All Questions
15 questions
4
votes
2
answers
89
views
Efficient method for generating combined spectra from N-body simulation data using Python (convolution)
(I asked this same question also in StackOverflow, due to being both astronomy/coding problem, here link : https://stackoverflow.com/questions/78166419/efficient-method-for-generating-combined-spectra-...
- 41
1
vote
0
answers
27
views
Obtaining Transit Spectrum for Celestial Bodies Using JWST NIRSPEC
I've recently been tasked with obtaining transit spectrum data for some fascinating celestial bodies, including Ceres, Enceladus, Ganymede, Io, and Titan. The goal is to compare their transit spectra ...
3
votes
2
answers
151
views
How to construct optimal Wiener Filter?
I am trying to construct a Wiener Filter, to filter the ratio of the peak from the cross-correlation function, between a galaxy spectra and a template spectra, with the peak of the auto-correlation ...
- 849
2
votes
1
answer
149
views
How to fit LOSVD of a galaxy with gauss hermite parametrization
I have recovered the following LOSVD from an elliptical galaxy, that I now want to fit a gauss-hermite-parametrization to and derive the kinematical parameters rotational velocity, velocity dispersion ...
- 849
3
votes
0
answers
87
views
S/N binning of 2D spectral galactic data
I have the 2D spectrum of the ellipical galaxy NGC 4697 taken by a long slit spectrograph. The x-direction (horizontal) corresponds to wavelength and the y-direction (vertical) corresponds to distance ...
- 849
1
vote
1
answer
172
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 ...
- 53
1
vote
1
answer
581
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 ...
- 849
3
votes
0
answers
30
views
How to find x-values of fourier-transformed correlation functions in velocity space?
I am trying to extract the kinematic parameters (rotation velocity, velocity dispersion, ...) of an elliptical galaxy by extracting the kinematical broadening function using the FCQ-Algortihm first ...
- 849
5
votes
1
answer
482
views
How to remove redshift from galaxy spectra in Python?
Hello I extracted a spectrum from the central region of the 2D spectrum of the major axis from NGC 4697 (I just took a central row in the 2D data set, see this question for more information: How to ...
- 849
5
votes
1
answer
382
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.....
- 849
1
vote
1
answer
156
views
Derive LOSVD from galaxy spectrum, using fourier method
I am trying to implement a programm, that derives the kinematics (specifically the kinematic parameters: mean rotation velocity, velocity, dispersion, hermite coefficients h3 and h4) from an ...
- 849
2
votes
0
answers
573
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 ...
- 849
2
votes
1
answer
4k
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 (...
- 849
2
votes
2
answers
644
views
How to do logarithmic wavelength binning (in Python) in order to find redshift?
In Tonry and Davis (1979), p.1513, they formulated a cross-correlation method for extracting velocity redshifts:
Theory of Correlation Analysis
a) Introduction
Let $g(n)$ be the spectrum of a galaxy ...
- 43
0
votes
0
answers
306
views
Smoothing an SED with binning
I have an (observed) SED of a galaxy, and am attempting to match model SEDs to it. To do this I need to be able to see its shape better, which would involve some sort of smoothing of the spectrum. I ...
- 303