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ELECTRONIC NEWSLETTER OF THE EUVE OBSERVATORY
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Vol 4, No. 7 13 Jul 1994 ISSN 1065-3597
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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
(EUVE) satellite, which is compiled and published monthly by the EUVE Science
Archive group at the Center for EUV Astrophysics (CEA) in Berkeley, CA. The
EUVE observatory performed well throughout the month of June, completing
observations of the following Guest Observer (GO) targets: 3C273 (a Quasar),
Comet Mueller, Jupiter (prior to the comet impact event), LVC 88+36 (an HI
filament), SAO 188337 (a B star), SS Cyg (dwarf nova), V1974 Cyg (Nova Cyg
1992), VW Hyi (cataclysmic variable), and zeta Oph (an O star). EUVE also
conducted some engineering test of its star trackers.
The contents of this issue of the EUVE electronic newsletter are as follows:
1. EUVE Third Episode GO Proposal Deadline
2. The EUVE Comet Impact Event: Cosmic Collisions
3. Abstracts of Recently *Accepted* EUVE Papers
4. Notes from the EUVE Science Archive
4.1 GO Data Release List for August and September 1994
4.2 New Documentation and Services
4.3 Accessing the Archive
5. Job Listings at CEA
To comment on, make suggestions for, or request subscriptions to the EUVE
electronic newsletter, send e-mail to ceanews@cea.berkeley.edu (Internet).
1. EUVE Third Episode GO Proposal Deadline
==========================================
by Dr. Ron Oliversen, EUVE Deputy Project Scientist at GSFC
The EUVE 3rd Episode NASA Research Announcement (NRA) release date has been
delayed. We expect, according to our current best estimates, the EUVE NRA will
be released on 8 August with a GO proposal due date of 7 October. Note, this
would be a 60-day instead of the usual 90-day notice between date of release
and the proposal deadline. All NRA appendices will be available electronically
or via hardcopy at the time of the NRA release. Specific details will be
available in next month's newsletter.
2. The EUVE Comet Impact Event: Cosmic Collisions
==================================================
*******************************************************
U.C. Berkeley's
NASA Extreme Ultraviolet Explorer satellite project
and
the Exploratorium
present
-------------------------------------
C O S M I C C O L L I S I O N S :
A Celebration of the Impending Impact
of Comet Shoemaker-Levy 9 on Jupiter
-------------------------------------
Thursday, July 14, 1994
6:30 pm - 10:00 pm
Palace of Fine Arts Theater
San Francisco
*******************************************************
Join Professor Timothy Ferris & guest speakers:
*Dr. Marcia Neugebauer
Comet Specialist, NASA's Jet Propulsion Laboratory
*Dr. Jere Lipps
Director, University of California Museum of Paleontology
*Dr. Randy Gladstone
Planetary Scientist, Southwest Research Institute,
Extreme Ultraviolet Explorer Guest Observer
*Kevin Anderson
Science Fiction Writer,
author of the current New York Times Best Seller
"STAR WARS; Dark Apprentice, Volume 2 of the Jedi Academy Trilogy"
*Poul Anderson
Science Fiction Writer,
author of "Harvest of Stars" and winner of seven Hugo and
three Nebula Awards.
--------------------------------------------------------------
The evening will highlight the upcoming comet impact, other comet
collisions in the past, including the comet theory of dinosaur mass
extinction, plus the role of cosmic collisions in popular culture.
EXHIBITS AND BOOTHS - doors open at 6:30 p.m. Tentatively Scheduled
Participants to include:
* Center for Extreme Ultraviolet Astrophysics
* Exploratorium
* Another Change of Hobbit
* Bay Area Musician's Forum
* Hearts of Space Records
* The Nature Company
* Leonardo/International Society of Arts, Sciences, and Technology
* Wired magazine
* YLEM: Artists Using Science and Technology
TALKS begin promptly at 7:30 p.m.
*************************************************************************
Both Kevin Anderson and Poul Anderson will be available for BOOK SIGNINGS.
*************************************************************************
General Admission ........... $10.00
Exploratorium Members ....... $ 8.00
Thursday, July 14, 1994, 6:30 pm - 10:00 pm,
Palace of Fine Arts, San Francisco
For tickets and further information, please contact CITY BOX OFFICE
- (415) 392-4400
*******************
TICKETS NOW ON SALE
*******************
3. Abstracts of Recently *Accepted* EUVE Papers
===============================================
Included below are abstracts of EUVE-related papers recently *accepted*
for publication. 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.
For those papers authored by CEA scientists, the EUVE publication number is
indicated. Unless otherwise noted, researchers may obtain preprints of these
papers by sending an e-mail request along with the publication number(s) of
interest to pub@cea.berkeley.edu.
--------------------------------------------------------------
TWO-SAMPLE DISCRIMINATION OF POISSON MEANS
M. Lampton
To appear in The Astrophysical Journal [CEA publication #590]
This paper presents a statistical test for detecting significant differences
between two random count accumulations. The null hypothesis is that the two
samples share a common random arrival process with a mean count proportional
to each sample's exposure. The model represents the partition of N total
events into two counts, A and B, as a sequence of N independent Bernoulli
trials whose partition fraction, f, is determined by the ratio of the exposures
of A and B. The detection of a significant difference is claimed when the
background (null) hypothesis is rejected, which occurs when the observed sample
falls in a critical region of (A, B) space. The critical region depends on f
and the desired significance level, alpha. The model correctly takes into
account the fluctuations in both the signal and the background data, including
the important case of small numbers of counts in the signal, the background,
or both. The significance can be exactly determined from the cumulative
binomial distribution, which in turn can be inverted to determine the critical
A(B) or B(A) contour. This paper gives efficient implementations of these
tests, based on lookup tables. Applications include the detection of
clustering of astronomical objects, the detection of faint emission or
absorption lines in photon-limited spectroscopy, the detection of faint
emitters or absorbers in photon-limited imaging, and dosimetry.
--------------------------------------------------------------
SPECTROSCOPIC, ORBITAL AND PHYSICAL PROPERTIES OF THE BINARY FEIGE 24 AND
DETECTION OF TRANSIENT HEII ABSORPTION IN THE SYSTEM
S. Vennes and J.R. Thorstensen
To appear in The Astronomical Journal [CEA publication #591]
We have obtained new high-dispersion optical spectroscopy at Kitt Peak
National Observatory (KPNO) and new International Ultraviolet Explorer (IUE)
spectroscopy of the white dwarf + red dwarf binary system Feige 24 (P =
4.23160 d). The optical range shows a composite DA+dM spectrum, together
with HI Balmer and HeI emission. The orbital phase dependence of the emission
shows that it results from extreme ultraviolet (EUV) light reprocessing in
the red dwarf upper atmosphere. The system is close enough and hot enough
to show this reprocessing signature only recently emerged from common-envelope
evolution. The ultraviolet spectrum exclusively emanates from the white
dwarf, traced by ultraviolet FeV lines. Combining these measurements, we
refined the orbital parameters presented by Vennes et al. (1991), and we
confirmed that the white dwarf gravitational redshift is exceptionally small
with 9 +/- 2 km/s. From this we deduced that the interior is either pure
helium or carbon with a thick hydrogen layer (=1e-4 M_solar), and we derived,
for the combined interior compositions, a white dwarf mass and radius of
M_WD = 0.44-0.50 M_solar and R_WD = 0.028-0.036 R_solar. We suggest that
Feige 24 could be a typical case of close binary evolution leading to the
formation of a low-mass helium white dwarf. The mass of the red dwarf and
the inclination of the system naturally follow: M_dM = 0.26-0.33 M_solar,
i >= 75 deg. High-dispersion H_alpha line profiles are asymmetrical, strongly
enhanced toward the blue, suggesting a moving atmosphere possibly linked to
a mass loss rate of 1e-10 M_solar/yr. The IUE spectra taken when the system
is near inferior conjunction show strong HeII 1640 A absorption. The profile
is highly variable in width (maximum FWHM = 90 km/s) and intensity. Because
it is correlated with the passage of the white dwarf at inferior conjunction,
the absorption may occur in some foreground plasma emanated by the red dwarf
and accumulating near a Lagrangian point or, alternatively, it may originate
in an accretion spot on the white dwarf surface co-aligned with the major
orbital axis. Either way, the HeII detection may imply a substantial mass
loss from the red dwarf with a corollary reclassification of Feige 24 as a
mixed He/H DAO white dwarf resulting from accretion of secondary mass-loss
material. Feige 24 is the prototype of a secondary and a hot H-rich white
dwarf; the class is characterized by optical (4686 A) and ultraviolet (1640 A)
photospheric HeII absorption, circumstellar CIV 1550 A absorption, and by the
presence of EUV-induced, phase-dependent Balmer fluorescence. These young
systems present the best opportunity to constrain theory of common-envelope
evolution.
Subject Headings: stars: binaries -- late-type -- white dwarfs -- individual
(Feige 24) -- ultraviolet: stars
--------------------------------------------------------------
DISCOVERY OF A NEW WHITE DWARF IN A BINARY SYSTEM (EUVE 0720-317) IN THE
EXTREME ULTRAVIOLET EXPLORER SURVEY AND IMPLICATIONS FOR THE LATE STAGES
OF STELLAR EVOLUTION
S. Vennes and J.R. Thorstensen
To appear in The Astrophysical Journal Letters [CEA publication #592]
A new pre-cataclysmic binary is identified in th Extreme Ultraviolet
Explorer (EUVE) all-sky survey. The bright source EUVE 0720-317 shows a
hot hydrogen-rich white dwarf optical continuum with overlying narrow
Balmer-line emission. Using high signal-to-noise spectroscopy in the
4100-6700 A range we identify a late-type companion and find a 1.3 d
periodic modulation in the emission-line velocities and strengths. We
determine the components' spectral types (DAO and dM0-2), orbital velocities
(gamma = 15 +/- 12 km/s). A first estimate of the white dwarf gravitational
redshift, gamma_g = 45 +/- 20 km/s, and theoretical mass-radius relationships
imply R_DAO = 0.010-0.016 R_solar and M_DAO = 0.55-0.90 M_solar. The orbital
inclination is therefore i >= 52 deg, consistent with the large amplitude
variations found in H_alpha equivalent widths that imply i >= 42 deg. We
show that the discovery of new close WD+MS binary systems in EUV sky surveys
has important implications for theory of common-envelope evolution, in
particular for the predicted close binary birthrate and orbital and stellar
parameters.
Subject headings: stars: binaries -- late-type -- white dwarfs -- individual
(EUVE 0720-317) -- ultraviolet: stars
--------------------------------------------------------------
SERENDIPITOUS EUV SOURCES DETECTED DURING THE FIRST YEAR OF THE EXTREME
ULTRAVIOLET EXPLORER RIGHT ANGLE PROGRAM
K. McDonald, N. Craig, M.M. Sirk, J.J. Drake, A. Fruscione, J.V. Vallerga,
and R.F. Malina
To appear in The Astronomical Journal [CEA publication #593]
We report the detection of 114 extreme ultraviolet (EUV; 58-740 A) sources,
of which 99 are new serendipitous sources, based on observations made with the
imaging telescopes on board the Extreme Ultraviolet Explorer (EUVE) during the
Right Angle Program (RAP). These data were obtained using the survey scanners
and the Deep Survey instrument during the first year of the spectroscopic guest
observer phase of the mission, from January 1993 to January 1994. The data
set consists of 162 discrete pointings whose exposure times are typically two
orders of magnitude longer than the average exposure times during the EUVE
all-sky survey. Based on these results, we can expect that EUVE will
serendipitously detect approximately 100 new EUV sources per year, or about
one new EUV source per 10 square degrees, during the guest observer phase of
the EUVE mission. New EUV sources of note include one B star and three
extragalactic objects. The B star (HR 2875, EUVE J0729-38.7) is detected in
both the Lexan/B (~100 A) and Al/Ti/C (~200 A) bandpasses, and the detection
is shown not to be a result of UV leaks. We suggest that we are detecting
EUV and/or soft X-rays from a companion to the B star. Three sources, EUVE
J2132+10.1, EUVE J2343-14.9, and EUVE J2359-30.6 are identified as the active
galactic nuclei MKN 1513, MS2340.9-1511, and 1H2354-315, respectively.
--------------------------------------------------------------
4. Notes from the EUVE Science Archive
======================================
by Brett A. Stroozas, DASS/Archive Manager
4.1 GO Data Release List for August and September 1994
------------------------------------------------------
The table below lists the GO observations which become public on 1 August
and 1 September 1994. 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, an indication of which (if any) EUVE CD-ROM
on which the observation appears, and the data identification code. All public
data sets may be ordered from the archive via CEA electronic (e.g., "mailorder
go0001") or postal mail. Please be sure to include in your order the DataID(s)
of interest.
The data rights policy on GO observations states that the GO has 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 complete observation. An exception to the one-year rule occurs when the
target was designated for calibration purposes. At the discretion of the
EUVE Project Scientist, calibration observations may be released before the
expiration of the normal one-year period (usually by only a few months). In
the list below, calibration targets have been marked with a "*".
=====================================================================
Target ~Exp Observation Date(s) SpT CD-ROM DataID
Name (ksec) Start End
=====================================================================
Data Sets Available 1 Aug 1994:
ALTAIR 88 27 Jun 1993 - 30 Jun 1993 A7V ---- go0077
G191-B2B 25 7 Dec 1993 - 8 Dec 1993 WD ---- go0084 *
H1504+65 68 5 Dec 1993 - 7 Dec 1993 WD ---- go0085 *
MOON 4 5 Apr 1993 - 5 Apr 1993 SS ---- go0082
MOON 1 9 Apr 1993 - 9 Apr 1993 SS ---- go0083
NGC5548 75 26 Apr 1993 - 29 Apr 1993 AGN ---- go0078
NGC5548 75 29 Apr 1993 - 1 May 1993 AGN ---- go0079
NGC5548 75 1 May 1993 - 4 May 1993 AGN ---- go0080
NGC5548 65 12 May 1993 - 14 May 1993 AGN ---- go0081
Data Sets Available 1 Sep 1994:
HD149499_B 99 23 Jun 1993 - 27 Jun 1993 K0V ---- go0086
HD165341 86 2 Jul 1993 - 5 Jul 1993 K0V ---- go0087
HD223816 67 6 Aug 1993 - 8 Aug 1993 F5IV ---- go0091
HR8210 98 23 Jul 1993 - 27 Jul 1993 A8m ---- go0090
HS1234+4811 86 19 Feb 1993 - 22 Feb 1993 WD ---- go0053
MCT2331-4731 57 8 Aug 1993 - 10 Aug 1993 WD ---- go0089
MOON 2 30 Jun 1993 - 30 Jun 1993 SS ---- go0088
SS_CYG 187 17 Aug 1993 - 23 Aug 1993 A1pe ---- go0092
=====================================================================
4.2 New Documentation and Services
----------------------------------
The Archive is pleased to announce some newly released EUVE material. The
following are now available via the World Wide Web from the CEA Uniform
Resource Locator (URL; http://ftp.cea.berkeley.edu):
* The Archive "Home Page" has been completely revamped, providing users with
a much friendlier (and less wordy) graphical point-and-click interface.
* A spectral data browser has been implemented which allows users to browse
and retrieve EUVE 1-d FITS spectra (see the "Spectra" listing under "Data").
* New forms for ordering EUVE CD-ROMs and public full GO data sets are now
available. Archival researchers may simply fill out a form requesting the
DataID(s) of interest and these requests will be forwarded and processed
by the Archive group at CEA.
* Additional EUVE-related publications have been added on-line. The long-term
goal is to make available the complete EUVE bibliography. The Archive
is continuously hooking in published papers so that researchers may access
them -- text, figures and tables -- on-line (see the "EUVE Bibliography"
listing under "Documentation").
In addition, The First EUVE Source Catalog (FESC; Bowyer, et al. 1994) is
now available from the CEA node of NASA's Astrophysics Data System (ADS). This
catalog, called "euve_cat1" and listed under the "Data:Catalogs" menu in ADS,
contains the detected EUV sources from the all-sky and deep surveys (tables 1
and 2 from the FESC paper). For completeness, a supplemental catalog will soon
be available which contains those sources from the Bright Source List (Malina,
et al., 1994) which did not meet the more stringent detection criteria set
forth in the FESC.
4.3 Accessing the Archive
-------------------------
Listed below are the various methods for accessing EUVE archival material:
o CEA World Wide Web URL:
http://ftp.cea.berkeley.edu (Mosaic/lynx remotely)
telnet ftp.cea.berkeley.edu 200 (lynx locally at CEA)
o NASA's Astrophysics Data System (general and account information):
http://adswww.colorado.edu/adswww/adshomepg.html (Mosaic/lynx)
ads@cuads.colorado.edu
o CD-ROM Series: Volumes 1.1, 2.1, and 2.2 (seven separate CDs) 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
5. Job Listings at CEA
======================
by Cathie Jones, CEA Personnel Manager
CEA is currently accepting applications for the following job positions.
--------------------------------------------------------------
Postgraduate/Assistant Research (depending on experience)
University of California
Center for EUV Astrophysics
Attn: Cathie Jones (Personnel)
2150 Kittredge St.
Berkeley, CA 94720
The Extreme Ultraviolet Explorer (EUVE) Program at the Center for EUV
Astrophysics, of the University of California, Berkeley, has opening for a
Research Scientist. Successful applicant will support the acquisition, and
reduction of pointed data from the EUVE satellite. Duties will include
monitoring the progress of observation scheduling and data acquisition,
pipeline processing and data reductions and analysis. The researcher will
assist Guest Investigators, through the Guest Observer program and the EUVE
Archive program, in understanding the performance of the EUVE scientific
instruments as well as provide scientific advice regarding use of the EUVE
spectrometer analysis packages, written primarily in IRAF. Additional duties
will involve assisting in the development of complex data analysis algorithms
and models, to be made available to the Guest Investigator community in the
EUVE IRAF packages and EUVE public archive.
The work will be performed under the direction of the EUVE Science Support
Project Manager, and will interact with the associated science and programming
staff in the EUVE Public Archive and Guest Observer Center. A fraction of time
(10%) will be available to allow pursuit of independent research.
Applicants must have a Ph.D. in astronomy, physics, or a related field.
Experience supporting NASA Archival Research, Guest Observer, and Guest
Investigator programs required. Experience in satellite or ground-based
astronomical data analysis and the ability to carry out research in the field
of EUV astronomy is highly desirable. Experience with IRAF would be most
helpful.
Applications should include a curriculum vitae, bibliography and three
letters of recommendation and should be submitted by April 30, 1994. EOE/AAE.
--------------------------------------------------------------
Staff Research Associate I
University of California
Center for EUV Astrophysics
Attn: Cathie Jones (Personnel)
2150 Kittredge St.
Berkeley, CA 94720
The Center for EUV Astrophysics (CEA) seeks candidates for the position of
Staff Research Associate (SRA) I. The successful candidate will support the
Science Archive for the Extreme Ultraviolet Explorer (EUVE) Satellite
Project. The SRA will handle Archive correspondence (e.g. answering questions
and filling order requests for data), participate in the organization and
maintenance of the Archive FTP and Mosaic sites, assist in the processing and
analysis of EUVE data sets to support public data releases, participate in the
production of EUVE CD-ROMs, and assist with activities (e.g. database and
service development, testing and installation) for the CEA node of NASA's
Astrophysics Data System (ADS). Other duties include documentation of work
results and support of Archive publications.
Required qualifications include a background in Astronomy, Physics, or other
applicable science, demonstrated knowledge of general astronomical data
reduction techniques, experience using astronomical data analysis packages
(especially IRAF), experience with shell scripts (C or Bourne) and the UNIX
operating system, strong organizational skills and attention to detail, and
excellent verbal and written communication skills. Desired qualifications
include previous experience with ADS, an "operations-oriented" (versus
"research-oriented") work style, and experience programming in the C and/or
FORTRAN languages.
Applications should include a curriculum vitae and the names, addresses,
and phone numbers of three people whom we can contact for references.
The University of California is an Equal Opportunity Affirmative Action
Employer.
--------------------------------------------------------------
REFERENCES
Bowyer, S., et al., The First EUVE Source Catalog, Astrophysical Journal
Supplement, 1994 (in press)
Malina, R.F., et al., The Extreme Ultraviolet Explorer Bright Source List,
Astronomical Journal, 107(2), 751-764, 1994
---------------------------------------------------------------------------
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: Drs. R.F. Malina and C.S. Bowyer. EGO and Archive Science Manger:
C.A. Christian. Archive 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.
The GSFC Project Manager: Paul Pashby, Project Scientist: Dr. Yoji Kondo,
Deputy Project Scientist: Dr. Ronald Oliversen. NASA HQ Program Scientist:
Dr. Robert Stachnik, 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
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