J/A+A/684/A202 Optical emission with radio structures (Lambert+, 2024)
Identification of the optical emission detected by Gaia with radio structures in
parsec-scale AGN jets.
Lambert S., Sol H., Pierron A.
<Astron. Astrophys. 684, A202 (2024)>
=2024A&A...684A.202L 2024A&A...684A.202L (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Interferometry ; Radio sources ; Optical
Keywords: techniques: interferometric - astrometry - reference systems -
quasars: general
Abstract:
We investigated the location of the optical emission with respect to
the parsec-scale radio structure and attempted to identify whether the
optical centroid is coincident with the radio core or a radio
component of the jet.
We used optical Gaia DR3 and 8 GHz ICRF3 positions and a model fitting
of 15 GHz imaging by the MOJAVE VLBA survey for 422 sources, mostly
blazars. We searched for possible associations between optical
centroids and radio components. We also compared the astrometric and
photometric properties of each category, looked for trends between the
various source parameters, and discussed possible biases.
Sources can be separated into four categories based on whether their
optical centroid (i) falls onto the radio core (category C), (ii) lies
close to the base of the jet (category B), (iii) coincides with a
radio component downstream in the jet (category J), or (iv) is not
found to coincide with a detected radio component (category O). Due to
a number of random and systematic errors, the number of sources
falling into each category remains approximate but close to 32%, 36%,
22%, and 10%, respectively. The family of quasars, mostly flat
spectrum radio quasars (FSRQs), clearly dominates the C and B
categories, with their percentage decreasing from categories C to O.
Conversely, the family of BL Lacs is spread over the four classes and
dominates the category O. Radio galaxies are mainly in classes O and
J, and the radio-loud narrow-line Seyfert 1 all belong to class C. An
individual analysis of O sources shows that, despite the absence of a
direct association with a specific radio component, the optical Gaia
centroid is globally related to the radio VLBI jet structure.
Our study shows that the spatial distribution of the optical
counterparts seen by Gaia below the 0.2-arcsec scale around the radio
cores appears in the vast majority of cases to be related to the AGN
core or to its jet, with most of them located downstream in the jet.
Those associated to the core also exhibit a bluer color index,
suggesting a possible contribution of the accretion disk to the
optical emission, while those associated to a radio knot in the jet
appear redder and tend on average to be found in more polarized radio
sources. Most BL Lacs have their optical emission coincident with the
jet base or a knot in the jet, while sources with an optical emission
on or close to the radio core are mostly FSRQs. Radio components
associated with the optical centroid at the jet base or along the jet
are mainly stationary or quasi-stationary features, with low apparent
MOJAVE velocities. There are indications that the apparent proper
motion of the Gaia centroids may be higher than the speed of the
associated radio components, but the significance of this trend
requires further investigation.
Description:
The table gathers the numerical quantities that allowed to built up
the analyses and conclusions of the article.
The tables contains the relative astrometric vectors (length and
position- angle) between the Gaia centroid, the MOJAVE putative radio
core, and the MOJAVE component identified as coincident with the Gaia
centroid. The labels follow the naming described in the sketch of
Figure 1 of the article. We also provide other photometric information
relevant to oour analyses. The very last column gives the source
category as defined by us (C, B, J, O).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 198 422 Numerical quantities that allowed to built up
the analyses and conclusions of the article
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See also:
J/A+A/620/A68 : Polarization of quasars (Hutsemekers+, 2018)
J/ApJS/234/12 : MOJAVE XV. VLBA 15GHz obs. of AGN jets 1996-2016 (Lister+ 2018)
J/ApJ/923/30 : MOJAVE XVIII. Bright radio-loud active AGNs (Lister+, 2021)
Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- IERS IERS B1950 source name (HHMM+DDd)
10- 16 F7.3 mas DV Gaia-ICRF3 vector length
18- 23 F6.3 mas E_DV Gaia-ICRF3 vector length error
25- 27 I3 deg thetaV Gaia-ICRF3 vector position-angle
29- 31 I3 deg E_thetaV Gaia-ICRF3 vector position-angle error
33- 39 F7.3 mas DG Gaia-MOJAVE core vector length
41- 46 F6.3 mas E_DG Gaia-MOJAVE core vector length error
48- 50 I3 deg thetaG Gaia-MOJAVE core vector position-angle
52- 54 I3 deg E_thetaG Gaia-MOJAVE core vector position-angle error
56- 57 I2 --- MOJCOMP [0/57]?=- Identifier of MOJAVE component
closest to Gaia (MCCG) following the
numbering of Lister et al.
(2021ApJ...923...30L 2021ApJ...923...30L, Cat. J/ApJ/923/30)
59- 64 F6.3 mas DM MCCG-MOJAVE core vector length
66- 68 A3 deg thetaM MCCG-MOJAVE core position-angle
70- 76 F7.3 mas DGM MCCG-Gaia vector length
78- 83 F6.3 mas E_DGM MCCG-Gaia vector length error
85- 87 I3 deg thetaGM MCCG-Gaia vector position-angle
89- 92 I4 deg E_thetaGM MCCG-Gaia vector position-angle error
94-100 F7.2 --- NormDG Gaia-MOJAVE core normalized separation
102-108 F7.2 --- NormDGM MCCG-Gaia normalized separation
110-114 F5.3 mas/yr VG ?=- Gaia proper motion
116-120 F5.3 mas/yr E_VG ?=- Gaia proper motion error
122-124 I3 deg phiG ?=- Gaia proper motion position-angle
126-128 I3 deg E_phiG ?=- Gaia proper motion position-angle error
130-134 F5.3 mas/yr VM ?=- MCCG proper motion
136-140 F5.3 mas/yr E_VM ?=- MCCG proper motion error
142-144 I3 deg phiM ?=- MCCG proper motion position-angle
146-148 I3 deg E_phiM ?=- MCCG proper motion position-angle error
150-156 F7.2 Jy MOJFLUX ?=- MCCG 15 GHz flux
158 I1 --- Type [0/7]?=- Activity Type (NED Homogenized
Classification) (1)
160-163 F4.1 --- z ?=- Redshift from NED
165-168 F4.1 mag Gmag Gaia G magnitude
170-174 F5.2 --- OPol ?=- Optical polarization from
Hutsemekers et al. (2018A&A...620A..68H 2018A&A...620A..68H,
Cat. J/A+A/620/A68)
176-180 F5.2 --- RPol ?=- Maximum of fractional radio polarization
from Lister et al. (2018ApJS..234...12L 2018ApJS..234...12L,
Cat. J/ApJS/234/12)
182-186 F5.3 mag BP-RP ?=- Gaia BP-RP colour index
188-190 F3.1 --- RUWE ?=- Gaia RUWE
192-196 F5.3 mas VLBIStab ?=- VLBI stability from geodetic time series
198 I1 --- Cat [1/4] Category (1: C, 2: B, 3: J, 4: O)
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Note (1): Activity Type as follows:
0 = FSRQ
1 = QSO
2 = BL Lac
3 = Seyfert 1
4 = Seyfert 2
5 = GPS
6 = CSS
7 = other
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Acknowledgements:
Sebastien Lambert, sebastien.lambert(at)obspm.fr
(End) Patricia Vannier [CDS] 12-Feb-2024