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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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17 views

How to improve the opreation temperature of MEMS gyroscope? [closed]

As we konw, MEMS gyroscopechips at present can't achieve 175℃ of high temperatures resistance without insulation sheild. Even if it can, the performance will be lower. have any technological ...
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17 views

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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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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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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1answer
38 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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1answer
22 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/...
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1answer
96 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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1answer
224 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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31 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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22 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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22 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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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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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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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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2answers
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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 ...
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1answer
520 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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38 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
90 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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3answers
225 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
62 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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21 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 ...
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1answer
57 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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50 views

Are sunspots named or individually tracked?

This is a follow-up question to How are the solar flares from May 23, 2021 extraordinary? which is about news of spaceweather.org. In the present question, I am curious solely about sun-spots and why ...
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Where to find all spectroscopic data about 28 CMa?

I am searching all available spectroscopic data (and particularly wavelength interval) of 28 CMa in the constellation Canis Majoris to measure radial velocities. Which database should I use?
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72 views

Logarithmic rebinning and continuum removal of stellar spectra

I am trying to learn how to derive the line of sight velocity distributions from galaxy spectrum to extract kinematical parameters like rotational velocity and velocity dispersion. Therefore I need to ...
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40 views

Kaggle dataset for Photo-Z estimation?

I would like to use the dataset for this kaggle but the competition was private, is closed and I have been unable to contact anyone directly. The challenge is machine learning for photo-z estimation ...
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46 views

Flickering and noise

I'm working with flickering measures from some stars. So, I take differential magnitudes, make a histogram and fit their standard deviation. My measure of flickering is the FWHM (full width at half ...
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1answer
57 views

Finding galaxy spectra in SDSS Catalog by object name

I am looking to find galaxy spectra of early type elliptical galaxies in the SDSS catalog by the objects name. See: https://dr12.sdss.org/advancedSearch. I dont know how to find out the PLATEID of my ...
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1answer
135 views

working with stellar spectra in fits format in python

Hey I am new to working with astronomical data in Python. I wanted to start working with stellar spectra and I am having trouble with the data. To get a first look I just wanted to plot a spectra (...
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2answers
292 views

Can automatic algorithms completely eliminate the impact of Starlink and other satellites?

According to a comment by user @J: With that said, other than aesthetics, machine vision algorithms are wildly more advanced today than in the past - strategies to remove passing satellites don't ...
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35 views

Can we identify planets, moons, and large asteroids in our solar system have a unique spectroscopy?

I'm looking to create a database of relatively consistent measurements for various cosmic bodies. Please inform if there's a way to gather reproducible signatures, with the same set of instruments to ...
4
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1answer
65 views

Accessing SDSS server SQL server via python

Is there a way to directly access any of the Sloan Digital Sky Survey servers via SQL via Python? Currently I have been able to run SQL queries from the website they provide (for example https://...
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2answers
38 views

Frequency analysis on Semiperiodic object(s) using Lomb-Scargle

So I already did a frequency analysis of the SRv-type's light curve using Period04. I already have the 'periodicities' of the object/star of choice which is quite hard since the latter/other periods ...
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113 views

Schechter Luminosity Function fitting plot of galaxies

I would like to plot the Schechter Luminosity function of galaxies. Here is my data(I have the Luminosity L[Ha] in erg/s). I would like to plot like this figure from this paper. In this paper, they ...
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102 views

What are some challenging astrophysics problems for which we have data available? [closed]

I am a Computer Science student, and I would like to pursue a PhD in the same area, by applying artificial intelligence techniques to astrophysics. Not being an astrophysicist, however, I was curious ...
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1answer
139 views

How to convert Proper Motion in RA & Dec to Galactic Coordinates

I'm trying to parse stellar data in the GAIA 2 release to galactic coordinates and am struggling with the velocity component. I've tried following online documentation and papers, but end up with ...
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2answers
195 views

Sample bias' contribution to "Planet 9" hypothesis, why was this not thoroughly addressed before?

Science Claim for giant 'Planet Nine' at Solar System's edge takes a hit arXiv No Evidence for Orbital Clustering in the Extreme Trans-Neptunian Objects The brightness of distant solar system objects ...
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1answer
37 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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38 views

In what ways are neural net classifiers "better" than search algorithms for eclipsing star system searches? (1D time series, not images of cats)

Neural net classifiers are both "hot" and useful. TIC 168789840: A Sextuply-Eclipsing Sextuple Star System is quite an interesting read, and describes the use of one trained on a ...
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131 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 ...
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1answer
41 views

SIMBAD TAP queries seem to indicate there are no distance measurements for a great many nearby stars, including Alpha Centauri or Barnard's Star

I'm attempting to create a map of all objects within 50LY, including main-sequence stars, binaries, planemos, etc. As such, I'm trying to do it all from first principles, building a micro-ETL to ...
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2answers
113 views

Do ASKAP and ALMA have "fast dump" interferometric modes? Can they see and perhaps report Fast Radio Bursts in real time?

Chatterjee et al 2017 The direct localization of a fast radio burst and its host nicely shows a VLA detection of a repeating FRB in 5 millisecond steps nicely demonstrating the dispersion slope ...
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47 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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1answer
37 views

Does a replacement exist for Dexter? (A tool that reconstructs data from a pdf of a graph)

Dexter was a tool from the German Astrophysical Virtual Observatory, made by the Center for Astronomy of Heidelberg University (ZAH). It was able to reconstruct data from a graph if you provided a pdf ...
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1answer
56 views

Computationally intensive technique to search for TNO's within the noise of historical photographic data?

I remember reading recently about a technique to search through lots of old survey images to try to identify trans-Neptunian objects that were so dim that they were "lost in the noise" in ...
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34 views

K-correction vs resizing photometric bands

Is there a difference between a K-correction (see Wiki https://en.wikipedia.org/wiki/K_correction) and simply "resizing" the bands, e.g. the 2-10 keV x-ray band, with the redshift? I've read ...
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1answer
204 views

"LinAlgError: SVD did not converge in Linear Least Squares" with eleanor.py

I'm doing some tests with eleanor module (i'm a novice). I'm using the example code written on eleanor.py website ...
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2answers
94 views

How to determine zenith coincidence from date time data sets

I have two or more sets of dates and times for which I am interested in the location of the Zenith at my location and whether they are coinciding. So far I have been comparing pairs of them on two ...
3
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1answer
64 views

How to derive the depth in my image (limit Magnitude )?

I saw that some survey said that their depth is 27.5 magnitudes. May I ask that if I have a dataset with magnitude and their errors, for example I have J band j_m, <...
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2answers
120 views

Technique for folding sparse event data in order to detect an underlying periodicity?

@JamesK's answer to When will the next transit of Earth be visible from Mars? Was the last one really on May 11, 1984? lists dates of 18 transits which I've converted to days since 1500-Jan-01 as <...