October science update: Part I
Hello world,
This past month was packed full of fun things to share with y'all. Because there is a lot to share, this newsletter will be split into 2 segments: Part I. Recent happenings and Part II. Data.
Observing at the Green Bank Telescope
Just last week a large group of us met in Green Bank, West Virginia. Green Bank, WV is in the middle of a national radio-quiet zone (no cell phones, wifi, etc. allowed), and as you might imagine, it is located in a very rural part of the country. To get there, you fly into the nearest metro airport then have a 2+ hour drive down windy roads with small farms scattered about the countryside here and there (and quite a few of the biggest Trump signs I have ever seen!). We met at Green Bank to make the first observations of our star with the world's largest steerable radio telescope at the Green Bank Observatory. Long story short, check out the Berkeley press release that describes these special observations, and includes a couple short videos. A few hours before the observations started, Jason Wright, Andrew Siemion, and I did a live chat answering questions about the project (watch the archived video here).
Before the observations took place, we talked about a observing strategy (details are too long for this report, perhaps I will expand upon it in another round). Basically, along with observing the science target, we want to observe other sources to make sure that the instrument is working the way we expect it to work (sanity check) and also to calibrate the science target data. Our sanity check was Mars!! This means that we pointed at Mars and took data on it just like our target (and we made up the verb: #marsing). At the end of the night we were able to do a quick look at the Mars data, and uncovered Martian signals! The signal not from native Martians of course, but from one of the Mars orbiters (or rovers) that was broadcasting back to Earth (we weren't able to figure out exactly which one we detected).
The observing control room itself is really cool - you are basically in a giant Faraday cage thats purpose is to confine all radio interference so that it wont be picked up by the detector (which is located about a mile away). While the observatory control room is quite large, that night it was so packed it was mostly standing room only (which doesn't sound so bad until you factor in the observations were taken all night until 4am). Amongst us astronomers making the observations were the trio mentioned above, plus a handful of students, postdocs, and engineers of the new Breakthrough instrument, the telescope operators, and some additional staff who were just curious. There was also the Atlantic reporter, Ross Anderson (and his 7 year old son!). We have him to blame for breaking the story of the star's mystery to the world just about a year ago to-date :). Finally, a film crew from the BBC Horizon documentary series was also present taking footage of the whole ordeal (we will be sure to post when the show comes out! You will then realize how packed the room was...). All-in-all, a major success! One final thing I would like to mention before I change topic is that Jason Wright will make all the data from this radio SETI project public! (There are a _lot_ of data here. Jason will keep you posted on these logistics.). Here is a pic of us the morning after the observing (Left to right: Drs Andrew Siemion, Tabby Boyajian, Jason Wright, Danny Price, Dave Macmahon).
Notable travel and workshops
I also attended two workshops since the last update. The first was workshop on stars known as "dippers". Yes, there are other stars that show dips that are ~somewhat~ similar to our star, but they all can be explained by some sort of orbiting disk of material. This theory is supported by those objects having an infrared excess. However our star has no detectable excess in the infrared, and thus the mystery persists. There were some amazing presentations and conversations to be had with experts in the field. I gave the keynote lecture presenting on WTF. Among the participants were three other scientists that have worked on WTF, and I managed to wrangle us for a photo in the local pub (Left to right: Drs Grant Kennedy, Mark Wyatt, Tabby Boyajian, and Eva Bodman.).
I had never met Grant and Mark in person, despite writing the discovery paper with them #ScienceIsGlobal. One notable activity to mention is that we special session on our star where the leading task was "explaining the dips *and* dimming without aliens". And hey - there were some good ideas that came up and are being worked though in more detail now - so stay tuned! BTW, its always a good idea to have a current passport at all times, just in case...
The second workshop was on "Hotwiring the Transient Universe" where I learned all about the ins-and-outs of time-domain astronomy from the worlds leading experts. The main issue I wanted to discuss was how to set up a fail-safe alert system while minimizing the probability of triggering on a false alarm. This is important to our program because we are collecting data with the intent to catch the star when it starts to dip again. When it is seen to dip, we will then send out alerts for intense monitoring and more detailed observations. But at what threshold do we call a dip detection? We don't want to have the threshold too sensitive, or it might trigger on outliers (all data sets have outliers for one reason or another). Then again, we don't want it too miss a possible significant event because we had the threshold too high. Our current plan of action is to look for three consecutive outliers that fall below the mean at the 5-sigma level. We know from the Kepler data that the dips last for a day or more, so this is sufficient to catch a real detection and have time to perform follow-up. As our pipeline improves over time, we will be able to modify this strategy to best suit our science goals. It is important to remember that our LCOGT observing strategy is to observe the star's brightness in multiple colors, which even by itself provides us with very valuable information on what is passing in front of the star. BTW, here's a shot of the LCO staff and I from the conference. (Left to right: Drs Nikolaus Volgenau, Curtis McCully, Ida Snyder, Tabby Boyajian, Rachel Street, Tim Lister, Sarah Greenstreet)
Lastly, I took a day away from the HTU-V workshop to visit Lehigh University to see a few colleagues and also to give a colloquium. I also got a chance to meet Roger Wehbe (a Kickstarter project backer who also does a tremendous amount of work moderating the star's sub-reddit. He also put together this nifty AAVSO dip notification tool) who works just across the street from the Lehigh campus, and was able to come to the colloquium and join us for dinner afterwards. Unfortunately we forgot to take a picture! Speaking of, I would be delighted to have the chance to meet with any of you if the opportunity presents itself. If you are ever in Baton Rouge, or if I am visiting your hometown, don't hesitate to reach out and connect in person!
I am now observing with the CHARA Array at Mount Wilson Observatory, where I have been several dozen times over the past decade. Nights this time of year are very long in the northern hemisphere, and this week has been exceptionally clear (so much that the LA harbor and freight ships in the Pacific were visible from the mountain top). So, we got lots of good data, but not a lot of sleep - I am OK with that!
It is not typical that I travel as much as I have in the past month, and I have learned the true meaning of exhaustion by managing this hectic schedule. But its the satisfying kind of exhaustion, because each activity has provided valuable knowledge, experience, and awareness for this project, all which are an important contribution to the advancement of the science we are doing.
