J/A+A/640/A132 BL Lacs optical light curves & X-ray prop. (MAGIC Coll., 2020)
Testing two-component models on very high-energy gamma-ray-emitting
BL Lac objects.
MAGIC Collaboration, Acciari V.A., Ansoldi S., Antonelli L.A.,
Arbet Engels A., Baack D., Babic A., Banerjee B., Barres de Almeida U.,
Barrio J.A., Becerra Gonzalez J., Bednarek W., Bellizzi L., Bernardini E.,
Berti A., Besenrieder J., Bhattacharyya W., Bigongiari C., Biland A.,
Blanch O., Bonnoli G., Bosnjak Z., Busetto G., Carosi R., Ceribella G.,
Cerruti M., Chai Y., Chilingarian A., Cikota S., Colak S.M., Colin U.,
Colombo E., Contreras J.L., Cortina J., Covino S., D'Amico G., D'Elia V.,
Da Vela P., Dazzi F., De Angelis A., De Lotto B., Delfino M., Delgado J.,
Depaoli D., Di Pierro F., Di Venere L., Do Souto Espineira E.,
Dominis Prester D., Donini A., Dorner D., Doro M., Elsaesser D.,
Fallah Ramazani V., Fattorini A., Ferrara G., Foano L., Fonseca M.V.,
Font L., Fruck C., Fukami S., Garcia Lopez R.J., Garczarczyk M.,
Gasparyan S., Gaug M., Giglietto N., Giordano F., Gliwny P., Godinovic N.,
Green D., Hadasch D., Hahn A., Herrera J., Hoang J., Hrupec D., Huetten M.,
Inada T., Inoue S., Ishio K., Iwamura Y., Jouvin L., Kajiwara Y.,
Karjalainen M., Kerszberg D., Kobayashi Y., Kubo H., Kushida J.,
Lamastra A., Lelas D., Leone F., Lindfors E., Lombardi S., Longo F.,
Lopez M., Lopez-Coto R., Lopez-Oramas A., Loporchio S.,
Machado de Oliveira Fraga B., Maggio C., Majumdar P., Makariev M.,
Mallamaci M., Maneva G., Manganaro M., Mannheim K., Maraschi L.,
Mariotti M., Martinez M., Mazin D., Mender S., Micanovic S., Miceli D.,
Miener T., Minev M., Miranda J.M., Mirzoyan R., Molina E., Moralejo A.,
Morcuende D., Moreno V., Moretti E., Munar-Adrover P., Neustroev V.,
Nigro C., Nilsson K., Ninci D., Nishijima K., Noda K., Nogues L.,
Nozaki S., Ohtani Y., Oka T., Otero-Santos J., Palatiello M., Paneque D.,
Paoletti R., Paredes J.M., Pavletic L., Penil P., Peresano M., Persic M.,
Prada Moroni P.G., Prandini E., Puljak I., Rhode W., Ribo M., Rico J.,
Righi C., Rugliancich A., Saha L., Sahakyan N., Saito T., Sakurai S.,
Satalecka K., Schleicher B., Schmidt K., Schweizer T., Sitarek J.,
Snidaric I., Sobczynska D., Spolon A., Stamerra A., Strom D., Strzys M.,
Suda Y., Suric T., Takahashi M., Tavecchio F., Temnikov P., Terzic T.,
Teshima M., Torres-Alba N., Tosti L., van Scherpenberg J., Vanzo G.,
Vazquez Acosta M., Ventura S., Verguilov V., Vigorito C.F., Vitale V.,
Vovk I., Will M., Zaric D., Nievas-Rosillo M., Arcaro C., D'Ammando F.,
de Palma F., Hodges M., Hovatta T., Kiehlmann S., Max-Moerbeck W.,
Readhead A.C.S., Reeves R., Takalo L., Reinthal R., Jormanainen J.,
Wierda F., Wagner S.M., Berdyugin A., Nabizadeh A., Talebpour Sheshvan N.,
Oksanen A., Bachev R., Strigachev A., Kehusmaa P.
<Astron. Astrophys. 640, A132 (2020)>
=2020A&A...640A.132M 2020A&A...640A.132M (SIMBAD/NED BibCode)
ADC_Keywords: BL Lac objects ; Photometry ; X-ray sources
Keywords: galaxies: active - galaxies: jets - BL Lacertae objects: general -
astronomical databases: miscellaneous -
radiation mechanisms: non-thermal - gamma rays: galaxies
Abstract:
It has become evident that one-zone synchrotron self-Compton models
are not always adequate for very high-energy (VHE) gamma-ray-emitting
blazars. While two-component models perform better, they are difficult
to constrain due to the large number of free parameters.
In this work, we make a first attempt at taking into account the
observational constraints from very long baseline interferometry
(VLBI) data, long-term light curves (radio, optical, and X-rays), and
optical polarisation to limit the parameter space for a two-component
model and test whether or not it can still reproduce the observed
spectral energy distribution (SED) of the blazars.
We selected five TeV BL Lac objects based on the availability of VHE
gamma-ray and optical polarisation data. We collected constraints for
the jet parameters from VLBI observations. We evaluated the
contributions of the two components to the optical flux by means of
decomposition of long-term radio and optical light curves as well as
modelling of the optical polarisation variability of the objects. We
selected eight epochs for these five objects based on the variability
observed at VHE gamma rays, for which we constructed the SEDs that we
then modelled with a two-component model.
We found parameter sets which can reproduce the broadband SED of the
sources in the framework of two-component models considering all
available observational constraints from VLBI observations. Moreover,
the constraints obtained from the long-term behaviour of the sources
in the lower energy bands could be used to determine the region where
the emission in each band originates. Finally, we attempt to use
optical polarisation data to shed new light on the behaviour of the
two components in the optical band. Our observationally constrained
two-component model allows explanation of the entire SED from radio to
VHE with two co-located emission regions.
Description:
Tuorla blazar monitoring program, Optical R-Band (Cousine), 2012
September 30 to 2018 July 21.
Swift-XRT, Spectral properties and flux, 2012 September 30 to 2018
October 9.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 72 5 General properties of the selected TeV BL Lacs
and the correction coefficients used in
optical, UV, and X-ray data analysis
tablea1.dat 35 1550 The optical (R-band) light-curve data
tablea2.dat 119 569 Results of Swift-XRT observations
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Name Source name
15- 16 I2 h RAh Right ascension (J2000)
18- 19 I2 min RAm Right ascension (J2000)
21- 24 F4.1 s RAs Right ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27- 28 I2 deg DEd Declination (J2000)
30- 31 I2 arcmin DEm Declination (J2000)
33- 34 I2 arcsec DEs Declination (J2000)
36 A1 --- l_z Lower limit on z based on spectroscopy
(Paiano et al., 2017ApJ...837..144P 2017ApJ...837..144P)
37- 41 F5.3 --- z Redshift
43- 47 F5.3 mag AR R-band Galactic extinction (1)
49- 52 F4.2 10+21cm-2 NH Equivalent Galactic hydrogen column density (2)
54- 56 F3.1 arcsec rap(ph) Aperture radius for optical photometry
58- 60 F3.1 arcsec rap(pol) Aperture radius for polarisation observation
62- 65 F4.2 mJy Fhostph Contribution of the host-galaxy flux (R-band)
within the aperture for optical photometry
66 A1 --- n_Fhostph [cbd] Note on Fhostph
68- 71 F4.2 mJy Fhostpol Contribution of the host-galaxy flux (R-band)
within the aperture for polarisation
observation
72 A1 --- n_Fhostpol [cbd] Note on Fhostpol (3)
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Note (1): reported by Schlafly & Finkbeiner (2011ApJ...737..103S 2011ApJ...737..103S) used for
correcting the optical observations.
Note (2): Equivalent Galactic hydrogen column density reported by Kalberla et
al. (2005A&A...440..775K 2005A&A...440..775K, Cat. VIII/76) used for correcting UV and X-ray
observations.
Note (3): Notes as follows:
b = Assumed to be zero based on the uncertainty of the redshift and
the reported redshift lower limit
c = Reported by Scarpa et al. (2000ApJ...532..740S 2000ApJ...532..740S)
d = Reported by Nilsson et al. (2007A&A...475..199N 2007A&A...475..199N)
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Name Taget name
15- 24 F10.2 d JD Julian date
26- 30 F5.2 mJy Flux Optical (R-band) flux
32- 35 F4.2 mJy e_Flux Optical (R-band) flux error
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Name Target Name
15- 22 F8.2 d MJD Modified Julian date (start of observation)
24- 34 I11 --- OID Swift observation ID
36- 39 I4 s ExpTime Exposure time
41- 44 F4.2 --- Gamma-PL ? Spectral index of power the law model
46- 49 F4.2 --- e_Gamma-PL ? Spectral index error of the power law
model
51- 55 F5.1 --- CHI2-PL ? Chi2 value of the fitted power law
model
57- 59 I3 --- DOF-PL ? Degree of the freedom of the fitted power
law model
61- 64 F4.2 --- Gamma-LP ? Spectral index of the logparabola model
66- 69 F4.2 --- e_Gamma-LP ? Spectral index error of the
logparabola model
71- 74 F4.2 --- Beta-LP ? Curvature parameter of the logparabola
model
76- 79 F4.2 --- e_Beta-LP ? Curvature parameter error of the
logparabola model
81- 85 F5.1 --- CHI2-LP ? Chi^2 value of the fitted logparabola
model
87- 89 I3 --- DOF-LP ? Degree of the freedom of the fitted
logparabola model
91 A1 --- l_Prob Limit flag on Prob
92- 96 F5.2 % Prob Null-hypotheses probability of the
F-test (1)
98-102 F5.1 10-15W/m2 F1 X-ray flux in the range of 2-10keV
104-107 F4.1 10-15W/m2 e_F1 X-ray flux error in the range of 2-10keV
109-114 F6.1 10-15W/m2 F2 X-ray flux in the range of 0.3-10keV
116-119 F4.1 10-15W/m2 e_F2 X-ray flux error in the range of 0.3-10keV
--------------------------------------------------------------------------------
Note (1): The logparabola model is preferred over the powerlaw model at 3-sigma
confidence level if the F-test probability value is less than 0.27%.
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Acknowledgements:
Vandad Fallah Ramazani, vafara(at)utu.fi
(End) Patricia Vannier [CDS] 10-Aug-2020