Digitization
products at BAO
Digitized
First Byurakan Survey – DFBS
The final products of the DFBS project are:
DFBS database, containing all
2000 FBS plates (180 MB each), 2D and 1D spectra of all objects present;
DFBS catalog, containing the
list of all 20,000,000 objects present in the FBS plates with their
positional, photometric and spectral information, as well as
cross-matching with objects from other available catalogs (MAPS,
USNO-B1.0, ROSAT, 2MASS, IRAS, NVSS, FIRST).
Digitized
Second Byurakan Survey – DSBS
The Second Byurakan Survey (SBS) was carried out
by Markarian, Stepanian, Erastova, Lipovetski, Chavushyan, and Balayan in
1978-1991 on the Byurakan Observatory 102/132/213cm Schmidt telescope
with 1.5°, 3° and 4° prisms, in combination with hyper sensitized
Kodak IIIaJ and IIIaF plates and filters, giving different ranges of
spectrum (3500-5400A, 4950-5400A and 6300-6950A, respectively) (Markarian
& Stepanian 1983, Stepanian 1996). In all, 550 plates have been
obtained in 65 fields, 4°x4° each. SBS covers 965 deg2 area at
high galactic latitudes (|b|>30) with 07h43m<a<17h15m and +49<d<+61. The limiting magnitude differs in the
range of 18m-20 m in V, and the survey is complete
to 17.5 m. 7 fields (covering 112 deg2) have
limiting magnitudes 19.5 m -20 m (so-called Selected
or Deep Fields of the SBS), and are of special interest. The dispersion
near H-g for spectra obtained with 1.5°, 3° and 4° prisms is 1800A/mm, 900A/mm, and 280A/mm,
respectively (and 1000A/mm near H-a for the 4° prism). SBS covers 3 zones of the FBS, with
central declinations +51°, +55° and +59°. In average, each SBS plate contains
low-dispersion spectra of some 50,000 objects, and there are some
3,000,000 objects in the whole survey.
Since 2003, the
digitization of the SBS has been started in parallel with the DFBS
project. The scanning photometric range is 16 bit, scanning resolution is
2400 dpi (getting 10m pixel size). 180 SBS
plates have been scanned so far.
Digitized
2.6m photographic spectra
Scanning of the 2.6m photographic spectra
obtained in 1987-1991 by H.V. Abrahamian, A.M. Mickaelian and K.S.
Gigoyan. Scanning resolution is 1600 dpi, photometric range: 16 bit. The
result is some 700 650x21 pix size spectra of the FBS blue stellar
objects & late-type stars. A new PN (FBS 2323+421), 7 white dwarfs
(DA, DAB, DZ), 78 hot subdwarfs, 9 HBB stars have been revealed so far
among the 101 published.
The 2D spectra are brought to a standard form for
automatic reduction with a dedicated macro in MIDAS extbaophot.prg.
Examples of a HBB star, sdB hot subdwarf, DA
white dwarf, and a planetary nebula (PN).
Coma
cluster plates
Photographic plates for search for variable
(flare) stars have been obtained in young stellar clusters. Photographic
chains have been obtained by means of shifting the telescope in R.A. for
each exposure, thus giving a possibility to compare the consequent 6-10
images of the same object. One of the clusters is the Coma, where 189
plates with a total number of more than 1200 exposures in 1965-1976 have
been obtained by L.K. Erastova with the Byurakan 21² and 40² Schmidt telescopes. The famous blazer ON 231 is
in the field giving a chance for study of its intraday variability. All
these plates have been digitized, and the study of variability of ON 231
is active.
A piece of the Coma cluster plate with stellar
chains and the 1D cut of 10 consequent images of one of the stars.
Armenian
Virtual Observatory – ArVO
Some projects based on the DFBS have been
already put forward, including search for new QSOs and other AGN,
continuation of the FBS Second Part, identifications of IR and X-ray
sources, etc. The DFBS is the basis for the Armenian Virtual Observatory
(ArVO), which is being created at present and will unify all available
astronomical data in Armenia, including all Byurakan archive and data from
the Byurakan telescopes. ArVO will be a part of the International Virtual
Observatories Alliance (IVOA).
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