J/ApJ/881/125 2014-2018 multiwavelength obs. of PKS 1502+106 (Ding+, 2019)
Exploring the origin of multiwavelength activities of high-redshift
flat-spectrum radio quasar PKS 1502+106 during 2014-2018.
Ding N., Gu Q.S., Geng X.F., Xiong D.-R., Xue R., Wang X.Y., Guo X.T.
<Astrophys. J., 881, 125 (2019)>
=2019ApJ...881..125D 2019ApJ...881..125D
ADC_Keywords: QSOs; Gamma rays; X-ray sources; Photometry, ultraviolet;
Optical; Radio lines; Polarization
Keywords: galaxies: active; galaxies: jets; quasars: individual (PKS 1502+106);
radiation mechanisms: nonthermal
Abstract:
The origin of the multiband activities (outbursts/flares) of blazars
is still a heavily debated topic. Shock and magnetic reconnection have
long been considered as possible triggers of the multiband activities.
In this paper, we present an exploration of the origin of multiband
activities for a high-redshift (z=1.8385) flat-spectrum radio quasar
PKS 1502+106. Utilizing multiband data from radio to γ-ray and
optical polarization observations, we investigate two dramatic
activities in detail: a γ-ray- dominated outburst in 2015 and an
optical-dominated outburst in 2017. Our main results are as follows.
(I) A fast γ-ray flare with a flux-doubling timescale as short
as 1 hr in 2015 is discovered. Based on the variability timescale, the
physical parameters of the flaring region (e.g., minimum Doppler
factor, emission region size, etc.) are constrained. At the peak of
the flare, the γ-ray spectrum hardens to
Γγ=1.82±0.04 and exhibits an obvious curvature/break
characteristic that is caused by the typical "cooling break." Modeling
of multiband spectral energy distributions reveal a very hard
electronic energy spectrum with the electronic spectral index of
1.07±0.53. This result suggests that this fast γ-ray flare may
be triggered by magnetic reconnection. (II) During the outburst in
2017, the degree of optical polarization and optical fluxes showed a
very tight correlation. By analyzing the Stokes parameters of
polarization observations, our results show that this outburst could
be triggered by a transverse shock with a compression ratio of
η>2.2, and the magnetic field intensity of the shock emission
region is about 0.032G.
Description:
Using the Fermi data server, the newest Pass 8 Fermi-LAT data of
PKS1502+106 from 2014 October 10 to 2018 October 10, are acquired.
See Section 2.1.
We also search for the available Swift observations from the
astronomical archival data retrieval service provided by the High
Energy Astrophysics Science Archive Research Center (HEASARC).
In order to obtain reliable photometric results, among the 50
observations, we only analyze the XRT data of 45 observations with net
exposure time greater than 0.5ks.
XMM-Newton performed an observation in the imaging mode for Mkn 841 on
2015 July 14. At this time, PKS 1502+106 happened to be in the
brightest stage in the γ-ray band. This observation, therefore,
provides an important serendipitous X-ray data with a net exposure
time of up to ∼13ks for PKS 1502+106.
Another instrument on the Swift, UVOT, provides ultraviolet/optical
data. In the 50 Swift observations carried out between 2014 October 10
and 2018 October 10, except for those observations where PKS 1502+106
falls outside the field of view, the UVOT data of 36 observations are
available.
As a part of the Fermi multiwavelength support program, the Steward
Optical Observatory of the University of Arizona perform long-term
optical monitoring for PKS 1502+106 (Smith+ 2009arXiv0912.3621S 2009arXiv0912.3621S). The
optical R-band and V-band photometric data and polarimetric data
(optical linear PD and polarization angle (PA)) of PKS 1502+106 can be
easily acquired from the public archival database.
PKS 1502+106 is observed in the radio band by the OVRO 40m Telescope
as a part of Fermi multiwavelength support program
(Richards+ 2011, J/ApJS/194/29). We obtain the radio data of
PKS1502+106 detected at 15GHz from 2014 October 10 to 2018 October 10.
Objects:
-----------------------------------------------------------
RA (ICRS) DE Designation(s)
-----------------------------------------------------------
15 04 24.98 +10 29 39.2 PKS 1502+106 = QSO B1502+1041
-----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 77 45 Summary of Swift-XRT Observations of PKS 1502+106
fig1.dat 349 191 Multiwavelength LCs of PKS1502+106
from 2014-Oct-10 to 2018-Oct-10
--------------------------------------------------------------------------------
See also:
B/swift : Swift Master Catalog (HEASARC, 2004-)
B/xmm : XMM-Newton Log (XMM-Newton Science Operation Center, 2012)
VIII/85 : SPECFIND V2.0 Catalog of radio continuum spectra (Vollmer+ 2009)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
VII/287 : Extragalactic linear polarizations (Friedman+, 2020)
J/A+A/441/915 : Alignments of quasar polarization vectors (Hutsemekers+, 2005)
J/AJ/131/1262 : Circular polarization images at 15GHz of AGNs (Homan+, 2006)
J/ApJ/672/40 : AO 0235+164 outburst in 2006 December (Hagen-Thorn+, 2008)
J/ApJS/189/1 : A 3.5mm polarimetric survey of radio-loud AGNs (Agudo+, 2010)
J/ApJ/722/520 : Gamma-ray light curves of Fermi blazars (Abdo+, 2010)
J/ApJS/194/19 : Optical linear polarization at McDonald Obs. (Wills+, 2011)
J/ApJS/194/29 : Observations of blazars at 15GHz (Richards+, 2011)
J/ApJS/199/31 : Fermi LAT second source catalog (2FGL) (Nolan+, 2012)
J/A+A/538/A26 : BL Lac objects beyond z=1.3 (Rau+, 2012)
J/A+A/541/A160 : Planck + X/γ observations of blazars (Giommi+, 2012)
J/ApJ/748/49 : Optical spectroscopy of 1LAC broad-line blazars (Shaw+, 2012)
J/ApJ/757/51 : FIRST-2MASS dust-reddened QSO spectra (Glikman+, 2012)
J/ApJ/761/125 : X and γ spectral indexes of Fermi blazars (Fan+, 2012)
J/ApJ/768/40 : R-band & polarimetry of the blazar S5 0716+71 (Larionov+, 2013)
J/MNRAS/439/690 : Optical/γ-ray variability in blazars (Hovatta+, 2014)
J/ApJS/218/23 : Fermi LAT third source catalog (3FGL) (Acero+, 2015)
J/ApJ/833/77 : gamma-ray bright blazars optical polarization (Itoh+, 2016)
J/A+A/586/A60 : PKS 1502+106 15, 43 and 86GHz images (Karamanavis+, 2016)
J/A+A/590/A10 : 3C 279 optical photometry and polarimetry (Kiehlmann+, 2016)
J/ApJS/226/20 : X-ray, opt. & radio SEDs of Fermi blazars (Fan+, 2016)
J/ApJ/851/33 : Multi-wavelength analysis of CGRaBS blazars (Paliya+, 2017)
J/ApJS/234/12 : MOJAVE XV. VLBA 15GHz obs. of AGNs 1996-2016 (Lister+, 2018)
J/ApJ/865/56 : Emission line & R-band continuum LCs of 17 QSOs (Lira+, 2018)
J/other/RAA/18.56 : gamma-ray spectrum for Fermi blazars (Kang+, 2018)
J/ApJ/880/29 : X-ray polarization predictions in blazars (Liodakis+, 2019)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 I11 --- ObsID [36388020/94003008] Observation identifier
13 A1 --- f_ObsID Flag on ObsID (1)
15- 25 A11 "Y/M/D" Date Date of observation (UT)
27- 34 F8.2 d MJD [57211.6/58338.5] Modified Julian Date
36- 42 F7.2 s Exp [566.89/4729.87] Net exposure time
44- 47 F4.2 10-15W/m2 Flux [0.41/2.71] 0.3-10keV model flux
in 10-12erg/cm2/s units
49- 52 F4.2 10-15W/m2 e_Flux [0.11/0.85] 1σ uncertainty in Flux
54- 57 F4.2 --- Gamma [1.03/2.11] Best-fit photon index ΓX
59- 62 F4.2 --- e_Gamma [0.1/0.61] 1σ lower uncertainty in Gamma
64- 67 F4.2 --- E_Gamma [0.1/0.63] 1σ upper uncertainty in Gamma
69- 73 F5.1 --- Cstat [9.9/130.5] C statistics
75- 77 I3 --- dof [24/180] Degree of freedom
--------------------------------------------------------------------------------
Note (1): The corresponding X-ray observations of the four epochs (pre-flare,
flare, post-flare I, and post-flare III) in Figures 4 and 7 are marked
by superscripts a, b, c, and d, respectively.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: fig1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.3 d MJDG [56985.5/58399.5] Modified Julian Date
of LAT observation
11- 16 F6.3 10-7ph/cm2/s FG [0.8/15.4] Fermi-LAT 0.1-300GeV flux
18- 22 F5.3 10-7ph/cm2/s e_FG [0.2/1.4] Uncertainty in F-G
24- 32 F9.3 d MJDX [57212.8/58338.5]? Modified Julian Date
of XRT observation
34- 40 F7.5 10-2ct/s FX [1.2/5.4]? Swift-XRT count rate
42- 48 F7.5 10-2ct/s e_FX [0.2/1]? Uncertainty in F-X
50- 58 F9.3 d MJDW2 [57211.6/58338.5]? Modified Julian Date
of W2 observation
60- 68 F9.7 mJy FW2 [0.02/0.33]? Swift-UVOT W2 band flux
density
70- 78 F9.7 mJy e_FW2 [0.002/0.02]? Uncertainty in F-W2
80- 88 F9.3 d MJDM2 [57211.6/58123]? Modified Julian Date
of M2 observation
90- 98 F9.7 mJy FM2 [0.12/0.4]? Swift-UVOT M2 band flux
density
100- 108 F9.7 mJy e_FM2 [0.005/0.02]? Uncertainty in F-M2
110- 118 F9.3 d MJDW1 [57211.6/58123]? Modified Julian Date
of W1 observation
120- 128 F9.7 mJy FW1 [0.14/0.48]? Swift-UVOT W1 band flux
density
130- 138 F9.7 mJy e_FW1 [0.008/0.02]? Uncertainty in F-W1
140- 148 F9.3 d MJDU [57211.6/58123]? Modified Julian Date
of U observation
150- 158 F9.7 mJy FU [0.27/0.83]? Swift-UVOT U band flux
density
160- 168 F9.7 mJy e_FU [0.01/0.04]? Uncertainty in F-U
170- 178 F9.3 d MJDB [57211.6/58123]? Modified Julian Date
of B observation
180- 188 F9.7 mJy FB [0.41/1.16]? Swift-UVOT B band flux
density
190- 198 F9.7 mJy e_FB [0.02/0.06]? Uncertainty in F-B
200- 208 F9.3 mJy MJDV [57211.6/58123]? Modified Julian Date
of V observation
210- 218 F9.7 mJy FV [0.53/1.58]? Swift-UVOT V band flux
density
220- 228 F9.7 mJy e_FV [0.04/0.09]? Uncertainty in F-V
230- 238 F9.3 d MJDVs [57014.5/58306.4]? Modified Julian Date
of Vs observation
240- 245 F6.4 mJy FVs [0.14/2.24]? Steward Observatory V band
flux density
247- 252 F6.4 mJy e_FVs [0.01/0.3]? Uncertainty in F-Vs
254- 262 F9.3 d MJDRs [57014.5/58306.4]? Modified Julian Date
of Rs observation
264- 269 F6.4 mJy FRs [0.18/3.08]? Steward Observatory R band
flux density
271- 276 F6.4 mJy e_FRs [0.02/0.4]? Uncertainty in F-Rs
278- 287 F10.4 d MJDRad [56940/58303.1]? Modified Julian Date
of Rad observation
289- 297 F9.7 Jy FRad [1.24/4.12]? OVRO 15GHz flux density
299- 307 F9.7 Jy e_FRad [0.01/0.15]? Uncertainty in F-Rad
309- 317 F9.3 d MJDPD [57014.5/58306.3]? Modified Julian Date
of PD observation
319- 323 F5.2 % PD [1.12/48.5]? Optical polarization degree
325- 328 F4.2 % e_PD [0.05/1.6]? Uncertainty in PD
330- 338 F9.3 d MJDPA [57014.5/58306.3]? Modified Julian Date
of PA observation
340- 344 F5.1 deg PA [59.3/345.1]? Optical polarization angle
346- 349 F4.1 deg e_PA [0.1/12.7]? Uncertainty in PA
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 26-Jan-2021