Comparison of multifrequency positions of extragalactic sources from ICRF3 and Gaia EDR3
| العنوان: | Comparison of multifrequency positions of extragalactic sources from ICRF3 and Gaia EDR3 |
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| المؤلفون: | Zi Zhu, N. Jiang, P. Charlot, N. Liu, X.-S. Wan, Jia-Cheng Liu, C.-Y. Ding, S. B. Lambert |
| المساهمون: | Systèmes de Référence Temps Espace (SYRTE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) |
| المصدر: | Astronomy and Astrophysics-A&A Astronomy and Astrophysics-A&A, EDP Sciences, 2021, 652, pp.A87. ⟨10.1051/0004-6361/202038179⟩ |
| بيانات النشر: | HAL CCSD, 2021. |
| سنة النشر: | 2021 |
| مصطلحات موضوعية: | Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, 0103 physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 010303 astronomy & astrophysics, 01 natural sciences |
| الوصف: | Context.Comparisons of optical positions derived from theGaiamission and radio positions measured by very long baseline interferometry (VLBI) probe the structure of active galactic nuclei (AGN) on the milliarcsecond scale. So far, these comparisons have focused on using theS∕X-band (2/8 GHz) radio positions, but did not take advantage of the VLBI positions that exist at higher radio frequencies, namely atK-band (24 GHz) andX∕Ka-band (8/32 GHz).Aims.We extend previous works by considering two additional radio frequencies (K-band andX∕Ka-band) with the aim to study the frequency dependence of the source positions and its potential connection with the physical properties of the underlying AGN.Methods.We compared the absolute source positions measured at four different wavelengths, that is, the optical position from theGaiaEarly Data Release 3 (EDR3) and the radio positions at theS∕X-,K-, andX∕Ka-band, as available from the third realization of the International Celestial Reference Frame (ICRF3), for 512 common sources. We first aligned the three ICRF3 individual catalogs to theGaiaEDR3 frame and compared the optical-to-radio offsets before and after the alignment. Then we studied the correlation of optical-to-radio offsets with the observing (radio) frequency, source morphology, magnitude, redshift, and source type.Results.The deviation among optical-to-radio offsets determined in the different radio bands is less than 0.5 mas, but there is statistical evidence that the optical-to-radio offset is smaller atK-band compared toS∕X-band for sources showing extended structures. The optical-to-radio offset was found to statistically correlate with the structure index. Large optical-to-radio offsets appear to favor faint sources, but are well explained by positional uncertainty, which is also larger for these sources. We did not detect any statistically significant correlation between the optical-to-radio offset and the redshift.Conclusions.The radio source structure appears to be a major cause for the radio-to-optical offset. For the alignment of theGaiacelestial reference frame, theS∕X-band frame remains the preferred choice at present. |
| اللغة: | English |
| تدمد: | 0004-6361 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::bfc9179209faad2c4c8b6b6a0be0d3d7 https://hal.archives-ouvertes.fr/hal-03453862 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi.dedup.....bfc9179209faad2c4c8b6b6a0be0d3d7 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 00046361 |
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