Database of Variable Stars Bingqiu Chen Dept of Astronomy Beijing Normal University

Outline Pulsating Variable Stars Data MACHO OGLE MySQL Database design Future work

Pulsating Variable Stars The pulsating stars swell and shrink regularly by stellar radius, magnitude and spectrum. The two most important types: Cepheids and cepheid-like stars. Long Period Variables.

Variable star observations Long period Long-term observation projects Microgravitational Lensing projects! MACHO & OGLE

MACHO Project MAssive Compact Halo Object Method: photometry monitor of several millions stars for a period of years Observation 50 inch telescope B & R filters 2*4* 2048*2048 CCDs high data rate (several GBytes per night)

Data from MACHO ~27,000 images since June Two colors for 8 million stars in the LMC & SMC and 10 million in the bulge of the Milky Way Retrieval variable stars data

Data of MACHO

OGLE Project The Optical Gravitational Lensing Experiment Phases OGLE-I: , filter I, 1-m Swope telescope,2048×2048 CCD OGLE-II: , BVI photometry, 1.3-m Warsaw telescope,2048×2048 CCD OGLE-III: 2001-, eight chip pixel mosaic. Each chip of the mosaicis a SITe ST-002a CCD detector with pixels of 15 μm size

Data from OGLE ( Variable Stars ) Galactic Bulge:Variable Stars( objects) Magellanic Clouds:Variable Stars( objects) LMC Eclipsing binary stars(2580 objects) RR Lyr stars(7612 objects) Cepheids(1414 objects) Ellipsoidal Variability of Red Giants(1670 objects) SMC Eclipsing binary stars in the SMC (2809 objects) RR Lyr stars from the SMC (571 objects) Cepheids from the SMC (2159 objects) Other:Cepheids in the Galaxy IC1613 (138 objects)

Data of OGLE Bulge var_stars(I,B,V) ic1613:cep LMC:cep;ecl;ell;lpv;rrlyr SMC:cep;ecl;rrlyr Dia(I) ac:LMC;SMC (.flux,.mag)

MySQL The software to build the database The MySQL® software delivers a very fast, multi-threaded, multi- user, and robust SQL (Structured Query Language) database server

Model Build Entity Relationship between entities Attribute ID Standardization

OGLE data model :Entity & Attribute Star:starID,Ra,Dec. Position:positionID,position(LMC,S MC,buldge,ic1613) Imag:ImagID,JD,Imag,Imagerr Iflux:IfluxID,JD,Iflux,Ifluxerr Type:typeID,type(ac,cep,ecl,ell,lpv,rrlyr) Idia:IDiaID,JD,Idia,Idiaerr B;V;I ( same as Idia )

OGLE data model: Relationship

MACHO data model: Entity & Attribute Star:StarID, Ra,Dec (same as OGLE:connection) Minfor:MinforID, MACHOID, observations, inceptionJD, Rmag,Bmag, chip coordinates, west- chunk, Pixel coordinate system Infor:InforID,JD,Obsid,Pier,Exposure,Ch ecklist,Airmass,rMag, rErr,rDS,rTF,rCP rX2,rMP,rCR,rA,rXpix,rYpix,rSky,rFWH M,Tobs,r,bMag,bErr,bDS,bTF,bCP,bX2 bMP,bCR,bA,bXpix,bYpix,bSky,bFWHM bTobs,b

MACHO data model: Relationship

As one single database Notice the entity star. Both MACHO’s and OGLE’s have the same attributes Add a entity: income:incomeID,income(OGLE, MACHO)

Physcal database design Entity table Attribute array ID not null array (primary key) Relationship forign key

TableArrayData typeNote starstarIDintprimary key RA(1)ascII(2) RA(2)ascII(2) RA(3)ascII(2) DEC(1)ascII(2) DEC(2)ascII(2) DEC(3)ascII(2) positionIDintforign key typeIDintforign key incomeIDintforign key positionpositionIDintprimary key positionvachar(8) incomeincomeIDintprimary key incomevachar(8) typetypeIDintprimary key typevachar(6) ImagImagIDintprimary key Imagascii(16) Imagerrascii(16) starIDintforign key IfluxIfluxIDintprimary key Ifluxascii(16) Ifluxerrascii(16) starIDintforign key

Future work Data read Database Science analysis…

Types The two most important types are: Cepheids and cepheid-like stars. They have short periods (days to months) and their luminosity cycle is very regular; Long Period Variables. Their period is longer, on the order of a year, and much less regular.

MACHO Project MAssive Compact Halo Objects Mount Stromlo Observatory, Canberra, Australia.

Telescope & CCDs 50 inch telescope. 2*4* 2048*2048 CCDs high data rate (several GBytes per night)

OGLE The Optical Gravitational Lensing Experiment 1.3 m Warsaw University Telescope Las Campanas Observatory, Chile

Telescope technical data 1.3m (51'') primary mirror diameter 1:9.2 (1:2.8 primary) Ritchey-Chretién system; 17.4 arcsec/mm focal scale 3-element field corrector - 1.5° diffraction limited field (80% of light within 0.5 arcsec diameter) Ultra Low Expansion (ULE) glass mirrors Fully automated, computer controlled operation Fork, paralactic mount, friction drives (no backlash) allowing any tracking rate in RA and DEC Light, steel enclosure with Ash-dome dome, easy ventilation (louvers on telescope and ground level). Minimalization of heat sources in the telescope building Remote control of the telescope and instruments from "control building" located 15 m away from the telescope building. Possibility of remote control over the Internet First "optical" light Feb 9, 1996, first "electronic" light Jul 18, 1996

CCD Camera Single chip camera (OGLE-II, ) SITe 2048×2049 thin chip 90% QE over wide range from B to I, also some sensitivity in U 0.4 arcsec/pixel scale 5 e- readout noise at 3.8 e-/ADU (16-bit ADC: levels) modular control system developed at Warsaw University Observatory - easily expandable to multi-chip mosaic, next generation cameras "Second generation" mosaic camera (OGLE-III, ) eight thin SITe 2048×4096 CCD chips (total of 8192×8192 pixels) 0.26 arcsec/pixel scale, 35'×35' total field of view 6-9 e- readout noise (depending on chip) at 1.3 e-/ADU gain 98 seconds readout time

Auto-Guiding System and Filter Wheel 512×512 pixels EEV CCD37 detector driven by the same electronics as scientific CCD (2.2 by 2.2 arcmin field) Automatic positioning of the guider probe with accuracy of 2 pixels over the entire field of view Automatically positioned filter wheel with 7 slots for up to 16 cm diameter filters. Standard UBVRI filters installed

Data from OGLE (analogous to MACHO) ftp://bulge.princeton.edu/ogle/ogle 2/dia/ Catalogs of concrete type of variables (Cepheids, RR Lyraes, eclipsing variables): ftp://bulge.princeton.edu/ogle/ogle 2/var_stars/