J/MNRAS/392/1181 BV(RI)c photometry of 3C 273 (Dai+, 2009)
The long-term multiband optical observations and colour index for the quasar
3C 273.
Dai B.Z., Li X.H., Liu Z.M., Zhang B.K., Na W.W., Wu Y.F., Hao J.M.,
Xiang Y., Jiang Z.J., Zhang L.
<Mon. Not. R. Astron. Soc., 392, 1181-1192 (2009)>
=2009MNRAS.392.1181D 2009MNRAS.392.1181D
ADC_Keywords: BL Lac objects ; Photometry, UBVRI
Keywords: BL Lacertae objects: general -
BL Lacertae objects: individual: 3C 273 - galaxies: photometry
Abstract:
The long baseline simultaneous multiband (BVRI) observations of blazar
3C 273 are presented. We have made 758 optical multiband observations
with the Yunnan Astronomical Observatory (YAO) 103cm and Shanghai
Astronomical Observatory (SHAO) 156cm from 2003 January to 2005
April. In our observational campaign, the average colour indices are
B-V=0.21, V-R= 0.26 and R-I=0.31 . The mean magnitudes in B, V, R and
I are 12.895, 12.698, 12.441 and 12.139, respectively. The source is
in a steady state over observational campaign. The correlations
between colour index and brightness are discussed. We find that the
correlations of B-V versus B, V-R versus V and R-I versus R have
significant negative correlation, while B-V versus V, V-R versus R and
R-I versus I have positive correlation. These strong correlations
imply that the spectrum becomes bluer (flatter) when the source
becomes brighter, and redden (softer) when the source fades both in
intraday and long-term variability. The spectral evolution trends of
3C 273 are consistent with those of BL Lac objects.
Objects:
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RA (2000) DE Designation(s)
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12 29 06.7 +02 03 09 3C 273 = 4C 02.32
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 46 757 The observations in B,V,R,I bands
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 d MJD Modified Julian date
11- 20 A10 "YYYY/MM/DD" Obs.date Observation date
22- 27 F6.3 h Obs.time Observation time (decimal hours)
29- 34 F6.3 mag mag Magnitude in band "Band"
36- 40 F5.3 mag e_mag rms uncertainty on mag
42 A1 --- Band [BVRI] Magnitude photometric band (1)
44- 46 A3 --- Tel Telescope used (SAO or YAO)
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Note (1): BV in Johnson and RI in Cousins photometry systems
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 07-May-2009