Unanswered Questions
154 questions with no upvoted or accepted answers
7
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Convert from Jy/beam km/s to W/m$^2$
I need to compare some ALMA observations of a protoplanetary disk to disk-integrated fluxes obtained from a model.
The ALMA observations are upper limits of non-detected spectral lines, where the RMS ...
- 1,386
6
votes
0
answers
135
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Radius of hydrogen cloud
I am using a 1.4 meter parabolic dish with HPBW of 10 degrees and a RTLSDR to study our milky way in hydrogen line. The structure of the galaxy is deduced as shown in the picture by plugging the ...
- 115
6
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What are the pros and cons of different types of echelle spectrograph cross-dispersers?
Echelle spectrographs, operating at high resolving power, typically consist of an echelle grating with a low numbers of lines/mm, used with high diffraction orders (often $n=$50-100). To separate the ...
- 30.7k
6
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104
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BLC1 and Proxima Centauri's activity
From Wikipedia BLC1:
A paper by other astronomers released 10 days before the news report about BLC1 reports the detection of "a bright, long-duration optical flare, accompanied by a series of ...
6
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206
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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. ...
- 30.7k
6
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Need help understanding stellar spectroscopy data from ESO
The European Southern Observatory webpage has a web page that has tabular spectrogram data from A. J. Pickles, University of Hawaii. There are over 130 .dat files there. Each one represents a ...
- 161
5
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457
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Why does titanium oxide around Betelgeuse produce this particular sawtooth-shaped absorption spectrum?
Betelgeuse Just Isn’t That Cool: Effective Temperature Alone Cannot Explain the Recent Dimming of Betelgeuse suggests that the recent dimming might be caused by increased optical absorption by dust ...
- 30.7k
5
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225
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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 ...
- 6,300
5
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188
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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 ...
- 1,449
5
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106
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Estimate the number of pixels required to map the full primary beam of a Radio Telescope station
I am practising some exam questions for a radio interferometry exam, and I am struggling with this question:
The physical size of a single LOFAR station, operating at 150MHz is about 50m.
Estimate ...
- 30.7k
4
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80
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DIY Radio Telescope (High School)
Background: I am attempting to build an RTL-SDR-based radio telescope for detecting hydrogen lines (21 cm) as a project with my HS Physics class. Several accounts are online, including parts lists ...
4
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425
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Calculation of average FWHM by PSF fitting of all the detected stars in the fits image
I need to calculate the FWHM of all the stars detected via the DaoStarFinder package/any other package by performing PSF fitting in Python. Here is the code for my detection.
...
- 111
4
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42
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Fitting a line or polynomial to optical and radio SEDs
I've been trying to fit functions to plots showing photometric data for AGN from both optical and radio measurements, such as:
but my supervisor says that this shouldn't be done; the radio and ...
- 126k
4
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52
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How does SDSS estimate photometric redshift of sources?
I'm looking through the data in SDSS DR 12:
...
- 2,620
4
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54
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What happens to the non-fusion formed metals in stars?
Let’s consider a population I star of some given metallicity.
I know that depending on the type of star, different structures are possible with convection zones and radiative zones trading around ...
- 3,404