Spreading Galaxies Gospel on Facebook April 11, 2010
Posted by sarah in: astro 2.0 . 7comments
Galaxy rotation curves: NOT flat (Noordermeer et al, 2007)
Paolo Salucci has a bone to pick with the community. The Trieste-based astronomer is fed up with his colleagues’ misconceptions about galaxy rotation curves and has decided to Do Something About It. In his short paper posted to astro-ph last Friday, he describes the experiment he’s set up to convince the world that galaxy rotation curves are not flat (oh sorry, that’s: NOT flat) – he has set up a Facebook group with plots, background, links and discussion, to orchestrate a change in the hearts and minds of astronomers around the world, to stamp out once and for all the damaging “hoax” of flat galaxy rotation curves.
Rotation curves describe how the rotation velocity in galaxies changes with increasing distance from the galactic centre. For spiral galaxies these curves are useful for learning about the galaxies’ matter distribution and, importantly, the presence of dark matter. But I’m not going to talk about rotation curves – it’s not my field and I’m happy to accept that they’re not flat.
APOD: Cold dust, Hot image March 22, 2010
Posted by sarah in: astronomy, pics . 1 comment so far
Today’s Astronomy Picture of the Day is this stunning image of a section of the Galaxy as seen at far-infrared wavelengths. The high-resolution parts come from the recently launched Planck satellite, the rest from the older infrared satellite IRAS. The bright material shown in the image is very cold gas and dust, whose radiation peaks at these long infrared wavelengths.
Image: ESA, Planck HFI Consortium, IRAS
Space, Not Safe For Work March 18, 2010
Posted by sarah in: astronomy, pics . Add a comment
Astropixie has started a new post on her blog called Dirty Space News, inspired by a rather unfortunate-looking figure in a paper she was reading from astro-ph. There have been lots of contributions with more suggestively shaped figured and images. I wonder if Sarah Gallagher, the paper’s lead author, knows the new movement her last paper has sparked?
I spotted the poster shown above in our corridor – its designers have amazingly managed to make the XMM satellite look even more phallic than it already did…. I’m starting to think X-ray astronomers have had a lot of fun with this over the years.
Go check it out here and send her your own Dirty Space images!
Astronomy and the Chile earthquake March 2, 2010
Posted by sarah in: astronomy, geology . Add a comment
Pretty Valaparaiso in 2005
I noticed a lot of traffic to the blog today from google searches for people looking for info on the fate of the telescopes in Chile after last weekend’s huge earthquake that has devastated the central part of the country. The bottom line is that they all seem to be fine – although let’s not forget that the damage to Chile’s infrastructure could easily pay for hundreds of VLTs. As for the lives lost, well, no hardware can replace those.
On a personal note, my only experience of earthquakes dates back to 2005, while observing at Gemini South at Cerro Pachon, near La Serena in Chile. In our week-long observing run we suffered 2 earthquakes of magnitudes 5.8 and 5.0 or so, if I remember correctly. Our telescope operator, recognising the distant rumble, gave us a few seconds’ warning that a quake was under way, giving me ample time to freak out completely. Having just escaped the London bombings a few weeks earlier, I guess my nerves were pretty shot, but it was still pretty scary. I can only imagine how terrifying a magnitude 8+ quake must be when you’re sound asleep in your home at 3 am and I truly hope I never get to find out.
Anyway, here’s a round-up of some of the statements released by the astronomy organisations with bases in the country.
On Software in Astronomy March 1, 2010
Posted by sarah in: astronomy . 16comments
Importance of the Hubble archive. The number of archival papers has exceeded the number of PI-led papers since 2006 (from White et al., 2009)
I’ve been giving some thought to software development in astronomy, which is a difficult topic. All astronomers agree that good data processing, and hence good software, is crucial to doing rigorous science. To interpret observational data, to translate electrons on a detector to scientific knowledge, requires a solid understanding of the instrument, the observing conditions, and of the exact process with which the data were treated. Many large ground- and space-based observatories, like those run by ESO, Gemini and NASA, strive to provide the community with “science-ready” data. This means that the data are processed to remove all instrumental signatures, allowing astronomers to dive straight into the analysis.
The rationale is that providing science-ready data essentially makes them usable by a much wider community than those involved in the observing campaign, or those used to working with a given instrument. Indeed, a big driver behind the global Virtual Observatory initiative is the “democratisation of astronomy” by providing anyone in the world with ready-to-use astronomical data, irrespective of their location or affiliation to large organisations.
