Evolution of the IGM and Galaxies via QSO Absorption Lines
Astronomy 698, Fall 2004
Dr. Chris Churchill
Rm. AY 119 ; T-Th 8:55-10:10 am
Department of Astronomy
New Mexico State University
Office: ASTR 206
Phone: 6-1913
Email: cwc
Assignments are due at the BEGINNING of class on the due dates.
ASSIGNED: Tuesday August 31, 2004
DUE: Tuesday September 7, 2004Write a code (you can choose you language- C, F77, or perl) that reads in the below quasar spectrum and produces the equivalent width spectrum and its uncertainty spectrum. Hand in a hard copy of your well commented code. Produce a plot identical to Figure 3 of Churchill etal 1999, ApJS, 120, 51. (Show the 1-sigma and 5-sigma criteria. You do not need to show the location of significant features, i.e., you do not need to find and show the dot-dot vertical lines at the absorption features). Use the formalism of Lanzetta, Turnshek, & Wolfe 1987, ApJ, 322, 739.
Data for Sarah B.
Data for Brandon
Data for Ryan
Data for Sarah G.
Data for Glenn
Data for Pey Lian
Data format: 6 columns: wavelength, dummy_zero, flux, sigma_flux, smoothed_sigma_flux, continuum
Use the sigma_flux data for the uncertainty spectrum.ASSIGNED: Tuesday August 31, 2004
DUE: Tuesday September 14, 2004Add to your code a subroutine (yes, a subroutine) that finds the significant absorption features in your spectrum. Compute each features equivalent width, uncertainty, and SL. Print out all features with SL >= 3 directly from your code with a clean format, including (i) central wavelength, (ii) EW, (iii) sigma_EW, (iv) SL. Hand in your well commented code and the print out from your code. Also, produce a LaTeX table with Title and Headings in ApJ style of those lines with SL >= 5. Lastly, produce a plot of the spectrum in flux units (not normalized) and place ticks above the absorption lines for the SL >= 5 sample. Again, use the formalism of Lanzetta, Turnshek, & Wolfe 1987, ApJ, 322, 739, except the range of the integrations should be computed as discussed in class.
ASSIGNED: Tuesday September 14, 2004
DUE: Tuesday September 21, 2004Write a code to convert HIRES/Keck spectra of the MgII 2796 and 2803 absorption profiles provided to you into apparent column density spectra Na(v) with uncertainties. (a) Plot Na(v) with error bars as a function of rest-frame velocity for both transitions (overplot). The data are in normalized flux and the rest-frame velocity is provided. Atomic data are provided below. (b) Using your code from HW1B, find the absorption features and report their EWs and uncertainties. (b) From the data, identify and discuss the velocity intervals where there is unresolved saturation. State what criterion you used to determine these regions. (c) Integrate under each feature to obtain the column density and uncertainties for each feature and for the full system. Do this for the 2796 and the 2803 transition. What does it mean when the answers are not consistent (3 sigma)? Are some of your results lower limits? Please present your results in the fashion of a journal paper, i.e. use LaTex and put your integrated column density results in a short table.
Data for Sarah B.[2796 | 2803 ]
Data for Brandon [2796 | 2803 ]
Data for Ryan [2796 | 2803 ]
Data for Sarah G.[2796 | 2803 ]
Data for Glenn [2796 | 2803 ]
Data for Pey Lian [2796 | 2803 ]
Data format: just use the first 4 columns: wavelength, rest-frame velocity, normalized flux, sigma_flux
Use the sigma_flux data for the uncertainty spectrum.Atomic Data (Tran, lambda, f, Gamma)
MgII2796 2796.352 0.6123 2.612e8
MgII2803 2803.531 0.3054 2.592e8
ASSIGNED: Thursday October 14, 2004
DUE: Thursday October 21, 2004You can pick up the homework assignment below:
Assignment 3 (PDF)
Figure 1 (PS)
Table of Systems (text)SOLUTION SET: and written-- handed out in class.
You can pick up the exam below:
Exam 1 (PDF)
Exam 1 (PS)
SOLUTION SET:
Exam 1 Solutions (PDF- the figure is a bit off)
Exam 1 Solutions (PS)
ASSIGNED: Thursday October 21, 2004
DUE: Tuesday November 2, 2004Choose three clear single component absorption lines from your FOS/HST spectrum that you used for Assignment 1. Write a code to fit a Gaussian profile to each absorption line using Chi^2 minimization. Your code should be a driver that calls the Numerical Recipes subroutine mrqmin. That code and the required subroutines to implement your fitting driver are avaliable here: [ covsrt | fgauss | gaussj | mrqcof | mrqmin ]. (NOTE: all provided codes are declared for double precision). A required feature of your code is that lines with fitted widths narrower than the instrumental profile should be refitted with the width held fixed at the instrumental profile width. Assume the resolution of your data is R=1200. Hand in your driver code (do not include all the Numerical Recipe subroutines). Individually plot you absorption profiles with your smooth fitted curve overlayed. You can plot them as normalized or unnormalized spectra. Provide a table of your fit parameters, including the line centers, the line depths, the line widths, the equivalent width, and their uncertainties. Compare the fitted equivalent widths to those you obtained using the aperture method for Assignment 1B. Are they consistent within the uncertainties? Comment. Please be sure your assignment is type written, and please include some explanation of your methodology.
ASSIGNED: Thursday October 21, 2004
DUE: Friday November 5, 2004Choose a blended absorption feature from your FOS/HST spectrum that has at least three visual subcomponents (If you cannot find a good candidate then see me). Generalize your Gaussian fitting code to fit this blended feature. Add to your driver from Assignment 5 the ability to perform an F-test that returns to you the confidence level that you have fit the minimum number of statistically significant component to your profiles. The codes you will need are: [ ftest | avevar | betacf | betai | gammln ] . Perform the F-test for a single, double, triple, etc., component fit and comment on the number of components you have chosen as your final model to your data. Hand in your driver code (do not include all the Numerical Recipe subroutines). Individually plot you absorption profile with your smooth fitted curve overlayed. You can plot them as normalized or unnormalized spectra. Provide a table of your fit parameters, including the line centers, the line depths, the line widths, the equivalent width, and their uncertainties. Compare the total fitted equivalent width to that you obtained using the aperture method for Assignment 1B. Are they consistent within the uncertainties? Comment. Please be sure your assignment is type written, and please include some explanation of your methodology.
ASSIGNED: Tuesday November 23, 2004
DUE: Thursday December 2, 2004Pick up HW 6 (PDF)
Pick up HW 6 (PS)
Pick up List of neutral hydrogen column densities.Pick up HW 6 Solutions (PDF)
Pick up HW 6 Solutions (PS)
ASSIGNED: Thursday December 2, 2004
DUE: Wednesday December 8, 2004Pick up Exam 2 (PDF)
Pick up Exam 2 (PS)
Problem 1: See the "book" for the needed discussion and equations to apply.
Problem 2: The codes you will need are: [ gammln | gammp | gcf | gser ] . You can read about their implementation in Numerical Recipes Chapter 6.
Problem 3: The paper you may want to look at is QSO Absorption Line Systems and Early Chemical Evolution by Lauroesch, J. T., Truran, J. W., Welty, D. E., & York, D. G. 1996, PASP, 108, 64.
Pick up Exam 2 Solutions (PDF)
Pick up Exam 2 Solutions (PS)