J/ApJ/944/177 MOMO. VI. Radio variability of OJ 287 (Komossa+, 2023)
MOMO.
VI. Multifrequency radio variability of the blazar OJ 287 from 2015 to
2022, absence of predicted 2021 precursor-flare activity, and a new binary
interpretation of the 2016/2017 outburst.
Komossa S., Kraus A., Grupe D., Gonzalez A.G., Gurwell M.A., Gallo L.C.,
Liu F.K., Myserlis I., Krichbaum T.P., Laine S., Bach U., Gomez J.L.,
Parker M.L., Yao S., Berton M.
<Astrophys. J., 944, 177 (2023)>
=2023ApJ...944..177K 2023ApJ...944..177K
ADC_Keywords: BL Lac objects; Radio sources; Millimetric/submm sources
Keywords: Blazars ; Radio active galactic nuclei ;
X-ray active galactic nuclei ; Jets ; Supermassive black holes
Abstract:
Based on our dedicated Swift monitoring program, MOMO, OJ 287 is one
of the best-monitored blazars in the X-ray-UV-optical regime. Here, we
report results from our accompanying, dense, multifrequency
(1.4-44GHz) radio monitoring of OJ 287 between 2015 and 2022 covering
a broad range of activity states. Fermi γ-ray observations were
added. We characterize the radio flux and spectral variability in
detail, including discrete correlation function and other variability
analyses, and discuss its connection with the multiwavelength
emission. Deep fades of the radio and optical-UV fluxes are found to
occur every 1-2 yr. Further, it is shown that a precursor flare of
thermal bremsstrahlung predicted by one of the binary supermassive
black hole (SMBH) models of OJ 287 was absent. We then focus on the
nature of the extraordinary, nonthermal, 2016/2017 outburst that we
initially discovered with Swift. We interpret it as the latest of the
famous optical double-peaked outbursts of OJ 287, favoring binary
scenarios that do not require a highly precessing secondary SMBH.
Description:
Due to a very dense and dedicated multiwavelength (MWL) Swift
(X-ray-UV-optical) monitoring campaign that we set up >6yr ago in the
course of the project MOMO (Multiwavelength Observations and Modeling
of OJ 287; Komossa+ 2021Univ....7..261K 2021Univ....7..261K), OJ 287 has one of the
best-covered long-term X-ray-UV-optical light curves and
simultaneous SEDs of any blazar (Paper IV;
Komossa+ 2021ApJ...923...51K 2021ApJ...923...51K), along with the dense multifrequency
radio monitoring presented here.
In particular, we have been using the Effelsberg 100m radio telescope
and the Neil Gehrels Swift observatory since 2015 December.
See Section 2.
Here we discuss all the data obtained until 2022 June. Observations
were carried out between 2.6 and 44GHz, and occasionally at 1.4GHz,
switching between up to eight receivers. See Section 3.
Flux density data at 1.3mm, and occasionally at 1.1mm and 870um, were
obtained at the Submillimeter Array (SMA) near the summit of Maunakea
(Hawaii). See Section 4.
The majority of the Swift data we obtained in the course of the
MOMO-UO (UV and optical) and MOMO-X (X-rays) program was presented in
previous work since 2017, including a detailed discussion of the full
2005-2021 Swift light curve of OJ 287 by Paper IV.
(Komossa+ 2021ApJ...923...51K 2021ApJ...923...51K). See Section 5.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
08 54 48.87 +20 06 30.6 OJ 287 = OHIO J 287
----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table6.dat 30 739 Radio flux density measurements of OJ 287 between
1.4 and 44GHz obtained at the Effelsberg telescope
in the course of the MOMO project between
2017 January and 2022 June
table7.dat 35 100 Radio flux density measurements of OJ 287 from
the SMA between 2015 October and 2022 June
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See also:
IX/67 : Incremental Fermi LAT 4th source cat. (4FGL-DR3) (Fermi-LAT col., 2022)
J/ApJ/700/597 : FERMI LAT detected blazars (Abdo+, 2009)
J/ApJ/716/30 : SED of Fermi bright blazars (Abdo+, 2010)
J/ApJ/764/5 : BR phot. of 2012 precursor flare in OJ287 (Pihajoki+, 2013)
J/A+A/596/A45 : Radio light curves of 8 AGN (Fuhrmann+, 2016)
J/AJ/151/54 : VRIJHK photometry of 3C 279 (Sandrinelli+, 2016)
J/A+A/597/A80 : GMVA 86GHz images of OJ 287 (Hodgson+, 2017)
J/A+A/619/A88 : High cadence polarization monitoring of OJ287 (Myserlis+, 2018)
J/ApJ/902/104 : Korean VLBI Network monitoring of OJ 287 (Lee+, 2020)
J/ApJ/923/30 : MOJAVE. XVIII. Bright radio-loud active AGNs (Lister+, 2021)
J/ApJS/260/12 : Jet kinematics of blazars at 43GHz (Weaver+, 2022)
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.3 GHz nu [1.4/43.75] Radio frequency
9- 17 F9.3 d MJD [57757.15/59752.63] Modified Julian date
(JD-2400000.5)
19- 24 F6.3 Jy Snu [2/11.2] Flux density
26- 30 F5.3 Jy e_Snu [0.003/1.4] Uncertainty in Snu
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.3 d MJD [57309.63/59760.21] Modified Julian date
(JD-2400000.5)
11- 16 A6 --- Band SMA radio band ("1.3 mm", "870 um" or "1.1 mm")
18- 23 F6.2 GHz nu [212.97/351.36] Radio frequency
25- 29 F5.3 Jy Snu [1.4/6.3] Flux density at nu
31- 35 F5.3 Jy e_Snu [0.07/0.5] Uncertainty in Snu
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History:
From electronic version of the journal
References:
Komossa et al. Paper Ia. 2017IAUS..324..168K 2017IAUS..324..168K
Myserlis et al. Paper Ib. 2018A&A...619A..88M 2018A&A...619A..88M Cat. J/A+A/619/A88
Komossa et al. Paper II. 2020MNRAS.498L..35K 2020MNRAS.498L..35K
Komossa et al. Paper III. 2021MNRAS.504.5575K 2021MNRAS.504.5575K
Komossa et al. Paper IV. 2021ApJ...923...51K 2021ApJ...923...51K
Komossa et al. Paper V. 2022MNRAS.513.3165K 2022MNRAS.513.3165K
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 28-Jan-2025