ALMA Observes Most Distant Starforming Galaxy

…but that’s not the really cool news. The cool news resides in ALMA itself!

Credit: ALMA (ESO/NAOJ/NRAO)

Credit: ALMA (ESO/NAOJ/NRAO)

The past week this headline (or variations of it) has been floating around the twitter-verse. And, while this headline is cool, I don’t think it addresses the awesome-ness of the topic.

To stat, the Atacama Large Millimeter/Submillimeter Array (or ALMA) is an array of radio telescopes in the Atacama desert of northern Chile. This array consists of 66 12-meter and 7-meter diameter telescopes observing at the millimeter and sub-millimeter wavelengths. Due to the large number of telescopes this array contains, it has a much higher sensitivity and resolution that the existing telescopes of it’s kind (James Clerk Maxwell Telescope, Submillimeter Array, etc.).

The main science goals of ALMA as as follows (from their website):

  • The ability to detect spectral line emission from CO or [CII] in a normal galaxy like the Milky Way at a redshift of z=3, in less than 24 hours,
  • The ability to image the gas kinematics in protostars and in protoplanetary disks around young Sun-like stars in the nearest molecular clouds (150 pc),
  • The ability to provide precise high dynamic range images at an angular resolution of 0.1 arcsec.

To summarize the first of the science goals above, ALMA will be used as a tool for studying star-formation in galaxies billions of years in the past. So, due to their distance away, most of the light from a wide range redshifted objects are observed in the millimeter and submillimeter wavelengths. Due to the unprecedented sensitivity and resolution of this telescope, it’s projected to offer a fantastic look into the distant universe to reveal loads about star-formation in the distance universe.

And, following this, ALMA became operational this month (March 2013) and though it is not fully operational has already released some very interesting results!

The new survey announced the observation of the most distance star-forming galaxy at 12.65 billion light-years (z = 5.7) as well as additional observations of a large number of other star-forming galaxies at high redshifts. These discovers are not out of the blue. An international team of researchers first discovered these distant star-forming galaxies with the National Science Foundations 10-meter South Pole Telescope (SPT; observes in microwavemillimeter-wave, and submillimeter-wave wavelengths), though an independent observation of redshifts was needed. ALMA provided a followup observation of these galaxies in order to preform an accurate redshift calculation of these sources.

The observation of these galaxies was made using gravitational lensing where the light from a distance galaxy is able to be observed due to the presence of a foreground gravitational source (such as a galaxy). Below shows a schematic for such an event.

Artist’s impression of one of the South Pole Telescope-discovered sources based on observation by ALMA and Hubble Space Telescope (HST). The massive central galaxy (in blue, seen by HST) bends the light of a more distant, submillimeter-bright galaxy, forming a ring-like image of the background galaxy which is observed by ALMA (red). (ALMA)

The light from the distant object is both distorted and magnified due to the gravitational force of the foreground object. The background object forms an Einstein ring around the foreground object. Astronomers are able to correct for the magnification and distortion to calculate various properties of the galaxies.

Of the galaxies found by the SPT, ALMA imaged 47 galaxies and collected spectra on 26. Due to the sensitivity of ALMA, astronomers were able to calculate the redshift of these 26 galaxies straight from the spectra rather than relying on independent visual or IR observations from other telescopes (which is not always possible due to the due to the dust obscuring the galaxy). Because of it’s precision it’s able to detect much more faint spectral lines and be able to determine the redshift out to these galaxies without requiring any multi-wavelength identifications!

From the spectra, ALMA was able to detect strong carbon monoxide lines (CO) in the spectra of these galaxies indicating intense star formation in the galaxy. These results were surprising as only a few starburst (intently star-forming) galaxies had been detected at these distances. It is still not clear how these galaxies could produce stars at such a furious rate so early in the Universe as these galaxies are forming 1,000 stars per year (for comparison the Milky Way galaxy has a star-forming rate of about 1 star per year). Overall, these discovered galaxies may be what today’s massive galaxies looked like in the past. These galaxies create stars many thousands of times faster than galaxies like our own!

Also, many of these galaxies have shown emission form water molecules, which is the most distance detection of water in the universe to date! How neat is that?!

They also found a higher sample mean redshift for these sources. Previously this value was found to be at z = 2.3 (10.76 Gyr), but new study has found the redshift mean to be at z = 3.5 (11.83 Gyr). This indicates that previous samples were biased towards lower redshift galaxies and may have missed a large fraction (≥ 50%) of these galaxies at redshift z>3.

This data is one of the first (if not the first?) data being released from an operational ALMA. And though it is only using 16 of its 66 planned telescopes and is only focusing on brighter galaxies, this study has almost doubled the number of star-forming galaxies seen at high redshifts (within the first 1.5 billion years of the universe). In addition, these observations only took 2 minutes to take, about one hundred times faster than before! Previously, a measurement of redshift for these sources would have to combine data from both visible-light and radio telescopes.

So more than the result, this study shows the capabilities of ALMA and the potential for exciting results to be found in the future. Due to its unprecedented resolution and sensitivity, this telescope should lead astronomers to understand much more about the formation of the early universe.

 

A comet from the plane

Well, after much scrounging around I managed to locate comet PAN STARRS in the photos from the plane back from Vancouver.

Comet_2

 

I really wouldn’t be surprised if you don’t believe me. It took a good hour to confirm what I was looking at, and really this just looks like background noise from my camera…BUT, I checked several images as well as the comets position using various astronomy programs. So this indeed is the correct position of Comet PAN STARRS on March 12, 2013. If you look carefully you can just make out the faint tail from the comet. But, that could just be my eyes playing tricks.

Also, sorry for the blur! Apparently, it’s hard to take clear photos from a large moving object.

Sneak Peak: Mar 18, 2013

Tonight co-hosts Ryan, Jesse, Pat (and maybe Lianne) will be discussing new data from the Curiosity Rover about the possibility of conditions for life in the past, Astronomers find unique supernova, Overwhelming proof that Cosmic Rays are indeed created by Supernovae and much much more! 

Tune in at 9 pm EDT or 1am UT (March 19th) ! And remember to log into our online public viewing chatroom starting at 7:30 EDT!

But, if you miss our live broadcast you can still tune into our re-runs on Astronomy.FM every 4 hours on Astronomy.FM or listen to our podcast published here after the show!

Comet Pan-STARRS

Just a quick post about the comet that’s travelling through out skies right now. While I was on the plane from Vancouver on Tuesday I was fortunate enough to have a fabulous view of the setting crescent moon. As the moon was only about 1% illuminated, the effect was stunning.  And, as we talked about on York Universe on Monday night, the comet Pan-STARRS was supposed to be very close to the moon. Unfortunately, I couldn’t see it naked eye (though I spent about 1/4 of the trip craning my head backwards towards the moon). I did manged to take a horribly noisy photo of it with my camera. I’ll post this photo up when I get home tonight, though really it’s even hard to make out in this.

Tonight is supposed to be clear so I’ll take my nice 10″ scope out and hopefully get a much cleaner view of the comet!

Clear skies all!

Pan-STARRS and New Stars: Mar 12, 2013

Show Notes: March 12, 2013 (GMT)

Title: Pan-STARRS and New Stars
Hosts: Ryan, Lianne, Paul

Kicking off Astronomy Night in Canada, the humble hosts of York Universe chatted about the VERY soon to be Cmdr Chris Hadfield. Come Pan-STARRS, part of our show name, is gracing the skies beautifully in both the north and the south (but better observed from the south). A new star system is discovered in our backyard, and astronomers perform reconnaissance of another solar system. Check out the show notes and podcast to see/hear the details.

Continue reading

Speedy Spin on Small Planets: Mar 5, 2013

Show Notes: March 5th, 2013

Title: Speedy Spin on Small Planets
Hosts: Ryan, Jesse, Paul
Special Event: We fielded live questions from the Warren Astronomical Society (@WarrenAstro) meeting located at the Cranbrook Institute of Science.

This evening’s show featured the return of ‘the dean,’ Paul Delaney, from his trip to the Canary Islands, where he got to visit the largest optical telescope in the world, at 10.4 m. SpaceX was in the news again with its ‘little-capsule-that-could,’ the Dragon capsule docked with the ISS over the weekend. We also (finally) chatted about the tiny planet Kepler 37-b, and how some astronomers using XMM-Newton and NuSTAR have made a reliable measurement of a super massive black hole’s spin….and it’s HUGE. See show notes and podcast below.

Continue reading

Closest Stellar System Chills Out

Alpha Centauri.  Not only is it an alien in Dr.who, a strategy game released in 1999, and an album released by the German electronic band tangerine dream, but it’s the brightest star in our closest stellar system.  Named for being the brightest star in the constellation Centaurus in the southern sky, its a little over 4 light years away from Earth, and is very similar to our sun in terms of size, age, mass, composition, and temperature. Here is a great infographic from Space.com.

Scientists have recently discovered that Alpha Centauri shares yet another resemblance to our home star: It has a strange, cooler layer in its atmosphere.

Star Layers, Credit:ESA
Layers of the Stellar Atmosphere Credit: ESA

 

The surface of the sun, called the photosphere, has a temperature of about 5700 Kelvin.  That’s about as hot as flames in the ol’ fireplace.  The center of the sun, where all the fusion happens, is upwards of 15 million Kelvin.  But further out past the photosphere we reach the corona, a powerful radiative zone where the temperature can reach about 2 million Kelvin.  We see the solar corona during a total eclipse of the sun.  Although the temperatures vary slightly in Alpha Centauri, it shares a similar pattern.

So why the drop in temperature? Or rather why the boost in temperature farther out? Astronomers aren’t completely sure, though they think its due to the same phenomenon that gives rise to solar flares: Twisting of magnetic field lines.

The important point is that this is the first time we’ve observed this phenomenon in a star other than the sun.  Is it present in all stars? Or only sun-like stars? Further study of Alpha Centauri and its similarities and differences when compared to the sun will give us an idea of the answers to these questions, and surely will result in a lot more questions, as is the way of science.

Return of the Dragon

This morning was the launch of the second SpaceX dragon capsule mission, officially designated mission CRS-2.  It launched at 10:10am today, Friday, March 1st from Cape Canaveral space launch complex 40.

A bit of background on Dragon: 

The two-stage rocket uses 9 engines to power the first stage out of the atmosphere, before the single rocket stage 2 takes the capsule the rest of the way.  The 14.4 foot tall dragon capsule is capable of carrying more than 7000 lbs of cargo split between pressurized and unpressurized sections.

On March 2nd, Astronauts will use the CanadaArm 2 to grab onto the capsule and unload the contents.  The crew will also load more than 2600 lbs of experiment samples and equipment for return to Earth during a scheduled parachute-assisted splashdown off the coast of California on March 25th.

This is the second of at least 12 planned missions by SpaceX for commercial resupply purposes for NASA.

Mission Update: The rendezvous with the International Space Station (ISS) will be delayed slightly, due to an issue with a propellant valve after achieving orbit.  The solar arrays have been deployed, though for a time only one of the three thruster pods was responsive.  At this point, according to the twitter feed of Elon Musk, CEO of SpaceX, a second thruster pod is up and running, and the craft has moved from free orbit to active control, and can now begin a burn to rendezvous with the ISS.

4:04pm – Thurster pods 1 through 4 all up and running, preparing to raise orbit to catch the ISS!