Questions tagged [quasars]
Questions about quasi-stellar radio sources, active galactic nuclei that are far away and quite old.
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Why would some sources in a cross-matched DESI/SDSS catalog have different spectroscopic redshifts?
I've crossmatched quasars from DESI DR9 and from SDSS DR16. When I plot the spectroscopic redshift from each of the individual catalogs for each source, I get:
Naively, I'd expect the $z_{spec}$ to ...
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How bright in the night sky would J0529-4351 (brightest quasar ever found) be if it were in our galaxy?
According to this article, the quasar (black hole) named J0529-4351 is the most luminous object in the known universe, being:
500 trillion times more luminous than the Sun
To put it in terms easier ...
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What "external illumination" source causes the heating of a quasar's accretion disc?
In Section 3.4, UV-to-optical continuum flux ratio, Gaskell et al. (2023) Estimating reddening of the continuum and broad-line region of active galactic nuclei: the mean reddening of NGC 5548 and the ...
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Is the code that produces the SDSS DR16Q quasar catalogue available?
I'm curious if it's available to investigate (from my question in the title), or even better, modify and re-run. See SDSS DR16Q quasar catalogue.
Not the data itself, that's in a fits file. The code ...
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What happens when the quasar remnants reach Earth in 3 million years?
According to this article (A quasar Milky Way six million years ago?), during:
(during) a quasar stage in its evolution (6 million years ago) ... the Milky Way’s central black hole swallowed a huge ...
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On the "periodic" lightcurves of Active Galactic Nuclei
So apparently they are all lightcurves of (likely candidates) Active Galactic Nuclei and in some way or the other they all appear to be periodic:
I'd like to know the reason for this and the ...
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What is the mechanism through which mass is converted to thermal energy in the accretion disc of a black hole?
In the book The Cosmic Perspective, it is stated that as matter is falling into a supermassive black hole, up to $40\%$ of its mass are converted to thermal energy, making the accretion of matter ...
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Trying to understand how to properly implement this equation to a healpix map
So i am working on reproducing a paper (Secrest, N. J., von Hausegger, S., Rameez, M., Mohayaee, R., Sarkar, S., & Colin, J. (2021). A test of the cosmological principle with quasars. The ...
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Why are all quasars so far away?
Why are all quasars so far away?
If the universe is homogeneous, we should expect to have a homogeneous distribution of quasars, but all of then seem to be far away from Earth. Why is that?
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Reduced chi square value
I am currently plotting a continuum of observed data. I need to check the effectiveness of the fitted continuum with the reduced chi-square method. Ideally, should the reduced chi-square value ...
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Are there any experiments or observations indicating that the Hubble flow can influence AGNs, quasars and galactic winds (outflows)?
Galactic winds (or outflows) are produced by AGNs (Active Galactic Nuclei), quasars, supernovas...etc which basically eject matter usually in form of waves or spheres, sometimes even arriving to the ...
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Can the Hubble expansion inject energy in AGN and quasar outflows?
I found this article about the behavior of quasar outflows in cosmology and how they can create a magnetic field.
In section 2.1.4., the authors say that when a quasar produces a "wave" or ...
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What does "Effective radius of [CII] line is 1.4 kpc" mean?
A recent paper (A dusty compact object bridging galaxies and quasars at cosmic dawn) describes one of their results as the "Effective radius of [CII] line" (Extended Data Table 2, p38):
I ...
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Could life develop in a galaxy with a quasar at its centre?
Quasars are a type of Active Galactic Nucleus that inhabit the centres of some galaxies. They are among the most energetic objects known in the universe, emitting up to a thousand times the energy ...
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Sudden spikes on the light curve of a Quasar from K2 mission
I obtained the optical light curve of 3C 273 QSO from the MAST repository off the K2 mission and plotted it by making the FITS into a CSV file through Pandas dataframe and plotting the obtained ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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