Questions tagged [radio-astronomy]

Questions about observation performed in the radio frequency range of the electromagnetic spectrum (between 10 MHz and 100 GHz).

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Has radio astronomy ever been done on objects that appear very close to the Moon? Is this avoided?

This answer to Which kinds of astronomical observations most need to avoid the Moon being up? mentions For completeness - radio, mid-infrared and mm-wave observations are unaffected (unless the ...
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Slope of log plot of luminosity-velocity in Tulley Fisher relation

My partner and I did some computation on the Tully Fisher relation at uni. In that, the slope of the logarithm plot between the luminosity and rotational velocity, was 2.6. Now, that slope ...
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What is a “21cm/mm absorption system” in the context of measuring old photons from quasars?

This answer links to Wikipedia's Time-variation of fundamental constants which cites Further Evidence for Cosmological Evolution of the Fine Structure Constant (J. K. Webb et al. 2001), the abstract ...
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What was the field of view of the Ohio State University Radio Observatory of Wow! signal fame?

This answer to Did comets 266P/Christensen or P/2008 Y2 (Gibbs) cause the Wow! signal? points out that the comets in question were nowhere near where the radio telescope was pointed. Wikipedia says ...
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Did comets 266P/Christensen or P/2008 Y2 (Gibbs) cause the Wow! signal?

Continuing my fascination with the Wow! signal, I stumbled upon an article from 2016 titled Famous Wow! signal might have been from comets, not aliens. It describes the hypothesis that the signal ...
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How do radio astronomers avoid having their receivers burned out by ground-imaging radar from satellites?

After about 34:00 in the 9th press conference of AAS 235, radio astronomer and NRAO's spectrum manager Harvey Liszt talks about Radio Astronomy in a New Era of ...
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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 ...
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What exactly is interplanetary scintillation; what was the Interplanetary Scintillation Array looking for? Did it successfully observe any?

The Interplanetary Scintillation Array is the radioastronomy observatory (i.e. big antenna) where the first pulsar was discovered by then graduate student Jocelyn Bell Burnell through careful and ...
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Has the plasma amplification of electromagnetic waves in solar type-III bursts (or otherwise in stars) been explored further?

This answer to the SciFi SE question In the novel The Three-Body Problem, does the Sun's amplification of radio transmissions have a scientific basis? cites a 1995 paper published in Chinese Astronomy ...
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What can be learned from low frequency radio astronomy available outside of Earth's ionosphere?

As discussions and answers to How large does refraction become in radioastronomy? point out, it is difficult to do radio astronomy much below 30 MHz (or 10 MHz depending on how aggressive you are in ...
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How can I hear (or at least detect) a pulsar at home?

Scott Manley's video Using Relativistic Raytracing &X-Rays To See Detail on Surface Of Neutron Star talks about X-ray measurements using the NICER X-ray telescope attached to the International ...
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How to use the APARM, BPARM and CPARM of REGRD task in AIPS?

I plan to regrid a 500 by 500 image in B1950 to 500 by 500 in J2000 using the AIPS task REGRD. How to proceed?
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Rescaling a radio image

After a radio image has been cleaned it is advised that the fluxes be rescaled if the source is near the galactic plane. Can someone explain why this is needed?
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Creating a 2D matrix from 2 FITS images of unequal dimensions for Radio/FIR correlation

I have two images of NGC 6946: ...
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Could we detect an extraterrestrial signal with the SKA radio telescope?

As I have not seen this question answered and, following the rules: https://stackoverflow.blog/2011/07/01/its-ok-to-ask-and-answer-your-own-questions/ , I would like to answer this important question. ...
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When do radio and tv signals become indistinguishable from background noise of the universe?

I understand the rate an EM signal broadcast uniformly from the Earth will decrease in its power is governed by the inverse square law. How far from Earth will radio and tv signals become ...
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who use the GADGET-2 pack for simulation? can I do it with my PC? [closed]

I want to do hydrodynamic simulatin for universe at vary redshifts. How can I do it? or how can I find an simulation of universe for use my work?
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Open dataset from antenna array

I am looking for a raw radio-astronomic antenna array dataset of relatively modest size (on the order a few MB, or even less), to evaluate a data processing algorithm. The dataset ideally should be ...
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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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Assuming no light pollution, was “2C. 1406” ever visible to the naked eye?

Joseph Needham, in his Science and Civilisation in China Vol. III, claimed that there was an ancient record of a nova about three thousand years ago. As a result of private correspondences with a "Dr ...
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How did Arecibo detect methane lakes on Titan, and image Saturn's rings?

This answer to Farthest distance to a solar system object that's been measured by radar? mentions that Saturn's rings, and the Uncover Travel post Arecibo Observatory, Puerto Rico – The World’s ...
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How to listen to our world from 10,000 light years away?

If you were 10,000 light years away from all radio stations and digital broadcasts from our world, what equipment would be necessary to detect and capture some information like a voice or a photo? If ...
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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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How do I download PSRCHIVE and Tempo2 for pulsar timing on Mac Mojave?

I am fairly new to pulsar astronomy, and I need to download PSRCHIVE and then Tempo2. I have followed the instructions online here: PulsarAstronomy.net I'm also pretty new to linux commands/Mac ...
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Would radio telescope located anywhere within a 100 light year radius detect our radio emissions? [duplicate]

If there was a radio telescope, as sophisticated as our best radio telescopes within a 100 light year radius from earth. AND if its sole purpose was search for signs of artificial/intelligent radio ...
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Requirements for an amplifier and filter for a horn antenna-based 21 cm radio telescope?

We are looking into the possibility of building a low budget horn antenna for detecting 21 cm hydrogen line radiation (~1420 MHz) and and possibly measuring its spectrum. What are the types of ...
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How far have individual stars been seen by radio telescopes?

Writing this answer got me thinking. As far as I understand it, stars themselves radiate most of their energy at optical wavelengths (near-IR through near-UV). Various types of stellar objects may ...
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1answer
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From whence is the Event Horizon Telescope black hole data available for amateur reconstruction?

Ralf Vandebergh's tweet shows his own reconstruction of an image of the accretion disk around a black hole, generated presumably from Event Horizon Telescope data. I'm assuming that the data came ...
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What Is The Maximum Distance Our Finest Instruments Could See When They're Perfected?

Radius of the observable universe is 47.5 billion light years,which means we are seeing things which are about 48 billion light years away. At a rough estimate,at what distance would our finest ...
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How is it determined that the X-ray and radio intensity come from a magnetic field bridge between two clusters of galaxies?

Gizmodo's Astronomers Spot Mysterious, 10-Million-Light-Year-Long Magnetic Field Connecting Two Galaxy Clusters shows the image below, and Space.com's A Weird 'Radio Bridge' 10 Million-Light Years ...
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Could images of (very) nearby targets be recovered from the EHT data

Reading this question I was struck by the fact that the "pointing" of an interferometer is effectively done in the correlator, at least within the common field of view of all the telescopes, which is ...
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How are pulsars detected from Earth?

This paper on Arxiv indicates that the signal period of known pulsars is 1 ms-15 s (0.07-1,000 Hz since F=1/T). I have an EE background and it's a long story how I ended up here, but suffice it to say ...
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How did Arecibo make radar images of ice on Mercury's poles?

How did Arecibo make radar images of ice on Mercury's poles? How were observations of the poles of Mercury geometrically possible from Earth? How was "high-resolution (1.5-km) imaging" possible from ...
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Is it more than a coincidence that the SEFD of the Arecibo dish is 1 Jansky?

In this answer I chose a system temperature of 50 Kelvin and estimated the System Equivalent Flux Density or SEFD of an Arecibo-size dish to be very close to 1 Janksy, or $1 \times 10^{-26} W/m^2/Hz$....
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Need some sources on radiotelescope sensitivity

Could anyone direct me to papers with info on minimal flux that can be registered with radiotelescopes?
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Which techniques are used to convert radio signals received by antenna to images?

I realized that after answering the question How do astronomers convert radio signals received by their antenna to images? I had missed the point that the OP was only asking about software. I've ...
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Where do local users of ALMA live and work?

These days with high speed internet, observational astronomy can be done from remote locations. Still I believe from time to time an experimenter might travel to work on-site for particularly ...
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1answer
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How do astronomers convert radio signals received by their antenna to images?

I'm very new to radio astronomy and I am curious how an the signals received by a radio antenna are converted to data on a computer and then images? Is there a popular software to use for this, or do ...
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1answer
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Have caged molecules ever been observed in space?

astrosnapper@'s thorough answer to the question What is precipitable water vapor in millimeter-wave radioastronomy and how is it measured? links to the paper Observing Conditions for Submillimeter ...
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Constant interval between pulses from all pulsars

It was found from the observations of the radiopulsars that the intervals between their pulses are changing periodically, besides, for all pulsars this period is the same and equal to one stellar (...
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What is the farthest we can see into the universe?

Is there a limit in which the mass in space obscure the ability to detect anything farther even as technology progresses? Related: Can the range of the observable universe be extended through an ...
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Why does the Event Horizon Telescope (EHT) not include telescopes from Africa, Asia or Australia?

The Event Horizon Telescope seems to include these radio telescopes currently: Image by European Southern Observatory (ESO)/O. Furtak; CC-BY 4.0-licensed, see the source on Wikipedia Commons and the ...
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What else could the Event Horizon Telescope Observe?

The Event Horizon Telescope was made possible in order to observe the details of supermassive black holes. This took a huge amount of work installing extra telescopes and developing the hardware and ...
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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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Why not capture also Milky Way's black hole image? [duplicate]

The world has now seen the black hole "close-up" of M87. Besides the recognition to how awesome science has become in the 21st century, I have the following question. Didn't they work also to ...
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Event Horizon Telescope Data Cleanup

I was wondering how the researchers were able to minimize or neutralize confirmation bias regarding the data collected? As I understand it, the algorithm pruned much of the data, which would make ...
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Does the “photo of a black hole” taken by EHT actually depict a visible light-based scenario?

I'm still at my bachelor of electronic and communications engineering, so I'm not an expert of radiotelescopes; however, I surely know that, typically, radio communications are characterized by a RX ...
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Do the actual false colours in the M87 black hole picture convey information?

As for the title. The picture could have been plotted in grey scale, B&W, whatever couple of colours, or perhaps using a window of wavelength in order to show shift of the Doppler/relativistic ...
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How can the Event Horizon Telescope image Sgr A* when it's not visible from all sites at one time?

I went to https://eventhorizontelescope.org/array and read about the ten sites listed as part of the EHT, I have a mashed-up screen shot of them below. I made a little script also shown below with ...
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MeerKAT's Epic Image of the Galactic Centre, what are we seeing?

In this answer as well as this one, I've linked to New Jersey Institute of Technology's Dr. Dale Gary's nicely-written Physics 728 Radio Astronomy; Lecture #1 notes where I can see the image below. It ...