J/ApJS/265/8 X-ray and radio components in extragalactic jets (Reddy+, 2023)
Offsets between X-ray and radio components in X-ray jets: the AtlasX.
Reddy K., Georganopoulos M., Meyer E.T., Keenan M., Kollmann K.E.
<Astrophys. J. Suppl. Ser., 265, 8 (2023)>
=2023ApJS..265....8R 2023ApJS..265....8R
ADC_Keywords: Active gal. nuclei; Radio sources; X-ray sources; Redshifts;
Morphology
Keywords: Active galactic nuclei ; Radio jets ; Relativistic jets ;
Astrostatistics ; High energy astrophysics
Abstract:
The X-ray emission mechanism of powerful extragalactic jets-which has
important implications for their environmental impacts-is poorly
understood. The X-ray/radio positional offsets in the individual
features of jets provide important clues. Extending previous work in
Reddy+ (Paper I; 2021ApJS..253...37R 2021ApJS..253...37R), we present a detailed
comparison between X-ray maps, deconvolved using the Low-count Image
Reconstruction and Analysis tool, and radio maps of 164 components
from 77 Chandra-detected X-ray jets. We detect 94 offsets (57%), with
58 new detections. In FR II-type jet knots, the X-rays peak and decay
before the radio in about half the cases, disagreeing with the
predictions of one-zone models. While a similar number of knots lack
statistically significant offsets, we argue that projection and
distance effects result in offsets below the detection level. Similar
deprojected offsets imply that X-rays could be more compact than radio
for most knots, and we qualitatively reproduce this finding with a
"moving-knot" model. The bulk Lorentz factor (Γ) derived for
knots under this model is consistent with previous radio-based
estimates, suggesting that kiloparsec-scale jets are only mildly
relativistic. An analysis of the X-ray/radio flux ratio distributions
does not support the commonly invoked mechanism of X-ray production
from inverse Compton scattering of the cosmic microwave background,
but does show a marginally significant trend of declining flux ratio
as a function of the distance from the core. Our results imply the
need for multi-zone models to explain the X-ray emission from powerful
jets. We provide an interactive list of our X-ray jet sample at
http://astro.umbc.edu/Atlas-X
Description:
The initial sample of X-ray jets was taken from a broad literature and
archive search, as previously described in Paper I
(Reddy+ 2021ApJS..253...37R 2021ApJS..253...37R). In addition, for this paper, we have
added four detections from Snios+ (2021, J/ApJ/914/130), three from
Marshall+ (2018ApJ...856...66M 2018ApJ...856...66M), and one each from
Worrall+ (2020MNRAS.497..988W 2020MNRAS.497..988W), Connor+ (2021ApJ...911..120C 2021ApJ...911..120C), and
Ighina+ (2022A&A...659A..93I 2022A&A...659A..93I), bringing the total count to 199 sources
listed in Table 5.
In total, we have newly analyzed 164 components from 77 jets in this
paper, joining the 37 features of 22 jets in Paper I. With the
literature cases, this comes to 226 components from 107 X-ray jets.
We mainly retrieved the radio data from the archives of the Very Large
Array (VLA) and, in a few cases, from the Australian Telescope Compact
Array (ATCA). See Section 2.2.
We obtained the X-ray data from the Chandra archives and reprocessed
them. See Section 2.3.
The adopted cosmology follows the NASA Extragalactic Database (NED):
H0=67.8km/s/Mpc, Ωm=0.308, and ΩΛ=0.692. The
spectral index α is given by the flux density, Fν=ν-α,
and the photon index is given by Γ=α+1.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 68 77 Details of radio observations
table2.dat 83 77 Details of Chandra X-ray observations
table4.dat 111 189 Offset analysis results and spectral data
table5.dat 125 199 List of all Chandra detected X-ray jets
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
J/MNRAS/392/1509 : Distribution of AGNs in galaxy clusters (Gilmour+, 2009)
J/ApJ/704/1586 : BCGs with radio AGN (Sun, 2009)
J/ApJS/197/24 : Chandra large-scale extragalactic jets. I. (Massaro+, 2011)
J/ApJ/914/130 : Chandra & VLA obs. of 14 high-redshift QSOs (Snios+, 2021)
http://hea-www.harvard.edu/XJET/ : XJET database home page
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Name Source name
15- 25 A11 --- PID Project code
27- 37 A11 "Y/M/D" Date Observing date (UT)
39- 43 F5.2 GHz Freq [1.43/20.16] Frequency of the observation
45- 48 F4.2 arcsec amaj [0.1/5] Major axis of the beam
50- 53 F4.2 arcsec bmin [0.1/4.3] Minor axis of the beam
55- 60 F6.2 deg PA [-87/173.5] Position angle of the beam
62- 68 F7.3 --- RMS [0.3/214] Image noise in 1e-5mJy/beam
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Name Source name
15- 64 A50 --- ObsID Chandra Observation IDs
66- 71 F6.2 s Exp [0.2/231] Effective exposure after removing any
background flares
73- 76 A4 --- Mode Chandra observation modes for each ObsID (1)
78- 83 F6.4 ct/s Rate [0.001/1.2] Average of the count rate
from each epoch
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Note (1): A single value is provided if all the current and subsequent obsIDs
have the same mode.
F = FAINT
V = VFAINT
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Name Name of the source
15- 19 A5 --- Comp X-ray feature's name
21- 25 F5.2 arcsec Sepa [0.02/10]? Angular X-ray/radio offset
27- 30 F4.2 arcsec e_Sepa [0.01/0.7]? Uncertainty in Sepa
32- 33 I2 --- r_Sepa [1/45]? Reference for previous Sepa
(see refs.dat file)
35- 45 A11 --- Type Type of the offset (1)
47- 51 F5.2 kpc Sepk [0/19]? Sky projected offset
53- 56 F4.2 kpc e_Sepk [0/2.5]? Uncertainty in Sepk
58- 61 F4.2 --- SpIndR [0.5/1.17]? Radio spectral index
63- 66 F4.2 --- e_SpIndR [0.03/0.5]? Uncertainty in SpIndR
68- 71 F4.2 --- SpIndX [0.1/2.4]? X-ray spectral index
73- 76 F4.2 --- e_SpIndX [0.01/0.9]? Uncertainty in SpIndX
78- 79 I2 --- r_SpIndX [1/37]? Reference for SpIndX
(see refs.dat file)
81- 85 F5.2 GHz nuR [1.4/20.16]? Radio frequency
87- 94 F8.2 mJy FR [0.18/11600]? Radio flux at nuR
96-101 F6.2 nJy FX [0.09/293.1] X-ray flux at 1keV
103-104 I2 --- r_FX [1/31]? Reference for FX
(see refs.dat file)
106-111 F6.2 --- Ratio [0.01/597]? X-ray-to-radio flux ratio
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Note (1): We adopt the nomenclature for the offset types from Paper I
(Reddy+ 2021ApJS..253...37R 2021ApJS..253...37R), where "Xf" indicates X-ray-first or the
X-rays peaking upstream of the radio; "Rf" indicates radio-first or
the radio peaking upstream of the X-rays; and "Co-s" or cospatial
indicates the lack of any significant evidence for an offset.
Tentative Co-s-types are indicated with a "(T)".
"Amb", signifying an ambiguous offset type, is used for components
where the direction of the jet is unclear (e.g., 3C 351; Figure 1.67)
or for those that lack unambiguous X-ray/radio spatial correlations
(e.g., knots or large-scale hot gas).
Furthermore, we specify additional attributes of the offset type,
based on the structure of the component:
"Bnd" indicates a knot lying at a bend in the jet;
"Flr" indicates the so-called flaring point, commonly found in
FRI-type sources; and
"Vnsh" is used if the emission from an FRII-type jet quickly
diminishes at the specified location, before re-emerging at a hotspot
farther downstream (e.g., 4C+19.44).
"Jet-HS" signifies that the hotspot presumably produces X-rays when
the jet enters the turbulent hotspot region, generally coinciding with
a faint radio peak that is followed by a much brighter radio hotspot.
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Code Code identifier for this work (1)
3- 26 A24 --- Name Primary identifier
28- 35 A8 --- IAU IAU identifier (HHMM+DDd; B1950)
37- 39 I3 h RAh Hour of Right Ascension (J2000)
41- 42 I2 min RAm Minute of Right Ascension (J2000)
44- 47 F4.1 s RAs Second of Right Ascension (J2000)
49 A1 --- DE- Sign of the Declination (J2000)
50- 51 I2 deg DEd Degree of Declination (J2000)
53- 54 I2 arcmin DEm Arcminute of Declination (J2000)
56- 59 F4.1 arcsec DEs Arcsecond of Declination (J2000)
61- 65 F5.3 --- z [0.002/6.1] Spectroscopic redshift
67- 71 F5.2 --- Beta [0.13/47]? Maximum apparent superluminal
motion (2)
73- 76 F4.2 kpc/arcsec Scale [0.02/8.7]? Angular scale
78- 92 A15 --- Class Radio jet morphology descriptor (3)
94-112 A19 --- Ref Reference's bibcode to the previous X-ray
observation
114-125 A12 --- XJET Name in the XJET table if any;
column added by CDS
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Note (1): Code as follows:
A = Source analyzed in this work (76 occurrences)
B = Source from reference (10 occurrences)
C = Remaining source (113 occurrences)
Note (2): Compiled from Keenan+ (2021MNRAS.505.4726K 2021MNRAS.505.4726K).
Note (3): Fanaroff-Riley I or II, CDQ (core dominated quasar), LDQ (Lobe
dominated quasar), BL Lac, and an optical spectroscopic
designation: LERG (low-excitation radio galaxy), HERG
(high-excitation radio galaxy), NLRG (Narrow-line radio galaxy),
BLRG (broad-line radio galaxy).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 17-Apr-2023