J/ApJ/813/51 γ-ray to IR study of the blazar CTA 102 (Casadio+, 2015)
A multi-wavelength polarimetric study of the blazar CTA 102 during a
gamma-ray flare in 2012.
Casadio C., Gomez J.L., Jorstad S.G., Marscher A.P., Larionov V.M.,
Smith P.S., Gurwell M.A., Lahteenmaki A., Agudo I., Molina S.N., Bala V.,
Joshi M., Taylor B., Williamson K.E., Arkharov A.A., Blinov D.A.,
Borman G.A., Paola A.D., Grishina T.S., Hagen-Thorn V.A., Itoh R.,
Kopatskaya E.N., Larionova E.G., Larionova L.V., Morozova D.A.,
Rastorgueva-Foi E., Sergeev S.G., Tornikoski M., Troitsky I.S., Thum C.,
Wiesemeyer H.
<Astrophys. J., 813, 51 (2015)>
=2015ApJ...813...51C 2015ApJ...813...51C (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Polarization ; Photometry, infrared ;
X-ray sources ; Gamma rays ; Photometry, UBVRI ; Ultraviolet ;
Millimetric/submm sources
Keywords: galaxies: active; galaxies: jets; quasars: individual: CTA 102;
techniques: interferometric; techniques: photometric
techniques: polarimetric
Abstract:
We perform a multi-wavelength polarimetric study of the quasar CTA 102
during an extraordinarily bright γ-ray outburst detected by the
Fermi Large Area Telescope in 2012 September-October when the source
reached a flux of F>100MeV=5.2±0.4x10-6photons/cm2/s. At the
same time, the source displayed an unprecedented optical and
near-infrared (near-IR) outburst. We study the evolution of the
parsec-scale jet with ultra-high angular resolution through a sequence
of 80 total and polarized intensity Very Long Baseline Array images at
43GHz, covering the observing period from 2007 June to 2014 June. We
find that the γ-ray outburst is coincident with flares at all
the other frequencies and is related to the passage of a new
superluminal knot through the radio core. The powerful γ-ray
emission is associated with a change in direction of the jet, which
became oriented more closely to our line of sight (θ∼1.2°)
during the ejection of the knot and the γ-ray outburst. During
the flare, the optical polarized emission displays intra-day
variability and a clear clockwise rotation of electric vector position
angles (EVPAs), which we associate with the path followed by the knot
as it moves along helical magnetic field lines, although a random walk
of the EVPA caused by a turbulent magnetic field cannot be ruled out.
We locate the γ-ray outburst a short distance downstream of the
radio core, parsecs from the black hole. This suggests that
synchrotron self-Compton scattering of NIR to ultraviolet photons is
the probable mechanism for the γ-ray production.
Description:
We have collected data from millimeter to γ-ray wavelengths,
extending our study from 2004 June to 2014 June. In particular, the
Fermi data extend from the start of the mission (2008 August) to 2013
September, X-ray and UV data cover the observing period from 2009
August to 2013 June, optical and NIR data from 2004 June to 2013
October, and the combined radio light curves cover the entire period
from 2004 June to 2014 June.
In the millimeter-wave range, we use data at (1) 350GHz (0.85mm) and
230GHz (1.3mm), obtained with the Submillimeter Array (SMA) at Mauna
Kea, Hawaii; (2) 230GHz (1.3mm) and 86.24GHz (3.5mm) with the 30m
Telescope of Institut de Radioastronomie Millimetrique (IRAM) at the
Pico Veleta Observatory (Spain); (3) 43GHz (7mm) with the VLBA; and
(5) 37GHz (8mm) with the 13.7m Telescope at Metsahovi Radio
Observatory of Aalto University (Finland).
NIR photometric data (JHK filters) were obtained at the Perkins
Telescope at Lowell Observatory (Flagstaff, AZ) using the MIMIR
instrument and at the 1.1m Telescope of the Main Astronomical
Observatory of the Russian Academy of Sciences located at Campo
Imperatore, Italy.
We have collected optical photometric data in the UBVRI bands from
numerous telescopes (see section 2).
We have analyzed the γ-ray data of the field containing CTA 102
from Fermi LAT from 2008 August to 2013 September, producing a light
curve between 0.1 and 200GeV with an integration time of 1day.
We collected X-ray (0.3-10keV) and UV data from 2009 August to 2013
June from the Swift archive.
Objects:
------------------------------------------------
RA (ICRS) DE Designation(s)
------------------------------------------------
22 32 36.4 +11 43 51 CTA 102 = 4C 11.69
------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
gamxray.dat 37 606 Gamma to X-ray data (part of table 1)
uvtorad.dat 52 3486 UV to Radio data (part of table 1)
table2.dat 84 298 VLBA 43GHz model-fit components' parameters
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See also:
J/ApJ/808/162 : VLBA 15 and 43GHz obs. of 3C 120 (Casadio+, 2015)
J/AJ/148/42 : S4 0954+658 outburst in 2011 March-April (Morozova+, 2014)
J/MNRAS/442/1693 : Gamma-ray-loud blazars opt. polarization (Pavlidou+, 2014)
J/A+A/566/A59 : 3.5 & 1.3mm polarimetric survey of AGNs (Agudo+, 2014)
J/AJ/146/120 : MOJAVE. X. Parsec-scale kinematics of AGNs (Lister+, 2013)
J/ApJ/768/40 : R-band & polarimetry of blazar S5 0716+71 (Larionov+, 2013)
J/A+A/551/A32 : Catching the radio flare in CTA 102 (Fromm+, 2013)
J/ApJS/206/17 : New gamma-ray blazar candidates in the 3PBC (Maselli+, 2013)
J/AJ/144/105 : MOJAVE. VIII. Faraday rotation in AGN jets. (Hovatta+, 2012)
J/ApJS/199/31 : Fermi LAT second source catalog (2FGL) (Nolan+, 2012)
J/ApJ/748/68 : WISE IR colors of gamma-ray blazars (D'Abrusco+, 2012)
J/ApJ/743/171 : The 2LAC catalog (Ackermann+, 2011)
J/ApJ/734/43 : 3C 111 X-ray, optical & radio monitoring (Chatterjee+, 2011)
J/ApJS/189/1 : A 3.5mm polarimetric survey of radio-loud AGNs (Agudo+, 2010)
J/ApJ/716/30 : SED of Fermi bright blazars (Abdo+, 2010)
J/AJ/138/1874 : MOJAVE. VI. Kinematic analysis of blazar jets (Lister+, 2009)
J/ApJ/672/40 : AO 0235+164 outburst in 2006 December (Hagen-Thorn+, 2008)
J/AJ/130/1418 : AGN jet kinematics (Jorstad+, 2005)
J/A+AS/131/303 : GHz-Peaked-Spectrum radio sources (Stanghellini+ 1998)
http://www.bu.edu/blazars/research.html : Research by BU blazar group page
Byte-by-byte Description of file: gamxray.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- lambda SED region ("Gamma-ray"=0.1-200GeV or
"X-ray"=0.3-10keV)
11- 17 F7.1 d MJD [52325.5/57043.5] Modified Julian date of
the observation
19- 27 E9.3 ph/cm2/s Flux Observed flux in energy range
29- 37 E9.3 ph/cm2/s e_Flux Uncertainty in Flux
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Byte-by-byte Description of file: uvtorad.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- lambda SED region ("UV", "Optical", "Near_Infrared"
or "Radio")
15- 21 F7.1 d MJD [52325.5/57043.5] Modified Julian date of
the observation
23- 31 E9.3 mJy Flux [0.181/10130] Observed flux in Band
33- 41 E9.3 mJy e_Flux [0.001/1600] Uncertainty in Flux
43- 45 I3 nm UVband ? Observational UV band (203, 223 or 263)
47- 50 F4.2 mm Radband ? Observational Radio band (0.85, 1.00, 3.00
or 8.00)
52 A1 --- Band Observational optical (UBVRI) or NIR (JHK) band
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Comp Component identifier (C0, C1, E1, S1 or N1-4) (1)
4- 10 F7.2 yr Obs.Y [2007.4/2014.5] Year of the observation
12- 18 F7.1 d MJD [54264.5/56829.5] Modified Julian Date of
the observation
20- 23 I4 mJy Flux [18/3423] VLBA 43GHz flux density
25- 27 I3 mJy e_Flux [12/347] Uncertainty in Flux
29- 32 F4.2 mas D-C0 [0.04/2.2]? Distance from C0 component (r)
34- 37 F4.2 mas e_D-C0 [0.01/0.5]? Uncertainty in D-C0
39- 44 F6.1 deg PA [-166.3/160.7]? Position angle
46- 49 F4.1 deg e_PA [0/18]? Uncertainty in PA
51 A1 --- l_amaj Limit flag on amaj
52- 56 F5.3 mas amaj [0.01/1] Angular major axis length
58- 62 F5.3 mas e_amaj [0.001/0.1]? Uncertainty in amaj
64- 67 F4.1 % DoP [0.2/75.1]? Degree of polarization
69- 73 F5.2 % e_DoP [0.1/11]? Uncertainty in DoP
75- 79 F5.1 deg EVPA [-89/176]? Electric vector position angle
81- 84 F4.1 deg e_EVPA [5/38]? Uncertainty in EVPA
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Note (1): Component E1, located at ∼2mas from the core, is a weak and extended
feature that appears to be quasi-stationary across some epochs, or to
move with a significantly slower velocity than other moving components
(see Figure 7). A stronger and more compact component, C1, can be
distinguished from the core at most of the observed epochs, located
at a mean distance of r∼0.1mas. We identify five other moving
components, N1, N2, N3, N4, and S1.
See section 4.1 for further explanations.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 12-Feb-2016