J/ApJS/277/18 Optical light curves & variability of S5 0716+714 (Li+, 2025)
Optical monitoring and long-term optical spectral variability of BL Lacertae
object S5 0716+714.
Li H.-Z., Guo D.-F., Qin L.-H., Liu F., Liu H.-T., Yi T.-F., Gao Q.-G.,
Huang S.-F., Gao X., Chen Xu
<Astrophys. J. Suppl. Ser., 277, 18 (2025)>
=2025ApJS..277...18L 2025ApJS..277...18L
ADC_Keywords: BL Lac objects; Photometry; Optical
Keywords: Blazars
Abstract:
We present photometric observations of the BL Lacertae object
S5_0716+714 with a temporal resolution of 120s in the Sloan i' and r'
bands. These observations were conducted using the Comet Search
Program telescope at Xingming Observatory from 2018 December 22 to
2020 February 15, and more than 5600 effective images were obtained on
each filter across 79 nights. Additionally, we compiled long-term
variability data spanning 34yr in the optical UBVRI bands. Using the
power-enhanced F-test and nested ANOVA test, we found intraday
variability (IDV) on 31 nights and possible IDV on 20 nights in the i'
band. Similarly, IDV was detected on 35 nights in the r' band, while
possible IDV was observed on 22 nights. The minimum variability
timescale is 7.33±0.74 minutes, and the estimated black hole
masses are (0.68∼5.12)x108M☉. The spectral variability and
long-term optical light curves reveal a bluer-when-brighter trend on
intraday timescales. The long-term optical flux density and spectral
index exhibit periodic variability with a timescale of about 1038d. An
anticorrelation between optical flux and spectral index was observed,
with a time delay of -140 days. Variability across different optical
bands exhibited a strong correlation, with no discernible time lag.
From the IDV, spectral variability, correlation, and time delays
between different bands, we conclude that these radiation
characteristics may result from the shock-in-jet model scenario.
Description:
From 2018 December 22 to 2020 February 15, BL Lacertae object
S5_0716+714 was observed on 79 nights using the Comet Search Program
(CSP) telescope at the Xingming Observatory. The Sloan r' and i' bands
were used during the observations. The exposure time for both filters
is 120s. More than 5600 effective images on each filter were obtained.
The analysis results for 158 light curves are presented in Table 3;
see Section 4.1
Objects:
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RA (ICRS) DE Designation(s)
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07 21 53.44 +71 20 36.3 S5 0716+714 = 8C 0716+714
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 69 5719 The log of observations of S5 0716+714 in the Sloan
i' and r' bands
table3.dat 62 158 Statistic parameters of intranight light curves
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See also:
J/A+A/327/61 : BV(RI)c photometry of S5 0716+714 (Ghisellini+ 1997)
J/A+AS/143/357 : Tuorla Quasar Monitoring (Katajainen+ 2000)
J/A+A/402/151 : S5 0716+714 UBVRI photometry (Raiteri+, 2003)
J/AJ/129/1818 : Photometry of S5 0716+714 (Wu+, 2005)
J/A+A/450/39 : BVRI photometry of 8 red blazars (Gu+, 2006)
J/A+A/451/435 : BV(RI)c photometry of S5 0716+714 (Montagni+, 2006)
J/AJ/133/1599 : B'V'R' photometry of S5 0716+714 (Wu+, 2007)
J/AJ/135/1384 : R-band variability in 5 blazars (Gupta+, 2008)
J/AJ/136/1846 : BVRI light curves of S5 0716+714 (Zhang+, 2008)
J/MNRAS/385/823 : UBVRI light curves of OJ 287 (Zheng+, 2008)
J/ApJS/185/511 : Optical microvariability of S5 0716+714 (Poon+, 2009)
J/ApJ/716/30 : SED of Fermi bright blazars (Abdo+, 2010)
J/ApJ/731/118 : R-band variability in blazar S5 0716+71 (Chandra+, 2011)
J/AJ/143/108 : B'V'R' phot. of the BL Lac object S5 0716+714 (Wu+, 2012)
J/A+A/558/A92 : S5 0716+714 microvariability observation (Bhatta+, 2013)
J/ApJ/768/40 : R-band and pol. of the blazar S5 0716+71 (Larionov+, 2013)
J/A+A/552/A98 : Optical monitoring of extragalactic sources (Taris+, 2013)
J/ApJ/783/83 : BVRI photometry of S5 0716+714 (Liao+, 2014)
J/ApJS/218/18 : 2004-2012 BVRI obs. of blazar S5 0716+714 (Dai+, 2015)
J/ApJS/222/24 : VRI LCs of Mrk 501 from 2010 to 2015 (Xiong+, 2016)
J/AJ/154/42 : BVRI photometry of S5 0716+714 in 2012 (Hong+, 2017)
J/ApJ/846/98 : Jet kinematics of blazars at 43GHz (Jorstad+, 2017)
J/ApJS/229/21 : VRI monitoring of the QSO 3C 273 in 2005-2016 (Xiong+, 2017)
J/ApJS/235/39 : Jet properties of γ-ray-loud 3FGL AGNs (Chen, 2018)
J/AJ/155/31 : 2005-2012 BVRI obs. of blazar S5 0716+714 (Hong+, 2018)
J/A+A/619/A45 : S5 0716+714 LCs (MAGIC Collaboration+, 2018)
J/A+A/620/A185 : Long-term optical monitoring of TeV Blazars (Nilsson+, 2018)
J/ApJ/880/155 : RI photometry of blazars S5 0716+714 and 3C 273 (Liu+, 2019)
J/ApJ/884/92 : 7yrs of VRI obs. of S5 0716+714 and its flares (Xu+, 2019)
J/ApJ/888/30 : BVRI and spectroscopic LCs of S5 0716+714 (Feng+, 2020)
J/ApJ/902/42 : Spectroscopic monitoring of blazar S5 0716+714 (Feng+, 2020)
J/ApJ/893/68 : RadioAstron. III. S5 0716+71 (Kravchenko+, 2020)
J/ApJS/247/49 : gri obs. of S5 0716+714 (2017-2019) (Xiong+, 2020)
J/ApJS/260/47 : 19.3yr R-band monitoring of 1ES 2344+514 (Cai+, 2022)
J/ApJ/928/86 : BVRI photometry of S5 0716+714 (Gorbachev+, 2022)
J/MNRAS/510/1791 : Blazars study with ZTF DR6 and Roma-BZCAT (Negi+, 2022)
J/ApJS/268/23 : Magnetic fields of Fermi blazars (Fan+, 2023)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "Y/M/D" Datei Observation date of i' band
12- 21 F10.5 d MJDi [8475/8895.5]? Modified Julian Date of i'
band observation; MJDi-50000
23- 28 F6.3 mag imag [11.8/14.7]? Apparent i' band magnitude
30- 34 F5.3 mag e_imag [0.001/0.2]? Uncertainty in imag
36- 45 A10 --- Dater Observation date of r' band; YYYY-MM-DD
format
47- 56 F10.5 d MJDr [8475/8895.5] Modified Julian Date of r' band
observation; MJDr-50000
58- 63 F6.3 mag rmag [12/15.1] Apparent r' band magnitude
65- 69 F5.3 mag e_rmag [0.001/0.3] Uncertainty in rmag
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 "Y/M/D" Date Observation date
12 A1 --- Band [RI] Band identifier
14- 16 I3 --- N [10/117] Number of observations per night
18- 22 F5.2 h DeltaT [0.8/11.8] Observation duration
24- 29 F6.2 --- FPeF [0.03/143.3] Power-enhanced F-test value
31- 34 F4.2 --- FPeFc [1.4/3.6] Power-enhanced F-test critical
value at 99% confidence
36- 40 F5.2 --- FNA [0.06/69.8] Nested ANOVA F-value
42- 46 F5.2 --- FNAc [2.5/25.5] Nested ANOVA critical value at 99%
confidence
48- 49 A2 --- V/N Microbariability label (1)
51- 56 F6.2 % Amp [7.4/100.8] Amplitude
58- 62 F5.2 mag mag [11.8/14.8] Average magnitude in Band
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Note (1): Microbariability label as follows:
N = non-variable (50 occurrences)
PV = possible variable (42 occurrences)
V = variable (66 occurrences)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 09-Feb-2026