The Nature of Accretion in Seyfert Galaxies

Nwankwo Ifeanyi Francis; Ogwo Jemima Ngozi

doi:doi:10.11648/j.ijass.20210902.12

| Peer-Reviewed

The Nature of Accretion in Seyfert Galaxies

Nwankwo Ifeanyi Francis, Ogwo Jemima Ngozi

Published in International Journal of Astrophysics and Space Science (Volume 9, Issue 2)

Received: 22 June 2021 Accepted: 7 July 2021 Published: 27 July 2021

Views: Downloads:

Download PDF

Share This Article

Twitter
Linked In
Facebook

Abstract

We present statistical results from a sample of 91,006 Seyfert galaxies obtained from SDSS DR14 (Sloan Digital Sky Survey Data Release 14). Using the ratio of the flux of doubly ionized oxygen [OIII] to that of the flux of hydrogen beta line H_β, the Seyfert galaxy sample was separated into Seyferts 1 and 2. For each class of Seyfert galaxy, both bolometric luminosity and Eddington luminosity were calculated and these results were used to investigate the nature of accretion in both classes by estimating their Eddington ratios. The susceptibility of the [OIII] line to reddening necessitated its being extinction corrected before calculating bolometric luminosity from L_bol=3500L_[OIII]. Our work shows that Seyfert 2 galaxies are 10 times more luminous than their Seyfert 1 counterparts. We also found Seyfert 2 galaxies to be centrally more massive than Seyfert 1 galaxies as a result of which Eddington ratio is less in Seyfert 1 galaxies. These results show that both Seyferts 1and 2 galaxies are powered by thick accretion disk and as such undergo predominantly super-Eddington accretion. Only a negligible percent of them (0.49% for Seyfert 1 galaxies and 0.28% for Seyfert 2 galaxies) are powered by thin accretion disk. Our results also indicate that black hole growth in both Seyfert 1 and Seyfert 2 galaxies is dominated by super-Eddington accretion rather than sub-Eddington accretion showing that though both Seyfert classes are good accretors, Seyfert 2 galaxies are better accretors and this means that Seyferts of thin accretion disks are still in the low-Eddington accretion era.

Published in	International Journal of Astrophysics and Space Science (Volume 9, Issue 2)
DOI	10.11648/j.ijass.20210902.12
Page(s)	32-36
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

Blackhole, Eddington-luminosity, Bolometric-luminosity, Eddington-ratio, Reddening, Accretion, Narrow Line Region, Broad Line Region, Extended Narrow Line Region

References

[1]	Antonucci R. R. J (1993). Unified Models for Active Galactic Nuclei and Quasars ARA and A, 31, 473.
[2]	Bassani L, Dadina M, Maiolino R, Salvati M, Risaliti G, Roberto D.C, Matt G, DellaCeca R., Zamorani G (1999). A three dimensional diagnostic diagram for Seyfert 2 galaxies: Probing X-ray absorption and Comptonthickness. ApJS, 121, 473.
[3]	Bian, W., & Zhao, Y. 2004, MNRAS, 347, 607.
[4]	Castello-Mor, N., Kaspi., Netzer. 2017, MNRAS, 467, 1209.
[5]	Contini M, Cracco V, Ciroi S, Mura L. A (2012). Distribution of the Heavy Elements Throughout the Extended Narrow-Line Region of the Seyfert Galaxy NGC 7212. Astron. Astrophys. 545: A72. doi: 10.1051/0004-6361/2012191.
[6]	Das, V., Crenshaw, D. M., Kraemer, S. B., & Deo, R. P. 2006, AJ, 132, 620 (paperII). Dopita M. A, Sutherland R. S., 1995, APJ, 455, 468.
[7]	Heckman T. M and Best P. N (2014). The Coevolution of Galaxies and Supermassive Blackhole: Insights from surveys of the contemporary Universe, ApJ 613, 109.
[8]	Kawaguchi, T., Pieren, A., & Hure, J.-M. 2004a A&A, 415, 47.
[9]	Meléndez, M., Kraemer, S. B., Armentrout, B. K., RP Deo et al. 2008, ApJ, 682, 94. Osterbrock, D. E., 1981, APJ, 249, 462.
[10]	Oyor D. I and Ogwo J. N (2019). On the Extent of the Existence of Broad LineRegion in Seyfert Galaxies; American Journal of Astronomy andAstrophysics. Vol7, No. 2 pp. 33-38. doi: 10.11648/j.ajaa.20190702.12.
[11]	Ricci C, Walter R, Courvoisier T. J. L and Paltani S (2011). Reflection in Seyfert Galaxies and the Unified Model of AGN. A & A 532, A102.
[12]	Vaona L., Ciroi S. Dimille F., Cracco V., Mura La G., Rafanelli P., MNRAS (2012). Spectral Properties of the Narrow Line Region in Seyfert Galaxies Selected from SDSS-7. Vol. 475 pg. 1266.

Cite This Article

Plain Text BibTeX RIS

APA Style

Nwankwo Ifeanyi Francis, Ogwo Jemima Ngozi. (2021). The Nature of Accretion in Seyfert Galaxies. International Journal of Astrophysics and Space Science, 9(2), 32-36. https://doi.org/10.11648/j.ijass.20210902.12

Copy | Download

ACS Style

Nwankwo Ifeanyi Francis; Ogwo Jemima Ngozi. The Nature of Accretion in Seyfert Galaxies. Int. J. Astrophys. Space Sci. 2021, 9(2), 32-36. doi: 10.11648/j.ijass.20210902.12

Copy | Download

AMA Style

Nwankwo Ifeanyi Francis, Ogwo Jemima Ngozi. The Nature of Accretion in Seyfert Galaxies. Int J Astrophys Space Sci. 2021;9(2):32-36. doi: 10.11648/j.ijass.20210902.12

Copy | Download

@article{10.11648/j.ijass.20210902.12,
  author = {Nwankwo Ifeanyi Francis and Ogwo Jemima Ngozi},
  title = {The Nature of Accretion in Seyfert Galaxies},
  journal = {International Journal of Astrophysics and Space Science},
  volume = {9},
  number = {2},
  pages = {32-36},
  doi = {10.11648/j.ijass.20210902.12},
  url = {https://doi.org/10.11648/j.ijass.20210902.12},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijass.20210902.12},
  abstract = {We present statistical results from a sample of 91,006 Seyfert galaxies obtained from SDSS DR14 (Sloan Digital Sky Survey Data Release 14). Using the ratio of the flux of doubly ionized oxygen [OIII] to that of the flux of hydrogen beta line Hβ, the Seyfert galaxy sample was separated into Seyferts 1 and 2. For each class of Seyfert galaxy, both bolometric luminosity and Eddington luminosity were calculated and these results were used to investigate the nature of accretion in both classes by estimating their Eddington ratios. The susceptibility of the [OIII] line to reddening necessitated its being extinction corrected before calculating bolometric luminosity from Lbol=3500L[OIII]. Our work shows that Seyfert 2 galaxies are 10 times more luminous than their Seyfert 1 counterparts. We also found Seyfert 2 galaxies to be centrally more massive than Seyfert 1 galaxies as a result of which Eddington ratio is less in Seyfert 1 galaxies. These results show that both Seyferts 1and 2 galaxies are powered by thick accretion disk and as such undergo predominantly super-Eddington accretion. Only a negligible percent of them (0.49% for Seyfert 1 galaxies and 0.28% for Seyfert 2 galaxies) are powered by thin accretion disk. Our results also indicate that black hole growth in both Seyfert 1 and Seyfert 2 galaxies is dominated by super-Eddington accretion rather than sub-Eddington accretion showing that though both Seyfert classes are good accretors, Seyfert 2 galaxies are better accretors and this means that Seyferts of thin accretion disks are still in the low-Eddington accretion era.},
 year = {2021}
}

Copy | Download

TY  - JOUR
T1  - The Nature of Accretion in Seyfert Galaxies
AU  - Nwankwo Ifeanyi Francis
AU  - Ogwo Jemima Ngozi
Y1  - 2021/07/27
PY  - 2021
N1  - https://doi.org/10.11648/j.ijass.20210902.12
DO  - 10.11648/j.ijass.20210902.12
T2  - International Journal of Astrophysics and Space Science
JF  - International Journal of Astrophysics and Space Science
JO  - International Journal of Astrophysics and Space Science
SP  - 32
EP  - 36
PB  - Science Publishing Group
SN  - 2376-7022
UR  - https://doi.org/10.11648/j.ijass.20210902.12
AB  - We present statistical results from a sample of 91,006 Seyfert galaxies obtained from SDSS DR14 (Sloan Digital Sky Survey Data Release 14). Using the ratio of the flux of doubly ionized oxygen [OIII] to that of the flux of hydrogen beta line Hβ, the Seyfert galaxy sample was separated into Seyferts 1 and 2. For each class of Seyfert galaxy, both bolometric luminosity and Eddington luminosity were calculated and these results were used to investigate the nature of accretion in both classes by estimating their Eddington ratios. The susceptibility of the [OIII] line to reddening necessitated its being extinction corrected before calculating bolometric luminosity from Lbol=3500L[OIII]. Our work shows that Seyfert 2 galaxies are 10 times more luminous than their Seyfert 1 counterparts. We also found Seyfert 2 galaxies to be centrally more massive than Seyfert 1 galaxies as a result of which Eddington ratio is less in Seyfert 1 galaxies. These results show that both Seyferts 1and 2 galaxies are powered by thick accretion disk and as such undergo predominantly super-Eddington accretion. Only a negligible percent of them (0.49% for Seyfert 1 galaxies and 0.28% for Seyfert 2 galaxies) are powered by thin accretion disk. Our results also indicate that black hole growth in both Seyfert 1 and Seyfert 2 galaxies is dominated by super-Eddington accretion rather than sub-Eddington accretion showing that though both Seyfert classes are good accretors, Seyfert 2 galaxies are better accretors and this means that Seyferts of thin accretion disks are still in the low-Eddington accretion era.
VL  - 9
IS  - 2
ER  -

Copy | Download

Author Information

Nwankwo Ifeanyi Francis

Department of Physics, Abia State University, Uturu, Nigeria
Ogwo Jemima Ngozi

Department of Physics, Abia State University, Uturu, Nigeria

Download PDF

Sections

Plain Text BibTeX RIS

APA Style

Nwankwo Ifeanyi Francis, Ogwo Jemima Ngozi. (2021). The Nature of Accretion in Seyfert Galaxies. International Journal of Astrophysics and Space Science, 9(2), 32-36. https://doi.org/10.11648/j.ijass.20210902.12

Copy | Download

ACS Style

Nwankwo Ifeanyi Francis; Ogwo Jemima Ngozi. The Nature of Accretion in Seyfert Galaxies. Int. J. Astrophys. Space Sci. 2021, 9(2), 32-36. doi: 10.11648/j.ijass.20210902.12

Copy | Download

AMA Style

Nwankwo Ifeanyi Francis, Ogwo Jemima Ngozi. The Nature of Accretion in Seyfert Galaxies. Int J Astrophys Space Sci. 2021;9(2):32-36. doi: 10.11648/j.ijass.20210902.12

Copy | Download

@article{10.11648/j.ijass.20210902.12,
  author = {Nwankwo Ifeanyi Francis and Ogwo Jemima Ngozi},
  title = {The Nature of Accretion in Seyfert Galaxies},
  journal = {International Journal of Astrophysics and Space Science},
  volume = {9},
  number = {2},
  pages = {32-36},
  doi = {10.11648/j.ijass.20210902.12},
  url = {https://doi.org/10.11648/j.ijass.20210902.12},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijass.20210902.12},
  abstract = {We present statistical results from a sample of 91,006 Seyfert galaxies obtained from SDSS DR14 (Sloan Digital Sky Survey Data Release 14). Using the ratio of the flux of doubly ionized oxygen [OIII] to that of the flux of hydrogen beta line Hβ, the Seyfert galaxy sample was separated into Seyferts 1 and 2. For each class of Seyfert galaxy, both bolometric luminosity and Eddington luminosity were calculated and these results were used to investigate the nature of accretion in both classes by estimating their Eddington ratios. The susceptibility of the [OIII] line to reddening necessitated its being extinction corrected before calculating bolometric luminosity from Lbol=3500L[OIII]. Our work shows that Seyfert 2 galaxies are 10 times more luminous than their Seyfert 1 counterparts. We also found Seyfert 2 galaxies to be centrally more massive than Seyfert 1 galaxies as a result of which Eddington ratio is less in Seyfert 1 galaxies. These results show that both Seyferts 1and 2 galaxies are powered by thick accretion disk and as such undergo predominantly super-Eddington accretion. Only a negligible percent of them (0.49% for Seyfert 1 galaxies and 0.28% for Seyfert 2 galaxies) are powered by thin accretion disk. Our results also indicate that black hole growth in both Seyfert 1 and Seyfert 2 galaxies is dominated by super-Eddington accretion rather than sub-Eddington accretion showing that though both Seyfert classes are good accretors, Seyfert 2 galaxies are better accretors and this means that Seyferts of thin accretion disks are still in the low-Eddington accretion era.},
 year = {2021}
}

Copy | Download

TY  - JOUR
T1  - The Nature of Accretion in Seyfert Galaxies
AU  - Nwankwo Ifeanyi Francis
AU  - Ogwo Jemima Ngozi
Y1  - 2021/07/27
PY  - 2021
N1  - https://doi.org/10.11648/j.ijass.20210902.12
DO  - 10.11648/j.ijass.20210902.12
T2  - International Journal of Astrophysics and Space Science
JF  - International Journal of Astrophysics and Space Science
JO  - International Journal of Astrophysics and Space Science
SP  - 32
EP  - 36
PB  - Science Publishing Group
SN  - 2376-7022
UR  - https://doi.org/10.11648/j.ijass.20210902.12
AB  - We present statistical results from a sample of 91,006 Seyfert galaxies obtained from SDSS DR14 (Sloan Digital Sky Survey Data Release 14). Using the ratio of the flux of doubly ionized oxygen [OIII] to that of the flux of hydrogen beta line Hβ, the Seyfert galaxy sample was separated into Seyferts 1 and 2. For each class of Seyfert galaxy, both bolometric luminosity and Eddington luminosity were calculated and these results were used to investigate the nature of accretion in both classes by estimating their Eddington ratios. The susceptibility of the [OIII] line to reddening necessitated its being extinction corrected before calculating bolometric luminosity from Lbol=3500L[OIII]. Our work shows that Seyfert 2 galaxies are 10 times more luminous than their Seyfert 1 counterparts. We also found Seyfert 2 galaxies to be centrally more massive than Seyfert 1 galaxies as a result of which Eddington ratio is less in Seyfert 1 galaxies. These results show that both Seyferts 1and 2 galaxies are powered by thick accretion disk and as such undergo predominantly super-Eddington accretion. Only a negligible percent of them (0.49% for Seyfert 1 galaxies and 0.28% for Seyfert 2 galaxies) are powered by thin accretion disk. Our results also indicate that black hole growth in both Seyfert 1 and Seyfert 2 galaxies is dominated by super-Eddington accretion rather than sub-Eddington accretion showing that though both Seyfert classes are good accretors, Seyfert 2 galaxies are better accretors and this means that Seyferts of thin accretion disks are still in the low-Eddington accretion era.
VL  - 9
IS  - 2
ER  -

Copy | Download