Questions tagged [active-galaxy]

Questions regarding galaxies that host a compact, energetic core at the center characterized by non-stellar emission.

10 questions with no upvoted or accepted answers
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Why do the Centaurus A radio jets have two "arms" each? (Event Horizon Telescope image)

Fig. 2: Image analysis of the final model: a, Model image corresponding to the image from Fig. 1 with a pixel size of 2 μas. Here, the tentative position of the jet apex is indicated with a circle. ...
4
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0answers
126 views

Spectral analysis of AGN (velocity dispersion of galaxy absorption, doppler shifts)

I was wondering what parameters I need to know/measure to calculate the velocity dispersion of a galaxy, specifically an AGN. Also, I have spectra where there are blueshifted and redshifted ...
3
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0answers
29 views

The activity of the galactic nucleus is cyclic?

Are there observations/theoretical calculations that prove or disprove a cyclic activity of the galactic nucleus (I mean the nucleus is active than stops than become newly active with a time ...
3
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0answers
98 views

Number of obscured AGN compared to unobscured AGN

Urry and Padovani 1995 proposed a unified model for Active Galactic Nuclei, which has since been recognised as a good model for AGN. If AGN are randomly oriented, then I'd expect there to be more ...
3
votes
0answers
48 views

What is the relationship between AGN and [OIII]

I read that we can observe [OIII] from AGNs but what processes in AGNs produces these lines why we can use them to trace or tell if that galaxy is active or not?
2
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0answers
19 views

Line Flux Ratios in Active galaxies

Good day to everyone. I wanted to know what is the importance of estimation of line flux ratios in active galaxies? What does it help in characterizing? As in Lyman $\alpha /$Carbon IV, or Mg II$/$...
2
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0answers
57 views

Radio loud AGN restarting as Radio Quiet AGN?

Is it possible for a Radio-loud object (eg., an FRI galaxy) to evolve into a Radio-quiet (eg., a Seyfert) source? Also, can this happen via AGN restart? That is, have there been instances where the ...
2
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0answers
24 views

Observed instances of massive gas inflow and AGN restart due to cluster-cluster merger?

Works such as Acreman et al. (2003) have demonstrated via simulations the possibility of gas being stripped off a galaxy due to interaction with a galaxy cluster. Have there been confirmed instances ...
1
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34 views

What is the O[III]/H$\alpha$ line ratio for Active Galactic Nuclei?

I have the H$\alpha$ line flux of an AGN and I am trying to calculate the Bolometric luminosity using it. Bolometric luminosity can be calculated from O[III] fluxes by $L_{\rm Bol} = 3500 L_{\rm O[III]...
0
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0answers
21 views

Searching for a modern AGN Catalog

I am searching for a simple, modern catalog of Active Galactic Nuclei. I expected a catalog similar to this or this, but instead found that they contain observed spectra instead of properties like the ...