Unanswered Questions
170 questions with no upvoted or accepted answers
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How well conserved is etendue in extreme gravitational lensing scenarios?
This excellent answer to Could dark matter exist in the Universe in the form of sufficiently dense objects? includes the following image and description:
Light from the background galaxy circles a ...
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7
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Convert from Jy/beam km/s to W/m$^2$
I need to compare some ALMA observations of a protoplanetary disk to disk-integrated fluxes obtained from a model.
The ALMA observations are upper limits of non-detected spectral lines, where the RMS ...
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Get the expression of probed volume between 2 redshifts
1) I can't manage to find/justify the relation (1) below, from the common relation (2) of a volume.
2) It seems the variable r is actually the comoving distance and not comoving coordinates (with ...
CommunityBot
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6
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Radius of hydrogen cloud
I am using a 1.4 meter parabolic dish with HPBW of 10 degrees and a RTLSDR to study our milky way in hydrogen line. The structure of the galaxy is deduced as shown in the picture by plugging the ...
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BLC1 and Proxima Centauri's activity
From Wikipedia BLC1:
A paper by other astronomers released 10 days before the news report about BLC1 reports the detection of "a bright, long-duration optical flare, accompanied by a series of ...
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How far have stars been seen beyond the center of the Milky Way?
What lies near the center of the galaxy is of great interest and in recent times the motion of dozen(s) of stars at the center of our galaxy orbiting around Sgr A* have been measured in great detail. ...
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5
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Do all the accretion disks around a compact object (black hole or neutron star) emit astrophysical jet outflow?
Do all the accretion disks around a compact object (black hole or neutron star) emit astrophysical jet outflow? I mean is it mandatory for a jet to be emitted from an accretion disk?
If so, then why?
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What are some good books/online resources for astronomy problem sets?
I am currently studying for the international olympiad for astronomy and astrophysics (the syllabus can be found here: https://www.ioaastrophysics.org/syllabus/). I am currently using Carroll Ostlie's ...
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How to apply Fast Folding algorithm?
I have High Time Resolution Universe dataset. I have applied de-dispersion on this HTRU dataset, and thereafter I applied the folding function to fold the dataset.
How I can find that the periodicity ...
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Why isn't the relativistic jet visible in the image of the M87 black hole?
I'm referring to the infamous relativistic jet, which consists of matter being accelerated to near the speed of light, originating at the poles of the black hole:
But in the image of the black hole ...
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Estimate the number of pixels required to map the full primary beam of a Radio Telescope station
I am practising some exam questions for a radio interferometry exam, and I am struggling with this question:
The physical size of a single LOFAR station, operating at 150MHz is about 50m.
Estimate ...
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Strength of core-envelope coupling in stars
For a star with a given Zero-Age Main Sequence (ZAMS) mass, as a function of metallicity how strongly is the star's core coupled to its envelope?
I understand that the core-envelope boundary is only (...
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4
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79
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DIY Radio Telescope (High School)
Background: I am attempting to build an RTL-SDR-based radio telescope for detecting hydrogen lines (21 cm) as a project with my HS Physics class. Several accounts are online, including parts lists ...
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Explanation for Planck 2018 temperature fluctuations strongest peaks
As it can be seen from Plank 2018 Cosmic Microwave Background temperature fluctuations data-
There are 3 sharp peaks at multipole expansions $\ell \approx 250, 550, 800 $. Also as multipole expansion ...
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How are shockwaves used to study magnetic fields of merging galaxy clusters?
Recently i read an article about how a shockwave 60 times larger than milky way galaxy is generated.When these shockwaves interacts with magnetic field, radio waves are emitted. I wanted to know how ...
