Intergalactic Media Densities of Extragalactic Radio Sources and Source Ages

Ezeugo Jeremiah Chukwuemerie

doi:doi:10.11648/j.ajaa.20210902.11

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Intergalactic Media Densities of Extragalactic Radio Sources and Source Ages

Ezeugo Jeremiah Chukwuemerie

Published in American Journal of Astronomy and Astrophysics (Volume 9, Issue 2)

Received: 16 March 2021 Accepted: 30 March 2021 Published: 20 April 2021

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Abstract

In this paper, we use analytical methods with some plausible assumptions to develop a mathematical model which may be used to obtain estimate of density of the intergalactic medium (IGM). This relation suggests that the plot of the linear sizes against the bolometric luminosities of the extragalactic radio sources in our sample should be able to furnish us with an estimate of the density of IGM in which the radio sources are domiciled. Moreover, for the purpose of obtaining an empirical relation similar to the theoretical model, we carry out linear regression analysis of linear sizes and luminosities of the 31 radio galaxies in our sample. The regression result shows an empirical relationship between observed source linear sizes and observed bolometric luminosities with slight correlation whose coefficient is 4. Moreover, we compared the theoretical relation and the empirical relation to obtain an estimate of the particle number density of the IGM in which the radio sources are located. The estimate indicates a very low density when compared with the values obtained by authors for the compact steep spectrum (CSS) sources. However, while the linear sizes of the CSS sources are of sub-galactic dimensions – they are located within the interstellar media (ISM) – those of the large extended extragalactic radio sources extend into the intergalactic media. The staggering difference in these obtained densities of IGM and ISM simply supports the general notion that there is a sharp decrease in the density at the IGM–ISM interface. Moreover, using theoretical approach again, with some plausible assumptions, we find another relation which may be used to estimate the ages of extragalactic radio sources. This relation possibly indicates that the plot of the linear sizes against velocities of the radio jets of the radio sources in our sample should be able to supply us with an estimate of the sources’ ages. We find from the simple linear regression analysis of linear sizes and jet velocities of the radio galaxies in our sample, a relation with correlation coefficient given as 4, which is also marginal. Comparison of the two relations – theoretical and the empirical relations – gives an estimate of age of the radio sources. The value shows that these large extended extragalactic radio sources are old sources.

Published in	American Journal of Astronomy and Astrophysics (Volume 9, Issue 2)
DOI	10.11648/j.ajaa.20210902.11
Page(s)	13-17
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), 2021. Published by Science Publishing Group

Keywords

Galactic-intergalactic Interface, Intergalactic Media Densities, Jet Velocity, Linear Size, Luminosity, Interstellar Medium, Radio Sources, Source Ages

References

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[2]	Robson, I., (1996) Active Galactic Nuclei”. Praxis Publishing Ltd, England.
[3]	Readhead, A. C., (1995) Evolution of Powerful Extragalactic Radio Sources. Proceedings of Colloquuium on Quasars and Active Galactic Nuclei, USA: National Academy of Sciences, Berkman Center, Irvine.
[4]	Jackson, J. C. (1999) Radio Source Evolution and Unified Schemes. Publications of Astronomical Society of the Pacific, 16, 124–129.
[5]	Kawakatu, N. and Kino, M. (2007) The Velocity of Large-scale Jets in a Declining Density Medium. Proceedings of Conference on Triggering Relativistic Jets, 27, 192–197. 2007.
[6]	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.
[7]	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.
[8]	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.
[9]	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.
[10]	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.
[11]	Nilson, K. (1998) Kinematical Models of Double Radio Sources and the Unified Scheme. Monthly Notices of Royal Astronomical Society, 132. 31–37.
[12]	O’Dea, C. P., Dally, R. A., Kharb, P. and Freeman, K. A. (2009) Physical Properties of Very Powerful FR II Radio Galaxies. Astronomy and Astrophysics, 494, 471–569.
[13]	Ubachukwu, A. A. and Chukwude, A. E. (2002) On the Relativistic Beaming and Orientation Effects in Core-Dominated Quasars. Journal of Astrophysics and Astronomy, 23, 235–24.
[14]	Ezeugo, J. C. (2015) On Jet Opening Angle and Dynamical Evolution of Some Powerful Extragalactic Radio Sources. American Journal of Astronomy and Astrophysics, 3, 40–43.
[15]	Owsianik, I. And Conway, J. E. (1998) First Detection of Hotspot Advance in a CSO – Evidence for a Class of Very Young Extragalactic Radio Sources. Astronomy and Astrophysics, 336, 69–79.

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APA Style

Ezeugo Jeremiah Chukwuemerie. (2021). Intergalactic Media Densities of Extragalactic Radio Sources and Source Ages. American Journal of Astronomy and Astrophysics, 9(2), 13-17. https://doi.org/10.11648/j.ajaa.20210902.11

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ACS Style

Ezeugo Jeremiah Chukwuemerie. Intergalactic Media Densities of Extragalactic Radio Sources and Source Ages. Am. J. Astron. Astrophys. 2021, 9(2), 13-17. doi: 10.11648/j.ajaa.20210902.11

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AMA Style

Ezeugo Jeremiah Chukwuemerie. Intergalactic Media Densities of Extragalactic Radio Sources and Source Ages. Am J Astron Astrophys. 2021;9(2):13-17. doi: 10.11648/j.ajaa.20210902.11

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@article{10.11648/j.ajaa.20210902.11,
  author = {Ezeugo Jeremiah Chukwuemerie},
  title = {Intergalactic Media Densities of Extragalactic Radio Sources and Source Ages},
  journal = {American Journal of Astronomy and Astrophysics},
  volume = {9},
  number = {2},
  pages = {13-17},
  doi = {10.11648/j.ajaa.20210902.11},
  url = {https://doi.org/10.11648/j.ajaa.20210902.11},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajaa.20210902.11},
  abstract = {In this paper, we use analytical methods with some plausible assumptions to develop a mathematical model which may be used to obtain estimate of density of the intergalactic medium (IGM). This relation suggests that the plot of the linear sizes against the bolometric luminosities of the extragalactic radio sources in our sample should be able to furnish us with an estimate of the density of IGM in which the radio sources are domiciled. Moreover, for the purpose of obtaining an empirical relation similar to the theoretical model, we carry out linear regression analysis of linear sizes and luminosities of the 31 radio galaxies in our sample. The regression result shows an empirical relationship between observed source linear sizes and observed bolometric luminosities with slight correlation whose coefficient is 4. Moreover, we compared the theoretical relation and the empirical relation to obtain an estimate of the particle number density of the IGM in which the radio sources are located. The estimate indicates a very low density when compared with the values obtained by authors for the compact steep spectrum (CSS) sources. However, while the linear sizes of the CSS sources are of sub-galactic dimensions – they are located within the interstellar media (ISM) – those of the large extended extragalactic radio sources extend into the intergalactic media. The staggering difference in these obtained densities of IGM and ISM simply supports the general notion that there is a sharp decrease in the density at the IGM–ISM interface. Moreover, using theoretical approach again, with some plausible assumptions, we find another relation which may be used to estimate the ages of extragalactic radio sources. This relation possibly indicates that the plot of the linear sizes against velocities of the radio jets of the radio sources in our sample should be able to supply us with an estimate of the sources’ ages. We find from the simple linear regression analysis of linear sizes and jet velocities of the radio galaxies in our sample, a relation with correlation coefficient given as 4, which is also marginal. Comparison of the two relations – theoretical and the empirical relations – gives an estimate of age of the radio sources. The value shows that these large extended extragalactic radio sources are old sources.},
 year = {2021}
}

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TY  - JOUR
T1  - Intergalactic Media Densities of Extragalactic Radio Sources and Source Ages
AU  - Ezeugo Jeremiah Chukwuemerie
Y1  - 2021/04/20
PY  - 2021
N1  - https://doi.org/10.11648/j.ajaa.20210902.11
DO  - 10.11648/j.ajaa.20210902.11
T2  - American Journal of Astronomy and Astrophysics
JF  - American Journal of Astronomy and Astrophysics
JO  - American Journal of Astronomy and Astrophysics
SP  - 13
EP  - 17
PB  - Science Publishing Group
SN  - 2376-4686
UR  - https://doi.org/10.11648/j.ajaa.20210902.11
AB  - In this paper, we use analytical methods with some plausible assumptions to develop a mathematical model which may be used to obtain estimate of density of the intergalactic medium (IGM). This relation suggests that the plot of the linear sizes against the bolometric luminosities of the extragalactic radio sources in our sample should be able to furnish us with an estimate of the density of IGM in which the radio sources are domiciled. Moreover, for the purpose of obtaining an empirical relation similar to the theoretical model, we carry out linear regression analysis of linear sizes and luminosities of the 31 radio galaxies in our sample. The regression result shows an empirical relationship between observed source linear sizes and observed bolometric luminosities with slight correlation whose coefficient is 4. Moreover, we compared the theoretical relation and the empirical relation to obtain an estimate of the particle number density of the IGM in which the radio sources are located. The estimate indicates a very low density when compared with the values obtained by authors for the compact steep spectrum (CSS) sources. However, while the linear sizes of the CSS sources are of sub-galactic dimensions – they are located within the interstellar media (ISM) – those of the large extended extragalactic radio sources extend into the intergalactic media. The staggering difference in these obtained densities of IGM and ISM simply supports the general notion that there is a sharp decrease in the density at the IGM–ISM interface. Moreover, using theoretical approach again, with some plausible assumptions, we find another relation which may be used to estimate the ages of extragalactic radio sources. This relation possibly indicates that the plot of the linear sizes against velocities of the radio jets of the radio sources in our sample should be able to supply us with an estimate of the sources’ ages. We find from the simple linear regression analysis of linear sizes and jet velocities of the radio galaxies in our sample, a relation with correlation coefficient given as 4, which is also marginal. Comparison of the two relations – theoretical and the empirical relations – gives an estimate of age of the radio sources. The value shows that these large extended extragalactic radio sources are old sources.
VL  - 9
IS  - 2
ER  -

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Author Information

Ezeugo Jeremiah Chukwuemerie

Department of Physics and Industrial Physics, Nnamdi Azikiwe University, Awka, Nigeria

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APA Style

Ezeugo Jeremiah Chukwuemerie. (2021). Intergalactic Media Densities of Extragalactic Radio Sources and Source Ages. American Journal of Astronomy and Astrophysics, 9(2), 13-17. https://doi.org/10.11648/j.ajaa.20210902.11

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ACS Style

Ezeugo Jeremiah Chukwuemerie. Intergalactic Media Densities of Extragalactic Radio Sources and Source Ages. Am. J. Astron. Astrophys. 2021, 9(2), 13-17. doi: 10.11648/j.ajaa.20210902.11

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AMA Style

Ezeugo Jeremiah Chukwuemerie. Intergalactic Media Densities of Extragalactic Radio Sources and Source Ages. Am J Astron Astrophys. 2021;9(2):13-17. doi: 10.11648/j.ajaa.20210902.11

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@article{10.11648/j.ajaa.20210902.11,
  author = {Ezeugo Jeremiah Chukwuemerie},
  title = {Intergalactic Media Densities of Extragalactic Radio Sources and Source Ages},
  journal = {American Journal of Astronomy and Astrophysics},
  volume = {9},
  number = {2},
  pages = {13-17},
  doi = {10.11648/j.ajaa.20210902.11},
  url = {https://doi.org/10.11648/j.ajaa.20210902.11},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajaa.20210902.11},
  abstract = {In this paper, we use analytical methods with some plausible assumptions to develop a mathematical model which may be used to obtain estimate of density of the intergalactic medium (IGM). This relation suggests that the plot of the linear sizes against the bolometric luminosities of the extragalactic radio sources in our sample should be able to furnish us with an estimate of the density of IGM in which the radio sources are domiciled. Moreover, for the purpose of obtaining an empirical relation similar to the theoretical model, we carry out linear regression analysis of linear sizes and luminosities of the 31 radio galaxies in our sample. The regression result shows an empirical relationship between observed source linear sizes and observed bolometric luminosities with slight correlation whose coefficient is 4. Moreover, we compared the theoretical relation and the empirical relation to obtain an estimate of the particle number density of the IGM in which the radio sources are located. The estimate indicates a very low density when compared with the values obtained by authors for the compact steep spectrum (CSS) sources. However, while the linear sizes of the CSS sources are of sub-galactic dimensions – they are located within the interstellar media (ISM) – those of the large extended extragalactic radio sources extend into the intergalactic media. The staggering difference in these obtained densities of IGM and ISM simply supports the general notion that there is a sharp decrease in the density at the IGM–ISM interface. Moreover, using theoretical approach again, with some plausible assumptions, we find another relation which may be used to estimate the ages of extragalactic radio sources. This relation possibly indicates that the plot of the linear sizes against velocities of the radio jets of the radio sources in our sample should be able to supply us with an estimate of the sources’ ages. We find from the simple linear regression analysis of linear sizes and jet velocities of the radio galaxies in our sample, a relation with correlation coefficient given as 4, which is also marginal. Comparison of the two relations – theoretical and the empirical relations – gives an estimate of age of the radio sources. The value shows that these large extended extragalactic radio sources are old sources.},
 year = {2021}
}

Copy | Download

TY  - JOUR
T1  - Intergalactic Media Densities of Extragalactic Radio Sources and Source Ages
AU  - Ezeugo Jeremiah Chukwuemerie
Y1  - 2021/04/20
PY  - 2021
N1  - https://doi.org/10.11648/j.ajaa.20210902.11
DO  - 10.11648/j.ajaa.20210902.11
T2  - American Journal of Astronomy and Astrophysics
JF  - American Journal of Astronomy and Astrophysics
JO  - American Journal of Astronomy and Astrophysics
SP  - 13
EP  - 17
PB  - Science Publishing Group
SN  - 2376-4686
UR  - https://doi.org/10.11648/j.ajaa.20210902.11
AB  - In this paper, we use analytical methods with some plausible assumptions to develop a mathematical model which may be used to obtain estimate of density of the intergalactic medium (IGM). This relation suggests that the plot of the linear sizes against the bolometric luminosities of the extragalactic radio sources in our sample should be able to furnish us with an estimate of the density of IGM in which the radio sources are domiciled. Moreover, for the purpose of obtaining an empirical relation similar to the theoretical model, we carry out linear regression analysis of linear sizes and luminosities of the 31 radio galaxies in our sample. The regression result shows an empirical relationship between observed source linear sizes and observed bolometric luminosities with slight correlation whose coefficient is 4. Moreover, we compared the theoretical relation and the empirical relation to obtain an estimate of the particle number density of the IGM in which the radio sources are located. The estimate indicates a very low density when compared with the values obtained by authors for the compact steep spectrum (CSS) sources. However, while the linear sizes of the CSS sources are of sub-galactic dimensions – they are located within the interstellar media (ISM) – those of the large extended extragalactic radio sources extend into the intergalactic media. The staggering difference in these obtained densities of IGM and ISM simply supports the general notion that there is a sharp decrease in the density at the IGM–ISM interface. Moreover, using theoretical approach again, with some plausible assumptions, we find another relation which may be used to estimate the ages of extragalactic radio sources. This relation possibly indicates that the plot of the linear sizes against velocities of the radio jets of the radio sources in our sample should be able to supply us with an estimate of the sources’ ages. We find from the simple linear regression analysis of linear sizes and jet velocities of the radio galaxies in our sample, a relation with correlation coefficient given as 4, which is also marginal. Comparison of the two relations – theoretical and the empirical relations – gives an estimate of age of the radio sources. The value shows that these large extended extragalactic radio sources are old sources.
VL  - 9
IS  - 2
ER  -

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