March LIGO-Virgo Meeting in Boston

So, I am at the LIGO-Virgo Meeting in Boston right now.  As you may (or may not) know, our two collaborations are very close knit.  We schedule our upgrades to be around the same time, we always share our data, and we collaborate on our science to get the most from our work.  Being a part of a big international collaboration is exciting and gives you a new perspective on international politics - in science they exist, but are much easier to deal with since we are all working for the same goal.

Here is the gorgeous view from my hotel window:

Personal Complexes:

Another thing about being one of over 800 scientists and engineers working on a project is that you can feel small.  I've written before about the Impostor Syndrome - when people who are fully qualified and competent feel inadequate.  Sometimes, these meetings bring those feelings back to me.  Every time someone comes to me and asks me what I do, I feel like my worth is being weighed.  But it absolutely isn't!  After all, I do the same thing to new colleagues that I meet and I am only interested in learning more about them and maybe working with them in the future.

I was starting to feel inferior while I was traveling here...  I was sitting at my gate during a layover and a colleague I consider a friend was sitting in his seat diligently working on his computer.  What was I doing?  Reading a vampire book.  The self-loathing voice in my head immediately chimed in with, "See, there is someone who is deserves the esteem of the collaboration.  He works hard and makes the most of his time.  What are you doing?  Reading a book about things that don't even exist!"  As I was resigning myself to mediocrity, he put his computer aside and started talking with me.  During our short conversation, he paid me the most unexpected complement.  I'm not going to repeat it here, but I was speechless and ecstatic at the same time and tried not to tear up.  I smiled and thanked him because his words forced me to think well of myself (not that I told him that).  If he is reading this, you know who you are and what you said even though you don't know how much it mattered to me - THANK YOU!

I've been trying to work more on these issues but I don't ever expect to completely get over feeling inferior to my peers.  Not that I really want to - I've met many scientists who thought they were a divine gift to science and I can't stand them (even if they are right)!

The Science:

The final data analysis from our last data run is finishing up and we've been talking about these results and preparing for the demands the MUCH more sensitive Advanced LIGO and Advanced Virgo detectors will place on our analysis infrastructure.  This has been a time of reorganization.  I gave a short talk about the functionality of the gravitational wave simulation software (called GravEn) I wrote while I was a graduate student.  This has been the standard software we've used to measure the sensitivity of of our burst data analysis methods.  We are also taking time to consider if there is a better way of doing it.  So far, it seems like GravEn is still the bee's knees and that makes me very happy!  (The science summary of the last burst data analysis paper is here.  The plots that show the sensitivity of our methods to different kinds of signals [the second and the third] were made using the simulations I produced.)

There have also been talks on the status of LIGO, Virgo, GEO, the Japanese KAGRA detector, and the status of what used to be the LISA space-based detector (this was a partnership between the ESA and NASA until budget issues forced NASA to cancel being a full partner).  There is progress being made on all of these fronts - even LISA (which is now led by the ESA and known as NGO for the New Gravitational-wave Observatory).  Every where you walk around the conference hotel, you see small groups working together on a project and a few very tall people in red uniforms (the Wisconsin Badgers are staying in our hotel for their NCAA Sweet 16 game tonight against Syracuse).

What Would YOU Like to Ask a LIGO Scientist/Engineer?

As part of a talk on the collaboration's outreach activities, this blog was featured!  (Those who don't know my science work will often still know me as the "Living LIGO Lady".)  It was also announced that I would like to feature interviews of gravitational wave people (scientists, engineers, etc.) on this blog.  When I originally started writing this, I wanted to make science human and accessible.  I feel like I am running out of human things about me to talk about (I'm not all that interesting).  But there are so many others with different backgrounds and stories that I would like to share with you.  I already have a list of questions I am thinking about asking (not all of them will be mandatory, of course) but I want to invite you to tell me what questions you would like to as a LIGO person?  Tweet them to me @livingligo or leave a comment here (below).  You can also email me at amber@livingligo.org.  I'm thinking of using my husband, a mechanical engineer for LIGO, as a Guinea pig (he can't cook and likes to eat, so I think I can convince him :P ).

Until next week!

Q: Is there anything like LIGO outside of the USA?

I mentioned before that I've noticed in my blog visit statistics that some people find my site by searching questions that they have about gravitational waves.  They show up as the search keywords (don't worry - I have no way of knowing who searched and visited this site).  Many of the questions are great and I am not sure that my blog completely answered their question, at least in a concise way.  Today, I am answering one of these "searched for" questions:

"Is there anything like LIGO outside of the USA?"

Yes!  First, let me establish that there are 2 LIGO observatories in the United States.

Why are there 2 LIGO's?

Detectors like LIGO, gravitational wave interferometers, are sensitive to gravitational waves coming from nearly any place in the sky, including the sky that's above the other side of the planet.  The fact that gravitational waves can travel through matter and come out the other side unchanged is a huge advantage over doing astronomy using different forms of light and allows LIGO to have this amazing sensitivity.  It does have the downside that, given only a single detector, we cannot tell where a detected gravitational wave came from on the sky.  So, we built 2 detectors in the United States to ensure that, even if no other countries built gravitational wave detectors, we would be able to narrow down the location of any detections. 

LIGO Livingston's sensitivity to sources coming directly above locations on Earth.  Red is the highest sensitivity and blue is the lowest.  Since this is a flat map of a spherical object, sizes are distorted.  CLICK TO SEE DETAIL.

The time it will take a gravitational wave traveling at the speed of light to travel between the LIGO Hanford and Livingston observatories in seconds.  The black line is the circle on the sky the would produce a detection at both LIGOs at the same time.  CLICK TO SEE DETAIL.

Note that I said "narrow down".  Given 2 detectors and the detection time at each, we can start to triangulate possible sky locations of a gravitational wave to a circle on the sky that corresponds to the locations that could produce the observed difference in detection time (since we expect gravitational waves to travel at the speed of light, the maximum time it would take to travel between the 2 LIGO detectors is about 0.01 seconds).  With 3 detectors we can narrow the location to 2 points on the sky and with 4 or more we can find the 1 source.  Of course, if there was an optical event like a supernova on the 2-detector sky circle that for a gravitational wave detection at the same time, it would be probable that the optical event was also the source of the gravitational wave.

Another reason to have at least 2 detectors is eliminate the possibility that a local vibration is mistaken for a real gravitational wave.  LIGO is very sensitive to vibrations from our environment.  It is possible for a passing truck or a dropped hammer near the detector to make the mirrors inside vibrate in such a way that it "looks" like a gravitational wave.  In order to avoid making mistakes like this, we do not believe that anything is a gravitational wave unless we see the same signal in both detectors within the time it would take it to travel between detectors.  Therefore, we only consider a candidate detection if we see the same signal within +/- 0.01 seconds of when the signal is seen in one of the detectors.

Now, back to the original question:

Is there anything like LIGO outside of the USA?

There are several other gravitational wave interferometers in other countries.  The Virgo detector is located outside of Pisa, Italy, the GEO600 detector is located in Hannover, Germany, and the TAMA300 and the future KAGRA (formerly known as the LCGT) is located in Japan.  LIGO collaborates extensively with all of these detectors so that any time detectors are collecting data at the same time, that data is shared.  We also share technology so that all of the detectors are as sensitive as they can be.  The more observatories that see the same gravitational wave, the better we can localize it and the more we can know about it.