Friday, February 20, 2015

Observing Galaxies with SAMI

I've been out at Siding Spring Observatory for the last week observing galaxies for the SAMI survey with the 4-metre Angle-Australian Telescope (AAT).  Here's the story. 

arrive at siding spring observatory and hope to see crisp blue skies above the telescope dome.

check the instrument hardware

plug the optical fibres into SAMI field plates.  each of the silver ones will look at individual galaxies. the orange ones look at sky. 

hope that you get to go for a ride with SAMI at prime focus (spot the astronomer!)

take a walk around the catwalk to enjoy the view of the warrumbungles and check the sky

get comfortable in the control room, where you will spend most of you waking hours for the next many nights. (there are a lot of monitors around!)

check the software to make sure it works (SAMI uses python mostly)

check software that talks to the instrument (SAMI) on the telescope

take some calibration frames and look at the raw data to check that it looks ok.

once the sky is dark and the stars are shining in the all-sky camera, focus the telescope and start collecting photons!

enjoy seeing those squiggles in SAMI raw data - gas in a distant galaxy! Each horizontal line is a single spectrum ("rainbow fingerprint") from a different place across the face of a galaxy. The very bright white streaks are cosmic rays, while the vertical dotted lines are glowing gas in Earth's atmosphere. squiggles show gas doppler shifted as it swirls around the center of the galaxy far, far away.

a quick reduction of SAMI galaxy data! each bundle on the right covers a single galaxy and has 61 individual optical fibres looking at a different spots across each galaxy. the left shows a quick reduction of the spectra collected from the light in each fiber. the squiggly lines show gas emission in the galaxy (hydrogen, nitrogen and silicon here). a single exposure points at 13 galaxies for a total of 800 spectra!

replug the fibres in the SAMI field plate in the spooky light of the middle of the night.

start to get goofy in the wee hours of morning by noticing you blend in with the couch.

and again the next night, unintentionally!

take a walk around the mountain during the days to get some sun and enjoy the views!

adding it all up, this observing run was 5 nights long, during which we collected new data for 84 galaxies!  that means we have 5,124 individual spectra.  woohoo!

the SAMI run continues for another five nights, but my shift is finished and i drive back to sydney tomorrow.  time to get back on a day schedule. 


Kirsch said...

I feel jealous of all the cool toys you get to play with.

heroineworshipper said...

So the self propelled fibers still haven't worked out.