Buenas Noches: Mission to Chile

Sunset left a beautiful sun pillar at Paranal tonight.

Twenty hours in the air, a few more in trains and taxis, and a brief overnight stay in sun-drenched Santiago: that’s all it takes to get to one of the most amazing places on Earth for astronomers, Cerro Paranal. Home to the VLT, VISTA and VST telescopes, Paranal is a big epicentre of astronomy in the Southern hemisphere, or indeed the world. I’m spending much of the next week here in Chile on a kind of reconnaissance mission for the GRAVITY project. 12 hours into my stay I have already forgotten the drudgery of airport security queues and whatever body clock issues I’m having, and I’m having a thoroughly good time.

GRAVITY is one of 2 second-generation instruments for the VLT Interferometer (VLTI), in which light from multiple telescopes is combined to beat the resolution limit of one single telescope. Interferometry is commonly used in radio astronomy, but for optical and infrared observations it’s extremely challenging. VLTI is one of the only large facilities offering such a mode.

The GRAVITY instrument will combine the light beams from 4 telescopes to carry out high-resolution observations in the near-infrared, particularly with a view to tracking the fast-moving stars close to the black hole in the centre of our Galaxy. Like so many instruments today, it’s a big project with 6 institutes involved and many subsystems that are all highly complex individually, yet they all have to play together nicely with a common goal. At MPIA I work as systems engineer for one of those subsystems, a set of 4 new wavefront sensors  for the adaptive optics systems on each of the four Unit Telescopes.

Because these sensors need to interface with lots of existing hardware and control software at the telescope, I’ve come on a fact finding mission to learn more about how certain aspects of the telescope and the interferometer are operated today, so we can optimise our strategy for the GRAVITY instrument.

The VLTI delay lines

It’s my first visit to Paranal and I’m excited to be here. The great thing about engineering visits is that I’m not as restricted as “regular” visiting astronomers (those who successfully applied for observing time for their science), and I really get to look under the hood. Most observers don’t get to come here for 5 days either. Within 15 minutes of arriving an engineer took me up to the telescopes, I’ve seen the Coudé lab below one of the telescopes where our sensors will be places, the VLTI delay lines (which are amazing, pic above for the aficionados), the VLTI instrumentation lab. Tonight’s astronomers were out of luck as the sky clouded over around the time of sunset, so when I came back down for dinner the domes remained closed. The sunset sure was pretty though!

 

Gas Cloud meets Black Hole: Nature most definitely wants to eat you

Gas cloud timelapse: watch the cloud (yellow arrow) move towards the black hole (white +) (Gillessen et al, 2011)

ResearchBlogging.orgEd Yong recently started a fun new Tumblr blog called Nature Wants To Eat You, showing pictures of scary-looking animal mouths that may or may not be out to gobble us up. But the scariest and most inescapable example of Nature Wanting To Eat Us is the stuff of astrophysics – in the way that astrophysics tends to kill all the sciences, really: black holes. This week, a team of scientists led by the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching posted their Nature paper to astro-ph, describing their observations of a cloud of gas speeding towards the black hole at the centre of the Milky Way galaxy.

Like with many of these results, the coolest thing isn’t that this is happening. Imagine the size of the Universe: everything you can possibly think of is probably happening right now, somewhere. The mindblowing thing is that we can see it, 27,000 lightyears away, just like you’re probably now watching Strictly Come Dancing or Match of the Day – and believe me, this gas blob is far more exciting.

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Forces of Attraction

To mark Valentine’s Day, Periodic Videos have released this cool video on forces of attraction in nature. You can watch extra footage here.

The Galactic Centre black hole in close-up

ResearchBlogging.orgThe research into the nature and properties of the black hole at the centre of the Milky Way galaxy is one of the highlights of astronomical discovery of the last two decades. Using the biggest telescopes on the planet and state of the art observing technology, we’ve been able to track the young massive stars that are whizzing around the black hole in a dense cluster, and shown with a high level of certainty that the galaxy’s central object really is a supermassive black hole, referred to as Sagittarius A*. Using these stellar orbits, we’ve also determined its mass – 4 million solar masses.

Now you see it, now you don't! The square arcsecond surrounding the galactic centre black hole, seen in the near-infrared. On the left, no source is visible, later on (right) a flare brought it into view. The star marked S2 is the closest known star to Sgr A*. Click to embiggen. (ESO)

With the next generation of infrared instrumentation, we’re planning to take the next step in the study of Sgr A*. For this, we’ll use interferometry – the combination of light beams from a number of telescopes – to zoom into the black hole closer than ever before. In a paper posted to the Arxiv late last year, Vincent et al discuss the potential of a new interferometric instrument, Gravity, for testing black hole physics near Sgr A*.

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One Minute Gravity

As gravity seems to be the topic of the day, I thought I’d post this great little video explaining gravity by Henry Reich. Reich submitted this video to the ongoing Ars Technica science video competition. Love it!