text: 153,97,1251148473354731521,742027674403672064,Johnny Greco,"🚨PAPER ALERT🚨  How far is a galaxy? Almost everything we want to know about it depends on the answer. In our new paper, we take a deep dive into the theory and feasibility of measuring distances to diffuse dwarf galaxies using *imaging data alone*: <LINK> <LINK> We use surface brightness fluctuations, which arise from pixel-to-pixel Poisson fluctuations in the number of bright stars in a galaxy image. The more distant the galaxy, the smaller the fluctuations. The effect is shown in this fig. Ω = resolution element. #DistancesAreHard <LINK> @rareflwr41 For you, anything🙂here's another: <LINK> We compare our calculations to observations of dwarf galaxies with independent distance measurements based on the TRGB. Single-age stellar pop models are in good agreement with red dwarfs, but blue dwarfs are more consistent with composite stellar pop models. #DistancesAreHard <LINK> To study SBF in practice, we inject artificial galaxies star-by-star into images from the #HyperSuprimeCam survey using one of my favorite tools: #ArtPop! @DanieliShany #DistancesAreHard  👇👇👇👇 <LINK> There’s more, but I’ll end with an exciting plot for the future. LSST will be capable of measuring SBF distances to dwarf galaxies out to ~25 Mpc! HUGE thanks to my amazing collaborators @DokkumPieter, @DanieliShany, Scott Carlsten, and Charlie Conroy! <LINK> <LINK> @dstndstn Thanks, Dustin! That means a lot coming from you.  Not naive all -- You want as many resolution elements as possible, so my expectation is that you want GOOD seeing (and you need to understand your PSF). And for the regime we are interested in, we are already short on pixels! @BenneHolwerda <LINK> @BenneHolwerda You mean for the gif? I certainly can! @rareflwr41 wanted one too, so I can make a higher resolution version and put it somewhere public. But we are working on making ArtPop open source sometime soon-ish so you can make one too! @JohnFeldmeier Thank you 🙏",https://arxiv.org/abs/2004.07273,"We present an in-depth study of surface brightness fluctuations (SBFs) in low-luminosity stellar systems. Using the MIST models, we compute theoretical predictions for absolute SBF magnitudes in the LSST, HST ACS/WFC, and proposed Roman Space Telescope filter systems. We compare our calculations to observed SBF-color relations of systems that span a wide range of age and metallicity. Consistent with previous studies, we find that single-age population models show excellent agreement with observations of low-mass galaxies with $0.5 \lesssim g - i \lesssim 0.9$. For bluer galaxies, the observed relation is better fit by models with composite stellar populations. To study SBF recovery from low-luminosity systems, we perform detailed image simulations in which we inject fully populated model galaxies into deep ground-based images from real observations. Our simulations show that LSST will provide data of sufficient quality and depth to measure SBF magnitudes with precisions of ${\sim}0.2$-0.5 mag in ultra-faint $\left(\mathrm{10^4 \leq M_\star/M_\odot \leq 10^5}\right)$ and low-mass classical (M$_\star\leq10^7$ M$_\odot$) dwarf galaxies out to ${\sim}4$ Mpc and ${\sim}25$ Mpc, respectively, within the first few years of its deep-wide-fast survey. Many significant practical challenges and systematic uncertainties remain, including an irreducible ""sampling scatter"" in the SBFs of ultra-faint dwarfs due to their undersampled stellar mass functions. We nonetheless conclude that SBFs in the new generation of wide-field imaging surveys have the potential to play a critical role in the efficient confirmation and characterization of dwarf galaxies in the nearby universe. ","Measuring distances to low-luminosity galaxies using surface brightness