Questions tagged [radio-astronomy]

Questions about observations performed in the radio frequency range of the electromagnetic spectrum.

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51 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 ...
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304 views

What programming languages does SETI (Search for ExtraTerrestrial Intelligences) most commonly use for signal processing?

Please give preference to those most widely used in the field, if possible.
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Why did it take five years to “figure out” how to use astrometric calibration sources to deblur LOFAR images?

Quanta Magazine's The Hidden Magnetic Universe Begins to Come Into View is a fascinating review of a rapidly evolving field in astronomy. It contains some statements: In their paper last year, van ...
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68 views

How can I correct for transit time?

I know the exact time a radio telescope detected a transient event. I also know the exact location of the telescope, and the galactic coordinates (galactic longitude, latitude) and right ascension and ...
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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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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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How do ASKAP's focal plane phased array feeds interact with the entire array phasing?

Sky & Telescope's ASKAP Joins the Hunt for Mysterious Bursts says: A new telescope, the Australian Square Kilometre Array Pathfinder (ASKAP), has joined the search for energetic and elusive ...
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331 views

What are the Similarities and Differences between ALMA and FAST?

What are the Similarities and Differences between ALMA (Atacama Large Millimeter Array) and FAST (Five hundred meter aperture spherical telescope)? What can they see, what's their resolution like? ...
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Which 16 antenna locations were used this MeerKAT radio image?

The final configuration of the MeerKAT radio array will be 64 dishes. In the press release of July 16, 2016 a radio image is shown using a completed sub-set of 16 dishes. Which 16 are these? I can ...
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How significant and accessible is modern Chinese astronomy?

Is China fully integrated in the international astronomical community, or does military secrecy and language problems and sanctions (ITAR) or something else stand in the way? Does China have valuable ...
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Specifications of a High Gain Antenna [migrated]

I am designing a telecommunications device capable of redundant communication from Earth to Saturn's moon Enceladus which ranges from 8 to 11 AU from Earth. I have decided on an X-band high-gain ...
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Is GAIA the only game in town for looking at quadrupole gravitational deflection of light?

From Gerry Gilmore (2018) Gaia: 3-dimensional census of the Milky Way Galaxy 4.4 Fundamental physics Relativistic effects are highly significant for Gaia measurement accuracy, with tests of General ...
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About coordinate systems and angle differences

If I want to measure the beam-width of a radio telescope sweeping through a ~ puntual object (the Sun) with a ~ constant flux output when measured: The value measured sweeping in one frame of ...
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Are there any ALMA or JCMT detections of extraterrestrial phosphine that have been confirmed by direct sampling?

Please note that I am not a professional astronomer but an interested layman. I've informed myself on the matters below by perusing arXiv--there are likely other publicly-accessible primary sources I ...
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How often are radio telescopes used to measure parallax? When was this first done?

The abstract of A magnetar parallax (also in MNRAS) says: TE J1810-197 (J1810) was the first magnetar identified to emit radio pulses, and has been extensively studied during a radio-bright phase in ...
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What is the O[III]/H$\alpha$ line ratio for Active Galactic Nuclei?

I have the H$\alpha$ line flux of an AGN and I am trying to calculate the Bolometric luminosity using it. Bolometric luminosity can be calculated from O[III] fluxes by $L_{\rm Bol} = 3500 L_{\rm O[III]...
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What does the Sun “look like” below 100 MHz?

Radio2space.com's The Radio Sun says: At very low frequencies (below 0.1 GHz) and therefore at very long wavelengths (> 3m) the solar disk appears much bigger and brighter in the center, and its ...
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How to read light curve from .fits?

I have a .fits file (this one, in fact) containing the data of a fast radio burst, FRB110523. Is it possible to, from that, make a simpler file containing the intensity (integrated over all bands) as ...
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Have non-periodic radio signals been analyzed for shannon entropy or put on a Zipf plot?

If aliens did exist, they would probably compress their communications. And they might use a fault tolerant infrastructure like TCP/IP. In either scenario, real communications would not be periodic ...
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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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66 views

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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75 views

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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62 views

Examples of radio correlations over times much longer than interferometric baselines?

Very Long Baseline Interferometry or VLBI such as the Event Horizon Telescope or JPL's delta-DOR (see below) uses baselines of the order of the Earth's diameter. Spacecraft position determination ...
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What could be observed with LOFAR in 230 MHz - 10.0 MHz wavelength?

Nuclear astrophysics greatly interests me and i was wondering if there is something that could be observed with the LOFAR project in this wavelength that would benefit the field? Also some general ...
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How does Canada's radiotelescope CHIME manage polarization-dependent apodization of the fast f/0.25 optics?

CHIME, the Canadian Hydrogen Intensity Mapping Experiment uses four parabolic cylinder reflectors and a dense linear array of 256 x 2 polarization feeds along each focal line. Each feed is a dual ...
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Estimating upper limits on flux values (Radio)

How to estimate upper limits on flux values for a radio source if it is not seen in NVSS (1.4 GHz survey) but is observed in lower radio frequency maps?
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radio Jove pcb manufacturing file

Hello I want to make the radio Jove receiver whose design is available on NASA website. I don't want to purchase the receiver. I want to make it. but I don't have any knowledge about pcb design for ...
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Can all astronomical signals be considered Gaussian noise?

While studying the techniques astronomers use to mitigate radio frequency interference (RFI) I found it's often assumed that astronomical signals are (band-limited) Gaussian noise. Is this a ...
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58 views

What information will SETI have access to from the SKA (Square kilometer array)

I read on on the website of the SKA (https://www.skatelescope.org/) that SETI will sort of have "passive" access to the data that they capture on the array, sort of like a "pigyback" concept and ...
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193 views

Does a photon need to have EXACTLY the right energy to be absorbed by a gas molecule?

From an answer to this question, https://physics.stackexchange.com/questions/281660/how-does-an-electron-absorb-or-emit-light, Absorption of a photon will occur only when the quantum energy of the ...
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145 views

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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Help with homwork - Astronomy

We might expect to not find life around halo stars (“Population II” stars) because: a) they are out of the plane of the galaxy and thus exposed to more cosmic rays (energetic nuclei) b) these stars ...
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How will they know when to start taking the picture of the black hole at the center of the Milky Way?

@csm's answer to Why not take a picture of a closer black hole? points out that it's necessary for the supermassive black hole at the center of a galaxy to be actively feeding for it to generate a ...
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How was Sugar Grove Station supposed to work?

Sugar Grove Station was an outpost designed to listen in on Soviet radio signals reflected off the moon. How would this work? Wouldn't the radio signals be distorted by the imperfect surface of the ...
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Hypothetical CMB space telescope design problem, received power from extended thermal source versus receiver front end NEP?

Consider the example of a large radio dish antenna in space equipped with a heat shield protecting it from the Sun. Let's say the amplifiers front-end effective temperature (for purposes of noise ...
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How often do they move most/all of ALMA's dishes?

The Phys.org article Unknown treasure trove of planets found hiding in dust reports on recently published radio measurements (~1.3mm) of planetary systems forming around stars in Taurus: Scientists ...
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Why is space-based VLBI scattering sub-structure “Hopefully, a new promising tool to reconstruct the true image of observed background target(s)”?

@HDE226868 mentioned in the observatory that the GBT@20 – The Celebration; Twenty Years of Innovation and Discovery was going on. There are plenty of YouTube videos and slide sets available as links. ...
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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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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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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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How did the authors determine both the spatial size of gas cloud HCN-0.009-0.044 and its central mass at the same time?

Phys.org's Hiding black hole found says: A research team led by Shunya Takekawa at the National Astronomical Observatory of Japan noticed HCN-0.009-0.044, a gas cloud moving strangely near the center ...
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How to create synthetic test images of stars?

Is there any python/IDL code available to create synthetic test images of stars with and without background noise?
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Did the Spectr-R space-based radio telescope use on-board accelerometer to measure non-gravitational acceleration for baseline correction?

This answer summarizes the contribution of the RadioAstron mission, a VLBI collaboration of radio telescopes using the Spectr-R space-based 10 m dish in high Earth orbit to produce "very-VLBI&...
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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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extracting visibility information from CASA measurement set

I am trying to export the UV wavelengths, visibilities and weights from a measurement set in CASA, but I haven't been able to find the right commands to do this. 'exportuvfits' might be what I am ...
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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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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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Strange behaviour of black holes [duplicate]

We know black holes emit streams of radiation ,also recently discovered that they emit visible light when they eat any nearby matter . "We find that activity in the vicinity of a black hole ...
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As of now did a radio telescope ever recorded something else than the silence of space? [closed]

When a radio telescope listen to the Universe; a constant sound is recorded. Is it the noise "of the mic" : interferences? Scientists says that when they will notice variations on this basic constant ...

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