Recent content by Joe Prendergast
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J
Graduate XSPEC Composite Model Partial Flux Calculations
Hello, I am running a model in XSPEC: phabs*(pow + cflux*gaussian) on a WSL Ubuntu terminal. The fit output shows lg10flux = -10.0803 which converts to a flux of 8.31189E-11 erg/s/cm^2. This is correct for the gaussian flux contribution. The flux command produces: 0.069691 photons (8.5637e-10...- Joe Prendergast
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- Flux calculation X-ray
- Replies: 0
- Forum: Astronomy and Astrophysics
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Graduate Spectral Data Availibility
Does anyone know of a reliable source from which to get star spectral data (flux versus wavelength)? The best source I've found is GAIA which has spectral data for some stars but for many it does not.- Joe Prendergast
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- Astronomy Astrophisics Spectral analysis
- Replies: 5
- Forum: Astronomy and Astrophysics
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Python Python scipy.optimize.minimize: ‘trust-constr’ and Hessian output
Never hurts to repeat in the body of the post :)- Joe Prendergast
- Post #5
- Forum: Programming and Computer Science
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Python Python scipy.optimize.minimize: ‘trust-constr’ and Hessian output
Python as stated in my subject line. Specifically the scipy package.- Joe Prendergast
- Post #3
- Forum: Programming and Computer Science
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Python Python scipy.optimize.minimize: ‘trust-constr’ and Hessian output
Hello, does anyone know how to retrieve the Hessian at the minimum when using method = ‘trust-constr’?- Joe Prendergast
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- Python
- Replies: 5
- Forum: Programming and Computer Science
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Graduate Bivariate Smoothing Splines
Does anyone know of a bivariate smoothing spline package that lets you set your own loss function? All of the public domain software I've been able to find (e.g., SCIPY) appears to minimize the sum of squared errors. For example, I'd like to set the spline coefficients to maximize the...- Joe Prendergast
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- Statistics
- Replies: 1
- Forum: Linear and Abstract Algebra
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Undergrad Why Do Stars in Binary Systems Assume a Teardrop Shape?
I did provide a reference above, but I will repeat it for you: Modern Astrophysics by Carrol and Ostlie. Additionally, Teardrop stars (associated with Roche Lobes) are covered on page 662.- Joe Prendergast
- Post #13
- Forum: Astronomy and Astrophysics
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Undergrad Why Do Stars in Binary Systems Assume a Teardrop Shape?
Educate yourself with a college level textbook. Start with Roche lobes.- Joe Prendergast
- Post #11
- Forum: Astronomy and Astrophysics
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Undergrad Why Do Stars in Binary Systems Assume a Teardrop Shape?
Thank you, just what I was looking for.- Joe Prendergast
- Post #7
- Forum: Astronomy and Astrophysics
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Undergrad Why Do Stars in Binary Systems Assume a Teardrop Shape?
See the answer below. This is what I was looking for.- Joe Prendergast
- Post #6
- Forum: Astronomy and Astrophysics
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Undergrad Why Do Stars in Binary Systems Assume a Teardrop Shape?
In almost any astrophysics textbook, for example, Modern Astrophysics by Carrol and Ostlie- Joe Prendergast
- Post #3
- Forum: Astronomy and Astrophysics
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Undergrad Why Do Stars in Binary Systems Assume a Teardrop Shape?
In binary star systems, it is said that one of the stars can assume a teardrop shape resulting from the gravitational pull of the companion star. This shape is typically portrayed as asymmetric (i.e., there is no teardrop shape on side of the star away from the companion star). Yet the...- Joe Prendergast
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- Binary system Tidal forces
- Replies: 14
- Forum: Astronomy and Astrophysics
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Undergrad Why Does Spectral Line Darkening Occur Despite Photon Re-Emission?
Suppose a photon from the sun's photosphere, initially traveling toward earth, is absorbed by an atom in the sun's chromosphere. The electron then transitions to its first excited state and spectral darkening is observed at a distinct wavelength on earth. I've read that the electron only stays...- Joe Prendergast
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- Photon
- Replies: 2
- Forum: Astronomy and Astrophysics
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Undergrad Question about Photons causing Electron Transitions in Atoms
Thanks for the explanation. I was wondering if you could recommend an introductory textbook on QFT.- Joe Prendergast
- Post #19
- Forum: Quantum Physics