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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 (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) : 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 <S> (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 <R> (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 <a> (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).
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 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 <a> 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;] 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
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