1. .... Chepelare, Bulgaria, June 1-4, 2010 VII Bulgarian-Serbian Astronomical Conference ASTROINFORMATICS Astroinformatics for the Flare Stars in Stellar Clusters and Associations Katya Tsvetkova Institute of Mathematics and Informatics, Institute of Astronomy, Bulgarian Academy of Sciences

2. .... Chepelare, Bulgaria, June 1-4, 2010 Flare Star Definition Flare activity: - a very quick increase of the brightness and a decline from maximum to minimum for some minutes up to some hours; - a common characteristic in the early evolution of all red dwarf stars. Belonging: - to the population of young stellar clusters and associations. Flare-like activity: some Wolf-Rayet stars, stars of B and A spectral types, RS Cvn system, some members of Algol and W UMa systems, FK Com stars and even evolved systems, containing white dwarfs. All observed characteristics - energy, amplitudes, time-scales, frequencies, shows differences which could be due to the different origin. That is why collecting flare star data we have restricted the observed phenomena - so called flares, classical flares, flashes, microflaring, to the UV Ceti type variability as is classified in the General Catalogue of Variable Stars (GCVS, Kholopov et al. 1985).

3. .... Chepelare, Bulgaria, June 1-4, 2010 Flare Star Light Curves LS6=ABC145 14 Jan 1985 Min (pg)=16.75 Max(pg)=15.60 Delta m=1.35

4. .... Chepelare, Bulgaria, June 1-4, 2010 International Cooperative Programme for Flare Star Searches in Stellar Clusters and Associations Observatories: Tonantzintla, Byurakan, Asiago, Abastumani, Konkoly, Rozhen, etc. Period: 1960 – 1995. Wide-field telescopes: Schmidt or Maksutov type. Method: photographic multi-exposure plate observations by the method of stellar chains.

5. .... Chepelare, Bulgaria, June 1-4, 2010 Results from the Flare Star Monitoring Optical Observations in Stellar Clusters and Associations Stellar cluster Number of Number of Observing time or association flare stars registered flares (hours) Orion M42/M43564 8271591 The Pleiades547 1635 3250 Taurus Dark Clouds 102 122 870 Cygnus NGC 700083 120 1168 Praesepe59 146 680 NGC 226442 43 105 Cygnus IC 131817 18 300 Coma Open Cluster14 21 338 Alpha Persei Cluster7 7 128 Scorpius-Ophiuchus14 15 321 Others70 70 800 Total1 1519 3024 9551

6. .... Chepelare, Bulgaria, June 1-4, 2010 Flare Stars in Stellar Clusters and Associations

7. .... Chepelare, Bulgaria, June 1-4, 2010 Flare Stars in Stellar Clusters and Associations

8. .... Chepelare, Bulgaria, June 1-4, 2010 Flare Stars in Stellar Clusters and Associations

9. .... Chepelare, Bulgaria, June 1-4, 2010 Catalogues of Flare Stars 1. Machine-readable version of the Tonantzintla Pleiades Flare Stars (Haro+ 1982), Boletin Inst. Tonantzintla 3, No. 1, 3, VizieR Catalogue - II/131 since 1987. 2. Catalogues of the Cygnus flare stars (Tsvetkov and Tsvetkova, 1990), Proceedings of the 137th Symposium of the IAU Flare Stars in Star Clusters Associations and the Solar Vicinity, eds. L. V. Mirzoyan, B. R. Pettersen and M. K. Tsvetkov, Kluwer Academic Publishers, p. 105. 3. Catalogue of flare stars in the Praesepe cluster (K.P.Tsvetkova, M.K.Tsvetkov and I.Jankovics, 1991).

10. .... Chepelare, Bulgaria, June 1-4, 2010 Flare Stars Database (FSDB) Tsvetkova et al. 1995, Tsvetkova et al. 1996 Database not only for UV Ceti type stars, but also for their registered flare-events, which are missing in the other existing astronomical catalogues and data sets like GCVS, the Set of Identifications, Measurements and Bibliography for Astronomical Data (SIMBAD), and the Database on UV Ceti Type Flare Stars and Related Objects (for 230 objects) of Gershberg et al. (1993).

11. .... Chepelare, Bulgaria, June 1-4, 2010 Structure and Content of the FSDB MAIN DATA FILE     Flare-event identifier Equatorial coordinates (R. A., DEC) of flare star for equinox J2000.0 Equatorial coordinates (R. A., DEC) of flare star for equinox J1950.0 Galactic coordinates in the l(II), b(II) system Julian date of the flare-event First registered flare-event Telescope used Stellar magnitude at minimum in U or Pg/ BPOSS bands Stellar magnitudes at maximum in U- and Pg bands Amplitudes in U and Pg bands Criterion -  m > 5  V magnitude, B-V and U-B indices at minimum Spectral class Aggregate membership Pointers to tables SIMBAD and NOTES     File CROSS-IDENTIFICATION File IDENTIFICATION CHARTS File REFERENCES File SIMBAD File NOTES

12. .... Chepelare, Bulgaria, June 1-4, 2010 Flare Stars Identifier DF CNC 750218 V 426 TAU 7111121 V 426 TAU 7212062

13. .... Chepelare, Bulgaria, June 1-4, 2010 FSDB RA Dec RA Dec Date Identifier (1950) (2000) V1581CYG750706 1953.9+4425 1952.3 +4417 19750706001 V1513CYG710730 2005.1+5427 2003.9 +5418 19710730002 V1513CYG710731 2005.1+5427 2003.9 +5418 19710731002 V 426TAU690918 033042+2226 19690918001 V 426TAU711112 033042+2226 19711112002 V 426TAU721206 033042+2226 19721206003 V 594TAU730226 033042+2308 19730226001 V 485TAU681019 033048+2250 19681019001 DF CNC750218 083524 +1815 19750218007 DF CNC750313 083524 +1815 19750313007 DF CNC750402 083524 +1815 19750402007 DF CNC760228 083524 +1815 19760228007 DF CNC760325 083524 +1815 19760325007 DF CNC760330 083524 +1815 19760330007 DF CNC800319 083524 +1815 19800319007

14. .... Chepelare, Bulgaria, June 1-4, 2010 Flare Stars Database: Problems A most serious obstacle for the FSDB is the lack in the literature for some stars of some necessary parameters of the flare-event: beginning of flare-events, duration, flare star identification charts, in the GCVS the information on stellar magnitude at minimum and maximum is not sufficient for assigning the flare event parameters. Very often, the lack of flare star identification charts is a reason for some missidentifications and errors here (Tsvetkova and Tsvetkov, 1989).

15. .... Chepelare, Bulgaria, June 1-4, 2010 Automated Flare Stars Search: Results When the plates are compared with a blink-comparator a selection effect due to the used 10-minute duration of the single exposure, which is a low time resolution, appears. Thus it may preclude detection of energetic, but low amplitude flare-events on bright stars. The flare star surveys with used flare star monitoring photographic method of multi-exposure images each of 10-minute duration usually discover the most chromospherically active stars. The less active stars could be missed. If the star is very faint it will be impossible to observe small flares. An automated flare stars search method was applied for some southern stellar aggregates with different age (Aniol et al. 1990, Winterberg et al. 1995). This procedure removes partially the selection effect and increases the number of discovered flares by 50 % compared to visual inspection by a Zeiss-comparator. The number of slow flare events, flares on bright stars and on In- type variables was mainly increased.

16. .... Chepelare, Bulgaria, June 1-4, 2010 Digital Plate Archives According to the main observing programmes: Aims: to assemble and explore massive data sets in order to reveal a new knowledge existing in the data, but still not recognized in any individual data set. Preparation of digital plate archives - as a part of the long-time programme for search, preservation and re-usage of the world wide-field photographic astronomical plate collections. The last step before the systematic astronomical research: The organization of the plate scans in an image database and the development of a software system for object plate identifications and for searching in an image database with many data storage variants as current tasks.

17. .... Chepelare, Bulgaria, June 1-4, 2010 Digital Plate Archives: Examples The Pleiades Plate Database - about 3100 plates obtained in the period 1885 – 1998 were found in the observatories in Asiago (Italy), Sonneberg (Germany), Harvard (USA), Kyiv (Ukraine), Moscow (Russia), Rozhen (Bulgaria), Konkoly (Hungary), Byurakan (Armenia), Potsdam (Germany), Edinburgh (UK), Bamberg (Germany). It gives the opportunity to obtain almost continuous photometric data set for the red dwarf stars in the cluster. The precise coordinates of the known Pleiades flare stars were determined as a necessary step to the further work of automated search for long-term brightness variations. The archive of the digitised plates in the Pleiades stellar cluster contains already about 1500 plates. The plate images are included into the developed Pleiades Plate Data Base (PPDB, Borisova et al. 2003; Tsvetkov et al. 2005).

18. .... Chepelare, Bulgaria, June 1-4, 2010 Digital Plate Archives: Examples Konkoly Supernova Digital Plate Archive (Tsvetkova et al. 2008, Baltic Astronomy) - observing programmes carried out with the 60/ 90/180 cm Schmidt telescope, started at the end of 1963, with which Konkoly Observatory for about more than a 30-year period took part in the international campaign initiated by F. Zwicky. Konkoly Flare Star Digital Archive – of representative plates obtained with the Schmidt telescopes of Konkoly observatory during the observation campaign for search and investigations of the flare stars in stellar clusters and associations in 1970-1990. Besides the primary aim to serve for investigations of the flare stars another result is the realization of an interlinking the electronic Information Bulletin on Variable Stars (IBVS) with the Wide-Field Plate Database (WFPDB). The plates are scanned with resolution 1200 dpi for plate visualization and to preserve the observer marks. The image is saved as TIFF file format with size 51.12MB and as JPEG file (compressed to 2000x2000 pixels) with size 1.65MB. After the cleaning the observer marks the plate is scanned with high resolution (2400 dpi) and saved as FITS file with size 409 MB. Carte du Ciel Plate Digital Archives – Uccle (Tsvetkova et al. 2007), Potsdam (Tsvetkova et al. 2009, Astronomische Nachrichten).

19. .... Chepelare, Bulgaria, June 1-4, 2010 Now having at disposal an observing material from the monitoring flare star observations in the Rozhen Observatory, done with the 50/70/172 cm Schmidt telescope in the period 1979 – 1994, we are going to apply an automated flare stars search method on the basis of scanned flare stars monitoring plates of the Rozhen Observatory. Rozhen Flare Stars Digital Plate Archives

20. .... Chepelare, Bulgaria, June 1-4, 2010 Rozhen Flare Stars Observations:Telescope 50/70/172 cm Schmidt

21. .... Chepelare, Bulgaria, June 1-4, 2010 Rozhen Flare Stars Observations:Telescope 50/70/172 cm Schmidt

22. .... Chepelare, Bulgaria, June 1-4, 2010 50/70/172 cm Schmidt Main Characteristics Rozhen Flare Stars Observations:Telescope WFPDB Tel.Orig. Aperture Focal Scale Tel. Field Years of Plate Instr. Ident. Name (m) Length (m) "/mm Type Size (deg) Operation Number ROZ050 Schmidt 0.50/0.70 1.72 120 Sch 4.5 1979-1994 7348

23. .... Chepelare, Bulgaria, June 1-4, 2010 Plate Library in Rozhen Observatory

24. .... Chepelare, Bulgaria, June 1-4, 2010 Stellar clusters and associations: the Pleiades, Gamma Cygni region, M42/43 in Orion, Praesepe, Alpha Per, Tauri Dark Clouds, the open cluster NGC 2264, the emission nebula NGC 7000. Number of Plates: totally 1564 plates. Rozhen Flare Stars Observations: Number of Plates

25. .... Chepelare, Bulgaria, June 1-4, 2010 Rozhen Flare Stars Observations: Number of Plates

26. .... Chepelare, Bulgaria, June 1-4, 2010 Rozhen Flare Stars Observations:Telescope WFPDB ROZ050 Catalogue

27. .... Chepelare, Bulgaria, June 1-4, 2010 Rozhen Flare Stars Observations: Emulsions and Plate Size Used emulsions: ORWO, Kodak Plate Size: 13x13 cm; 16x16 cm

28. .... Chepelare, Bulgaria, June 1-4, 2010 Sofia Sky Archive Data Center: PDS1010plus microdensitometer with possibility for high precision; Flatbed Scanner: EPSON EXPRESSION 1640XL Flatbed Scanner: EPSON PERFECTION V700 PHOTO Rozhen Observatory: Flatbed Scanner: EPSON EXPRESSION 10000XL Rozhen Flare Stars Digital Plate Archive: Scanners

29. .... Chepelare, Bulgaria, June 1-4, 2010 Sofia Sky Archive Data Center: FB Scanner EPSON EXPRESSION 1640XL Scanning platform: 310x437 mm; Resolution: 1600x3200dpi, Duration: 5min 16x16 cm plate; Plate Storage: FITS with volume 120 MB.

30. .... Chepelare, Bulgaria, June 1-4, 2010 Rozhen Observatory: FB Scanner EPSON EXPRESSION 10000XL Scanning platform:310x437 mm Resolution: 1600x3200dpi Duration: 5min 16x16 cm Plate Storage: FITS 2m RCC plates 30x30 cm Previews:Adobe Photoshop 600dpi, 24bit colour TIFF; JPEG Scans: Scanfits 1600dpi, 16bit grayscale FITS (612MB)

31. .... Chepelare, Bulgaria, June 1-4, 2010 Rozhen Flare Stars Digital Plate Archive: Scanning Main parameters of the available flatbed scanners ScannerDmax Color depth Grayscale depth Resolution (dpi) 1640XL 3.6 42/42 14/14 1600 10000XL 3.842/42 16/16 2400x4800 The used software for scanning is the standard one for making preview images - Adobe Photoshop, and the programme Scanfits for the real scans in FITS format.

32. .... Chepelare, Bulgaria, June 1-4, 2010 Rozhen Flare Stars Digital Plate Archive: Scanning Preview images: aim: easier web accessibility and to store the information from the observer’s marks on the plate a system for quick plate visualization Parameters: 1200 dpi in TIFF format and compressed 1000x1000 pxl JPEG format; color depth: 8-bit 24 bit Color Real scans: Scanning Parameters: 2400 dpi, FITS format, density range (0 – 255) and Gamma = 1.00; color depth - 16-bit Grayscale.

33. .... Chepelare, Bulgaria, June 1-4, 2010 Rozhen Flare Stars Digital Plate Archive: Scanned plates ROZ050 000291 Gamma Cyg region

34. .... Chepelare, Bulgaria, June 1-4, 2010 Rozhen Flare Stars Digital Plate Archive : Scanned plates ROZ050 000383 M42/43 region

35. .... Chepelare, Bulgaria, June 1-4, 2010 Acknowledgements This work is supported by the Bulgarian National Science Fund (grant BG NSF DO-02-275).