In my post conference fog as I boarded the tube in London following #dwarfgalaxies2024 I almost completely blanked a fellow attendee! Took my tired brain a few minutes to recognise a fellow dwarf galaxy fan ✨ my bad 🙈. Too much awesome science floating around 🧠
#dwarfgalaxies2024 but, this is probably to do with dust implementation. Then, model agrees up to z~14. These brightest galaxies were living in dwarf halos. Now in much more massive ones.
#dwarfgalaxies2024 dwarf galaxies are important for both galaxy formation physics and dark matter physics. When Carlos first showed simulations of galaxies forming by mergers, someone threw a shoe at him. It was his friend though, so it's ok.
#dwarfgalaxies2024 Carlos Frenk: once a shoe was thrown at him for suggesting that galaxies have significant mergers!
Bringing #dwarfgalaxies2024 to a close we have the inimitable Carlos Frenk! He covers pressing questions and future prospects. One pressing questions is why isn't his side show full screen? The organising team leaps into action to solve this. Moving on!
#dwarfgalaxies2024 6/24 (25%) of the HI dwarfs are in pairs, compared to 5% in optical spectroscopic surveys, which may be biased against dwarfs due to fiber collisions. Preliminarily, ~10-13% of galaxies have a companion (2x higher rate than SDSS).
#dwarfgalaxies2024 standard dwarfs follow the baryonic Tully fisher relation but UDGs are slightly offset. Also 6/24 galaxies are in close pairs. Higher fraction than you see in optical surveys. Probably as there are lots surface brightness.
#dwarfgalaxies2024 Barbara Siljeg: the HI APERTIF survey is 2200 sq deg but with 15"x15" spatial resolution instead of one galaxy at a time. Get 24 galaxies with MHI < 10, logMstar < 9, at least partially resolved. Though not yet fully resolved, they lean away from the BTFR.
#dwarfgalaxies2024 has our last speaker before the closing talk, given by Barbara Silijeg. She's talking about dwarf galaxies in the Apertif HI survey. They have collected 24 isolated dwarfs with resolved HI data that bridge the gap from normal galaxies to gas rich udgs. 1/3 sample are UDGs.
#dwarfgalaxies2024 J0139+4328: a HI detection in FAST, 4e6 in stellar mass but 6e7 Msun in gas. What is the Mbary-Mhalo relation (instead of Mstar-Mhalo)?
#dwarfgalaxies2024 also discusses finding a stellar counterpart to the claimed dark galaxy from FAST. Very faint, but has a very large HI mass (comparatively speaking). What does this tell us about the Mbary-Mhalo relation (which isn't measured yet)
#dwarfgalaxies2024 Betsy Adams: HI is great, highlights HI detections of UDGs/redshifts and SHIELD result that several galaxies have no Ha but significant HI/FUV: No Ha is no O stars, not no star formation.
#dwarfgalaxies2024 alfalfa HI survey revealed a population of ultra diffuse, gas rich galaxies. Some of them seem to have mad crazy halos. SHIELD survey has found an interesting population of star forming dwarfs with no Halpha! So no Halpha !=quenched
Betsey Adams is next with dwarf galaxy populations as revealed by neutral gas #dwarfgalaxies2024. She is here to remind us that there is more to dwarfs than stars. They have gas too, you know 😉HI is a beautiful tracer of low mass galaxies.
#dwarfgalaxies2024 public data release planned 2025!
#dwarfgalaxies2024 main science driver is ultra diffuse galaxies. They find them and then follow up with Keck. They can also produce a Galactic cirrus map.
#dwarfgalaxies2024 Will Bowman: Dragonfly Ultrawide Survey search for LSB galaxies. An amazing image here of cirrus. The data storage/reduction is done in the cloud on AWS (costs ~$100s/month, few $1000s for full reduction for 20k core hours or a few days wall time)
William Bowman follows on with news about the dragonfly ultra wide survey #dwarfgalaxies2024 this survey has been running since 2019 and it's 91% done. They're using Amazon web services for data processing and storage, you bring your code to the data, which is all the rage these days (e.g Rubin)
#dwarfgalaxies2024 Sarah Sweet: how to find local group analogues, what properties matter, and how typical is it? Getting gas observations of dwarf galaxies of LG analogues at 10-30Mpc and mock catalogs of DG analogues.
#dwarfgalaxies2024 highlights some work selecting 5 local group analogues to search for satellites. They have between 2-11 satellites. Studying them in more detail will let us know how typical our LG is
We are into the final session of #dwarfgalaxies2024 and we begin with Sarah sweet who asks how typical is the local group? Can we design equitable methods to compare more distant systems to the LG (and simulations).
#dwarfgalaxies2024 Daniel Piacitelli: studies simulated CGM of dwarf galaxies
Ryoungwook Kang: compares numerical/feedback choices in GADGET vs RAMSES for high-z simulations
#dwarfgalaxies2024 poster flash talks:
Kyle Oman: many different effects can mess up gas rotation curves
Pierre Thibodeaux: shows how spectroscopy can distinguish star clusters from small dwarf galaxies
Elham Saremi: new pipeline for VISTA K band images preserving LSB structures
#dwarfgalaxies2024 Viraj Manwadkar adds chemical evolution to the GRUMPY dwarf galaxy formation model (including stochastic IMF and IGM sampling). Can broadly reproduce MW satellite population chemistry just based on the default model without any tuning.
#dwarfgalaxies2024 mass metallicity relation very sensitive to feedback and this is also degenerate with yields. You can break this degeneracy by jointly looking at the satellite luminosity function.
Now we have Viraj Manwadkar on a detailed chemical abundance model for dwarfs. #dwarfgalaxies2024. His work uses the GRUMPY dwarf galaxy model which is a bathtub/regulator model for dwarfs. Can it be used to model dwarf galaxy chemistry? This is what Viraj is trying to do.
#dwarfgalaxies2024 Zhu also ran hydrodynamical simulations showing that the CGM of dwarf galaxies is removed very quickly and leaves CGM tails (that form HI but not stars).
#dwarfgalaxies2024 Jingyao Zhu: new spatially resolved HI survey with WALLABY and MHONGOOSE. With DR1 see that some hosts have very high numbers of HI-rich satellites.
#dwarfgalaxies2024 idealised simulations also shows that it's really easy to ram pressure strip the CGM from a dwarf galaxy.
Now we have Jingyao Zhu on gas and stripping in small satellite galaxies #dwarfgalaxies2024. Using WALLABY and MHONGOOSE survey, you can see that low mass galaxies have a range of gaseous satellites. 10% have 0-4 and 10% have 4+! What's going on with the latter?
