A much anticipated telescope has finally opened its eyes. And, oh, the wonders it can see…
The very first images from the Atacama Large Millimeter/submilimeter Array, or ALMA, have been released to the public today. With just this first image, the potential of the new instrument to peer into the darkest and most exciting recesses of the universe can be seen. And the telescope hasn’t even begun.
In the picture above, we can see a multi-wavelength composite of the galaxies NGC4038 and NGC4039, better known as the Antennae. The white and pink are from Hubble Telescope data, the blue from the radio emission seen by the Very Large Array, and the yellow and orange the new contributions from ALMA. The Antennae are a pair of spiral galaxies in the process of smashing together.
When galaxies collide, no stars collide due to their immense distances from each other, but gas can collide, igniting one of the grandest fireworks displays in the cosmos.
New stars are born, burn brightly, and die in fantastic supernovae in the span of just tens of millions of years. The complex process of star formation itself, however, is still a great puzzle for astronomers to piece together.
This is one area where ALMA will shine. Millimeter and submillimeter wave radiation can penetrate the thick, obscuring dust that surrounds the forming stars in the earliest stages. In the image below, the yellow and orange represents the emission seen by ALMA, tracing star formation even where the visible light image shows only a dark region.
Top: No ALMA. Bottom: ALMA. (No ALMA. ALMA. No ALMA. ALMA. No ALMA. ALMA…you get the gist.)
Though an impressive amount of science has been done with previous mm/sub-mm telescopes, they lacked the sensitivity and ability to see fine details. They laid the groundwork whereas ALMA will be the first major workhorse telescope in these bands.
Observing at these wavelengths is very challenging because of the amount of water in Earth’s atmosphere. Water absorbs and distorts the mm/sub-mm light coming from space, so astronomers had to go to the high desert region of the Chilean Andes in order to build this telescope. When completed, it will have 66 individual antennas working as one complete telescope using one of my favorite techniques ever, interferometry.
Though it can take a lot of work to produce an image from a radio interferometer, especially one with so many challenges from the atmosphere, ALMA has been designed to calibrate for weather effects and eventually have a pipeline process for data so that astronomers new to radio astronomy can get science-quality data for their work with little tweaking.
I should note, also, that ALMA’s power is not only in imaging but in spectroscopy. The light collected by ALMA can be spread out by frequency (or wavelength, depending on your tastes) where tons and TONS of emission lines can be seen from molecules in space. The identities of many of these molecules are unknown, so ALMA will be like a chemistry lab for the universe as well, with its own set of tools.
On a personal note, I’ve been hearing about ALMA since I was a wee undergrad just getting into this radio astronomy business. I heard it discussed while I was a summer student at MIT’s Haystack Observatory in 2003, and a little more when I got my first internship at the National Radio Astronomy Observatory (NRAO), the organization contributing the US share of the telescope’s development.
I even visited the three test antennas out in New Mexico when they were decided on final designs. Now, I live and work in Charlottesville, home of the North American ALMA Science Center at NRAO headquarters. I’ve seen engineers designing and building special receivers for the telescopes at the NRAO Technology Center. We even have a joke amongst the grad students that no astronomer can give a talk in Charlottesville without mentioning ALMA somewhere in the talk!
So, yeah, though I’ve been watching from the sidelines, I am thrilled to see this come to fruition after the dedicated hard work of so many people for so long.
On Friday, ALMA Early Science officially started at 1pm EDT. In case you didn’t believe me about the anticipation for this telescope, over nine hundred proposals were sent in for Early Science. That means, the full array isn’t built and they’re still working out the bugs, but that won’t deter eager astronomers!
ALMA will begin to make its mark on the entire field of astronomy with studies into extrasolar asteroid belts, star formation, and the behemoth supermassive black hole at the center of our own Milky Way Galaxy. Yeah, it’s safe to say that I’m excited, and I hope you are, too! The universe is about to open up for us once more in a brand new way.
Images: Top and Middle Credit - B. Saxton, (NRAO/AUI/NSF); ALMA (ESO/NAOJ/NRAO); HST (NASA, ESA, and B. Whitmore (STScI)); J. Hibbard, (NRAO/AUI/NSF); NOAO/AURA/NSF; Bottom – The three test antennas in New Mexico, circa 2004. Credit – me.