J/ApJS/269/60 Optical monitoring from 2020-2022 of BL Lac (Yuan+, 2023)
Optical monitoring and intraday variabilities of BL Lacertae.
Yuan Y.H., Du G.J., Fan J.H., Liu Y., Yang J.H., Ding G.Z., Pei Z.Y.
<Astrophys. J. Suppl. Ser., 269, 60 (2023)>
=2023ApJS..269...60Y 2023ApJS..269...60Y
ADC_Keywords: BL Lac objects; Photometry, SDSS
Keywords: Galaxies ; Blazars ; CCD photometry
Abstract:
BL Lacertae is a key monitoring target of the 1.26m National
Astronomical Observatory-Guangzhou University Infrared/Optical
telescope. Within the monitored duration from 2020 September 4 to 2022
September 28, we report 13,948 observations at the g, r, and i bands
(g band: 4498, r band: 4866, i band: 4584).
(1) In the monitored duration, this source is located in a very bright
and variable state. The maximum variabilities are
Δmg=2.013±0.073mag at g band, Δmr=1.900±0.049mag
at r band, and Δmi=2.279±0.089mag at i band.
(2) Among the gri intraday lightcurves, there are 104 portions of data
sets displaying intraday variabilities (IDVs), with the IDV timescales
(ΔT) being in the range of 15.84-375.84 minutes and the biggest
variable value Δm=0.430±0.041mag.
(3) The distributions of ΔT show frequency-dependent behavior,
and with the frequency increasing, ΔT tend to be shorter. The
variable rates (V=Δm/ΔT) from the g band are more intense
than the values (Vr) from the r band, but are more stable than the
values (Vi) from the i band.
(4) On three days (2020-September-7, 2020-September-19, and
2022-September-7), we find the intraday periodic oscillations, whose
periods are around 150 minutes, 232 minutes, and 150 minutes,
respectively, and which might come from the source "flickering."
(5) Based on the distributions between flux densities (Fgri) and
spectral indices (α), they show the bluer-when-brighter
behaviors and some uneven locations, which should come from the
ministructures of the jet, the shock-induced particle acceleration,
or magnetic reconnection in the jet.
Description:
We used the 1.26m National Astronomical Observatory-Guangzhou
University Infrared/Optical telescope (NGT), located at Xinglong
station, National Astronomical Observatories, Chinese Academy of
Sciences, to monitor the object BL Lacertae. The filters adopt
standard Sloan Digital Sky Survey (SDSS) g, r, and i bands.
Objects:
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RA (ICRS) DE Designation(s)
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22 02 43.29 +42 16 39.9 BL Lac = 1ES 2200+420
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 62 4865 gri observations of BL Lacertae (1ES 2200+420)
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See also:
J/ApJ/430/467 : Superluminal motions for extragal. sources (Vermeulen+, 1994)
J/ApJ/833/77 : gamma-ray bright blazars optical polarization (Itoh+, 2016)
J/ApJ/837/45 : 2006-2012 Rc-band & 4.8GHz obs. of AO 0235+164 (Fan+, 2017)
J/ApJS/229/21 : VRI monitoring of the QSO 3C 273 in 2005-2016 (Xiong+, 2017)
J/AJ/155/31 : 2005-2012 BVRI obs. of blazar S5 0716+714 (Hong+, 2018)
J/A+A/620/A185 : Long-term optical monitoring of TeV Blazars (Nilsson+, 2018)
J/ApJS/262/43 : NGT gri monitoring of the FSRQ 3C 454.3 (Yuan+, 2022)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 F7.3 d gJD [97.69/851.9]? Julian date of g-band observation,
gJD-2459000
9- 14 F6.3 mag gmag [12.6/14.7]? Observed SDSS g-band AB magnitude
16- 20 F5.3 mag e_gmag [0.005/0.2]? Uncertainty in gmag
22- 28 F7.3 d rJD [97.69/851.9] Julian date of r-band observation,
rJD-2459000
30- 35 F6.3 mag rmag [11.7/13.7] Observed SDSS r-band AB magnitude
37- 41 F5.3 mag e_rmag [0.006/0.2] Uncertainty in rmag
43- 49 F7.3 d iJD [97.69/851.9]? Julian date of i-band observation,
iJD-2459000
51- 56 F6.3 mag imag [10.7/13.1]? Observed SDSS i-band AB magnitude
58- 62 F5.3 mag e_imag [0.003/0.1]? Uncertainty in imag
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 15-Feb-2024