AY3: Freshman Seminar (Automated Discovery of the Universe)

Astronomy is now and will continue to undergo a profound change. When I was a graduate student (which, I remind you, was in the last century) astronomy was a data starved area of science. It took great effort to simply collect the data. The analysis tools were accordingly suited to small amounts of data. In contrast, today, the field of optical/IR (OIR) astronomy is inundated with data -- thanks to technological progress which has given us large format detectors, decreasing costs for unit telescopes, advances in electro-mechanical systems (allowing robotocizatoin) and of course all the advances in computers and related areas. A similar revolution is happening in radio astronomy.

Who will succeed and make discoveries in the new era? Answer: those who will have ability to deal with big data sets, connect diverse catalogs and invent new algorithms whilst being grounded in astronomical phenomenology and physics.

The purpose of this class is to give you a taste of the new era. The class will revolve around the Zwicky Transient Facility (first light is July 2017), the successor to the recently concluded Palomar Transient Facility (PTF). You will be introduced to the methodology of time domain astronomy and undertake several pedagogical exercises involving periodogram, FFTs and statistical inference. You will then have an opportunity to analyze fresh data. Should you make a discovery, even if modest, then you will be encouraged to write up as a real paper and submit to a journal. Along the way you will be asked to give presentations of your work (and thus help develop good speaking skills, an essential part of life). The class meets in Cahill, room 211 as follows: Monday 2-3p and Friday 3-4p. The timetable below presented below is the planned timetable. It will get updated as we progress along the course.

Data analysis requires strong skills in programming and also an ability to be a "power user". It is my view that a good researcher must be deeply ground in UNIX and Python (and Matlab for specialized research, especially in applied sciences & engineering). I would, in fact, say that a key benefit of taking this class is that you will get a good start along these lines.


  1. Introduction to Time Domain Astronomy (TDA) [6 Jan]
    Talk by Prof. Hillenbrand. Presentation. Homework: Top Argelander Stars: Pedagogy & Prize
  2. The Zwicky Transient Facility (ZTF) [9 Jan]
    Talk by Dr. L. Yan & lab tour by Roger Smith
  3. The Gaia Mission
    Talk by Dr. N. Blagorodnova. Presentation
  4. Time & Calendar [13 Jan]
    Solar day, Cesium clock second, Gregorian calendar, Julian Day Number
  5. Astronomical Coordinates (RA, DEC) [16 Jan]
    Altitude, Azimuth, Right Ascension, Declination
  6. Local Sidereal Time & Offsets [ 18 Jan]
    Sidereal time, LST at midnight, Computing angular offsets (spherical trig; arcseconds)
  7. Photometry & Magnitude [20 Jan]
    Poisson noise, Background, Aperture Photometry
    Magnitude, Zero point (AB, Vega), Error on Magnitude
  8. Introduction to UNIX [20 Jan]
    notes
    pwd, cd, mkdir, ls, cat, rm, mv, rmdir, more, less, head, tail,
    which, info, man, wc, wget, curl, compress, uncompress, paste,
    grep, sed, [.,*,..,#,|,~,$] cut, sort, uniq, tr, df, du
    find, perhaps the most complex Unix command
    Helpful sites: cmd
  9. Simple exercise in Statistics [23 Jan]
    I reviewed basic concepts in statistics (mean, median, histogram) and also first introduction to reading files (UNIX, Python etc). See for homework
  10. Introduction to Python [Jan 25]
    Nadia's Python presentation  |  Supernova lightcurve data file
  11. Period Folding [Jan 27]
    This class is focused heavily on periodic signals. In optical astroomy RR Lyrae are famous for distance indicators. These are pulsating stars. Please review the presentation on RR Lyrae . Next, please read the note.
    Next, please review my MATLAB demonstration .
    Please read the file PeriodicSignal.dat. Fold this file at period clearly noted in the demonstration package. Use 21 bins for the folded profile. However, plot the profile for two periods (i.e. plot the 21-bin profile twice). Why? Change the period to a slightly different value and then fold the input data series.
  12. RR Lyrae from PTF [Jan 30]
    RRLyrae Exercise Goal: read ASCII files and fold time series to given period.
  13. Introduction to the Galactic Marshal [Feb 1]
  14. Fourier Transforms [Feb 3]
    Introduction to Fourier Transform. The formal notes for this specific class can be found here .
  15. Visit & Overnight Stay at Palomar [Feb 4]
    Tour of the grounds, P48, P60 and P200.
  16. Understanding Fourier Transforms [Feb 6]
    You should work through the tutorial.
  17. Application to Pulsar Astronomy [Feb 8]
    In Pulsar Data Base please find time series for three pulsars. The headers are given in ascii files. The data is simply a series of 32-bit "floats". Read the data and Fourier transform the time series. Plot the power spectrum. You will notice the low frequency spectrum is huge. Ignore this (i.e. set the y-limits) and look for the harmonics. You may benefit from reading Notes on FFT and also reviewing my Matlab analysis
    Each of you is expected to present your analysis of the pulsar data (I suggest that you choose either bright or medium pulsar, not the faint one). Here are guidelines for presentation. Please have your talk ready as a pdf file.
  18. Presentation by students (FFT/Pulsars) [Feb 10]
    Rules for Giving Talk
  19. PTF data: An introduction to periodic stars [Feb 13]
    Dr. Thomas Kupfer Presentation
  20. Periodogram: introduction and application to PTF data [Feb 15]
    Dr. Thomas Kupfer. Data sets are provided. Every dataset consists of about 20 stars. Most of them were selected from PanSTARRS colors and show signs of variability in PTF but have not been tested for periodic variability. Each student is expected to analyze one data set and report on Feb 22 (see below).
  21. The Kepler Mission [Feb 17]
    presentation
  22. Student presentation of Light Curves of PTF data [Feb 20]
  23. Student presentations continued [Feb 22]
    Talks
  24. Discussion of Findings [Feb 24]
    Studnets discuss the nature of binaries (tidal, reflection, eclipsing, Algol, ..). Exciting report: discovery of a rare g-mode pulsating sdB/sdO star by student
  25. Discussion of Findings, continued [Feb 27]
    Graduate student Kevin Burdge explains sample selection and reports other new finds from the larger PTF data set of other interesting binaries.
  26. Introduction to searching for pulsators & planets with Kepler [March 1]
    Dr. Courtney Dressing will walk us through Kepler data analysis and conclude with a talk on her research. The data sets can be found here
  27. In class laboratory: Anlysis of Kepler datasets led by Dr. Dressing [March 3]
    Students should work on the three notebooks in order given: (1) Box Least Squares periodogram and search for planets notebook (2) BATMAN package to model transit light cuves with parametric input notebook and (3) overplot Kepler data and transit models notebook
  28. Inference: Introduction [Mar 6]
    Poisson process: time between intervals, Poisson statistics.
  29. Inference: Confidence Intervals [Mar 8]
    Numerical experiments: what is the distribution of time between gamma-ray bursts? For a measured number of photo-electrons determine [1%, 99%] confidence interval.
  30. Inference: Normal Distribution [Mar 9]
    The central role of Gaussian distribution. The Central limit theorem. The concept of "3-sigma" and the occasional fallacy.