Questions tagged [spectroscopy]

Questions about the measurement of light waves whereby the wavelength is classified by its position in the electromagnetic spectrum.

23 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
5
votes
0answers
91 views

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 ...
4
votes
0answers
108 views

Does the current “fainting” of Betelgeuse show any spectral trends that differ from it's normal variability?

The Astronomers Telegrams #13341 The Fainting of the Nearby Red Supergiant Betelgeuse and #13365 Updates on the “Fainting” of Betelgeuse (both in December 2019) discuss the importance of measuring ...
4
votes
1answer
88 views

What are realistic and unrealistic values for the high energy gamma ray spectral indices of pulsar wind nebulae?

This summer, I was working on a project fitting very high energy gamma ray spectra of the Crab Nebula, a pulsar wind nebula. At energies about $\sim$1 TeV, a simple power law suffices, i.e. $\phi(E)\...
3
votes
0answers
40 views

What is the difference between spectroscopy, spectrography and spectrometry?

Spectroscopy is the study of spectra, spectrography is the writing of the spectra, and spectrometry is the measure of spectra. So from an etymological perspective, there is no real difference between ...
3
votes
0answers
120 views

Strong orange line in wood fire spectrum?

I just built a DIY spectroscope using a CD and after making some tests, I noticed a really strong emission line located in the orange-yellowish zone of the fire spectrum (specifically, burning wood). ...
3
votes
0answers
73 views

How do people derive ionized gas mass from optical emission lines in a galaxy spectrum?

Suppose you had an optical spectrum of a galaxy, and you unambiguously detected emission lines from cooling ionized gas -- both forbidden lines like [O II] 3727AA and [O III] 4959,5007AA, as well as ...
3
votes
0answers
62 views

H-alpha velocity fields of spirals falling into a cluster

What kind of impact would you expect ram pressure stripping / tidal interactions / harassment / interactions with the cluster potential (etc!) to have on the h-alpha velocity fields of infalling ...
2
votes
0answers
63 views

Correction to inverse square law for cosmology

While reading about the discovery of quasars and the spectroscopic analysis of 3C 273 in this paper by Maarten Schmidt, I came across the following quote: At these distances, corrections to ...
2
votes
0answers
88 views

Source for Identification of Balmer Hydrogen Absorption Lines

I'm working on an assignment, where I have to classify stars using the raw data of the telescope. I'm now trying to calibrate the pixel to armstrong ratio, and for that I need to identify the ...
2
votes
0answers
1k views

What is meant by ionization states?

I am going through the theory of saha equation but I am not able to understand the concept of ionisation state? What are ionization states actually?
2
votes
0answers
390 views

How to use spectral profiles to determine luminosity class?

I know the luminosity classes are: Ia-0 ( Hypergiants ), Ia ( bright supergiants ), ... , VII ( white dwarf ). I also have learned that you can use the presence of absorption lines ( ie. use spectral ...
1
vote
0answers
38 views

How to calculate Equivalent Width of a spectrum with continuum at 0

I am trying to calculate the Equivalent Width of emission lines of a spectrum whose continuum is at 0, making the calculation of the EW impossible. I have the spectrum of a transient in a galaxy, so ...
1
vote
0answers
44 views

What is an “Off Rowland-circle Telescope”?

The NASA Goddard news item NASA to Demonstrate New Star-Watching Technology with Thousands of Tiny Shutters says: The technology, called the Next-Generation Microshutter Array (NGMSA), will fly for ...
1
vote
0answers
61 views

Does Nickel show up in spectra of Nova?

Does a nova, not a supernova, get hot enough that nickel is produced despite its formation by fusion being an endothermic reaction? If nickel is made, does it make it out of the star into the nebula? ...
1
vote
0answers
28 views

Relation between oscillator strengths $\log{gf}$ and the Einstein $A$-coefficient, rotational quantum number,

I'm analyzing the spectra of M dwarfs. Some authors characterize the lines with the oscillator strengths $\log{gf}$ while others follow different paths with the Einstein $A$-coefficient. I would like ...
1
vote
0answers
42 views

How do you fit a model SED to an observed galaxy spectrum with photometric data?

I have a spectrum of a galaxy from HST data and SDSS data (resulting in a nearly continuous SED from the FUV~1000 Angstroms through infrared). I have created a model SED with the galaxy simulation ...
1
vote
0answers
41 views

Doppler Spectroscopy - Finding mass of an exoplanet

An astronomer, T observed the spectrum of a distant star X. The spectral lines were observed to have tiny blueshifts and redshifts regularly with a period of 1.27 years. T concluded that the star is ...
1
vote
0answers
61 views

Help understanding the false MRO observations of hydrated minerals on Mars

The Science News article An orbiter glitch may mean some signs of liquid water on Mars aren’t real begins: Some signs of water on Mars may have just dried up. Thanks to the way data from NASA’...
1
vote
0answers
66 views

Why does D4000 affect stellar age?

From my understanding D4000 is a ratio between the 'flux densities between 4050 and 4250 Angstroms and that between 3750 and 3950 Angstrom', from Poggianti et al (1997). However I do not understand ...
1
vote
0answers
190 views

How does the ESPRESSO Echelle spectrograph fold the spectrum so nicely?

The CBC News Technology and Science Q&A This ESPRESSO machine doesn't make coffee but scans the skies for habitable planets includes a nice description of ESPRESSO (Echelle SPectrograph for Rocky ...
1
vote
0answers
68 views

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 ...
0
votes
0answers
26 views

what/how do we mean/derive statistical equilibrium equation of certain energy levels?

While reading the research paper "Excitation of the Fe XIII Spectrum in the Solar Corona" by D.R. Flower and G. Pineau des Forets in the summary I found the concept of statistical equilibrium equation ...
0
votes
1answer
197 views

Redshifting restframe SED

I have a template spectral energy distribution (SED) at z=0. I want to shift the template SED to an arbitrary redshift (z>0), how to do this in python?