provide direct
evidence through a search for photospheric He absorption features. We
have analyzed four well exposed spectra from the EUVE public archive,
finding no evidence for any photospheric He. Using a grid of stratified
model atmospheres we are able to determine lower limits to the mass of
the outer H layer, which are significantly larger than those derived from
earlier broad band results.
--------------------------------------------------------------
THE DISTRIBUTION OF NEUTRAL HYDROGEN IN THE INTERSTELLAR MEDIUM.
I. THE DATA.
A. Fruscione, I. Hawkins, P. Jelinsky, and A. Wiercigroch (CEA)
to be published in The Astrophysical Journal Supplement Series
We compile, from the existing literature, the largest sample to date
(842 data points) of hydrogen column density measurements, N(HI), of the
gas in the interstellar medium. We include only results obtained from ab-
sorption measurements toward individual stars (594 in our sample), in an
effort to construct a three-dimensional picture of the interstellar gas.
We derive hydrogen column densities toward a fraction of the stars in the
sample from published column density measurements of metal ions. A three-
dimensional physical model derived from this data set will be presented in
a companion paper. The observed stars span distances from a few parsecs
to a few thousand parsecs, and more than half of the sample serves to de-
scribe the local interstellar medium within a few hundred parsecs of the
Sun. Hydrogen column densities range from 1e17-1e22 cm^(-2). We describe
here the various observational methods used to estimate the hydrogen col-
umn densities and present the table with the stellar and hydrogen column
density data. The provided table is intended as a global reference work,
not to introduce new results.
Subject headings: interstellar: abundances -- interstellar: matter --
astronomical databases -- catalogs
--------------------------------------------------------------
IONIZATION NEBULAE SURROUNDING SUPER-SOFT X-RAY SOURCES
S. Rappaport, E. Chiang (MIT), T. Kallman (NASA/GSFC), and R. Malina (CEA)
to be published in the Astrophysical Journal
In this work we carry out a theoretical investigation of a new type of
astrophysical gaseous nebula, viz, ionized regions surrounding super-soft
X-ray sources. Super-soft X-ray sources, many of which have characteristic
luminosities of 1e37-1e38 ergs/s and effective temperatures of ~4e5 K,
were first discovered with the Einstein Observatory. These sources have
now been shown to constitute a distinct class of X-ray source, and are be-
ing found in substantial numbers with ROSAT. We predict that these sources
should be surrounded by regions of ionized hydrogen and helium with proper-
ties that are distinct from other astrophysical gaseous nebulae. We pres-
ent calculations of the ionization structure and temperature profiles of
these ionization regions, as well as the expected optical line fluxes.
The ionization profiles for both hydrogen and helium exhibit substantially
more gradual transitions from the ionized to the unionized state than is
the case for conventional HII regions. The calculated optical line inten-
sities are presented as absolute fluxes from sources in the Large Magel-
lanic Cloud and as fractions of the central source luminosity. We find,
in particular, that [OIII] lambda-5008 and HeII lambda-4686 are especially
prominent in these ionization nebulae as compared to other astrophysical
nebulae. We propose that searches for super-soft X-rays via their charac-
teristic optical lines may reveal sources in regions where the soft X-rays
are nearly completely absorbed by the interstellar medium.
--------------------------------------------------------------
4. EUVE Session at the RAS/EAS94 Meeting
========================================
by Mihalis Mathioudakis, CEA Scientist
For those planning to attend the 1994 meeting of the Royal/European
Astronomical Society (RAS/EAS94) in Edinburgh, UK on 5-8 April 1994, you
should know that there will be a 1-hour session on EUVE. We will review
the most recent results from the mission and discuss future opportunities
available for GOs. The session is currently planned for Friday, 8th April
at 13:00; an abstract is available on request. For further details, please
contact:
Mihalis Mathioudakis mihalis@cea.berkeley.edu
Richard Lieu lieu@cea.berkeley.edu
5. "Space News" Highlights EUVE Innovation in Science Operations
================================================================
by Dr. Roger Malina, EUVE Principal Investigator
The 21-27 February issue of "Space News" carries an article (p. 10) by
Debra Werner titled "Artificial Intelligence Eyed to Cut the Cost of Satel-
lite Operations" which describes the efforts underway on EUVE. NASA Code C
has funded the first year of a multi-year program to introduce new software
technology into the EUVE Science Operations Center. This new software will
allow EUVE to move from 3-shift around-the-clock human-tended operations
to a single such shift with the other two being operated autonomously.
This will lead to a significant reduction in operations cost; the hope is
that these techniques will also lead to a corresponding reduction in the
spacecraft operations. A recent report from GSFC (directed by Ron Polidan)
outlines the plan to not only reduce EUVE operations costs significantly,
but to have EUVE serve as a test-bed for techniques that can be applied on
other missions.
6. SOMOWG Meeting Notes
=======================
by Dr. Carol Christian, EGO/Archive Science Manager & SOMOWG Chair
The SOMOWG, the scientific working group that oversees the Mission Op-
erations and Data Analysis aspect of the Astrophysics Division of NASA,
met on 27 January 1994 in Washington D.C. The highlights of the meeting
have been provided on the CEA Mosaic server and are accessible from the
CEA Home Page. Very soon, these notes will be offered through the NASA
Mosaic Home Page.
7. Notes from the EUVE Public Science Archive
=============================================
by Brett A. Stroozas, DASS/Archive Manager
7.1 Reminder on Ordering EUVE CD-ROMs
-------------------------------------
The EUVE Public Science Archive CD-ROM series has been established in
order to more easily distribute the large data sets generated with EUVE
(typically hundreds of megabytes). The initial EUVE CD-ROM -- Volume 1,
Number 1 (Drake, 1993) which was released at the June, 1993 AAS meeting in
Berkeley, CA -- includes a spectrometer observation of the Late-Type star
AT Mic. The second EUVE CD-ROM -- Volume 2, Number 1 A/B/C (Stroozas,
1994) -- was released at the January, 1994 AAS meeting in Washington, D.C.
This set of three CDs contains 11 selected spectrometer calibration obser-
vations, arranged thematically on the various discs: four White Dwarfs on
disc A, two Late-Type stars on disc B and five assorted targets on disc C.
EUVE CD-ROMS may be ordered by electronic or postal mail. To order by
e-mail, send a mail message to archive@cea.berkeley.edu with the words
"mailorder cdromX" (quotes omitted)
as the body of the message (the Subject line is ignored), where "X" is the
CD volume and number (the currently available allowed values for "X" are
"1.1", "2.1a", "2.1b", and "2.1c"). Multiple "mailorder" commands are
allowed in a single mail message. For example, to order both Volume 1,
Number 1 AND Volume 2, Number 1 -- disc A, send the following message:
mail archive@cea.berkeley.edu
Subject:
mailorder cdrom1.1
mailorder cdrom2.1a
In order to control costs and to make sure that requesting parties receive
only the data of interest, we require that each CD be ordered individually;
a request of "mailorder cdrom2.1" will not be processed but will require
that we contact you for further clarification. So, in order to speed up
CD deliveries, and to minimize efforts, please be specific in ordering in-
dividual CDs.
To order CDs via conventional postal mail, send your correspondence to
EUVE Science Archive
Center for EUV Astrophysics
2150 Kittredge Street
University of California
Berkeley, CA 94720
and include the Volume/Number for each CD requested. Again, please be spe-
cific as to which individual CDs you are requesting. All CD orders will be
sent out via postal mail and should arrive within one month (for domestic
orders; international orders will take longer).
7.2 Archive Moving from FTP to Mosaic
-------------------------------------
In order to make EUVE archival material more readily and easily availa-
ble, the Archive is moving all currently available material from the
anonymous ftp site into the Mosaic environment. For those unfamiliar
with this environment, Mosaic provides a very powerful and user-friendly
hyperlink-based interface for browsing, previewing and retrieving infor-
mation across the Internet. For those who currently have the Mosaic
software (available via anonymous ftp from ftp.ncsa.uiuc.edu), the EUVE
Archive may be accessed through the CEA Mosaic "Home Page" URL at
http://ftp.cea.berkeley.edu
Those without windowing capabilities may access this information using the
lynx software. For those having access to neither of these software pack-
ages on their systems, you may run lynx here locally by making a telnet
connection to CEA port #200 (telnet ftp.cea.berkeley.edu 200).
The Archive currently has the following information available on Mosaic:
o data -- survey catalogs (Malina, 1994; Bowyer, 1994) and images; 1-d
spectra
o software -- ISM, EGO Center software and reference data
o documentation -- Archive access information, past issues of this news-
letter, the special EUVE edition of the Journal of the British
Interplanetary Society (JBIS; a good source of general overview
articles), and the EUVE bibliography and papers
This is an on-going process; material is, and will continue to be, added
into the Archive as it becomes available.
7.3 Archive Access Information
------------------------------
Once again, listed below are the various methods for accessing EUVE
archival material:
o CEA WWW Server:
http://ftp.cea.berkeley.edu (Mosaic/lynx remotely)
telnet ftp.cea.berkeley.edu 200 (lynx locally at CEA)
o NASA's ADS: contact ads@cuads.colorado.edu for account information
o CD-ROM Series: Volumes 1 and 2 (four separate CDs) are available
o e-mail: archive@cea.berkeley.edu
(include word "help" -- quotes omitted -- as body of message)
o anonymous FTP (or gopher): ftp.cea.berkeley.edu
o EUVE Electronic Newsletters: ceanews@cea.berkeley.edu (to subscribe)
o Postal Mail:
The EUVE Public Science Archive
Center for EUV Astrophysics
2150 Kittredge St.
Berkeley, CA 94720
510-642-3032 (voice) or 510-643-5660 (fax)
archive@cea.berkeley.edu
8. "egi" Notes for GOs
======================
The following information, originally disseminated on the "egi" mailer
by the EGO Center, contain information useful for GOs (e.g. for data anal-
ysis). The sections included here briefly summarize the original postings
and serve as reminders to the GO community of important events that may
warrant their attention. Any questions or comments should be directed
to the EGO Center (egoinfo@cea.berkeley.edu).
8.1 EGOINFO Update
------------------
by Anne Miller, EGO Technical Writer
All mail to egoinfo@cea.berkeley.edu is now handled by EGO Center staff
and the previously advertised capability to send certain documents auto-
matically has been disabled. All documents are now available via ftp and
telnet at the site mentioned above. In addition, the auto-reply capability
of egoinfo has also been disabled, to avoid unnecessary repeated messages
between the EGO Center and other sites that auto-reply. We repeat that
egoinfo is still the correct address for all electronic questions and cor-
respondence with the EGO Center; staff members will direct your query
to the appropriate person. Users who wish to contact the Center by tele-
phone should call 510-643-5056; your call will be returned promptly.
8.2 Software Release
--------------------
by Anne Miller, EGO Technical Writer
The newest version of the EGO Center data reduction software, EUV1.4,
has been released and is available through the CEA anonymous ftp site in
the /pub/software/euv1.4 directory. The new version includes software
tasks to simulate the effect of interstellar medium (ISM) absorption on
source spectra, and input/output tasks for converting EUVE QPOE files into
FITS format. The software should be used with the recent reference data
release, EGODATA1.8.1, which incorporates the newest and most accurate
wavelength solutions yet available for the EUVE spectrometers; its use
results in more accurate line centers and better correction of spectral
curvature.
EGOCS1.4 has been used for data reduction at the EGO Center since mid-
January; the data on all tapes received by GOs in February have been pro-
cessed with the new wavelength solution. GOs who received their data prior
to this may want to obtain the new software and reference data, rerun the
event pipeline "cep" on their ST tables, and re-extract their spectra.
8.3 Sensitivity Loss at the Boresight Position in the DS
--------------------------------------------------------
by Kelley McDonald and Martin Sirk, DASS Staff Research Associates
On 18 February 1993 at 01:07:04 GMT the Deep Survey instrument (DS)
was pointed at the bright white dwarf HZ43. The intense EUV light from
this star caused a permanent loss in sensitivity at the DS boresight in
a roughly circular region 28 pixels (2.1 arc-minutes) across at FWHM. As
a result, centroid determinations of point sources are subject to system-
atic errors of up to 5 pixels (about 0.4 arc-minutes), and count rates
are affected by as much as 80%.
The problem is believed to be correctable and is being worked upon by
the DASS group at CEA. The current strategy involves building a "flat
field" to correct for the differential sensitivity across the affected
region. If and when a technique is developed, all GOs will be informed
and, if it's requested, given the necessary data to correct the problem.
9. CEA Job Listings
===================
by Cathie Jones, CEA Personnel Manager
Project Manager -- Center for EUV Astrophysics at UC Berkeley, NASA Extreme
Ultraviolet Explorer Project. Oversee all aspects of science operations,
data processing, computer systems and software development. A major focus
will be to implement innovative low cost approaches to science and mission
operations and manage collaborations for development and implementation of
innovative engineering test-beds. Qualifications: Advanced degree in
Physics and/or Astronomy or a related field; or an equivalent combination
of education and experience. Extensive experience with satellite projects
required. Experience with scientific analysis methods and knowledge of
software development preferred. Recent NASA program management experience
preferred. Send resume and names of three references by 31 March 1994,
Cathie Jones/Personnel, Center for EUV Astrophysics, 2150 Kittredge St.,
University of California, Berkeley, CA 94720. EEO/AA.
REFERENCES
==========
o Bowyer, et al., "The First EUVE Source Catalog", Astrophysical Journal
Supplement Series, 1994 (in press)
o Drake, et al., "The Extreme Ultraviolet Explorer Science Archive:
Selected Data and Software", Eds. S. Bowyer and R.F. Malina,
1:1 in the CD-ROM series (ISSN# 1069-7497), 1993
o JBIS, 46(9), September 1993
o Malina, et al., "The Extreme Ultraviolet Explorer Bright Source List",
Astronomical Journal, 1994 (in press)
o Stroozas, et al., "The Extreme Ultraviolet Explorer Science Archive:
Selected Data and Software", Eds. S. Bowyer and R.F. Malina,
2:1 in the CD-ROM series (ISSN# 1069-7497), 1994
---------------------------------------------------------------------------
The EUVE Electronic Newsletter is issued by the Center for Extreme Ultra-
violet Astrophysics, University of California, Berkeley, CA 94720, USA.
The opinions expressed are those of the authors. EUVE Principal Investi-
gators and Newsletter Publishers: Drs. R.F. Malina and C.S. Bowyer. EGO
and Archive Science Manger: C.A. Christian. Archive Manager and News-
letter 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. The GSFC Project Manager:
Paul Pashby, Project Scientist: Dr. Yoji Kondo, Deputy Project Scientist:
Dr. Ronald Oliversen. NASA HQ Program Scientist: Dr. Robert Stachnik,
Deputy Program Scientist: Dr. D. Buzasi, Program Manager: Dr. G. Riegler.
GSFC Project Operations Director: Mr. Kevin Hartnett. 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
[HomePage]
[Email]
[Search]
[Glossary]
Page created by webmastr@cea.berkeley.edu
Last modified 10/4/97