Spectra extraction and analysis software for theDigitized First Byurakan Survey (DFBS)
and research projects
A.M. Mickaelian1, L.A. Sargsyan1, R. Nesci2, G. Cirimele3, A. Sarkissian4
1 – Byurakan Astrophysical Observatory, Armenia, 2 – La Sapienza Universita di Roma, Italy, 3 – M.I.G.G. srl., Italy, 4 – LATMOS, France

Abstract
The Digitized First Byurakan Survey (DFBS) is the largest Armenian astronomical database and is unique in the world for its specific requirements to the extraction andanalysis of its low-dispersion prism spectra. The project is a collaboration between the Byurakan Astrophysical Observatory, "La Sapienza" Universita di Roma, Cornell
University, and VO-Paris. A dedicated software bSpec was created by one of the authors (GC) to extract and measure all spectra in any field of the DFBS. However, moreaccurate software EXATODS (Extraction and Analysis TOol of DFBS Spectra) was recently written by another author (AS) and have successfully been used for theextraction and study of the asteroids spectra from the DFBS. It scans full plate to find bright spectra and measures the angle of the rotation of each individual spectrum andfollows the direction for the dispersion to obtain the correct wavelength calibration. We have developed a dedicated workflow in the VO framework. We will describe thesesoftware and present future research possibilities based on the DFBS spectra.

Dedicated software bSpec

Dedicated software EXATODS

Software “bSpec“: automatedextraction and classification of
the spectral data in a DFBS
plate. Coded under Linux using
the Borland Kylix compiler
Performs all the operations
necessary to build the DFBS
database
DevelopedbyGiuseppe Cirimele and theMIGG s.r.l. team. A catalogue
driven approach: an object list
from the USNO-A2 catalogue.
Starting
fromtheUSNO
coordinates, each spectrum wasre-centered with a combinationof two parameters a) peakposition, b) baricenter.
The local background aroundeach object was estimated using
the median value of the pixel
distribution in two parallel strips
to the spectrum direction.
Automatic transformation from
DN to I (in arbitrary units) for
each plate, finding the “redhead”
andextraction
ofspectrum subtracting the local
background.
A preliminary mag calibration ismade using 300 objects in thecentral part of each plate:
instrumental B & R mags areevaluated
integrating
thespectrum between pixels 20-40(R) and 55-90 (B). A polynomial
fit of these mags against their
USNO-A2 mags provides acalibration curve > Computing
DFBS mag for all objs.
For each object, the database
contains: USNO-A2 ID, RA andDEC, position of the red head inpix, B and R mags (USNO-A2 &DFBS), the local backgroundvalue, a quality flag, thespectrum length, and theextracted spectrum.

For the extraction and analysis of the asteroid spectra from the DFBS plates,
dedicated software has been developed by Alain Sarkissian "EXATODS" Extraction and Analysis TOol of DFBS Spectra.
It is developed to overcome the main difficulty to analyze DFBS spectraconneceted with their wavelength and photometric calibrations.
It scans full plate to find bright spectra than 2 scan each individual spectra andmeasures the angle of the rotation of each individual spectrum and follows thedirection fo the dispersion to obtain the correct wavelength calibration.
Moreover, alignment of the objective prism, the plate and the scanning
direction is variable from plate to plate and within the same plate spectra lookvertical and others are slightly inclined). To solve these issues, we havedeveloped a dedicated workflow in the Virtual Observatory framework.
An extended DFBS spectrum of an asteroid is shown in Fig. 1. Fig. 2 shows
how EXATODS works: right panels show the extracted 2D and 1D spectra,
upper left panel shows inclination of the spectrum versus pixel number, andlower left panel shows spectrum relative to the solar spectrum (Istar/Isun) verus
wavelengths.

Ongoing projects based on the DFBSSIA Access to DFBS images (for ALADIN, etc.)
SSA Access to DFBS low-dispersion spectra (for VOSpec)
Extraction and analysis of DFBS spectra
Search and studies of asteroids in DFBS
Search and studies of new bright AGN in DFBS
Search for Blue Stellar Objects (BSOs) in DFBS
Search for Extremely Red Objects (EROs) in DFBS
Search and study of high proper motion stars
Variability studies based on DFBS
Optical identification of IR sources (IRAS, SST)
Optical identification of radio sources (NVSS, FIRST, etc.)
Optical identification of X-ray sources (ROSAT, etc.)

Related papers
Mickaelian A.M., Nesci R., Rossi C., Weedman D., Cirimele G., Sargsyan L.A., Erastova L.K., Gigoyan K.S., Mikayelyan G.A., Massaro E., Gaudenzi S., Houck J., Barry D.,
D’Amante L., Germano P., A&A 464, 1177-1180, 2007.
Mickaelian A., Sarkissian A., Dubernet M.-L., Le Sidaner P., Prugniel P., Nesci R., et al., Science with Virtual Observatories: JENAM-2007, SpS #8, Yerevan 2007.
Thuillot W., Berthier J., Sarkissian A., Mickaelian A., Sargsyan L., Iglesias J., Vachier F., Birlan M., Simon, G., IAU GA XXVI, SpS3, Prague 2006.
Mickaelian A.M., Gigoyan K.S., Nesci, R., Rossi C., Mem.SAIt. 77, 1159, 2006.
Mickaelian A.M., Sargsyan L.A., Mikayelyan G.A., Erastova L.K., Sinamian P.K., Heron Press Science Series, 82-92, 2006.