As I write this, we are just getting on-sky with the Green Bank Telescope to do some neutral hydrogen (HI) observations. We are remotely observing and David is at the controls getting things going. The first step is to focus the telescope (easy to do at L-band!), determine pointing offsets (difference between where the telescope thinks it’s pointing, and where it actually is pointing), and balance the IF rack (ensure the system responds linearly to incoming signal). This first portion takes about 10 minutes or so. Once that is done, we will move to a strong calibrator source, generally a radio loud quasar or a radio galaxy which is unresolved by the GBT. We will do quick observations of a calibrator so we can later calibrate our data to accurate measurements.
Once the setup and calibration is completed, we will move to our source and begin taking data. This evening’s observations are part of a modest survey to look for HI in compact groups of galaxies. They are an interesting selection of objects, much smaller than large galaxy clusters or groups. There is a mix of elliptical galaxies and spiral galaxies, although elliptical galaxies seem to be more prevalent. We only have a 1.5 hour observing block tonight, so with calibrations and overhead (slewing the telescope, etc), we will only be observing a single compact group. We have already observed a number of groups, and will observe more during future runs, including one tomorrow and one on Wednesday.
But, soon it’s off to the calibrator!
The last few days I have had an extra body around. Mike left his siberian husky with me for the past few days. It has been a fun time. It is my first experience taking care of a dog for a decent term (4 days in this case). So far it seems manageable and quite fun. We have gone on runs and plenty of walks around my neighborhood. As is expected the rather warm weather here is not to her liking, but she has certainly been enjoying the air conditioning!
I have also had a few human visitors this weekend. Mike was here for a bit, his girlfriend stopped by for a while, and I was also host to one of my friends and former roommates from Rochester and her boyfriend. Been good to see everyone.
My Sunday is wrapping up with a bit of work, writing a summary of my last month’s worth of progress. Mike will be by later to pick up his dog, so I’ll have to say goodbye to her. I guess we will see how used to having a dog around I am.
The 2009 Tour de France is now under way, having just wrapped up the 9th stage. The race is still pretty tight and will probably stay so until the race hits the Alps in a week. I’ve managed to keep tabs on most of the stages, watching them live on the internet or replays in the evening. It’s been a pretty good race so far.
Correspondingly, I have taken it upon myself to do some needed maintenance on my bicycles. My Giant OCR-3 is now in pieces in the living room, mostly re-greased and ready to go, but with a few minor things to do before putting it back together. I’ve also given my XC mountain bike a once-over and it is mostly ready, but is having a persistent issue with the headset. Needless to say, my hands have been covered in bike grease for several of the past few evenings. It’s been good times.
But, I’ve also been riding bikes, not just disassembling them. I’ve done some of the usual commuting to work in addition to getting out and mountain biking once a week around McCormick Observatory. It’s great to have a bit of suitable biking terrain right there next to the office.
The past day and a half of work was spent on something which seems to occur somewhat regularly in my investigations of active galactic nuclei. While trying to determine the properties and influence of an object which is tiny compared to it’s host galaxy (smaller than 1 kiloparsec), you often need to consider the effect emission from stars might have. So, in my recent modeling efforts of the nucleus of Cygnus A, I have been working on constraining the amount of emission due to starlight in the galaxy.
After a bit of literature searching and a tiny bit of math, I think I have arrived at an answer regarding the contribution of starlight. Older optical imaging and near-infrared imaging give a consistent answer for the relative contribution of starlight to the emission seen (and modeled). Of course, for the answer, you’ll have to wait until the work has been published 
I was all over the place for 4th of July weekend. Friday morning was spent near DC, climbing at Carderock on the Potomic (pictures below). We set up a top rope on a slabby area and climbed around for a bit.
Misc Climbing – on Flickr
Friday evening consisted of this year’s installment of the “3rd of July Party”, which is always a good time. Met new people including one of the neighbors who is originally from New Zealand. Very interesting guy. We chatted about biking and hiking, so naturally it was a fun conversation.
Around noon on Saturday, Aleya and I drove up to Scranton to spend the 4th of July with her family. We got to see the <a href=”http://www.twitvid.com/F4520″>fireworks in town</a>, and light some of our own off. Unfortunately that was cut short due to the prowling of the neighborhood security who apparently dislike anything beyond (and possibly including!) sparklers. Oh well. Now I have a bag full of unused fireworks. 
We headed back to DC on Sunday afternoon and were able to meet up with my Uncle, whom I haven’t seen in a few months. It’s always nice to catch up with family, and we had a good time together.
That pretty much wrapped up the weekend. I arrived back in Cville today and resumed working. Lately I’ve been doing a lot of reading to get caught up on the state of Luminous Infrared Galaxies (LIRGs). Quite a lot of interesting work is going on there and I am looking forward to focusing more on it starting this fall.
