The life of a grad student gets pretty crazy from time to time, but I’m excited about returning to blogging as things cool down a bit. As mentioned in my last post, I’ve got a list of fun things that have caught by attention recently, so I hope to churn those out in time! Today, I’ll showcase the NRAO Newsletter, or the news and happenings at the National Radio Astronomy Observatory where I work.
Back in January, it was announced that the Milky Way is much bigger than previously thought, in fact, almost two times bigger! That allows our home galaxy to rival the nearby Andromeda Galaxy in size. These are based on a set of Very Long Baseline Array observations, and most of the astronomical community is not familiar with VLBI. These measurements are great for being very precise and work purely from geometrical arguments, which limits the amount of assumptions about your objects that need to be made. But they do conflict with the prevailing model based on decades of observational evidence, so it will take some time for these new measurements to be accepted by the broader community. And surely, more observations that agree would help. So do read the NRAO Newsletter version by Reid et al., linked above for more on how these observations are done. Maybe they will have to rescale the beautiful Galaxy Garden* after all!
Click to go to larger version. By Reid et al. 2009. Caption from article, “Rotation speed versus radius for the Andromeda galaxy and the Milky Way. The red squares are based on HI observations of Andromeda tabulated by Carignan et al. (2006, ApJ, 641, L109). The blue filled circle is our best estimate of solar rotation speed = 254 ± 16 km/s at radius = 8.4 kpc for the Milky Way, derived from the parallax and proper motions of high mass star forming regions. The blue dot-dashed line is for a flat rotation curve, and the blue dashed line corresponds to a slightly rising rotation curve of 2.3 km/s/kpc. These lines are plotted over the range of Galactocentric radii sampled by the parallax and proper motion results. Note that these two galaxies have nearly identical rotation speeds over this range.”
For those who want to look at something more technical, check out the “Lab Notebook” report by Matt Morgan and Rick Fisher (yes, THAT Fisher of the Tully-Fisher relation!). As radio telescopes become more sophisticated, using focal plane “imaging” arrays on single dish telescopes and larger arrays for interferometry, the need for more and better receivers is growing. Read all about their progress with digital phase shifting technology for GHz-range receivers. It is important for a world-class observatory to maintain large facilities and focus on the interesting science. However, no radio observatory can be complete without a robust research and development program so they can stay on top of the next big technological advances that will change how we observe the universe.
Finally, radio astronomy gets some love for Google Sky. It kind of bothered me that you can open up showcases in the 0ptical, infrared, ultraviolet, and x-ray, but the fascinating and amazing images of the radio sky don’t get much play. I haven’t actually taken the time to play around with this yet, but you can now create KML files of the radio sky and upload them to Google Sky. Take a look at the examples in the newsletter, showcasing the Galactic Center region and Kepler’s supernova remnant.
Click to embiggen. I kind of see it…. oh THERE it is!
Radio astronomy lets you see processes that are so alien to our usual, optical way of looking at the universe. Keep up with all the good stuff by subscribing to the newsletter RSS feed!
Nicole
Tim
[...] sure your yeast is at least as fresh as the radio news from Nicole at One Astronomer’s Noise – don’t try this with a packet that’s been in the back of your cupboard for [...]
Andromeda is still my favorite :-p.