Questions tagged [quasars]

Questions about quasi-stellar radio sources, active galactic nuclei that are far away and quite old.

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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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Obtaining the Flux-Time plot for a Quasar

As a follow up question to this question, I wish to know how to obtain a Light curve for a quasar observation like this one over here. Is there an archival repository where I can find processed csvs ...
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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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1answer
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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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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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1answer
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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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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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1answer
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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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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 to calculate the luminosity of a quasar?

Is there a relation between the distance ($d$) and the apparent bolometric magnitude ($m_{bol}$) of a quasar and its luminosity ($L$) in watt? If so, what is that relation? Thanks in advance!
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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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51 views

Can Quasars generate Heavy Elements?

Pretty sure Quasars were involved in increasing Galactic metallicity but is there evidence of quasar AGN's generating heavy elements, such as radioactive ones and shooting them across the universe in ...
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How does hawking radiation work without virtual particles?

How does hawking radiation work without the existence for virtual particles? I read that certain quantum fields are distorted when a black hole forms on top of them. But what fields specifically? If ...
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1answer
85 views

How do accretion disks around black holes evaporate via winds?

I'm curious as to how accretion disks around black holes evaporate. I've heard winds play a crucial role in this. But what winds specifically and how do they form? Is it a stellar wind of sorts? If so ...
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1answer
116 views

In the 1950's how were radio-astrometric positions with portable dishes so precise they could be assigned to their dim optical counterparts (Quasars)?

In my question Why are quasars so far away that they couldn't be optically resolved in the 1950's? I included the following short paragraph, but then added strikethrough to the second sentence ...
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Why are quasars so far away that they couldn't be optically resolved in the 1950's? [duplicate]

Wikipedia's Quasar includes the following in its introduction: The term quasar originated as a contraction of quasi-stellar (star-like) radio source, because quasars were first identified during the ...
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Why would the merger of spinning black holes within the accretion disk of a supermassive black hole cause them to "shoot straight up" out of the disk?

I just tried to read the new New York Times article Two Black Holes Colliding Not Enough? Make It Three which links to the new 25-June-2020 Physical Review Letter Graham et al. Candidate ...
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1answer
105 views

What enhances the capture and merge rates of pairs of small black holes orbiting around supermassive black holes?

I just tried to read the new New York Times article Two Black Holes Colliding Not Enough? Make It Three which links to the new 25-June-2020 Physical Review Letter Graham et al. Candidate ...
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1answer
260 views

Is there a recent update on the mysterious M82 radio source reported in 2010?

The Wikipedia page on the "Cigar Galaxy" (M82) has the following summary about an "unknown object": In April 2010, radio astronomers working at the Jodrell Bank Observatory of the University of ...
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How to model blazar light curves

I have SED data spanning over a couple of days and I'm able to find the parameters of the SED (R, B, break energy,...) using least squares method. My question is how to model light curves (with t_acc, ...
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1answer
243 views

How bright would Sagittarius A* be from Earth if it became an Active Galactic Nucleus?

Essentially I'd like to know how bright our central black hole could appear from earth in relation to full moon brightness. Assuming maximum energy output (like when it's gobbling up an entire ...
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1answer
300 views

How to convert luminosity at rest frame wavelength of 1450 A to absolute magnitude at 1450 A?

How do I convert the luminosity (erg sec$^{-1}$ Hz$^{-1}$) of a quasar at a rest frame wavelength of 1450 Angstroms to absolute magnitude at the same wavelength? I know that the bolometric ...
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Absorption line in quasar spectrum

I have quasar spectrum which includes emission and absorption lines. I need to find absorption lines in between 2 wavelength. How can I do it with coding?
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3answers
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light emission of quasars

I'm studying Astrophysics and I have some video's from a past course. I'm currently studying the reionization of the universe. At the current point in the class, the instructor is talking about ...
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How are neutrinos produced in blazar jets?

I was watching the press release about measuring neutrinos and gamma rays from a distant blazar. One of the presenters mentioned that the neutrinos are associated with very high energy protons caught ...
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Why the space is so dark even there are billions of stars and many quasars emitting light [duplicate]

In our galaxy itself, there are millions of stars, and there are many more other galaxies in our local group and billions in the observable universes. For sure they all emit a lot of light, still why ...
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1answer
206 views

Do gravitationally bound (e.g. orbiting) objects really resist the expansion of space?

Thinking about the expansion of space, it is commonly explained that gravitationally bound objects (like galaxies and galaxy clusters) will not be affected by the expansion of space (dark energy). I ...
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1answer
63 views

Regions and size of an AGN

In this diagram of the regions and approximate scale of an AGN: which is from this paper, what do the x and y scales log(z/pc) and ...
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What compounds are present in 3C273?

Anyone know if we have any chemical reactions occuring in this quasar?
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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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Causes of emission of accretion disk

As far as I can see, there are two main sources for the emission of energy from an accretion disk: release of gravitational potential energy of the infalling matter; friction from differential ...
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2answers
428 views

Quasar Redshifts

How can the gravitational redshift of a very distant quasar be distinguished from its cosmological redshift? Quasars are very massive objects,thought to be supermassive black holes,so therefore must ...
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1answer
84 views

How to convert the observed magnitude of a Quasar to it's bolometric luminosity?

How can I convert the observed magnitude to Bolometric Luminosity? I know the relation for the star but should it be same for a Quasar? Basically I want to convert the X-axis of this plot to ...
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Anisotropy of quasar distribution

In a paper titled Arp, H. (1984). Distribution of quasars on the sky. Journal of Astrophysics and Astronomy, 5(1):31-41. at Journal of Astrophysics and Astronomy, Halton Arp wrote that there is ...
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Are quasars simply AGNs that are viewed from a particular angle?

I found the picture below in an answer to the post "Was the Milky Way ever a quasar". The picture is published on a website belonging to "NASA/IPAC Extragalactic Database". In the answer that has 16 "...
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1answer
63 views

What values can a color index variable get?

I am a statistician with love and passion for astronomy. I try to explain some outliers I found in the values of quasars - color indexes. I found four (4) values close to twenty (20). Is that ...
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Correction to inverse square law for cosmology

While reading about the discovery of quasars and the spectroscopic analysis of 3C 273 in this paper by Maarten Schmidt, I came across the following quote: At these distances, corrections to ...
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1answer
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How can gravitational lensing makes a quasar appear brighter?

How can gravitational lensing makes a quasar brighter than it would in the absence of a foreground galaxy?
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How does science knows what is the early universe?

I've read about Hubble seeing the brightest quasar in the early universe. Question is, how does science knows what is early and what is late? Please correct me if I'm wondering, but after the big ...
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Can I take logarithms of magnitudes (which are already log) [closed]

I'm investigating the relationship between the magnitude of quasars in various wavelengths, and their redshift $z$. I've found that if I take the $log$-$mod$-transform ($L_{mag}$) of the magnitudes, ...
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What fractions of matter are retained and displaced by quasars?

Following on from a query concerning quasar mass, what fraction of matter is ejected compared to matter that is lost to the BH? Is there a graph that describes the fractions of the mass of quasars ...
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1answer
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3C273 jet mass estimate

In this picture of 3C273, we can see a jet—estimated to be around 200,000 light-years long—being emitted. I'm trying to find an estimate for the mass of the jet. It's a stream of ...
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Quasar mass and accretion rates

This page on Wikipedia -- Quasars mentions that the "The largest known [quasar] is estimated to consume matter equivalent to 600 Earths per minute". However, there is no citation for this comment. How ...
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Can we extract power from quasars? [closed]

As they say, "In cosmos near earth but beyond atmosphere there are too much dangerous and powerful radiation frm quasars or gammy burst .,etc". So if there is so much cosmic radiations being emitted, ...
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1answer
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Is it possible that quasars are not powered by black holes but some other kind of compact, massive object?

AFAIK, objects in the universe thought to be black holes show evidence of radiatively inefficient accretion flow. But is this the case with Quasars? If not, is there a possibility that the core of a ...
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2answers
158 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 ...
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1answer
111 views

Gravitational lensing of quasars

Are there any cases in which the gravitational lensing of a quasar has been observed in both visible light and in radio waves, and if so, is the radio-wave resolution good enough to show that the ...
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1answer
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Has the Lyman-alpha forest ever been used to test Arp's theory?

Has the Lyman-alpha forest ever been used to test Halton Arp's theory that quasars are not cosmological but instead are ejected from relatively near-by galaxies? If Arp was right, then the spectra of ...
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1answer
146 views

What resolution is needed to see a quasar through the galactic center?

The center of the galaxy is densely packed with stars and obscured by a whole lot of dust between us and it. For those reasons, groups that study the motion of stars around the super-massive black-...
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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 ...