J/MNRAS/415/1061 Variability of FBS blue stellar objects (Mickaelian+ 2011)
Accurate photometry and variability of the FBS blue stellar objects Mickaelian A.M., Mikayelyan G.A., Sinamyan P.K. <Mon. Not. R. Astron. Soc. 415, 1061 (2011)> =2011MNRAS.415.1061M
ADC_Keywords: Blue objects ; Photometry, photographic ; Binaries, cataclysmic ; Stars, white dwarf Keywords: surveys - catalogues - photometry - methods: statistical - active galactic nuclei - cataclysmic variables - white dwarfs Abstract: A new method for combined calculations of magnitudes based on accurate measurements of POSS1 and POSS2 epoch plates is given. The photometric accuracy of various surveys and catalogs has been estimated and established and statistical weights for each of them have been calculated. To achieve the best possible magnitudes, weighted averaging of data from USNO-A2.0, APM, MAPS, USNO-B1.0, and GSC 2.3.2 catalogs have been used. The rms accuracy of magnitudes achieved for POSS1 is 0.184 mag for B and 0.173 mag for R and for POSS2 is 0.138 mag for B and 0.128 mag for R. We have derived the best POSS1 and POSS2 magnitudes for the FBS blue stellar objects. We have refined the transformation formulae between the POSS1 and POSS2 magnitudes and SDSS ones and standard UBV system. Using these accurate magnitudes, we have estimated the variability of the FBS blue stellar objects and revealed probable and possible variables. We have worked out methods to control and exclude accidental errors that appear in any survey. We have compared and combined our results with those given in NSVS database and obtained better candidates for variability. Having excluded variables, we have combined POSS1 and POSS2 data for the rest of objects to achieve even better magnitudes and colors; the rms being smaller than 0.1 mag both in B and R and for the B-R colors. This approach has been applied to the First Byurakan Survey blue stellar objects containing significant number of white dwarfs, cataclysmic variables, as well as extragalactic objects (quasars, Seyferts, BL Lac objects). Altogether 336 variable objects have been revealed with POSS2-POSS1 ≥ 3σ of the errors. An electronic table of these objects is given. Candidate variables are divided into 4 classes: extreme, strong, probable and possible variables. For a more reliable sample of variable objects we excluded possible ones from the list and were left with 161 objects. Analyzing radio and X-ray properties of these objects, we have revealed their nature and re-discovered or revealed candidate AGN, CVs, WDs and other objects. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table8.dat 115 1103 Accurate photometry of FBS blue stellar objects table13.dat 162 336 Variability of FBS blue stellar objects
See also: II/223 : First Byurakan Survey (FBS), 2nd Program (Abrahamian+, 1990-96) III/258 : Revised and updated First Byurakan Survey (FBS) (Mickaelian, 2008) J/MNRAS/407/681 : Proper motions of FBS blue stellar objects (Mickaelian+ 2010) J/A+A/426/367 : FBS blue stellar objects DSS1/DSS2 astrometry (Mickaelian 2004) Byte-by-byte Description of file: table8.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Seq [1,1103] FBS blue stellar objects number 7- 15 A9 --- FBS FBS BSOs object name (HHMM+DDMMA) 17- 21 F5.2 mag B1mag ? POSS1 best blue magnitude 23- 27 F5.2 mag R1mag ? POSS1 best red magnitude 30- 33 F4.2 mag e_B1mag ? Errors of POSS1 best blue magnitude 35- 38 F4.2 mag e_R1mag ? Errors of POSS1 best red magnitude 41- 45 F5.2 mag B-R ? POSS1 best B-R color index 48- 55 F8.3 yr Epoch1 Date of observation (yyyy.yyy) for POSS1 58- 60 A3 --- r_B1mag [MAU ] Used measurements for POSS1 B (1) 62- 64 A3 --- r_R1mag [MAU ] Used measurements for POSS1 R (1) 68- 72 F5.2 mag B2mag ? POSS2 best blue magnitude 74- 78 F5.2 mag R2mag ? POSS2 best red magnitude 80- 84 F5.2 mag I2mag ? POSS2 best infrared magnitude 87- 90 F4.2 mag e_B2mag ? Errors of POSS2 best blue magnitude 92- 95 F4.2 mag e_R2mag ? Errors of POSS2 best red magnitude 98-105 F8.3 yr Epoch2 Date of observation (yyyy.yyy) for POSS2 108-109 A2 --- r_B2mag [GU ] Used measurements for POSS2 B (1) 111-112 A2 --- r_R2mag [GU ] Used measurements for POSS2 R (1) 114-115 A2 --- r_I2mag [GU ] Used measurements for POSS2 I (1)
Note (1): the references are M=MAPS, A=APM, U=USNO (A2 and B1)
Byte-by-byte Description of file: table13.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Seq [1,1103] FBS blue stellar objects number 7- 15 A9 --- FBS FBS BSOs object name (HHMM+DDMMA) 17- 21 F5.2 mag B1mag ? POSS1 best blue magnitude 23- 27 F5.2 mag R1mag POSS1 best red magnitude 30- 33 F4.2 mag e_B1mag ? Errors of POSS1 best blue magnitude 35- 38 F4.2 mag e_R1mag Errors of POSS1 best red magnitude 41- 48 F8.3 yr Epoch1 Date of observation (yyyy.yyy) for POSS1 51- 55 F5.2 mag B2mag POSS2 best blue magnitude 57- 61 F5.2 mag R2mag POSS2 best red magnitude 63- 67 F5.2 mag I2mag POSS2 best infrared magnitude 70- 73 F4.2 mag e_B2mag Errors of POSS2 best blue magnitude 75- 78 F4.2 mag e_R2mag Errors of POSS2 best red magnitude 81- 88 F8.3 yr Epoch2 Date of observation (yyyy.yyy) for POSS2 91- 95 F5.2 mag Bdiff ? POSS2 bestB-POSS1 bestB magnitude difference 97-101 F5.2 mag Rdiff POSS2 bestR-POSS1 bestR magnitude difference 104-111 A8 --- Bvar Variability class based on B magnitude (2) 114-121 A8 --- Rvar Variability class based on R magnitude (2) 124-131 A8 --- Var Combined variability from B+R magnitudes (2) 134-139 F6.3 mag Rnsvs ? NSVS median R magnitude 141-145 F5.3 mag Rsct ? NSVS R magnitude scatter 147-151 F5.3 mag e_Rnsvs ? NSVS R magnitude error 154-162 A9 --- Type Objects type and subtype
Note (2): the four variability classes are: * possible: magnitude variations in range 2-3σ * probable: magnitude variations in range 3-5σ * strong: magnitude variations in range 5-10σ * extreme: magnitude variations larger than 10σ.
History: * 06-Mar-2011: Prepared by the author (A.M. Mickaelian) * 05-Aug-2011: Tables renamed (table2 into table8, table5 into table13) to be consistent with the printed paper.
(End) A. Mickaelian [Byurakan Astrophysical Observatory] 06-Mar-2011
|The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line|