A r A S N e w s
N E W S L E T T
E R OF THE
ARMENIAN
ASTRONOMICAL SOCIETY (
A r A S )
No.
9 (
Editor: T.Yu.Magakian, tigmag@sci.am
The ArAS Newsletter in the INTERNET: http://www.aras.am
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______________________________________________________________________________________
CONTENTS:
1) Administrative
changes in Byurakan
2) Announcement
about the
3) Announcement
about the
4) The Digitized
First Byurakan Survey (DFBS)
5) Contact
information
______________________________________________________________________________________
ADMINISTRATIVE CHANGES IN BYURAKAN
In October 2003,
the position of the Byurakan Astrophysical Observatory director was
announced vacant. Three candidates were nominated firstly to fill the vacancy
but Prof. Elma Parsamian and Prof. Arthur Nikoghossian refused their consent and only Dr. Haik Harutyunian agreed to be voted for the position.
However the elections did not happen till the mid February and the Presidium of
the Armenian National Academy of Sciences decided to appoint Dr. Harutyunian
to this position on February 20. He was requested to represent the new staff of
the academic council, which is done already. At present the package of
suggestions on the further development of the observatory is prepared to be
approved by the academic council and the Presidium of NAS. We are going to tell
Announcement about the
The ArAS III
Annual Meeting will be held on the last fortnight week of August this year
in Byurakan.
The Meeting will
cover all astronomical topics to allow the participation of all
interested scientists, including Solar, stellar and extragalactic astronomy,
theoretical astrophysics and astronomical instrumentation.
The Organizing
Committee includes H.Harutyunian, T.Magakian, A.Mickaelian, T.Movsessian,
and E.Nikoghossian.
Important! We
need to know beforehand if scientists from other than
To register,
please send your personal data and the title of your contribution to OC before June
30.
Contact: elena@bao.sci.am (Elena Nikoghossian)
______________________________________________________________________________________
Announcement about the
Nominations may
be made by
The deadline
for applications is December 1. A special committee will make the
selection and the results will be announced in the last issue of ArAS
Newsletter at the end of each year. A diploma and sum of $100
will be awarded to the winner.
ArAS Co-President
Prof. Yervant Terzian
is sponsoring the first ArAS Annual Prize for Young Scientists. There is a
suggestion to name the prize after B.E.Markarian.
There are plans
to establish an
______________________________________________________________________________________
The Digitized First Byurakan Survey (DFBS)
The Armenian
astronomers, as well as the whole astronomical community through Internet will
have the Digitized First Byurakan Survey (DFBS) very soon. This project
is being carried out by the Byurakan Astrophysical Observatory (
The First
Byurakan Survey (FBS) is the largest spectroscopic survey
covering 17,008 sq. degrees at high galactic latitudes (|b|>15). FBS has
been carried out by B.Markarian, V.Lipovetski and J.Stepanian
in 1965-1980 with the Byurakan Observatory 1m Schmidt telescope using 1.5 deg. prism. 1874 photographic plates in 1139 fields (4x4 deg.
each) have been obtained. The dispersion is 1800A/mm near H-gamma, and the
limiting magnitude is 17.5-18. Some 20,000,000 spectra are present in the whole
survey covering a range 3400-6900A thus giving important information especially
on the nature of all these objects.
The FBS was
conducted originally for search for galaxies with UV-excess (UVX): 1500
such galaxies have been discovered. Their study brought to discovery of many
new Seyferts and their first spectral classification, as well as to the
definition of starburst galaxies. Markarian survey was the first systematic
survey for AGNs, it was a new method of search for AGNs.
Two catalogs of Markarian galaxies have been published (Mazzarella & Balzano
1986; Markarian et al. 1989). A few other projects have been
fulfilled on the basis of FBS, including the survey for blue stellar objects
and late-type stars, optical identifications of IRAS
point sources. They allowed discover thousands of new interesting objects,
including new bright QSOs, other types of AGN, white dwarfs, subdwarfs,
cataclysmic variables, carbon stars, etc.
The FBS
digitization project is active since 2002. All 1874 plates have been
scanned during 2002-2003 with an EPSON EXPRESSION 1680 Pro scanner. The
program "scanfits" allowed to write directly the resulting image in FITS format with
corresponding information on the plate in its header. The scanner gave data
numbers (DN) in the range 0 (dark) to 16383 (transparent) corresponding to a
4.2 dynamic range. The scanning resolution was 1600 dpi, giving a pixel size of
15.875 microns corresponding to 1.542", and the width of spectra occupies
~5 pixels. The length of an FBS spectrum is ~1.7mm, thus we have obtained 107
pixels along the wavelength scale, giving 32.7 A/pix average dispersion. A 175
MB file has been obtained for each FBS plate. The whole database is written
onto 85 DVDs and its parts are already available on request.
Data reduction
includes plate solution (pixels-to-coordinates conversion), wavelength
calibration (pixel-to-wavelengths conversion), and intensity and flux
calibration (DN-to-I and I-to-flux conversion). A procedure to make the
plate solution for the DFBS plates uses the Tycho catalog stars and IRAF. It is
a manual process in a two-step procedure, including the identification of 20-25
bright stars from the Tycho catalogue and a preliminary plate solution, and
then automatic identification of all Tycho stars present in the field and
refinement of the first solution. The final solution is computed and written in
the FITS header. The positional accuracy obtained is typically 1 pixel rms,
quite sufficient for safe object identification.
The extraction,
wavelength, density and flux calibration procedures are being worked out as
well and will be applied for the DFBS plates to obtain maximum possible information.
A classification scheme will be created to distinguish objects of
various nature such as QSO/AGN, galaxies, white
dwarfs, carbon stars, stars of different spectral types, etc. Template
spectra will be made up and search for new objects will be possible.
Finally, the DFBS
catalog and database with positional, photometric and spectral information
on some 20,000,000 objects will be created. The DFBS and the corresponding
software will be written on DVDs and distributed to the main astronomical centers,
as well as will be available through Internet from the DFBS web page which is
in the process of creation too.
A few new
research projects based on the DFBS have been put forward such as searches for
faint Markarian galaxies, new bright QSOs and Seyferts, new white dwarfs and
cataclysmic variables, faint carbon stars, optical identifications of radio,
IR, and X-ray sources, etc. The DFBS may become a basis for the Armenian
Virtual Observatory and a significant contribution to the International
Astrophysical Virtual Observatories, especially for its unique spectral
information.
The DFBS community:
A.Mickaelian, L.Sargsyan, L.Erastova, S.Balayan, K.Gigoyan, L.Hovhannisyan (BAO);
D.Weedman, J.Houck, D.Barry, B.Brandl (Cornell);
R.Nesci, D.Trevese, C.Rossi,
S.Sclavi, S.Gaudenzi, E.Massaro (Roma).
______________________________________________________________________________________
CONTACT
INFORMATION
Address: Byurakan
Astrophysical Observatory (BAO), Byurakan 378433,
Aragatzotn province,
Tel/fax:
+374-1 53-27-51 (Areg
Mickaelian)
E-mail: aras@web.am, aras_org@freenet.am
Web page:
http://www.aras.am