I'll be doing some minor tweeting for #AstroBowl. I am on the @OSUPhysics and @OSUAstro faculty, a member of @osuccapp , and a 2002 graduate of the @uwastronomy and UW physics (why no twitter?) departments. Stay tuned for more about my group, @HowWeScience !
TBH, I have no idea when the game starts today. My husband and son are out at @COSI today, I'll be setting up my course website (intro E&M for engineers) while tweeting.
I am a physicist who uses the tools of theoretical physics and astronomy to learn about the fundamental physics of dark matter. What is dark matter? #AstroBowl (1/N)
That's what I want to know. We know a lot about dark matter, except for what it actually is. Dark matter is probably some new form of matter, but it could also be a bunch of black holes. Ask @AstroKatie or @BradleyKavanagh about black hole dark matter. #AstroBowl (2/N)
Most of what we know about dark matter comes from astronomy. Lab experiments have been able to tell us what dark matter CAN'T be, astronomy tells us what it MIGHT be. For more on lab searches, see @lbaudis, @profcooley, @ADMXDarkMatter, @physicsmatt, @IBJIYONGI #AstroBowl (3/N)
Please add your lab search experimentalists + theory friends to the list if you want! I don't know who all is on Twitter, and would love to know.
From astronomy, we know pretty precisely how much dark matter there is in our Universe. That's useful because dark matter has to be born some way. The amount of it is a clue to its origin story. #AstroBowl (4/N)
How much of it is there? A lot! This cupcake is the Universe. Most of the Universe behaves strangely--we call it ``dark energy". Gas, dust, stars, planets, people are lightly sprinkled on top. Dark matter is the frosting that holds all that stuff together. #AstroBowl (5/N) 
There is about five times more dark matter than there is the type of matter that makes up everything we see (astronomers call it "baryons"). Dark matter is the glue that holds galaxies together. Without it, there would be no us. #AstroBowl (6/N)
``Dark matter" is really a misnomer. When physicists say that something is dark, what they mean is that it absorbs light. As @IBJIYONGI and others remind us, "dark" matter is really invisible matter, because it doesn't interact with light (basically at all). #AstroBowl (7/N)
And from astronomy, we can quantify what "doesn't interact with light basically at all" means. There's been a lot of excitement about the EDGES experiment and its implications for dark matter. Check out @astrobites, a grad student run blog, for their take. #AstroBowl (8/N)
From astronomy, we also know that dark matter can't be too "speedy", otherwise it wouldn't be able to clump together to form the birthplaces of galaxies. Constraining the speediness of dark matter is something @stacyyckim and I care about. #AstroBowl (9/N)
How do we constrain speediness? The speediness determines how many clumps, called ``halos", exist as a function of mass. If we knew how to associate galaxies with halos, we could take a census of galaxies (especially tiny ones) to take a census of halos. #AstroBowl (10/N)
For big galaxies, @OSUAstro's David Weinberg and @RisaWechsler's groups have changed the game on linking galaxies with halos. Much excitement now focuses on tiny galaxies, where the effects of speediness are expected to be biggest. #AstroBowl (11/N)
Two problems with tiny galaxies: we don't know how many there are, and we don't know how to link them with halos. @fdmtweets, @MBKplus, @jbprime, and others are using giant simulations for the latter. My group uses (semi-)analytic tools w/@abensonca, @annafrebel #AstroBowl (12/N)
We have to find tiny galaxies too! We @HowWeScience are mining existing data and getting new data with #MADCASH to find them. Three students (incl. @BonnEllywick) and @NSF fellow @johnnypgreco focus on searches. A fourth is finding them statistically w/@amn3142 #AstroBowl (13/N)
I've got to take a break to start dinner and check the score. My husband is taking one for the team to keep our overtired and highly energetic kid distracted so I can have some quiet time. I owe him a good dinner!
And I'm back! What we are really looking forward to is @LSST, which will map out the sky in incredible detail to find tiny galaxies. We'll need more data to confirm those tiny galaxies (actually a huge issue), so there will be fun times for the next decade! #AstroBowl (14/N)
Below some mass scale, halos are not expected to have galaxies in them. For such small halos, we rely on the bending of light, "gravitational lensing", to tell us where small halos are. This field is busting open. Check out @amn3142 @lamoustakas @CoraDvorkin #AstroBowl (15/N)
My group (including @stacyyckim) in collaboration w/@abensonca @lamoustakas @amn3142 @CyrRacine (sorry, should have added you above, forgot you were on twitter!) are making predictions for next-gen experiments. New field for me, very exciting! #AstroBowl (16/N)
The speediness of dark matter can also affect how matter is distributed in halos. Also, if dark matter is part of a rich "hidden sector" (something like our Standard Model but not connected to us by electromagnetism), it can affect the matter distribution #AstroBowl (17/N)
We used to think that these signatures would be pretty striking. The work done by @fdmtweets, @ReadDark, @MBKplus, @jbprime and others shows that the effect is more subtle because of BARYONS. Turns out even small galaxies can fling around dark matter. #AstroBowl (18/N)
There are a lot of other ways that novel dark matter physics can affect the distribution of matter in the Universe. @stacyyckim and I worked on simulations of collisions of galaxy clusters to find hints of dark matter collisionality. That's just one example. #AstroBowl (19/N)
Check out my review article w/@physicsmatt where we summarize more. I've been so excited about the explosion of cool ideas in the field, even since we wrote that! adsabs.harvard.edu/abs/2018PhR...… #AstroBowl (20/N)
As usual, the Milky Way (and to a lesser extent, Andromeda) are inspiring people because it is close. There's awesome work on using the veil of stars, the stellar halo, of the Milky Way to illuminate dark matter physics @adrianprw @NealWeiner @anabonaca #AstroBowl (21/N)
People are using @ESAGaia in creative ways for astro dark matter searches! Even ways you wouldn't think of, like finding more strong lenses that might reveal small dark matter halos. #AstroBowl (22/N)
I am so impressed by the many creative uses of data. I wish I had more time to think deeply about more novel approaches. #AstroBowl (23/N)
As @BenneHolwerda pointed out, we can also use gravitational lensing to link galaxies with halos, but that becomes hard for small halos, which are not very great lenses. Still, people are thinking about how low we can go with next-gen instruments. #AstroBowl (24/N)
For hints of dark matter physics from halo structure, knowing the halo mass is critical to interpreting results. One of the big open issues for the next generation of surveys. You can see how important it is with the controversy over @DanieliShany's ONE GALAXY. #AstroBowl (25/N)
The other type of very important astro method is to look for the feeble interactions of dark matter with luminous matter. @IBJIYONGI and @gulesrabulbul are experts on using x-ray experiments to look for axion and sterile neutrino dark matter. #AstroBowl (26/N)
And @osuccapp 's @trlinden is an expert at using gamma rays with @NASAFermi to find annihilating dark matter within the Milky Way's neighborhood. #AstroBowl (27/N)
.@trlinden, @osuccapp director John Beacom, @osoccapp students and alums and I are working on solar dark matter searches. We found that the Sun had RIDICULOUSLY UNEXPECTED gamma-ray emission, which makes searches harder. We are accidental solar physicists now. #AstroBowl (28/N)
We collaborated with the @HAWC_Obs on limits on dark matter during the last solar maximum during their first three years of operation. Check it out! adsabs.harvard.edu/abs/2018PhRvD.… #AstroBowl (29/N)
For physicists, a good place to start about the gamma-ray Sun is adsabs.harvard.edu/abs/2018PhRvL.…. If you aren't a physicist or don't want to go that deep (thanks, @SuperASASSN), I recommend @ShannonWHall's scientificamerican.com/article/the-su… and @emcconover's sciencenews.org/article/strang… #AstroBowl
That's it for me for a bit, the dudes are on their way home and it's time for us to eat. The cats already ate.
Tweetstorm is part of #AstroBowl during the #RoseBowl.
