Questions tagged [quasars]
Questions about quasi-stellar radio sources, active galactic nuclei that are far away and quite old.
81
questions
2
votes
1
answer
186
views
How to convert spectra to log-wavelength and interpolate them into linear spacing in log-wavelength
I want to write a function that cross correlates a spectrum with a quasar template
I’d like to ask you how can I convert my flux density vs wavelength spectrum to log-wavelength. It’s not clear to me ...
- 4,471
4
votes
2
answers
177
views
How to interpret this spectrum of the "new DESI Quasar at z = 6.53"; what causes the big edge at about 9150 Angstroms?
I'm not exacty sure why but Scitech Daily's Seeing Dark Energy’s True Colors: DESI Creates Largest 3D Map of the Cosmos includes the graphic and caption below.
It indicates a quasar in a Hubble image ...
- 38.9k
3
votes
1
answer
163
views
Intergalactic Lyman-alpha absorption for high redshift quasars (Gunn-Peterson effect)
This is a follow up to a recent question on SE asking about the apparent suppression of radiation shortward of the (red-shifted) Ly-$\alpha$ line of a quasar at redshift $z=6.53$.
The general ...
- 38.9k
1
vote
2
answers
206
views
Is there an official list of objects in the sky?
I would like to know how many known quasars there are in the Universe as well as x-ray binary black holes (not Neutron stars) but I don't seem to be able to.
I also want to know how many black holes ...
- 126k
2
votes
2
answers
146
views
Could quasars be interior to the event horizon of a SMBH?
My question is prompted by suspicion of three current ideas in astrophysics:
GR predicts a singularity at the center of a BH without regard to QM.
quasar hyper-luminosity is caused by an acretion ...
2
votes
1
answer
59
views
Obtaining the Flux-Time plot for a Quasar
As a follow up question to Obtaining the Light curve of a a Quasar, I wish to know how to obtain a Light curve for a quasar observation like this data set over here.
Is there an archival repository ...
- 4,800
3
votes
1
answer
91
views
Obtaining the Light curve of a a Quasar
So, I am relatively comfortable with handling $\textit{FITS}$ files and hence I choose Python for the following operation.
The thing is that I need to analyse some Quasar light curves and hence I went ...
- 136
2
votes
1
answer
663
views
What does "TON" in TON 618 stand for?
I don't think TON 618 is a random name, but rather a composition of category name and a number.
But when I tried to google it, any article about TON 618 did not contain anything about its name origin ...
- 30.7k
4
votes
1
answer
326
views
Is quasar 2M1310-1714 outside the observable universe?
This Einstein ring
Image credit: NASA / ESA / Hubble / T. Treu / Judy Schmidt
shows multiple images of the quasar 2M1310-1714. Its distance is quoted at 17 billion light years and although the age ...
- 156k
6
votes
1
answer
106
views
Why are the radio images of the jet of 3C 273 different?
At NASA/IPAC Extragalactic database, we can see images of the jet of matter being ejected from the quasar 3C 273. Here are a couple from the radio spectrum as examples:
My question is: why are the ...
- 152
0
votes
2
answers
65
views
How can I find more information on a certain galaxy when NED isn't helping?
The paper High Frequency Peakers: Young radio sources or flaring blazars? by S.Tinti et.al. lists some nice radio-wavelength SEDs, like these for instance:
When looking for more photometric info on a ...
- 17.3k
2
votes
1
answer
67
views
Radio SEDs for quasars
Using data from https://ned.ipac.caltech.edu/, I can get nice-looking spectral energy distributions for quasars, such as for these two:
but most of their points are in UV to IR range. I'm looking ...
- 37.3k
4
votes
2
answers
136
views
How much light comes from quasars in an AGN?
From what I've been able to gather, the very bright spot at the center of galaxies is produced by both the central quasar and a dense cluster of millions of stars that surround it. How much of the ...
- 5,636
3
votes
0
answers
177
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 ...
- 5,636
4
votes
1
answer
186
views
Why do Seyfert Galaxies emit less energy than Quasars and Blazars, and how is the emitted energy measured?
When I was reading information about QSOs on a website, it said that Seyfert Galaxies emit less energy than Quasars and QSOs.
Why do Seyfert Galaxies emit less energy than quasars, and how is this ...
- 5,636