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              ELECTRONIC NEWSLETTER OF THE EUVE OBSERVATORY
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Vol. 8, No. 2             11 October 1999                  ISSN 1065-3597
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          (C) 1999, Regents of the University of California
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Notes from the Editor
=====================
   by Jennifer Cullison, EUVE Project Specialist

   Welcome to the electronic newsletter for NASA's Extreme Ultraviolet
Explorer (EUVE) satellite, compiled and published quarterly 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 Satellite Mission Operations News
    1.1 Operations Highlights
    1.2 Observation Log
 2. EUVE Science News
    2.1 Science Highlights
    2.2 Proposal Deadline extended: 18 October for EUVE Cycle 8
    2.3	EUVE Science Advisory Board (ESAB) Public Meeting Planned
    2.4 Recent EUVE Director's Discretionary Time (DDT) Observations
    2.5 Recent EUVE Calibration Observations
    2.6 Recent EUVE Data Releases
    2.7 EUVE Publications: July - September 1999
        
To comment on or make suggestions for the EUVE electronic newsletter,
please send e-mail to ceanews@cea.berkeley.edu (Internet).


1 EUVE Satellite Mission Operations News
========================================

1.1 Operations Highlights
-------------------------

EUVE operations highlights for the third quarter of 1999 are:

July:  EUVE's on-board telemetry monitoring modules (TMONs) were updated.
Flight Dynamics Facility (FDF) delivered the first-ever EUVE three day 
ephemeris product on July 6th; after simulator testing, EUVE destaffed
weekend operations.  Realtime operations at the EUVE Science Operations 
Center (ESOC) are now scheduled for single shifts on Monday, Wednesdays, 
and Fridays (i.e. no longer on Tuesdays, Thursdays, and weekends).
    
Details (including general notes and Y2K status) are available at:
http://www.cea.berkeley.edu/~pubinfo/html/EUVE_operations_high_opshigh.html


1.2 Observation Log
-------------------

EUVE observed 11 different targets for regular observations over the course of 
the third quarter of 1999 including ACO1795, 2EUVE J0138+253, EUVE J1636+528, 
Her X1, HD223816, PictorA, PKS0521-36, RX J0152-23, RX J0323-49, RX J16290+4007, 
and V772 Her.  Additional observations were made for an engineering survey to 
calibrate the star trackers and for the EUVE/Chadra cross-calibration 
(Capella and HR 1099).
 
Details and previous observation information are available at:
http://www.cea.berkeley.edu/~science/data/dynamic/exposures.html or
http://www.cea.berkeley.edu/~science/html/EUVE_call99_euvelog.html


2. EUVE Science News
====================

2.1 Science Highlights
----------------------

EUVE science highlights for the third quarter of 1999 are:

Sept/Oct: EUVE Observations of the Venus Dayglow

	  EUVE Observations of Ar UMa
	  
	  EUVE Spectroscopy Shows Iron in G191-B2B Atmosphere 
	  has a Depth-Dependent Abundance
	
July:  EUVE Observation of Her X-1 at the End of the Short High State
       Serendipitous Discovery of the AM Her star EUVE J0425.6-5714 

Details and previous months' highlights are available at:
http://www.cea.berkeley.edu/~science/html/Resources_high.html


2.2 Proposal Deadline extended: 18 October for EUVE Cycle 8
-----------------------------------------------------------

The EUVE project released a call for proposals on August 11, 1999.  
So far, the project has received 43 letters of intent - very near the number 
received last year.  

Letters of Intent are still being accepted, though the suggested deadline 
has passed (September 15).  Interested parties should submit e-mails to 
euveprop@cea.berkeley.edu informing the project of the PI's name and the 
appropriate category of EUVE science (Solar System Objects, Interstellar 
Medium, Compact Objects and Hot Stars, Cool Stars and Related Binaries, 
Cataclysmic Variables and Related Binaries, Extragalactic Objects, or Other).  

The proposal deadline was recently extended to October 18, 1999 (8 a.m. PDT).  
Further details can be found at 
http://www.cea.berkeley.edu/~science/html/EUVE_call99.html.


2.3  EUVE Science Advisory Board (ESAB) Public Meeting Planned
-----------------------------------------------------------------

The EUVE Science Advisory Board (ESAB) will be holding a public meeting on
the last day of the American Astronomical Society meeting in Atlanta, GA, 
Saturday, January 15, 2000, from 1-2 p.m.  ESAB members will discuss 
developments and future plans for the EUVE project.  Guest Observers and 
the general public are invited and encouraged to attend.
    
    
2.4 Recent EUVE Director's Discretionary Time (DDT) Observations
----------------------------------------------------------------

                                           estimated
                                            exposure  awarded   EUVE
Obs. Completed  PI              Target(s)       ksec    ksec   cycle
--------------  --              ---------       ----    ----   -----
Mar 24, 1999    Fruscione       NGC 4051         30      30        7
May 25, 1999    Starrfield      Nova Velorum      3       3        7
July 11, 1999   Bowyer          ACO 1795        152     160        7
TBD             Lisse           Comet           TBD     100        7

EUVE DDTs do not have proprietary rights.  Interested parties should be able
to download this data from 
http://www.cea.berkeley.edu/~science/html/Archive_pointed_order.html
(see "Recent EUVE Data Releases" below).


2.5 Recent EUVE Calibration Observations
----------------------------------------


		      est. exposure
Obs. Completed	Target         ksec         
 -------------	------ 	       ---- 
May 17, 1999 	HZ_43            82            
May 21, 1999 	GD_153            4            
June 16, 1999 	Sco_X-1          24
Sept 13, 1999   Capella         160

Here are summaries of the spring 1999 EUVE calabration results to date:

Deep Survey (DS) Imaging Instrument, by Dr. Brian Flynn
-------------------------------------------------------

The white dwarf GD153 was observed for 2 orbits with the DS lexan imager
on May 21, 1999. We report that the count rate measured from this
observation, 9.25 counts/sec, indicates no significant change in
sensitivity when compared with 4 previous DS lexan observations of GD153
dating back to 1993. The average count rate from all 5 observations was
9.39 counts/sec, with +/-12% variation about this mean.

Spectrometer, by Dr. Jean Dupuis
--------------------------------
We report on the degradation of the LW spectrometer response. A May
1999 observation of HZ 43 shows that the response has decreased by as
much as 60% below 340 Angstroms and up to 40% above 600 Angstroms.

It is difficult to establish with certainty how far back in time this
degradation happened. We know that the response was nominal in
February 1998 when we last observed GD 153, a hot white dwarf bright
in the LW spectrometer. Most likely, the degradation has formed
progressively until now. Fortunately, the most affected portion of the
spectrum is below 340 Angstroms which is overlapping with the MW.  So
we recommend using the MW for flux measurement.

We believe we will be able to restore most of the LW response by
resetting the lower level discriminator to a lower value. We therefore
do not recommend to take the current degradation into account in your
exposure time calculation for cycle 8.

Scanner and DS Imaging Filter X-Ray Leak, submitted by Mr. Martin Sirk
----------------------------------------------------------------------
There are several source types where knowledge of the EUVE X-ray
throughput is useful: super nova remnants, galaxy clusters,
cataclysmic variables, active galactic nuclei, and pulsars.  While the
response below 44 Ang was known previously to be low (Sirk et al,
1997), details in the effective area curves were lacking.  With this
current calibration the ratios of the effective area curves shortward
of 68 Ang are now well enough understood to provide the photometric
information required to distinguish between soft X-ray sources and EUV
sources.  Objects once simply classed as "probable X-ray leak" may now
be placed into one of three wavelength bins; 15 to 44 Ang, 44 to 68
Ang, or > 68 Ang (true EUV) by utilizing the effective area curve
ratios (provided the sources are observed by the scanners, or DS and
scanners, and the flux longward of 150 Ang is known a priori to be
negligible).

The effective area curve as a function of wavelength for each of the
EUVE Deep Survey (DS) and Scanner A and B passbands is the product of
the geometrical area of the entrance apertures, the reflectivity of
the gold plated mirrors, the transmissions of the thin foil filters,
and the quantum efficiency of each detector.  Absorption edges of C,
B, and Al (at approximately 44, 68 and 171 Ang, respectively) define
distinct boundaries of the passbands.  The edges of MgF2 and Ti (at
approximately 18 and 27 Ang) add additional structure.  Below 13 Ang,
the reflectivity of gold plummets to less than 0.001 its value at 100
Ang (at the 5 to 10 degree graze angles employed by EUVE).  Thus, EUVE
has no appreciable sensitivity to hard X-rays ( lambda < 13 Ang, or E
> 1 keV ).  However, in the soft X-ray region from 15 to 68 Ang, the
DS and Scanners show a small sensitivity at about 1 to 2 % of the peak
in-band levels.

Coming Soon
-----------
Scanner Imaging
Gain Sag Investigation
Dead Spot Investigation

These summaries as well as formal, detailed results of all of 1999 calibration 
studies will be posted on the web as they become available.  See
http://www.cea.berkeley.edu/~science/html/Resources_calibration99.html.

Calibration data has no proprietary rights.  Interested parties should be able
to download this data from permanent links at 
http://www.cea.berkeley.edu/~science/html/Archive_pointed_order.html
(see "Recent EUVE Data Releases" below).

Copies of Capella (and other AXAF cross calibrations) data are 
also temporarily available at ftp://ftp.cea.berkeley.edu/pub/axafcal/.


2.6 Recent EUVE Data Releases
-----------------------------

Following is a list of EUVE data sets released over the third quarter of 1999.

For releases prior to this see
http://www.cea.berkeley.edu/~science/html/Archive_pointed_newrelease.html

You may search for and download data sets from 
http://www.cea.berkeley.edu/~science/html/Archive_pointed_order.html
					

                             Exp.                  Type      Release
Object Name      Obs Date    (ks) Observer         Spec      Date
-----------      --------    ---- ------------   ------      --------
 
1ES 2254-37.1    Nov 20 1998   24 K. LEIGHLY         AGN      Jul 1 1999
2EUVE J1131 68.9 Nov 22 1998   29 K. LEIGHLY         AGN      Jul 1 1999
ACO 1795         Jan 3 1999    28 C. S. BOWYER       AGN      Jul 1 1999
ACO 1795         Jan 5 1999    29 C. S. BOWYER       AGN      Jul 1 1999
ACO 1795         May 31 1999   14 C. S. BOWYER       AGN      Jul 1 1999
ACO 4059         Nov 23 1998  122 R. LIEU            AGN      Jul 1 1999 
NGC 253          Oct 24 1998   48 R. J. DETTMAR      AGN      Jul 1 1999 
NGC 4051         Mar 8 1999    33 A. FRUSCIONE       AGN      Jul 1 1999 
NGC 4051         Mar 9 1999     3 A. FRUSCIONE       AGN      Jul 1 1999 
NGC 4051         Mar 10 1999    3 A. FRUSCIONE       AGN      Jul 1 1999
NGC 4051         Mar 11 1999    3 A. FRUSCIONE       AGN      Jul 1 1999 
NGC 4051         Mar 12 1999    3 A. FRUSCIONE       AGN      Jul 1 1999 
NGC 4051         Mar 13 1999    3 A. FRUSCIONE       AGN      Jul 1 1999
NGC 4051         Mar 21 1999    3 A. FRUSCIONE       AGN      Jul 1 1999 
NGC 4051         Mar 22 1999    3 A. FRUSCIONE       AGN      Jul 1 1999 
NGC 4051         Mar 23 1999    3 A. FRUSCIONE       AGN      Jul 1 1999 
NGC 4051         Mar 24 1999    3 A. FRUSCIONE       AGN      Jul 1 1999 
NGC 4051         Mar 24 1999    2 A. FRUSCIONE       AGN      Jul 1 1999
VW CEP           Oct 28 1998  158 A. K. DUPREE       K0VVAR   Jul 1 1999
VW CEP           Nov 15 1998   56 A. K. DUPREE       K0VVAR   Jul 1 1999
VW CEP           Nov 19 1998   17 A. K. DUPREE       K0VVAR   Jul 1 1999
3 UMA            Nov 30 1998   66 E. F. GUINAN       M2V      Aug 1 1999
3 UMA            Dec 5 1998   107 E. F. GUINAN       M2V      Aug 1 1999
2EUVE J0841+03.3 Dec 3 1998    32 B. WOLFF           NOID     Sep 1 1999
2EUVE J0841+03.3 Dec 26 1998   57 B. WOLFF           NOID     Sep 1 1999 
UZ FOR           Nov 19 1998   32 S. B. HOWELL       CV       Sep 1 1999
UZ FOR           Dec 22 1998   36 S. B. HOWELL       CV       Sep 1 1999 
UZ FOR           Jan 24 1999   35 S. B. HOWELL       CV       Sep 1 1999
COMA CLUSTER     Jan 12 1999   47 C. S. BOWYER       ClGal    Sep 30 1999
COMA CLUSTER     Feb 4 1999    57 C. S. BOWYER       ClGal    Sep 30 1999 
1136+1551        Dec 25 1998   16 C. S. BOWYER       PULS     Oct 1 1999
2EUVE J0425-57.2 Dec 15 1997   75 H. L. MARSHALL     AGN      Oct 1 1999
2EUVE J0425-57.2 Jan 3 1998   181 H. L. MARSHALL     AGN      Oct 1 1999 
ALGOL            Jan 14 1999  188 J. SCHMITT         B8V+K2IV Oct 1 1999


2.7 EUVE Publications: July - September 1999
--------------------------------------------

The full EUVE bibliography (1978 to present) is available at:
http://www.cea.berkeley.edu/~science/html/Resources_pubs_euvebib.html

Following is citation and abstract information for all known publications 
released over the third quarter (July through September) of 1999. 

Abstracts of these papers are available at the NASA Astrophysics Data System:
http://adswww.harvard.edu/abstract_service.html.

Late Type Stars
---------------
Extreme-Ultraviolet Explorer Observations of Hercules X-1 at the End of
the Short High State, D.A. Leahy and H. Marshall, ApJ Letters, 521, 
p. 328, August 1999.

An EUVE Observation of the Globular Cluster M15: The First Detection of a
Low-Mass X-Ray Binary? P.J. Callanan, J.J. Drake, and A. Fruscione, ApJ 
Letters, 521, p. 125, August 1999.


Observation of Quasi-Continuum Line Emission from FE VII to FE X in the
Extreme-Ultraviolet Region below 140 , P. Beiersdorfer, J.K. Lepson, 
G.V. Brown, S.B. Utter, S.M. Kahn, D.A. Liedahl, C.W. Mauche, ApJ Letters,
519, p. 185, July 1999.

White Dwarfs
------------
The EUV Spectrum of the Unique Bare Stellar Core H1504+65, K. Werner and 
B. Wolff, A&A Letters, 347, p.9, July 1999.


Cataclysmic Variables
---------------------
RXTE, ROSAT, EUVE, IUE, and Optical Observations through the 45 Day
Supercycle of V1159 Orionis, P. Skody, A. Linnell, K. Honeycutt, 
J. Robertson, A. Silber, D.W. Hoard, L. Pastwick, V. Desai, I. Hubeny, 
J. Cannizzo, W. Liller, R. Zissell, and G. Walker, ApJ Supplement, 
521, p. 262, August 1999.

Extragalactic
-------------
High- and Low-Energy Nonthermal X-Ray Emission from the Abell 2199 Cluster 
of Galaxies, J.S. Kaastra, R. Lieu, J.P.D. Mittaz, J.A.M. Bleeker, R. Mewe,
S. Colafrancesco, F.J. Lockman, ApJ Letters, 519, p. 119, July 1999.


--------------------------------------------------------------------------

  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 Investigator and Newsletter Publisher: Dr. Roger F.
  Malina.  EUVE Newsletter Editor: Jennifer Cullison.  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; Drs. Brian Flynn and Jean Dupuis, EUVE 
  Observatory Deputy Directors; Mr. Brett Stroozas, EUVE Project 
  Manager; 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