Getting dual images on DS9
1. Pull up the image on DS9
2. Centre the star (middle click on the star)
3. Pull up the DSS ImagesGo to Frame - Match Frames - WCS
4. File - title
5. Load Region
Make a .gif image of lightcurves
1. plotlcs ./ 1 star# 1
2. open a new terminal
3. scp mcba11/address:/location/*gif*
* Once a candidate has been identified, high resolution, multi-coloured follow-up photometric observations must be done to rule out binaries or systematics. This is typically done with the ANU 40-inch Telescope at Siding Spring Observatory (or on some previous occasions, the ANU 24-inch Telescope which has now been decomissioned). The 40-inch Telescope will be decomissioned on 01 January 2008.
Getting Transit times/dates for Follow-up Observations
A Perl script called ttime.pl (transit time) was written to determine when an object would be transiting given certain info.
ttime.pl P t_o t_now n dur durf depth +za name >> Transit_Schedule
Most of the following data can be found on the candidates page from trsearch.txt or worked out by hand.
* P = Period (days)
* t_o = Time (JD) cooresponding to the middle of the transit
* t_now = Current JD (Julian Date - 245000... example: 4100)
* n = Number of times to repeat the transit (a low number will only cover a few days, a larger number will cover weeks/months)
* dur = Duration of transit (days)
* durf = Duration of flat-part of transit (days)
* depth = Depth of magnitude dip (eg 20 mmag, 100 mmag, etc)
* +za = (+ Zenith Angle) - for daylight savings, put "1"... otherwise, put "0". The script is set to UT+10 by default
* name = Name of the object in the form of UNSW-TR-##
* >> Transit_Schedule simply puts the data in a file
You can get the period from trsearch.txt, and use MyPlot to check if the trsearch period can be improved - especially check whether it has separated out primary and secondary depth transits by doubling the period and seeing how the result looks.
The centre of the first transit you see is your t_o, remember that the plots we have are funny with the hours and it's best to read the JD from the lightcurve file. Playing around with MyPlot (see below) gives you the other info (dur, durf, etc) when you're doing the fitting.
Getting the Contour and Radial Plots on DS9
* Open IRAF
* cd into directory with images
* Upload image on DS9
* Type "imexam" (or imexamine) in IRAF
* Type "e" for contour plot
* Type "r" for radial plot
Using MyPlot
MyPlot will fold the lightcurve at a given period and plot it. It will also overplot a very simple model (whose parameters you have to calculate visually) and calculate estimates of the physical parameters of the system (based on Seager & Mallen-Ornelas 2003, ApJ 585, 1038).
MyPlot takes a star id as an argument (if you run it without args you'll see it also takes other optional args). The rest of the parameters are read from a file called star#.ptt (e.g. 00107.ptt for star 107). This file should follow the following format:
objid = UNSW-TR-29 (optional, object name printed in plot)
period = 1.409120 (period in days)
t0 = 3579.5150 (JD-2450000 at centre of transit)
dur = 0.0700 (total transit duration in days)
durf = 0.0340 (duration of "flat part" of transit in days)
depth = 0.0180 (transit depth in magnitudes)
The order of these lines is unimportant, but make sure there's a space on either side of the '=' sign.
The directory should contain the lightcurve file (star#.lcs) and the parameters files (star#.ptt). To execute, type:
myplot star#
This will give you two things: 1) The phase-folded lightcurve and 2) the derived parameters. The red-line is a line of best fit. You should edit the parameters in the .ptt file until you get a line of best fit.
To make an image, type:
myplot star# 20 1
This will produce a .png file of the image binned at 20 min intervals.
* In the folder of a particular object, a file should be present labelled star#.ptt.
* Type myplot star# in a directory containing the star#.lc and star#.ptt files. It will then display a graph of the phase-folded lightcurve and produce a line of best fit.
If you type "myplot" only, the prompt will show
istart [wbin output period t0 dur emax]
* wbin (time bins in minutes)
* output (=1 makes png image)
* period is the period of the transit
* t0 is JD-2450000 at centre of transit
* dur is the duration of the transit
* emax