J/ApJ/925/139 Blazar 4C+01.02 opt. LCO phot. & SALT spectropol. (Schutte+, 2022)
Modeling the spectral energy distributions and spectropolarimetry of blazars --
application to 4C+01.02 in 2016-2017.
Schutte H.M., Britto R.J., Bottcher M., van Soelen B., Marais J.P.,
Kaur A., Falcone A.D., Buckley D.A.H., Rajoelimanana A.F., Cooper J.
<Astrophys. J., 925, 139 (2022)>
=2022ApJ...925..139S 2022ApJ...925..139S
ADC_Keywords: Active gal. nuclei; Photometry; Spectra, optical; Polarization
Keywords: Active galaxies ; Galaxy jets ; Flat-spectrum radio quasars ;
Spectropolarimetry ; Blazars ; Active galactic nuclei
Abstract:
The optical radiation emitted by blazars contains contributions from
synchrotron radiation by relativistic electrons in the jets, as well
as thermal radiation emitted mainly by the accretion disk (AD), the
broad-line region (BLR), and the host galaxy. The unpolarized
radiation components from the AD, BLR, and host galaxy present
themselves by decreasing the total polarization in the
optical/ultraviolet (UV) spectrum. A combined model for the spectral
energy distribution (SED) and degree of optical/UV polarization is
constructed, enabling the disentanglement of the synchrotron and AD
components. Our model is applied to the multiwavelength SED and
spectropolarimetry observations of the flat-spectrum radio quasar
4C+01.02 (z=2.1) in its 2016 July-August flaring state and
2017 July-August quiescent state, using data from the Fermi Large Area
Telescope, the Southern African Large Telescope, and the Las Cumbres
Observatory network of telescopes. By constraining the AD component,
the mass of the supermassive black hole is obtained as
∼3x109M☉. Furthermore, the model retrieves the characteristics
of the relativistic electron distribution in the jet and the degree of
ordering of the magnetic field. Our results highlight the potential of
spectropolarimetry observations for disentangling thermal from
nonthermal (jet) emission components, thus revealing the physics of
particle acceleration and high-energy emission in active galactic
nucleus jets.
Description:
The Las Cumbres Observatory (LCO) was used to obtain photometric
observations of 4C+01.02 in the B, V, and R bands during MJD
57602-57605 and MJD 57626-57643, covering parts of the 2016-Jul-Aug
gamma-ray outburst. A set of four observations (B, V, R, and I
filters) was also taken on 2017 July 28 (MJD 57962.1671-57962.1796).
Optical spectropolarimetry observations of 4C+01.02 were carried out
on 2016 July 9 (MJD57578.1354-57578.1638) and on 2017 July 25
(MJD57959.1062-57959.1347) using the Robert Stobie Spectrograph (RSS)
on SALT. The observations covered a wavelength range of ∼3200-8500Å
with a resolving power of R∼167-533.
A spectrum in the 3000-8500Å range was also taken with the SpUpNIC
spectrograph on the SAAO 1.9m telescope on 2016 August 1 (MJD57601.10,
during the "postflare" period).
Objects:
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RA (ICRS) DE Designation(s)
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01 08 38.77 +01 35 00.3 4C+01.02 = CGRaBS J0108+0135
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig1.dat 45 1886 Optical spectropolarimetry data of 4C+01.02
fig4.dat 30 214 LCO light-curves in the R, V and B bands
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See also:
VIII/76 : Leiden/Argentine/Bonn (LAB) Survey of Galactic HI (Kalberla+ 2005)
VII/286 : SDSS quasar catalog, fourteenth data release (Paris+, 2018)
J/ApJ/851/33 : Multi-wavelength analysis of CGRaBS blazars (Paliya+, 2017)
Byte-by-byte Description of file: fig1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 "D/M/Y" Date Date of the observation
13- 15 A3 --- Units Units of the last two columns (1)
17- 25 E9.3 0.1nm lambda [3804/7748] Wavelength; Angstroms
27- 35 E9.3 --- YAxis [0.14/11.65] The y axis value (1)
37- 45 E9.3 --- e_YAxis [0.2/1.15]? Uncertainty in YAxis
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Note (1): The spectra have units of counts while the linear polarization is a
percentage. There are 905 rows for each spectrum.
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Byte-by-byte Description of file: fig4.dat
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Bytes Format Units Label Explanations
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1 A1 --- Filt [RVB] Filter
3- 13 F11.5 d MJD [57602/57962.2] Modified Julian Date
15- 22 F8.5 mag mag [16.56/18.5] Apparent Vega magnitude in Filter
24- 30 F7.5 mag e_mag [0.01/0.09] Uncertainty in mag
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 06-Sep-2023