We have used analytical methods in this paper to obtain a mathematical relation that describes relationship between the linear size of compact steep spectrum (CSS) sources and their redshift. Result shows that the source linear size has an inverse power-law dependence on the redshift. Moreover, for the purpose of obtaining an empirical relation that shows relationship between the liner size and the redshift, we carry out simple linear regression analyses on the observed linear sizes of the CSS sources in our sample against their respective observed redshifts. Results of the analyses indicate that the linear sizes of the quasars have direct power law relationship with their respective redshifts; while the converse is the case for their galaxy counterparts. Their correlation coefficients are marginal. In comparison with the obtained theoretical relation, we notice that for the CSS quasars, the linear size–redshift data show an inverse correlation. This is comparable with the theoretical relation. So, it suggests that the dynamical evolution of the source linear sizes may have some cosmological effects on it. However, the converse is the case for the CSS galaxies – the correlation is direct. The possible explanation for this difference is that quasars are observed at higher redshifts than their galaxy counterparts. Hence, the cosmological effects are expected to be more pronounced on the quasars. Furthermore, we use analytical methods again to obtain a theoretical relation that shows relationship between luminosity and redshift. The relation indicates that luminosity of a radio source has an inverse power-law relationship with redshift. This suggestively implies that the intrinsic luminosity of a radio source may be modified by cosmological evolution. Moreover, for the purpose of obtaining an empirical relation for comparison with the theory, we carry out linear regression analysis of observed luminosities against observed redshifts of the CSS quasars and galaxies in our sample. Results show that luminosities have excellent direct power-law relationship with redshifts. However, this is in contradiction to the obtained theory which shows inverse relationship between the two parameters. This excellent direct correlation has been attributable by some authors to strong luminosity selection effects in which samples with high luminosities are found at high redshifts. Therefore, if the selection effects are taken care of, we may be able to see the comparability of the theory with the empirical relation. Hence, we conclude that source radiated power may have some cosmological implications just like we saw in the size/redshift relation.
| Published in | American Journal of Astronomy and Astrophysics (Volume 9, Issue 1) |
| DOI | 10.11648/j.ajaa.20210901.12 |
| Page(s) | 8-12 |
| Creative Commons |
This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited. |
| Copyright |
Copyright © The Author(s), 2024. Published by Science Publishing Group |
Radio Sources, Redshift, Steep Spectrum, Compact, Evolution, Cosmology, Luminosity
| [1] | Mahatma, V. H., Hardcastle, M. J., Williams, W. L (2019) LoTSS DR1: Double-double Radio Galaxies in the HETDEX field. Astronomy and Astrophysics, 622, A13. |
| [2] | Mingo, B. J., Croston, H., Hardcastle, M. J. (2019) Revisiting the Fanaroff-Riley Dichotomy and Radio Galaxy Morphology with the LOFAR Two-Meter Sky Survey (LoTSS). Monthly Notices of the Royal Astronomical Society, 488, 2701–2721. |
| [3] | Hardcastle, M. J., Williams, W. L., Best, P. N. (2019) Radio-loud AGN in the First LoTSS Data Release – The Lifetimes and Environmental impact of Jet-Driven Sources. Astronomy and Astrophysics, 622, A12. |
| [4] | Dabhade, P., Gaikwad, M., Bagchi, J. (2017) Discovery of Giant Radio Galaxies from NVSS: Radio and Infrared Properties. Monthly Notices of the Royal Astronomical Society, 469 (3), 2886–2906. |
| [5] | Robson, I., Active Galactic Nuclei. (1996) Praxis Publishing Ltd, England. |
| [6] | O’Dea, C. P. (1998) The Compact Steep Spectrum Sources and Gigahertz Peaked Spectrum Radio Sources. Publications of the Astronomical Society of the Pacific, 110, 493–532. |
| [7] | Fanti, C., Fanti, R., Dallacasa, D. C., Schilizzi, R. T., Spencer, R. E., and Stanghellini, C. (1995) Are Compact Steep Spectrum Sources Young? Astronomy and Astrophysics, 302, 317–326. |
| [8] | Zhang, J., Zhang, H., Gan, Y., Yi, T., Wang, J. and Liang E. (2020) Jet Properties of Compact Steep Spectrum Sources and an Eddington-ratio-driven Unification Scheme of Jet Radiation in Active Galactic Nuclei. The Astrophysical Journal, 899, 2. |
| [9] | Murgia, M. Fanti, R., Gregorini, L., Klein, U., Mark, K. H., and Vigotti, M. (1999) Synchrotron Spectra and Ages of Compact Steep Spectrum Radio Sources,. New Astronomy Reviews, 345, 769–777. |
| [10] | Cavalho, J. C. (1998) The Evolution of GHz-peaked Spectrum Radio Sources. Astronomy and Astrophysics, 329, 845–852. |
| [11] | Jackson, C. A. (1999) Radio Source Evolution and Unified Schemes. Publications of Astronomical Society of Australia, 16, 124–129. |
| [12] | Jeyakumar, S., Wiita, P. J., Saikia, D. J. and Hooda, J. S. (2005) Jet Propagation and the Asymmetries of CSS Radio Sources. Astronomy and Astrophysics, 432, 823–833. |
| [13] | Ubachukwu, A. A. and Ogwo, J. N. (1999) Redshift and Luminosity Dependence of Linear Size of Compact Steep Spectrum Sources and the Quasar/galaxy Unification Scheme. Australian Journal of Physics, 52, 141–146. |
| [14] | Ezeugo, J. C. and Ubachukwu, A. A. (2010) The Spectral Turnover – Linear Size Relation and the Dynamical Evolution of Compact Steep Spectrum Sources. Monthly Notices of the Royal Astronomical Society, 408, 2256–2260. |
| [15] | Cavalho, J. C. 1998. “The Evolution of GHz-peaked Spectrum Radio Sources”. Astronomy and Astrophysics, 329: 845–852. |
APA Style
Ezeugo Jeremiah Chukwuemerie. (2021). On Cosmic Epochand Linear Size/Luminosity Evolution of Compact Steep Spectrum Sources. American Journal of Astronomy and Astrophysics, 9(1), 8-12. https://doi.org/10.11648/j.ajaa.20210901.12
ACS Style
Ezeugo Jeremiah Chukwuemerie. On Cosmic Epochand Linear Size/Luminosity Evolution of Compact Steep Spectrum Sources. Am. J. Astron. Astrophys. 2021, 9(1), 8-12. doi: 10.11648/j.ajaa.20210901.12
AMA Style
Ezeugo Jeremiah Chukwuemerie. On Cosmic Epochand Linear Size/Luminosity Evolution of Compact Steep Spectrum Sources. Am J Astron Astrophys. 2021;9(1):8-12. doi: 10.11648/j.ajaa.20210901.12
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Download@article{10.11648/j.ajaa.20210901.12,
author = {Ezeugo Jeremiah Chukwuemerie},
title = {On Cosmic Epochand Linear Size/Luminosity Evolution of Compact Steep Spectrum Sources},
journal = {American Journal of Astronomy and Astrophysics},
volume = {9},
number = {1},
pages = {8-12},
doi = {10.11648/j.ajaa.20210901.12},
url = {https://doi.org/10.11648/j.ajaa.20210901.12},
eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajaa.20210901.12},
abstract = {We have used analytical methods in this paper to obtain a mathematical relation that describes relationship between the linear size of compact steep spectrum (CSS) sources and their redshift. Result shows that the source linear size has an inverse power-law dependence on the redshift. Moreover, for the purpose of obtaining an empirical relation that shows relationship between the liner size and the redshift, we carry out simple linear regression analyses on the observed linear sizes of the CSS sources in our sample against their respective observed redshifts. Results of the analyses indicate that the linear sizes of the quasars have direct power law relationship with their respective redshifts; while the converse is the case for their galaxy counterparts. Their correlation coefficients are marginal. In comparison with the obtained theoretical relation, we notice that for the CSS quasars, the linear size–redshift data show an inverse correlation. This is comparable with the theoretical relation. So, it suggests that the dynamical evolution of the source linear sizes may have some cosmological effects on it. However, the converse is the case for the CSS galaxies – the correlation is direct. The possible explanation for this difference is that quasars are observed at higher redshifts than their galaxy counterparts. Hence, the cosmological effects are expected to be more pronounced on the quasars. Furthermore, we use analytical methods again to obtain a theoretical relation that shows relationship between luminosity and redshift. The relation indicates that luminosity of a radio source has an inverse power-law relationship with redshift. This suggestively implies that the intrinsic luminosity of a radio source may be modified by cosmological evolution. Moreover, for the purpose of obtaining an empirical relation for comparison with the theory, we carry out linear regression analysis of observed luminosities against observed redshifts of the CSS quasars and galaxies in our sample. Results show that luminosities have excellent direct power-law relationship with redshifts. However, this is in contradiction to the obtained theory which shows inverse relationship between the two parameters. This excellent direct correlation has been attributable by some authors to strong luminosity selection effects in which samples with high luminosities are found at high redshifts. Therefore, if the selection effects are taken care of, we may be able to see the comparability of the theory with the empirical relation. Hence, we conclude that source radiated power may have some cosmological implications just like we saw in the size/redshift relation.},
year = {2021}
}
TY - JOUR T1 - On Cosmic Epochand Linear Size/Luminosity Evolution of Compact Steep Spectrum Sources AU - Ezeugo Jeremiah Chukwuemerie Y1 - 2021/04/07 PY - 2021 N1 - https://doi.org/10.11648/j.ajaa.20210901.12 DO - 10.11648/j.ajaa.20210901.12 T2 - American Journal of Astronomy and Astrophysics JF - American Journal of Astronomy and Astrophysics JO - American Journal of Astronomy and Astrophysics SP - 8 EP - 12 PB - Science Publishing Group SN - 2376-4686 UR - https://doi.org/10.11648/j.ajaa.20210901.12 AB - We have used analytical methods in this paper to obtain a mathematical relation that describes relationship between the linear size of compact steep spectrum (CSS) sources and their redshift. Result shows that the source linear size has an inverse power-law dependence on the redshift. Moreover, for the purpose of obtaining an empirical relation that shows relationship between the liner size and the redshift, we carry out simple linear regression analyses on the observed linear sizes of the CSS sources in our sample against their respective observed redshifts. Results of the analyses indicate that the linear sizes of the quasars have direct power law relationship with their respective redshifts; while the converse is the case for their galaxy counterparts. Their correlation coefficients are marginal. In comparison with the obtained theoretical relation, we notice that for the CSS quasars, the linear size–redshift data show an inverse correlation. This is comparable with the theoretical relation. So, it suggests that the dynamical evolution of the source linear sizes may have some cosmological effects on it. However, the converse is the case for the CSS galaxies – the correlation is direct. The possible explanation for this difference is that quasars are observed at higher redshifts than their galaxy counterparts. Hence, the cosmological effects are expected to be more pronounced on the quasars. Furthermore, we use analytical methods again to obtain a theoretical relation that shows relationship between luminosity and redshift. The relation indicates that luminosity of a radio source has an inverse power-law relationship with redshift. This suggestively implies that the intrinsic luminosity of a radio source may be modified by cosmological evolution. Moreover, for the purpose of obtaining an empirical relation for comparison with the theory, we carry out linear regression analysis of observed luminosities against observed redshifts of the CSS quasars and galaxies in our sample. Results show that luminosities have excellent direct power-law relationship with redshifts. However, this is in contradiction to the obtained theory which shows inverse relationship between the two parameters. This excellent direct correlation has been attributable by some authors to strong luminosity selection effects in which samples with high luminosities are found at high redshifts. Therefore, if the selection effects are taken care of, we may be able to see the comparability of the theory with the empirical relation. Hence, we conclude that source radiated power may have some cosmological implications just like we saw in the size/redshift relation. VL - 9 IS - 1 ER -
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