Questions tagged [data-analysis]

Analysis of data is a process of inspecting, cleaning, transforming, and modeling data with the goal of discovering useful information, suggesting conclusions, and supporting decision making.

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24 views

Is there a tool to convert N-body RAMSES simulation file formats to GADGET 2 format in Python?

I am looking for a way to convert RAMSES files to GADGET-2 binary files because I want to use the package SimSpin (https://github.com/kateharborne/SimSpin/blob/master/R/make_simspin_file.R) which is ...
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how to plot Gauss-Hermite moment maps from arrays of star velocity values in Python?

I want to calculate Gauss-Hermite moments, such as h1,h2, h3, h4 moments from the values in an array of numbers which represent velocity distribution of stars in a galaxy. How would I fit a curve to ...
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1answer
63 views

Downloadable GCNS (Gaia Catalog of Nearby Stars)

Has Gaia made the "Gaia Catalog of Nearby Stars" (GCNS) available for offline processing? Ideally I'd like the full 100pc data set in a format that doesn't require any specialized libraries ...
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1answer
579 views

How to determine scalar-to-tensor ratio r from CMB polarization spectrum?

CMB polarization spectrum can tell us about the primordial scalar and tensor perturbation. By analyze B and E mode angular spectrum power spectrum and temperature power spectrum we can determine the ...
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1answer
37 views

How to interpret this spectrum of the "new DESI Quasar at z = 6.53"; what causes the big edge at about 9150 Angstroms?

I'm not exacty sure why but Scitech Daily's Seeing Dark Energy’s True Colors: DESI Creates Largest 3D Map of the Cosmos includes the graphic and caption below. It indicates a quasar in a Hubble image ...
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1answer
68 views

Examples of the oldest "precoveries"; objects that were first discovered in recent data but then looking back are confirmed in much older data

Example from Ars Technica's Radio astronomers scouring the archives spotted black hole devouring a star: Astronomers found another TDE in 2020 (dubbed AT 2019qiz), which provided the first direct ...
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31 views

Maximum number of pixels across a synthesized beam in an ALMA image?

I have some ALMA data, from which I have created images using the TCLEAN task in CASA. I understand that with this type of data, it is necessary to have at least 2 pixels across the FWHM of the ...
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2answers
218 views

Understanding expected TESS data structure

I'm interested in trying to use the data that will be returned by TESS to apply some machine learning/computer sciences concepts. I'm not sure yet what I want to try to do with it (though I have some ...
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2answers
304 views

How do you propagate asymmetric errors? (on the practical way to...)

I've used uncertainties's ufloatpackage to propagate uncertainties as I thought it's the standard way to do it. Now I want to ...
10
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1answer
1k views

What is sin i in this graph and why is it there?

This is some data presented in a lecture on exoplanets that depicts the distribution of the sizes of super-Earths in comparison to the mass of Jupiter. I would like to know what the argument of the ...
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How to quickly loop through many small fits files for data analysis?

I need to extract information from a few columns in ~20k different fits files with python. Each file is relatively small, ~0.2MB. I have been doing this so far with a loop and ...
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4answers
5k views

Milky Way position on the sky

I'm looking for some sort of boundary data to be able to render the milky way on a star map, as visible from Earth. Something that looks like this: For that, I need something like a collection of RA ...
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1answer
101 views

Query with Gaia: I have a list of 1000+ source_id's. How do I find the associated stars and their data?

I have a table of around 1700 source id's from gaiadr2 (in csv format). I would like to see the data that Gaia has for each star in a new table. I'm really struggling to figure out how to do this ...
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1answer
80 views

How to plot 68% contours?

I am doing a grid search of omega_Matter vs Omega_dark_energy by iterating over ranges of both and determining the chi-squared to determine the optimal value of both for a LambdaCDM model. I have my ...
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1answer
30 views

How to handle empty tables returned by astroquery Nist.query() in Python?

I'm writing a code to extract wavelengths of certain species of atoms/ions in a given wavelength range using the Nist.query() command of the Python package ...
4
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1answer
125 views

Procedures to test an hypothesis

In the context of planet formation and with the intention of testing different migration and in situ formation scenarios, I'm wondering what are the standard procedures to test and rank different ...
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1answer
65 views

Why Nyquist Sampling Rate depends on Bandwidth and not max frequency?

Is the Nyquist sampling rate same for different bands if those bands have same bandwith? E.g. Would the Nyquist Sampling rate be same for 1000-1400 MHz band as for 100-500 MHz band because both the ...
2
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1answer
40 views

How to calculate an infrared SED from the specific intensities?

I have values of total infrared fluxes (SED) in literature expressed in Jy (Jansky) for galaxies. I want to assure that my infrared radial profiles of the same galaxies in MJy/sr (and other in Jy/...
2
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1answer
62 views

Extracting specific star data from Gaia DR2?

I would like to extract all Gaia DR2 sources which have six-parameter solutions as well as their radial velocities and effective temperatures. Is this possible as DR2 only specifies that there are 1,...
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50 views

How does the Hubble Space Telescope measure the speed of the wind inside Jupiter's Great Red Spot?

Space.com's Jupiter's winds of change show increased storm speeds in Great Red Spot and Hubblesite.org's Hubble Shows Winds in Jupiter's Great Red Spot are Speeding Up both link to the recent open ...
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0answers
19 views

What are mag_a, mag_i, mag_z, a*, and sin_i * from the SDSS Moving Objects Data?

I'm currently working on the SDSS Moving Objects data sets and came across the column names mag_a, mag_i, mag_z, aprime, and sin_iprime. Can someone describe what these attributes mean, or where I can ...
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66 views

Obtaining the derived period of $\omega$ Canis Majoris

I have read these two papers: On the nature of the Be phenomenon I. The case of ω Canis Majoris Stellar and circumstellar activity of the Be star ω CMa II. Periodic line-profile variability In the ...
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How to calculate S/N in galaxy absorption spectra?

I want to calculate the S/N of an galaxy absorption spectrum. I therefore chose a part of the spectrum which contains very little to none absorption features and should be only made up of noise and ...
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0answers
18 views

Curated dataset of labelled images for NEO detection

I am looking for a dataset of images. Some images should contain NEO's (1 or more), others should not. With the dataset, there should also be an accompanying file, of which should contain 'labels'. ...
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2answers
122 views

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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1answer
99 views

Why histogram does not look like the Gaussian curve?

I have data consisting of radial velocities and times (covering about 10 000 days). The radial velocity changes with a period. I tried to find out the period using Stellingwerf's method (it was ...
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0answers
47 views

Tracing back OMNI data to the sun

I have been reading the OMNIWeb data documentation in order to clarify one particular question without success. I need to associate each measurement in the OMNI dataset to a moment in time at the sun (...
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1answer
234 views

What is z in this program?

Does z stad for the mass fraction of all the remaining chemical elements except helium and hydrogen, please? Source: https://github.com/chrysante87/pyterpol/wiki
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32 views

Solving the inverse problem - inspection

After solving the inverse problem*, how to investigate whether the solution is unique or not? When I check theoretical values and published values during the convergence and search for the lowest ...
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0answers
24 views

What is Euclidean fluence scaling in the context of bounding constraints on FRB all-sky rates? Would non-Euclidean scaling give a different answer?

The recent Chromatic periodic activity down to 120 MHz in a Fast Radio Burst contains two paragraphs in which X's are given "assuming an Euclidean fluence scaling". To me, a non-astronomer, ...
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0answers
30 views

Star Catalog with radius, luminosity, and spectra class?

I am looking for a star catalog (hopefully a .csv file) that contains radius, luminosity, and spectra class data for 1000+ stars. I have checked catalogs like the HIP, HD, and GAIA catalogs. I have ...
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88 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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1answer
44 views

Where do Astronomers usually get their wavelengths? Where do they turn to look up standard, accepted values for spectral features?

When identifying isolated observed spectral features or fitting complex observed spectra or even running complex numerical simulations, one needs a reliable, standard table of known wavelengths and ...
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0answers
36 views

How to find published data with the article?

How to find data published with an article, please? For instance, let us consider this paper. There are data products and the link to SIMBAD on the right. Then, the table with objects appears, but ...
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2answers
87 views

How the data collected during 5 year DESI operation will be analyzed with regards to finding what dark energy really is?

Dark Energy Spectroscopic Instrument, or DESI at the end of it's 5 years operation will create the largest 3-D spectroscopic map of the universe. How the data collected during 5 year DESI operation ...
4
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1answer
274 views

Will the SKA's total bandwidth still exceed the Earth's internet's bandwidth?

In the early 2010's there were many popular articles that said that the total bandwidth of the the Square Kilometer Array's optical fiber network for raw data from each dish would be larger than the ...
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0answers
140 views

Time evolution data of the Great Red Spot on Jupiter?

Jupiter's Great Red Spot fascinates scientists for ages, so it does me. Where can I find a table (e.g. as CSV-file) with the time evolution of longitude, latitude, horizontal and vertical extension of ...
2
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0answers
94 views

Asteroseismology; recordings of star vibrations duration and data availability?

A short video titled "Why Tess is recording the "sounds of stars" at the bottom of the page of the BBC News article Planet-hunter launches from Florida gives a short description of Asteroseismology by ...
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1answer
1k views

On what basis is the information about the distance and velocity of the Voyager probes determined?

Voyager 1 was the first-ever object to reach interstellar space on August 25, 2012 when it passed beyond the sun’s realm of plasma influence (the heliosphere)[...] (source) Although some of their ...
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1answer
529 views

Conventional units for astronomical object coordinates

I would like to know what the conventional units for identifying a celestial object (J2000.0) are. For instance, I am reading a paper in which they refer to object SDSSJ170013.70+400855.6; I am ...
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1answer
114 views

How to extract galaxy spectra for different radii in Python for spectra taken by long slit spectrograph?

I am trying to extract the kinematics from the elliptical galaxy NGC 4697 using the Fourier Correlation Quotient (FCQ) algorithm described by Bender (http://adsabs.harvard.edu/full/1990A%26A...229.....
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0answers
39 views

Estimate the shape of an object based on flux curve

Is there an aproximation to know the shape of a dust cloud,etc based on the magnitude/flux curves of stars they transit? Example, can I know if the shape is (at least in 2 dimensions) elliptical, ...
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1answer
87 views

Challenge with a Transit Method Curve

My assignment is to identify how many planets are in this curve and what the orbital period is. I'm just confused on the way it looks, as most curves I've seen up to this date are more smooth and ...
3
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1answer
68 views

Orbital resonances - expansion of disturbing function

I want to study the orbital resonance type 3:1 between an asteroid and Jupiter. For this purpose, I found the expansion of the disturbing function, $R$, in Celletti A., Stability and Chaos in ...
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3answers
281 views

Role of power laws in astronomy?

I often see astronomers fitting data to power laws. What about power laws makes them so useful in astronomy? Why are so many astronomical observations well-fit by power laws? I know it's a relation ...
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1answer
61 views

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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127 views

DAMIT how do they get 3D shape and rotational trajectory of a tumbling asteroid from photometry?

This question asks about an algorithm used in Project DAMIT. @RobJeffries' answer led me to Wikipedia's William Herschel Telescope which led me to Wikipedia's 2008 TC3 which led me to the animation ...
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23 views

How to create synthetic galaxy spectrum by broadening stellar spectra with a gaussian

I am trying to create a synthetic galaxy spectrum, by convolving a gaussian-velocity-distribution f(v) with my stellar spectra S. I have already logarithmically rebinned the spectrum and removed the ...
3
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2answers
42 views

Did the International Sun-Earth Explorer detect cosmic rays other than gamma rays?

In looking at the available datasets described by NASA for the International Sun-Earth Explorer, I am only see gamma ray burst data. Was the platform capable of recording cosmic rays other than gamma ...
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1answer
133 views

Locating a star cluster on a Hertzsprung-Russell diagram with other color index

Recently I took pictures of the NGC 884 cluster in the B and I bands and selected some 30-what stars from them. I've reduced the data to a colour-magnitude diagram (absolute magnitude in the I band $...

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