J/A+AS/136/455 BVRI photometry of 3 BL Lac objects (Bai+, 1999)
Photometric monitoring of three BL Lac objects in 1993-1998
Bai J.M, Xie G.Z., Li K.H., Zhang X., Liu W.W.
<Astron. Astrophys. Suppl. Ser. 136, 455 (1999)>
=1999A&AS..136..455B 1999A&AS..136..455B (SIMBAD/NED BibCode)
ADC_Keywords: BL Lac objects ; Photometry, UBVRI
Keywords: BL Lacertae objects: general ; BL Lac; OJ 287; PKS 0735+178 -
galaxies: jets
Abstract:
The results of optical photometric (BVRI) monitoring of three BL Lac
objects over a time interval of about four years are presented. The
sources are three classical radio-selected BL Lac objects, BL Lac, OJ
287 and PKS 0735+178. During our observation OJ 287 was in the stage
of a large periodic outburst which consisted of at least two peaks.
Almost all the observations obtained over consecutive nights detected
intranight variations. In 1995 and 1996 BL Lac kept in faint states,
with fewer and smaller rapid flares and fluctuations. On the contrary,
in late 1997 BL Lac was at the stage of a large outburst, accompanied
with much more large amplitude rapid flares and fluctuations. PKS
0735+178 was almost at its faint end from 1994 to early 1998. Over
this time interval, the intraday variations and microvariations in PKS
0735+178 were rare and the amplitude was very small, except a rapid
darkening of ∼0.4mag on 24 January 1995. Previous work by Webb et al.
(1988AJ.....95..374W 1988AJ.....95..374W), Wagner et al. (1996AJ....111.2187W 1996AJ....111.2187W) and
Pian et al. (1997ApJ...486..784P 1997ApJ...486..784P) also showed the same behaviour of
variability as BL Lac and PKS 0735+178 in BL Lac, S5 0716+714, PKS
2155-304, respectively. We propose that the motion of orientation of
the relativistic jet in a BL Lac object be responsible for these
variability behaviours.
Objects:
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RA (2000) DE Designation(s)
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22 02 43.4 +42 16 40 BL Lac
08 54 48.9 +20 06 31 OJ 287
07 38 07.4 +17 42 19 PKS 0735+178
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 47 1205 Photometric data of three BL Lac objects
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See also:
J/A+AS/98/393 : 1Jy BL Lac Objects: Observational Data (Stickel+ 1993)
J/A+AS/106/361 : CCD Photometry of BL Lac objects (Xie+ 1994)
J/AZh/71/717 : Polarimetric Observations of BL Lac (Gagen-Torn+ 1994)
J/AJ/104/28 : JHKL photometry of BL Lac Objects (Bersanelli+ 1992)
J/A+AS/116/403 : VRI photometry of stars in 12 BL Lac objects (Fiorucci+, 1996)
J/A+AS/132/361 : Optical observations of eight BL Lacs (Raiteri+ 1998)
J/A+AS/132/83 : BVRI photometry of 7 BL Lac objects (Bai+ 1998)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 "DD/MM/YY" Date Observation date
10- 21 F12.4 d JD Julian Date
23- 27 F5.2 mag mag Magnitude
29- 32 F4.2 mag e_mag rms uncertainty on mag
34 A1 --- Band [BVRI] Filter used for the magnitude
36- 47 A12 --- Object Name of the object observed
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Acknowledgements: J.M. Bai <baijm@163.net>
(End) Patricia Bauer [CDS] 22-Feb-1999