Friday, September 25, 2015

Thems The Breaks....

Sara Camnasio (left) , Munazza Alam (center), and Haley Fica 
(right) are excited outside the DuPont telescope as we prepared
for night 1 of observing. 
As the Rolling Stones said so profoundly, "You Can't Always Get What You Want".  This observing run is the epitome of that sentiment.  I'm currently on Night 3 of 3 at Las Campanas with my undergraduate assistants Haley Fica, Sara Camnasio, and Munazza Alam.  On Night 1 we had high humidity which would not allow us to open.  We wished for winds to help clear the clouds and that wish was granted!  The winds picked up and pushed the clouds away from the DuPont telescope and lowered the humidity.  However the winds overdid their job and we couldn't open because they were too strong.  Around 1am Chile time, they died down enough so we could open but the seeing was a large 2 arcseconds (translate big fat stars that are bad for science).  It improved only slightly throughout the night.  I was attempting to get the ever important epochs on some very close by brown dwarfs for which I can measure their distances with my multitude of data.  Unfortunately, I'm not sure Night 1 data will be very useful.

Sara shows the sad picture of the 
observing conditions at Magellan 
on Night 2.  We never opened 
due to high humidity and freezing 
temperatures which left ice on
the dome.
Staying positive, we went into Night 2 with an excited fervor to be using one of the big telescopes on the mountain, the 6.5m Baade telescope.  The students were singing "I'm so excited" as we did afternoon calibrations.  Unfortunately high humidity was once again our enemy.  The wind attempted to clear the ugly clouds that sat on top of us but couldn't quite get them away at a fast enough rate.  When the sky finally cleared and the humidity dropped (ish), the temperature plummeted to a nasty -0.8 degrees.  It was cold.  And that cold froze the moisture from the clouds leaving a layer of ice on the railings between the telescopes and on the dome itself making it impossible to open.  Night 2 was a wash.
Despite poor observing conditions, my awesome trio of female
undergraduates celebrated seeing a 6.5m world class telescope.
Not to be defeated we went into Night 3 with a smile and a determined attitude to get some data!  There were some clouds on the horizon during calibrations but we were not going to let those get in our way.  By sunset the sky was looking pretty good.  But when we opened the seeing was an astonishingly bad 5 arcseconds (translate REALLY big fat stars that are bad for science)!!!!  What on Earth was going on!  I was pretty sure I needed to sacrifice a student (kidding of course). After 2 hours of sitting on a bright target we had to close because the clouds had closed in and covered the moon.  The wind then moved things and we opened.  Which is where we are now. Collecting as many photons as we can in the last hour of the night as we battle with the wind and clouds to stay open and reach our faintest (and most exciting) brown dwarf targets.

We need some luck.


Setting Foot in Chile (and trying to keep it still)

When I originally proposed for a National Geographic Young Explorer's Grant with my research "sister" Munazza Alam, we had planned to go to the NASA Infra-Red Telescope Facility (IRTF) on Mauna Kea (Hawai'i). Due to delays, partly caused by concerns around the controversial construction of the Thirty Meter Telescope (TMT), we ended up at Mauna Kea, but funded by a different grant. We thought we missed our shot of becoming "Nat Geo Explorers".

Shortly after our run at IRTF, National Geographic conveniently informed us we had been awarded the grant. We were ecstatic. We tweaked our proposal and asked if we could use the grant to follow up on southern targets from Las Campanas Observatory in Chile. Nat Geo gave the O.K. – it was January 2015.

Run the clock forward 9 months and I am sitting in front of my empty bag, confronting the fact that I am about to visit another hemisphere for the first time. When one packs for South America, I think there's always some sort of denial associated with the winter. I remember looking at the forecast for La Serena while picking clothes, yet I still ended up with 50% of my luggage being mysteriously filled with floral dresses, shorts and spring tanks. Since I've set foot here, I have been religiously relying on the other 50%.

Our flight from Santiago to La Serena was fun. My colleague and travel buddy Haley and I landed on the national holiday of "Dieciocho", so we were treated with all sorts of delicious treats. Some highlights include a divine yogurt and honey bar, a crunchy chocolate cookie, and a dulce de leche filled "tube" (any suggestions?). The weather was crisp and pleasant. When astronomer Katie Kaleida picked us up from the airport to drive us to the AURA Recinto, we had not seen any signs of the earthquake and tsunami yet.

My travel buddy Haley Fica and Katie Kaleida walking uphill to a Dieciocho BBQ in the AURA Recinto
We spent the weekend at BBQs and get togethers at different astronomers' houses, celebrating Dieciocho – or at least trying to. There was a lot of small talk about the inconveniences everyone at the recinto had experienced due to the quake. Water and power outages, broken decorations and pepper shakers, and power lines exploding into fireworks all sounded very unfortunate, but I could feel that a much bigger shadow had been casted on La Serena that week. So Katie took us to the beach.

We started our post-disaster trail from La Serena beach, a little before (what remains of) Tsunami bar, for the locals, and we headed South from there towards Coquimbo. What unraveled in front of our eyes was a scene of increasing destruction.

We started off with gorgeous views and barely any visible debris
We noticed debris as we proceeded towards Coquimbo
"Chile" / Kids with kite / Walking into tsunami aftermath
Getting closer to Coquimbo

Probably best DYI of the year: when a local American farmer returned to find his home and front yard completely submerged by ocean water, he rolled up his sleeves and put his 3 water pumps to action. 3/4 of his job now that the water is getting drained at 1 cm/hour is explaining passersby that he's not dumping water into the street at random – he's actually unclogging a drainage system and re-directing the water to a nearby functioning one. 

Chilean army gathered on one of Coquimbo's beaches earlier today. Aftershocks from the big quake are still going strong (felt a couple of ones within the past hour). Looks like the birds have had enough, they're gonna hang on a boat until the ground stops being moody.

By the time we arrived to Coquimbo our feet felt really heavy, perhaps from stepping on too many plastic remains and rotten fruits. We headed back to La Serena to have some pescado and some hot tea at a local restaurant.

The rest of the weekend was more cheerful: we had lots of Carmenère wine and we listened to some good records while talking about Alejandro Jodorowsky and his crazy films.

After three days of La Serena ups and downs, we were ready to get to work. We picked up Jackie Faherty and Munazza Alam from the airport, and we headed for the mountains...

In the next post: "0 to 8000 – a first-timer's guide to Las Campanas Observatory"

Tuesday, September 22, 2015

It's a Ladies Extravaganza at Las Campanas

Sara Camnasio (left) , Haley Fica (center) , and Munazza Alam
(right) join me for a three night observing run at Las Campanas.
Tonight I report to you from a seriously female full control room at the DuPont Telescope.  I'm joined by three undergraduate students who work with my Brown Dwarf New York City (BDNYC) research group.  The fantastic trio includes Munazza Alam and Sara Camnasio, two City University of New York seniors, who have been members of my group for 3.5 years!  That's right, myself Kelle Cruz and Emily Rice have been training these excellent female researchers for most of their undergraduate careers.  And now they are ripe and ready for graduate school.  Both will be applying for programs or fellowship opportunities this fall.  Sara has an interest in the intersection of Science and Art and Munazza will do traditional Astronomy PhD programs.  They have both made their way here to Las Campanas with National Geographic Young Explorers grants.  Rounding out the fantastic three is Haley Fica who joined my team this past summer.  She is currently a junior at Barnard college and earned this trip because she spent two months reducing FIRE data for an upcoming exciting paper I have on the edge of submission.  On this run we are obtaining parallaxes for young brown dwarfs using CAPSCam on the DuPont and then parallaxes for cold brown dwarfs using FourStar on Baade and spectra for a potpourri of objects using FIRE.  Stay tuned for some posts from my female crew as we adventure through the land of (current) high humidity, high winds, and earthquakes.


Monday, September 14, 2015

Classical vs. queue observing - a radio-turned-optical perspective

As a radio-turned-optical astronomer (I fully embrace the dark side now), I wanted to write about observing schemes. In astronomy, there are two main schemes to observing, classical and queue observing.
Edwin Hubble classically showing us how it's done
Classical observing
An astronomer submits a proposal for a certain number of nights at a telescope. Upon proposal acceptance, the astronomer is scheduled to run said telescope for a certain number of nights. On those nights, the astronomer has complete control of what the telescope looks at. This is the much older-school way to observe (think: Edwin Hubble).
Pros: spontaneity, ability to change observing strategies “on-the-fly”, a deeper relationship with the instrument.
Cons: one must travel to the site, which can be very remote, no guarantee that you will get any data (it could be too windy, too cloudy, an instrument could have had problems…) without the ability to make up for the lost time. And you are going to be completely flipping your sleep schedule.

Queue observing
The CARMA array at Cedar Flat, purely queue based
An astronomer submits a proposal to observe a certain set of sources. Upon proposal acceptance, the astronomer sets up the observing strategies / scripts and submits them to the telescope. Staff experts check the script, and submit the observations to a common queue to be observed in order of priority, optimizing the telescope itself to take the most data.
Pros: If you have a high priority project, you are very likely to get your data, without a dependence on the weather. Experts set up the telescope for you to optimize the telescope for your particular science goals, you do not have to travel to the remote site (in the case of Hawaii, this might also be considered a con…)
Cons: Basically the same as the pros of classical observing. You are not able to change your mind about sources, and you won’t have a personal relationship with the telescope when you are reducing your data.

For decades, the radio astronomy community has favored a queue observing format, partially because understanding an interferometer like the Very Large Array is highly complex, and usually takes many years to truly understand how the data go from acquisition to publishable. Because of this, only a few people were able to dedicate the time it took to have a personal relationship with the telescope. I served enough shifts at the CARMA array (RIP…) to understand the special pitfalls and quirks, but it took me years. In these cases, the queue observing is likely the best method. This is how ALMA works - they hire experts that have a personal relationship with the ALMA telescope to write your observing scripts and reduce your data for you. At the same time, something special seems to be missing.

The 6.5m Baade Telescope at Las Campanas Observatory
Magellan on the other hand is a pure classical instrument. If you are awarded time, you will be flying to Chile and staying at Las Campanas. Currently, I am spending time at a summer school for the IRAM 30m, a single-dish millimeter telescope located in the Sierra Nevada in Spain. The 30m is a hybrid, where you propose for sources which go into a queue, but also has an on-site option, which is currently how I am using it. In both my recent Magellan run as well as this current IRAM run, I am really glad we were classically observing, because the spontaneity was essential. At Magellan, I looked at my final source of the run, and realized that it was not as interesting as I thought it was, so I dropped it. So all of a sudden, I had 2 free hours of 6.5m time and needed something to do. I took to Twitter and Skype to chat with my collaborators, and we decided that it made a lot of sense to get a spectrum of a mysterious clump located to the northwest of the nucleus of the galaxy I had already observed, so we to get a spectrum of the clump, requiring a longer integration. Because we had that flexibility, it is possible I found something new and novel.

At the 30m, a similar thing happened. We are observing CO lines to try to determine the redshift of a submillimeter galaxy. We had a few guesses as to where the lines might be, but were blown away at how bright it was when we found the correct redshift. Instead of taking an hour to get the line, we needed only 15 minutes! So, what to do with the last 3 hours of the night… if this was queue observing, we would have had one amazingly high signal-to-noise spectrum of one line. Instead, we zipped back to our other possible lines, switched the observing strategy to detect more lines in the forest, and even attempted to detect other fainter lines (and succeeding). Instead of one “the redshift of this thing is z=XX”, we now have the possibility to publish a paper with a CO SLED, and astrochemical analyses from the additionally detected lines.
Me in front of the IRAM 30-meter single dish in the Sierra Nevadas in Spain
In an era where we are seeing classical observing facilities go extinct in favor of queue observing, I think we need to recognize what we might be losing. As a radio astronomer who was raised as a queue observer, it was my experience on a radio telescope classically observing that has motivated my call to keep the option of classical observing - you never quite know what you are going to get!