Unanswered Questions
100 questions with no upvoted or accepted answers
2
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BVR photometry and Luminiscense
I have the values from B, V and R filters. How do I obtain the total luminescence of a star?
My ultimate aim is to find the relative masses and luminescence of various stars/galaxies in a galactic ...
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2
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51
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How to identify Hydrogen lines of slitless spectrograph of Type A9 star
Hi I am analysing slitless spectrograph of type A9 star Canopus. Here is as sample of the spectrograph.
I basically did a simple summing up of the columns and added the data (as a simple spectrum co- ...
2
votes
0
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56
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Calculate change in spectral line intensity for a change in temperature
I am trying to do some simple modelling of spectral line emission. I am starting with some ALMA observations of a protoplanetary disk, where the emission from a particular molecule at frequency 344GHz ...
- 1,386
2
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60
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What could these LMC objects in this color-color diagram be?
I have performed a color-color and colour-magnitude plot of various sources detected in an LMC image (JWST NIRCAM F200W, F150W and F115W filters). I then also queried SIMBAD to collect relevant ...
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84
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How can I compute reasonable errors on my Gaussian fits to the observed strong optical lines of interest?
I'm fitting Gaussians to optical lines spanning from H-beta to Sulfur using Astropy's Gaussian (https://docs.astropy.org/en/latest/api/astropy.modeling.functional_models.Gaussian1D.html) model with a ...
- 156k
2
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125
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How does one estimate the mass of a galaxy using the Balmer break region?
I am currently reading the recent astrophysical paper "A population of red massive galaxies ~600Myr after the Big Bang'.
In the first paragraph/abstract it mentions, "It has been difficult ...
- 21
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47
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Is there any open data base for raw spectroscopy data?
I'm msc. student in physics and will start my thesis in a month. We are in search of a topic with my thesis professor and we talked about many ideas. After all, "what will this give us ...
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How do I calculate the flux density of a substellar object?
I am currently trying to generate photometric passband colors for brown dwarfs and planets generated through MESA (Modules for Experiments in Stellar Astrophysics). I believe I understand the ...
- 61
2
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109
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Different types of line broadening in stellar and galactic spectra
When analyzing stellar and galactic spectra with spectrographs, the spectral lines get broadened from the instrument. Why do the spectral lines get broadened after the light moves through the ...
- 849
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277
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Calculate the uncertainty in measured flux density from an integrated intensity map
I have some ALMA data, in the form of a spectral cube, which I have integrated along the velocity axis to create an integrated intensity ('moment 0') map.
The integrated intensity map shows emission ...
- 1,386
2
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49
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General questions about SDSS
I'm considering doing research on SDSS spectral classification (STAR, GALAXY, QSO) with machine learning for my school dissertation. Not sure if this is an appropriate place for these kinds of ...
2
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0
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23
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Stromgren photometric data in Vizier
Is there a catalog in Vizier that provides Stromgren photometric data for stars, (the all four uvby, not just the indices b-y, m and c)
I would like to try the photometric transform given in my book, ...
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60
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Would Atlas Pro's prediction about the color of plant in Kepler-186F work as a biosignature to search for life?
The Atlas Pro video that prompted this question is this.
Tl;dr: it is argued that due to the different spectrum of radiation emitted by Kepler-186 and what is known about the evolution of ...
- 4,800
2
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55
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Spurious periods of stars
What exactly is meant by spurious periods of stars? E. Tanner writes in Spurious Periods in Spectroscopic Binaries in 1948
Furthermore: Can spurious periods be produced by aliasing, and how can they ...
- 4,800
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17
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Is threre a relation between relative or absolute error and standard deviation for ratio of power spectra?
I have to compute the variance on this ratio, that is to say on the observable $O$ :
$$O=\left(\frac{C_{\ell, \mathrm{gal}, \mathrm{sp}}^{\prime}}{C_{\ell, \mathrm{gal}, \mathrm{ph}}^{\prime}}\right)=\...
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