J/A+A/690/A111 IceCube neutrinos-blazars association (Kouch+, 2024)
Association of the IceCube neutrinos with blazars in the CGRaBS sample.
Kouch P.M., Lindfors E., Hovatta T., Liodakis I., Koljonen K.I.I.,
Nilsson K., Kiehlmann S., Max-Moerbeck W., Readhead A.C.S., Reeves R.A.,
Pearson T.J., Jormanainen J., Fallah Ramazani V., Graham M.J.
<Astron. Astrophys. 690, A111 (2024)>
=2024A&A...690A.111K 2024A&A...690A.111K (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Neutrino ; Radio sources
Keywords: astroparticle physics - neutrinos - galaxies: active -
galaxies: jets - galaxies: statistics
Abstract:
The origin of high-energy (HE) astrophysical neutrinos has remained an
elusive hot topic in the field of HE astrophysics for the past decade.
Apart from a handful of individual associations, the vast majority of
HE neutrinos arise from unknown sources. While there are
theoretically-motivated candidate populations, such as blazars -- a
subclass of AGN with jets pointed towards our line-of-sight -- they
have not yet been convincingly linked to HE neutrino production. Here,
we perform a spatio-temporal association analysis between a sample of
blazars (from CGRaBS catalog) in the radio and optical bands and the
most up-to-date IceCube HE neutrino catalog. We find that if the
IceCube error regions are enlarged by 1° in quadrature, to account
for unknown systematic errors at maximal level, a spatio-temporal
correlation between the multiwavelength light curves of the CGRaBS
blazars and the IceCube HE neutrinos is hinted at least at a
2.17σ significance level. On the other hand, when the IceCube
error regions are taken as their published values, we do not find any
significant correlations. A discrepancy in the blazar-neutrino
correlation strengths, when using such minimal and enlarged error
region scenarios, was also obtained in a recent study by the IceCube
collaboration. In our study, this difference arises because several
flaring blazars -- coinciding with a neutrino arrival time -- happen
to narrowly miss the published 90%-likelihood error region of the
nearest neutrino event. For all of the associations driving our most
significant correlations, the flaring blazar is much less than 1°
away from the published error regions. Therefore, our results indicate
that the question of the blazar-neutrino connection is highly
sensitive to the reconstruction of the neutrino error regions, whose
reliability is expected to improve with the next generation of
neutrino observatories.
Description:
Here we present three data tables: neutrino.dat, blazars.dat, and
assoc.dat, which respectively contain the list of all IceCube
high- energy neutrino events used in this study (referred to as
IceCat1+), the list of all CGRaBS blazars whose light-curves are
monitored by OVRO, and the list of all blazar-neutrino spatial
associations along with their respective spatio-temporal signals (both
weighted and unweighted).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
neutrino.dat 120 283 IceCat1+: high-energy neutrino events used
blazars.dat 104 1157 CGRaBS blazars: monitored by OVRO
assoc.dat 148 275 All blazar-neutrino spatial associations
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See also:
J/ApJS/175/97 : CGRaBS: survey of γ-ray blazar candidates (Healey+, 2008)
J/ApJ/851/33 : Multi-wavelength analysis of CGRaBS blazars (Paliya+, 2017)
Byte-by-byte Description of file: neutrino.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- IC IC ID of the high-energy neutrino event (1)
11- 21 F11.5 d MJD Modified Julian Date (MJD) of the arrival time
23- 28 F6.1 TeV E Energy estimate
30- 34 F5.3 --- Sness Signalness
36- 41 F6.2 deg RAdeg Right Ascension (J2000)
43- 48 F6.2 deg E_RAdeg Error on Right Ascension (upper value)
50- 55 F6.2 deg e_RAdeg Error on Right Ascension (lower value)
57- 62 F6.2 deg DEdeg Declination (J2000)
64- 67 F4.2 deg E_DEdeg Error on Declination (upper value)
69- 73 F5.2 deg e_DEdeg Error on Declination (lower value)
75- 84 F10.5 deg+2 OmMin Omega in the published error region scenario (2)
86- 95 F10.5 deg+2 OmMax Omega in the enlarged error region scenario (2)
97-103 F7.5 --- wMin Weight in the published error region scenario (2)
105-111 F7.5 --- wMax Weight in the enlarged error region scenario (2)
113-120 A8 --- Ref IceCube paper reference for the event
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Note (1): The high-energy neutrino events (283) are taken from two references.
267 are from Ice-Cat1 (Abbasi et al., 2023ApJS..269...25A 2023ApJS..269...25A,
[10.3847/1538-4365/acfa95]).
16 are from off-line events analyzed in (Abbasi et al. 2022ApJ...928...50A 2022ApJ...928...50A,
[10.3847/1538-4357/ac4d29]).
The IC ID of the latter events ends in an 'X'.
Note (2): The published and enlarged error region scenarios are described in
Section 3.3 of the paper.
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Byte-by-byte Description of file: blazars.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Blz CGRaBS blazar name (JHHMM+DDMM)
12- 18 F7.3 deg RAdeg Blazar right ascension (J2000)
20- 26 F7.3 deg DEdeg Blazar declination (J2000)
28 A1 --- BZCc Blazar 5BZCat type (1)
30- 32 A3 --- FGLc Blazar 4FGL class (2)
34-104 A71 --- Alias Aliases of the blazar separated by '/'
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Note (1): The 5BZCat blazar types are 'B' for BL Lac objects, 'Q' for Flast
Spectrum Radio Quasars, 'U' is for uncertain, and '-' means that the
source is not in the 5BZCat catalog.
Note (2): The 4FGL classes are low-, intermediate-, and high-synchrotron peaked
sources, respectively, denoted by LSP, ISP, and HSP. Most of the
sources do not have a 4FGL class and are marked with '-'.
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Byte-by-byte Description of file: assoc.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- IC IC ID of spatially-associated neutrino events
11- 20 A10 --- Blz CGRaBS name of spatially-associated blazars
22- 30 F9.5 deg dBN Distance between the neutrino and blazar
32- 40 F9.5 deg dMin Distance between the neutrino and published
edge (1)
42- 50 F9.5 deg dMax Distance between the neutrino and enlarged
edge (1)
52- 59 F8.5 Jy Sr Unweighted mean radio flux density (1)
61- 67 F7.5 Jy wSrMin Weighted mean radio flux density (published) (1)
69- 75 F7.5 Jy wSrMax Weighted mean radio flux density (enlarged) (1)
77- 84 A8 mJy So Unweighted mean optical flux density (1)
86- 92 A7 mJy wSoMin Weighted mean optical flux density
(published) (1)
94-100 A7 mJy wSoMax Weighted mean optical flux density
(enlarged) (1)
102-108 F7.5 --- AIr Unweighted radio activity index (1)
110-116 F7.5 --- wAIrMin Weighted radio activity index (published) (1)
118-124 F7.5 --- wAIrMax Weighted radio activity index (enlarged) (1)
126-132 A7 --- AIo Unweighted optical activity index (1)
134-140 A7 --- wAIoMin Weighted optical activity index (published) (1)
142-148 A7 --- wAIoMax Weighted optical activity index (enlarged) (1)
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Note (1): 'Published' refers to the published error region scenario and
'enlarged' refers to the enlarged error region scenario. These are
explained in Section 3.3 of the paper.
The weighting scheme is explained in Section 3.2 of the paper.
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Acknowledgements:
Pouya Kouch, pouya.kouch(at)utu.fi
(End) Pouya Kouch [Uni. of Turku, Finland], Patricia Vannier [CDS] 10-Jul-2024