J/ApJ/758/84 Relativistic jets in the RRFID database. II. 10yr (Piner+, 2012)
Relativistic jets in the Radio Reference Frame Image Database.
II. Blazar jet accelerations from the first 10 years of data (1994-2003).
Piner B.G., Pushkarev A.B., Kovalev Y.Y., Marvin C.J., Arenson J.G.,
Charlot P., Fey A.L., Collioud A., Voitsik P.A.
<Astrophys. J., 758, 84 (2012)>
=2012ApJ...758...84P 2012ApJ...758...84P (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Radio continuum ; QSOs ; BL Lac objects
Keywords: BL Lacertae objects: general; galaxies: active; galaxies: jets;
quasars: general; radio continuum: galaxies
Abstract:
We analyze blazar jet apparent speeds and accelerations from the RDV
series of astrometric and geodetic very long baseline interferometry
(VLBI) experiments. From these experiments, we have produced and
analyzed 2753 global VLBI images of 68 sources at 8GHz with a median
beam size of 0.9 milliarcseconds (mas) and a median of 43 epochs per
source. From this sample, we analyze the motions of 225 jet components
in 66 sources. The distribution of the fastest measured apparent speed
in each source has a median of 8.3c and a maximum of 44c. Sources in
the 2FGL Fermi LAT catalog display higher apparent speeds than those
that have not been detected. On average, components farther from the
core in a given source have significantly higher apparent speeds than
components closer to the core; for example, for a typical source,
components at ∼3mas from the core (∼15pc projected at z∼0.5) have
apparent speeds about 50% higher than those of components at ∼1mas
from the core (∼5pc projected at z∼0.5). We measure accelerations of
components in orthogonal directions parallel and perpendicular to
their average velocity vector. Parallel accelerations have
significantly larger magnitudes than perpendicular accelerations,
implying that observed accelerations are predominantly due to changes
in the Lorentz factor (bulk or pattern) rather than projection effects
from jet bending. Positive parallel accelerations are significantly
more common than negative ones, so the Lorentz factor (bulk or
pattern) tends to increase on the scales observed here. Observed
parallel accelerations correspond to modest source frame increases in
the bulk or pattern Lorentz factor.
Description:
Our sample for this paper is drawn from the RDV (Research &
Development - VLBA) series of astrometric and geodetic VLBI
experiments. This series of experiments was fully described in Paper I
(Cat. J/AJ/133/2357). The RDV experiments are conducted using the 10
antennas of the National Radio Astronomy Observatory's VLBA, along
with the addition of up to 10 geodetic VLBI antennas in both the
northern and southern hemispheres that provide global VLBI coverage.
Observations are made in a simultaneous dual-frequency mode at both
the S band (2GHz) and X band (8GHz).
The analysis presented in this paper uses the NRAO imaging results at
8GHz only (from 1994 Jul 8 to 2003 Dec 17), because the higher
resolution afforded by the 8GHz observations is needed for precise
measurements of jet kinematics. The 8GHz observations presented in
this paper that were recorded after 1997 have similar angular
resolution to the observations from the MOJAVE survey (Lister et al.
2009, Cat. J/AJ/137/3718).
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 39 68 Sources in the RDV (Research & Development - VLBA)
sample
table3.dat 90 8571 Gaussian models
table5.dat 67 225 Apparent component speeds from linear fits
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See also:
VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)
J/A+A/555/A134 : Variability monitoring of QSO B1156+295 at 4.8GHz (Liu+, 2013)
J/A+A/544/A34 : Bright AGN VLBI imaging study at 2 and 8GHz (Pushkarev+, 2012)
J/AJ/144/105 : MOJAVE. VIII. Faraday rotation in AGN jets. (Hovatta+, 2012)
J/ApJ/743/171 : The 2LAC catalog (Ackermann+, 2011)
J/ApJ/742/27 : 15GHz and jet properties of MOJAVE blazars (Lister+, 2011)
J/ApJ/740/98 : Synchroton peak for blazars and radio galaxies (Meyer+, 2011)
J/ApJ/722/L7 : Fermi/LAT detected MOJAVE AGNs (Pushkarev+, 2010)
J/ApJ/707/L56 : VLBI and bright Fermi/LAT sources (Kovalev, 2009)
J/ApJ/706/1253 : MOJAVE VII. Blazar jet acceleration (Homan+, 2009)
J/AJ/138/1874 : MOJAVE. VI. Kinematic analysis of blazar jets (Lister+, 2009)
J/AJ/137/3718 : 15GHz monitoring of AGN jets with VLBA (Lister+, 2009)
J/AJ/133/2357 : Pap. I. Relativistic jets in the RRFID database (Piner+, 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/AJ/127/3587 : VLBI ICRF. II (Fey+, 2004)
J/ApJ/609/539 : Kinematics of parsec-scale radio jets (Kellermann+, 2004)
J/A+A/381/757 : List of extra-galactic radio jets (Liu+, 2002)
J/ApJS/128/17 : VLBA obs. of radio reference frame sources. III. (Fey+, 2000)
http://rorf.usno.navy.mil/RRFID/ : RRFID VLBA page
http://www.obs.u-bordeaux1.fr/BVID/ : The Bordeaux VLBI image database
http://astrogeo.org/vlbi_images/ : VLBI image database
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- IERS IAU source name (HHMM+DDd; B1950)
10 A1 --- f_IERS [efg] Note on source (1)
12- 20 A9 --- OName ? Other source name
22- 23 I2 --- Nep [20/50] Number of epochs observed
25- 29 A5 --- Class Source optical class (2)(3)
31- 35 F5.3 --- z [0.004/4]? Redshift (2)
37 A1 --- MOJ [Y ] Presence in MOJAVE? (4)
39 A1 --- Fer [Y ] Presence in Fermi? (5)
--------------------------------------------------------------------------------
Note (1): Flag as follows:
e = Tentative redshift from NED. (Redshift not in Veron-Cetty & Veron 2010,
Cat. VII/258)
f = Source is in the TANAMI sample (Ojha et al. 2010A&A...519A..45O 2010A&A...519A..45O).
g = Optical class and redshift are from Ackermann et al. (2011,
Cat. J/ApJ/743/171). (Source not in Veron-Cetty & Veron 2010,
Cat. VII/258)
Note (2): Unless otherwise noted, optical class and redshift are from
Veron-Cetty & Veron (2010, Cat. VII/258).
Note (3): Class as follows:
Q = quasar,
B = BL Lac object,
G = galaxy,
HP = high polarization,
U = unidentified.
Note (4): Whether or not source is in MOJAVE survey, using sample listed in
Table 1 of Lister et al. (2009, Cat. J/AJ/137/3718). (Y = Yes)
Note (5): Whether or not source is in the Fermi LAT 2 year AGN catalog,
Ackermann et al. (2011, Cat. J/ApJ/743/171). (Y = Yes)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- IERS IAU Name (HHMM+DDd; B1950)
11- 16 F6.3 Jy S [0.002/19.2] Component flux density at 8GHz
19- 24 F6.3 mas Rad [0/30] Radial position of component center
27- 32 F6.1 deg PA [-180/180] Position angle of component center (1)
35- 40 F6.3 mas a [0/14] Full-width at half maximum size of component
43- 47 F5.3 --- b/a Axial ratio of component
50- 54 F5.1 deg PAa [-90/90] Position angle of major axis of
elliptical component (1)
57 I1 --- Type [0/1] DIFMAP component type (1 = Gaussian)
60- 66 F7.2 yr Epoch [1994/2004] Epoch of observation
69- 70 I2 --- Comp [0/99] Component ID (2)
73- 77 F5.2 mas ab [0.6/17.1] Beam major axis (3)
80- 83 F4.2 mas bb [0.4/4.5] Beam minor axis
86- 90 F5.1 deg PAb [-90/90] Beam position angle
--------------------------------------------------------------------------------
Note (1): All position angles are measured from north through east.
Note (2): An ID of '0' indicates the presumed core. An ID of '99' indicates
a flagged component not used in the analysis. Other components are
numbered from 1 to 11, from the outermost component inward.
See section 3 for further explanations.
Note (3): Beam parameters are computed using natural weighting specifically
'uvweight = 0,-1' in DIFMAP.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- IERS IAU Name (HHMM+DDd; B1950)
10- 11 I2 --- Comp [1/11] Component ID
13- 17 F5.3 Jy [0.006/7.1] Mean flux density at 8GHz
19- 23 F5.2 mas <Rad> [0.1/21.4] Weighted mean radial separation
from core
25- 28 F4.2 mas e_<Rad> [0/0.5] <Rad> uncertainty
30- 33 I4 uas/yr mu [-193/2964] Proper motion (in µarcsec/yr)
35- 38 I4 uas/yr e_mu [1/1075] mu uncertainty
40- 46 F7.3 c beta [-16.4/42.6]? Apparent speed β
in units of the speed of light
48- 53 F6.3 c e_beta [0.003/15.5]? beta uncertainty
55- 61 F7.2 yr t0 ? Ejection time is given for proper motions
with significance above 3σ
63- 67 F5.2 yr e_t0 [0.04/19.6]? t0 uncertainty
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Piner et al. Paper I. 2007AJ....133.2357P 2007AJ....133.2357P Cat. J/AJ/133/2357
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 07-Jul-2014