J/ApJ/846/98 Jet kinematics of blazars at 43GHz with the VLBA (Jorstad+, 2017)
Kinematics of parsec-scale jets of gamma-ray blazars at 43GHz within the
VLBA-BU-BLAZAR program.
Jorstad S.G., Marscher A.P., Morozova D.A., Troitsky I.S., Agudo I.,
Casadio C., Foord A., Gomez J.L., MacDonald N.R., Molina S.N.,
Lahteenmaki A., Tammi J., Tornikoski M.
<Astrophys. J., 846, 98-98 (2017)>
=2017ApJ...846...98J 2017ApJ...846...98J (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Radio continuum ; Gamma rays ;
Photometry, RI ; Interferometry
Keywords: galaxies: active; galaxies: jets; techniques: interferometric
Abstract:
We analyze the parsec-scale jet kinematics from 2007 June to 2013
January of a sample of γ-ray bright blazars monitored roughly
monthly with the Very Long Baseline Array at 43GHz. In a total of
1929 images, we measure apparent speeds of 252 emission knots in
21 quasars, 12 BL Lacertae objects (BLLacs), and 3 radio galaxies,
ranging from 0.02c to 78c; 21% of the knots are quasi-stationary.
Approximately one-third of the moving knots execute non-ballistic
motions, with the quasars exhibiting acceleration along the jet within
5pc (projected) of the core, and knots in BLLacs tending to decelerate
near the core. Using the apparent speeds of the components and the
timescales of variability from their light curves, we derive the
physical parameters of 120 superluminal knots, including variability
Doppler factors, Lorentz factors, and viewing angles. We estimate the
half-opening angle of each jet based on the projected opening angle
and scatter of intrinsic viewing angles of knots. We determine
characteristic values of the physical parameters for each jet and
active galactic nucleus class based on the range of values obtained
for individual features. We calculate the intrinsic brightness
temperatures of the cores, Tb,intcore, at all epochs, finding that
the radio galaxies usually maintain equipartition conditions in the
cores, while ∼30% of Tb,intcore measurements in the quasars and
BLLacs deviate from equipartition values by a factor >10. This
probably occurs during transient events connected with active states.
Description:
The VLBA-BU-BLAZAR monitoring program consists of approximately
monthly observations with the VLBA at 43GHz of a sample of AGNs
detected as γ-ray sources. In this paper, we present the results
of observations from 2007 June to 2013 January. The sample consists of
21 FSRQs, 12 BLLacs, and 3 radio galaxies (RGs). It includes the
blazars and radio galaxies detected at γ-ray energies by EGRET
with average flux density at 43GHz exceeding 0.5Jy, declination north
of -30°, and optical magnitude in the R band brighter than 18.5.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 71 36 The VLBA-BU-BLAZAR sample
table2.dat 84 9647 Modeling of jets by Gaussian components -
updated version
table3.dat 69 295 Jet structure
table5.dat 91 258 Velocity and acceleration in jets
table7.dat 65 120 Physical parameters of jet features
--------------------------------------------------------------------------------
See also:
J/A+A/604/A111 : 22GHz image of 3C 273 (Bruni+, 2017)
J/A+A/597/A80 : GMVA 86GHz images of OJ 287 (Hodgson+, 2017)
J/AJ/152/12 : MOJAVE. XIII. New 15GHz obs. on 1994-2013 (Lister+, 2016)
J/AJ/151/142 : Five years of blazar obs. with VERITAS (Archambault+, 2016)
J/ApJ/816/53 : Multiwavelength obs. of BL Lac in 2012-2013 (Wehrle+, 2016)
J/ApJ/813/51 : γ-ray to IR study of the blazar CTA 102 (Casadio+, 2015)
J/ApJ/808/162 : VLBA 15 and 43GHz obs. of 3C 120 (Casadio+, 2015)
J/A+A/578/A22 : Mrk421 in March 2010 (Aleksic+, 2015)
J/AJS/218/23 : Fermi LAT third source catalog (3FGL) (Acero+, 2015)
J/ApJ/804/7 : SaMOSA: optical spectroscopy of 7 Fermi blazars (Isler+, 2015)
J/ApJ/798/134 : MOJAVE. XII. Acceleration of blazar jets (Homan+, 2015)
J/AJ/148/42 : S4 0954+658 outburst in 2011 March-April (Morozova+, 2014)
J/ApJ/789/135 : Gamma-ray bright blazars spectrophotometry (Williamson+, 2014)
J/MNRAS/441/1899 : Fermi bright blazars (Fuhrmann+, 2014)
J/AJ/147/143 : MOJAVE. XI. Spectral distributions (Hovatta+, 2014)
J/ApJ/787/151 : Fitted jet components in BL Lacertae (Cohen+, 2014)
J/A+A/559/A75 : 43GHz observation of the blazar Mrk 421 (Blasi+, 2013)
J/AJ/146/120 : MOJAVE. X. Parsec-scale kinematics of AGNs (Lister+, 2013)
J/ApJ/772/13 : VLBI observations of 3C 279 at 230GHz (Lu+, 2013)
J/ApJ/768/40 : R-band and polarimetry of blazar S5 0716+71 (Larionov+, 2013)
J/A+A/541/A160 : Planck + X/γ observations of blazars (Giommi+, 2012)
J/A+A/535/A69 : AGN Fermi/LAT γ-ray and 37GHz fluxes (Nieppola+, 2011)
J/ApJ/740/98 : Synchroton peak for blazars and radio galaxies (Meyer+, 2011)
J/AJ/138/1874 : MOJAVE. VI. Kinematic analysis of blazar jets (Lister+, 2009)
J/ApJ/706/1253 : MOJAVE VII. Blazar jet acceleration (Homan+, 2009)
J/AJ/135/2453 : Sample of BL Lac objects from SDSS and FIRST (Plotkin+, 2008)
J/ApJ/657/706 : EGRET blazar gamma-ray spectrum (Nandikotkur+, 2007)
J/AJ/130/2473 : Fine-scale structure in 250 sources at 15GHz (Kovalev+, 2005)
J/AJ/130/1418 : AGN jet kinematics (Jorstad+, 2005)
J/ApJ/609/539 : Kinematics of parsec-scale radio jets (Kellermann+, 2004)
J/ApJS/123/79 : Third EGRET catalog (3EG) (Hartman+, 1999)
http://www.bu.edu/blazars/VLBAproject.html : VLBA-BU-BLAZAR program home page
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- ID Source identifier (HHMM+ddd; B1950)
10 A1 --- f_ID Flag on ID (1)
12- 23 A12 --- OName Common name
25- 28 A4 --- Type Object type
30- 35 F6.4 --- z Redshift from NED
36 A1 --- f_z [d] d: Redshift has not been confirmed
38- 42 F5.2 Jy S43avg [0.2/18.1] Mean VLBA 43GHz flux density <S43>
44- 47 F4.2 Jy e_S43avg [0.07/10] S43avg uncertainty
49- 53 F5.2 --- Sgamavg [2/78] Average γ-ray photon flux at
0.1-200GeV; in 10-8ph/cm2/s
55- 60 F6.2 --- e_Sgamavg [1.9/158] Sgamavg uncertainty (2)
62- 66 F5.2 mag Rmagavg [12.3/19.3] Average magnitude in R band from
Perkins telescope (Lowell Observatory)
observations
68- 71 F4.2 mag e_Rmagavg [0.05/1.4] Rmagavg uncertainty
--------------------------------------------------------------------------------
Note (1): Flag as follows:
a = Source added to the sample in 2009.
b = Source added to the sample in 2010.
c = Source added to the sample in 2012.
Note (2): Average γ-ray photon flux at 0.1-200GeV standard deviation
based on γ-ray light curves, which we calculate using photon and
spacecraft data provided by the Fermi Space Science Center (for
details, see Williamson+ 2014, J/ApJ/789/135).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- ID Source identifier (HHMM+ddd; B1950)
10- 18 F9.4 yr Epoch Epoch of observation start
20- 24 I5 d MJD Modified Julian Date of observation start
26- 31 F6.3 Jy S43 [0.001/21.8] Flux density at 43GHz
33- 37 F5.3 Jy e_S43 [0.008/1.1] The 1σ uncertainty in S43
39- 43 F5.3 mas R [0/9] Distance to the core
45- 49 F5.3 mas e_R [0.003/2.6]? The 1σ uncertainty in R
51- 56 F6.1 deg theta Relative position angle with respect to the core
58- 61 F4.1 deg e_theta [0/39]? The 1σ uncertainty in theta
63- 67 F5.3 mas a [0/2.6] Angular size (1)
69- 73 F5.3 mas e_a [0.003/0.2] The 1σ uncertainty in a
75- 83 E9.3 K Tb Observed brightness temperature (2)
84 A1 --- l_Tb [L] Lower limit flag on Tb (3)
--------------------------------------------------------------------------------
Note (1): Corresponding to the FWHM of the circular Gaussian component.
Note (2): Where Tb = 7.5e8 S/a2 K (see Section 3.2 for calculation details).
Note (3): For details see Section 3.2.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- ID Source identifier (HHMM+ddd; B1950)
10- 12 A3 --- Knot Knot designation
14- 15 I2 --- N [3/76] Number of epochs knot was detected
17- 22 F6.3 Jy S43avg [0.01/11.3] Mean 43GHz flux density (1)
24- 28 F5.3 Jy e_S43avg [0.008/6.1] Standard deviation in S43avg
30- 34 F5.3 mas Ravg [0/5] Mean distance (2)
36- 40 F5.3 mas e_Ravg [0.01/2]? Standard deviation in Ravg
42- 47 F6.1 deg thetaavg ? Mean position angle for knot <θ> (3)
49- 52 F4.1 deg e_thetaavg [0.4/44.1]? Standard deviation in thetaavg
54- 58 F5.3 mas aavg [0.02/1.3] Mean knot size (1)
60- 64 F5.3 mas e_aavg [0.01/0.5] Standard deviation in a
66- 69 A4 --- Type Knot type (4)
--------------------------------------------------------------------------------
Note (1): Of the knot over the epochs when it was detected.
Note (2): Of the knot over the epochs when it was detected. This represents the
typical distance at which a knot was observed, although it is not
necessarily the mid-point of its trajectory
Note (3): Of the knot over the epochs when it was detected, except the core.
In the case of the core it is the average projected direction of the
inner jet (see Section 3 for full details).
Note (4): See Section 3 for full details. Knot type as follows:
Core = Core component;
St = quasi-stationary, detected ≥10 epochs and with proper motion
µ<2σµ.
M = moving feature, proper motion µ≥2σµ.
CJ = counter-jet, detected upstream of the core at ≥6 epochs.
T = trailing component, see Agudo+ (2001ApJ...549L.183A 2001ApJ...549L.183A).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- ID Source identifier (HHMM+ddd; B1950)
10- 12 A3 --- Knot Knot designation
15- 15 I1 --- l [1/4] Order of polynomial to fit motion
16 A1 --- f_l [b] Flag on l (1)
18- 22 F5.3 mas/yr muavg [0.002/4] Mean proper motion <µ>
24- 28 F5.3 mas/yr e_muavg [0.002/0.2] Uncertainty in muavg
30- 35 F6.1 deg Phiavg ? Mean direction of motion <Φ>
37- 40 F4.1 deg e_Phiavg [0.1/70.1]? Uncertainty in Phiavg
42- 47 F6.3 mas/yr2 dotmu-ll [-1/4]? Acceleration along jet direction
(dµ/dt)||
49- 53 F5.3 mas/yr2 e_dotmu-ll [0.001/0.2]? Uncertainty in dotmu-ll
55- 60 F6.3 mas/yr2 dotmu-pp [-1/0.8]? Acceleration perpendicular to
jet direction ((dµ/dt)⊥)
62- 66 F5.3 mas/yr2 e_dotmu-pp [0.002/0.2]? Uncertainty in dotmu-pp
68- 72 F5.2 --- betaavg [0.02/78] Mean apparent speed in units of
the speed of light <βapp>
74- 77 F4.2 --- e_betaavg [0.01/9] Uncertainty in beta
79- 85 F7.2 --- Tcirc [1983.9/2012.8]? Epoch of ejection
86 A1 --- f_Tcirc [b] Flag on Tcirc (2)
88- 91 F4.2 --- e_Tcirc [0.02/3.5]? Uncertainty in Tcirc
--------------------------------------------------------------------------------
Note (1):
b = Designates cases when the χ2 criterion is not reached for fitting
the trajectory of a knot with polynomials of order from 0 to 4.
Note (2):
b = Designates cases when the time of ejection is calculated based on the
best-fit polynomial for the R coordinate.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- ID Source identifier (HHMM+ddd; B1950)
10- 12 A3 --- Knot Knot designation
14- 18 F5.3 yr tau [0.1/3.2] Timescale of variability of
flux density
20- 24 F5.3 yr e_tau [0.007/0.9] Standard deviation in tau
26- 29 F4.2 mas aavg [0.07/0.6] Mean knot size
31- 34 F4.2 mas e_aavg [0.02/0.3] Standard deviation in aavg
36- 37 I2 --- o_tau [3/46] Number of measurements for
calculating tau
39- 42 F4.1 --- delta [1.3/60] Variability Doppler factor δvar
44- 47 F4.1 --- e_delta [0.4/24] Standard deviation in delta
49- 52 F4.1 --- Gamma [3.7/37.3] Bulk Lorentz factor Γ
54- 56 F3.1 --- e_Gamma [0.7/9] Standard deviation in Gamma
58- 61 F4.1 deg theta [0.3/22.1] Intrinsic viewing angle Θdeg
63- 65 F3.1 deg e_theta [0/5.1] Standard deviation in theta
--------------------------------------------------------------------------------
Acknowledgements:
Jorstad, Svetlana G. [Boston University; http://www.bu.edu/blazars/]
History:
From electronic version of the journal
06-Jun-2018: insert into VizieR FTP.
21-Jun-2018: table2.dat updated with values of QSO B1253-055
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 30-Apr-2018