All Questions
Tagged with interferometry radio-astronomy
22
questions
2
votes
2
answers
103
views
Could we hear alien radio transmissions using radio interferometry?
Suppose money and engineering wasn't a concern. Could we actually build a bunch of radio telescopes in space, and use radio interferometry, so that we could actually hear the sort of radio ...
- 51
13
votes
2
answers
258
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Why hasn't VLBI been used to try and image giant exoplanets?
A Jupiter-sized object at 10 pc subtends an angle of 0.0001 arcseconds (100 micro-arcsec) at the Earth. The Event Horizon Telescope interferometry network is capable of a (demonstrated) angular ...
- 156k
1
vote
3
answers
136
views
How does Very Long Baseline Interferometry work?
According to internet sources, this technique increases the effective diameter of the telescope, thus improving the angular resolution of the telescope. However I don't understand how this actually ...
- 779
6
votes
2
answers
107
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In terms of results, how similar is a bunch of telescopes across the globe to an Earth-sized telescope?
The Event Horizon Telescope emulates an Earth-sized telescope by syncing a bunch of radio telescopes across the planet to do take pictures with a small enough angular resolution to take pictures of a ...
- 1,758
1
vote
1
answer
319
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If we put a radio telescope on Mars and use it in array with earth radio telescopes, how much will we able to see?
If we put a radio telescope on Mars and use it in array with earth radio telescopes, how much will we able to see? Will it allow us to see planets, like we do with black hole?
- 256
3
votes
1
answer
384
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Estimate upper limits on flux values in the case of a non-detection?
I have ALMA data which are non-detections of some spectral lines in a protoplanetary disk. The data is in the form of spectral cubes. I am hoping to estimate an upper limit on the flux of each of the ...
- 1,386
6
votes
1
answer
1k
views
rms noise, confusion and dynamic range in radio images
I have been trying to understand imaging in radio astronomy. Below are some of my questions related to it and my understanding of their answers. I am not very confident about my understanding of them ...
- 131
7
votes
0
answers
499
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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 ...
- 1,386
7
votes
1
answer
106
views
What could a cloud of mini radio dishes see?
Suppose an astronomer gave a 1 m radio dish to 500 people scattered over the face of the Earth and connected them to the internet. The people are directed to set their radio antennae up in their ...
- 652
4
votes
1
answer
118
views
What is the significance of using baseline pairs in radio interferometry?
Radio interferometry utilizes arrays of smaller telescopes that are linked together to synthesize a larger aperture telescope. Astronomical radio observatories, such as the Very Large Array in New ...
- 1,111
4
votes
1
answer
962
views
In astronomical interferometry, what values do the points in the uv-plane have?
As I understand it, the image of an interferometer is the inverse fourier transform of the information in the uv plane. For each baseline (vector between any two telescopes in the array), representing ...
- 1,800
2
votes
1
answer
50
views
The role of 'the interference of waves' in VLBIs'
I've been trying to find out how VLBIs work. It says in this book I've read that many radio telescopes around the world work in tandem to use the interference of waves to get a clearer picture of ...
- 23
2
votes
1
answer
183
views
How is VLBI delay calculated?
I’m working on a research project wherein we are trying to solve a problem very similar to VLBI delay. We have two radio receivers, and we know their locations. We also know at what time one receiver ...
3
votes
1
answer
257
views
Has optical interferometry been done at radio frequency using heterodyning with a laser in a nonlinear material?
If one collects narrow band optical emission from a large telescope with frequency $f_1$ and mixes it in a nonlinear crystal with laser light of a nearby frequency $f_2$, it would produce two new ...
- 30.7k
6
votes
1
answer
116
views
What is the role of the mesh on which dipole elements of the MWA antennas are placed?
I was reading about the radio telescope - Murchison Widefield Array (MWA) situated in Western Australia. Antennas of this telescope are quite unique and different from the usual dish radio telescope. ...
- 341
3
votes
2
answers
195
views
Would "layered" radio interferometry work?
tl;dr - Is splitting up the process of interferometry as shown in the diagram possible, and if so, is it more efficient and/or easier than traditional methods?
I have been doing some research into ...
- 1,443
3
votes
1
answer
96
views
What are the challenges for the building and data analysis of the CHIME telescope?
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) has discovered the second repeated fast radio burst recently. However, its structure is simple apparently. I wonder why we did not build a ...
- 3,137
5
votes
0
answers
106
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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 ...
- 163
5
votes
1
answer
166
views
Can weak gravitational lensing or microlensing-induced wavefront distortion limit resolution of absurdly large aperture telescopes?
This is a theoretical question.
This answer to the question If we had the right technology could we see a distant star in detail? (presumably space-based) primarily addresses the scaling of ...
- 30.7k
3
votes
1
answer
158
views
Could the E.H.T. produce an image of the human artifacts on the moon?
Two days ago the New York Times featured the Event Horizon Telescope (E.H.T.), a huge virtual radio telescope emerging from combining data from several dishes scattered around the world. While the E.H....
- 1,040
4
votes
3
answers
8k
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Converting Jy/beam to Jy?
Maybe its a dumb question, but to convert Jy/beam to Jy, I just have to multiply it by the beam size in sr right?
Being $\Omega$ the beam size:
$\Omega = \frac{\pi \theta_{maj} ~~ \theta_{min}}{4 \...
- 81
2
votes
1
answer
104
views
Is radar interferometry used, or feasible, for ground based astronomy?
I've heard of "interferometric synthetic aperture radar" being used for Earth observation from satellites and airplanes. Is active radar used interferometrically for astronomical purposes too? Such as ...
- 11.4k