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 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:
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FileName Lrecl Records Explanations
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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
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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
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Bytes Format Units Label Explanations
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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)
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Note (1): the references are
M=MAPS, A=APM, U=USNO (A2 and B1)
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Byte-by-byte Description of file: table13.dat
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Bytes Format Units Label Explanations
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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
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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.
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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