Revisiting Likelihood

Nick, David and Adam want me to check that the single epoch likelihood computation is correct. I also need to address some long-standing questions about the likelihood method including:
1. Why are we getting z > 3 when we aren't targeting these objects?
2. What is the proper normalization of the likelihood objects?
And several other questions posted a while back and never answered.

The likelihood code is at the following location on the repository:
https://trac.sdss3.org/browser/repo/boss/bosstarget/trunk/pro/qso-like/

I've also downloaded it here on riemann:
/home/jessica/boss/bosstarget/trunk/pro/qso-like

The varcat files are here (on riemann):
/home/schlegel/varcat4

The star/qso template files are here on the repository:
https://trac.sdss3.org/browser/repo/boss/bosstarget/trunk/data

I've also downloaded it here on riemann:
/home/jessica/boss/bosstarget/trunk/data

Myers sent me a fits file that has the single epoch targets with the likelihoods he computed. He wants me to check that they look reasonable. The file is in an email sent Nov 18/19 from Adam Myers with the subject line: Likelihood Method.

Below is an email I sent to Myers today regarding this check:

-------------------
From: Jessica Ann Kirkpatrick
Date: Mon, Nov 23, 2009 at 4:15 PM
Subject: Re: Likelihood method
To: Nic Ross
Cc: Joseph Hennawi , Adam Myers, David Schlegel

Adam,
when I compute the likelihoods I get the same values as you do for
like_ratio, like_everything, like_QSO_Z (well, within expected
rounding errors).

One thing that I had a question about is how like_rank is numbered. I
was assuming that like_rank = 0 would be the target with the largest
like_ratio, but it seems it is the reverse (like_rank = 0 is the
lowest like_ratio object).

So we are sorting target selection by largest ranking to smallest?

I've attached a color-color (ug, gr) plot of the 10,000 highest ranked
likelihood objects (cyan) on top of "everything" objects (red) and
qsos (green). You can see that these targets fall in the quasar zone.

Color-Color (ug, gr) plot of the 10,000 highest ranked
likelihood objects (cyan) on top of "everything" objects (red) and
qsos (green). You can see that these targets fall in the quasar zone.

Useful Mac Tips of the Day (via Demitri):
If you want to ssh into your Mac, go to

• System Preferences -> Sharing -> Remote Login
• Turn Remote Login on. Then find out your IP address by typing the following into a web browser: http://whatismyipaddress.com/

You can then ssh/scp into your Mac in the normal way using jessica@myipaddress!

Also... Alexia will be happy to know that I finally implemented different terminal colors for different computers that I am logged into (so much less confusing):

Top terminal window (green) is riemann,
lower terminal window (black) is my Macbook.

And... Demitri showed me how to turn any mp3 into a ring tone using Garage Band. What a great day for cool tricks! Now my alarm clock will be the beginning of James Brown's Sex Machine: "Get-up, get-on-up. Get-up, get-on-up."