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Sensitive Barometers of Galaxy Formation

Sensitive Barometers of Galaxy Formation. Benjamin D. Oppenheimer Leiden Observatory. Simone Weinmann , Romeel Dave, Kristian Finlator , Jason Tumlinson , Rob Crain & others. Are Flat or Rising Star Formation Histories in Dwarfs (Low-Mass Centrals) Required?.

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Sensitive Barometers of Galaxy Formation

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  1. Sensitive Barometers of Galaxy Formation Benjamin D. Oppenheimer Leiden Observatory Simone Weinmann, Romeel Dave, KristianFinlator, Jason Tumlinson, Rob Crain & others

  2. Are Flat or Rising Star Formation Histories in Dwarfs (Low-Mass Centrals) Required? Main Sequence Integration- Leitner (2012) VESPA SSP Modelling- Tojeiro et al. (2009) Abundance matching- Behroozi et al. (2012)

  3. Stellar Mass Assembly Histories Are Diverse, DM Accretion Histories Not So Much SFHs independent of ΛCDM dark matter assembly are difficult to reproduce in SAMs and simulations (Weinmann et al. 2012). Behroozi, Wechsler, & Conroy 2o12

  4. Simulated and SAM SFHs Assemble Dwarfs Way Too Early (It Seems). “The overproduction of low-mass galaxies at z > 0.5 in all SAMs and hydrodynamical simulations explored here may thus be symptomatic of the limited range of feedback prescriptions currently in use, and indicates that alternative models of feedback need to be explored.” --Weinmann et al. (2012) Weinmann et al. (2012)

  5. Wind Mode: A Way to Separate SFHs from DM Accretion Histories? Opp. et al. 2010 Opp. et al. 2010 AllAssembly w/ wind mode W/O Wind Mode We separated stellar assembly based on whether stars formed from pristine, cold accretion or re-accreted winds accreted from the circumgalactic medium (CGM).

  6. Recycling Winds Assembles Mass in Dwarf Centrals at Late Times M*=109.27-109.77Msol Opp. et al. 2010 Opp. et al. 2010 AllAssembly w/ wind mode W/O Wind Mode Weinmann et al. (2012) Wind recycling is a way of moving stellar mass assembly to late times via cycles through the circum-galactic medium (CGM).

  7. The Money Plot… Literally. Oppenheimer-style resolution of the same 1011.2Msol halo 129 orbits to observe the CGM of z=0-0.1 dwarfs at 20-150 kpcs (PI J. Tumlinson)

  8. We Are Searching for the Baryons Missing from Stellar Assembly in Dwarf Halos No Winds: No Metals in CGM, most baryons form into stars. Fast Winds: 700 km/s blows most baryons out of CGM, only a cool few metals left behind Momentum-driven Winds: slower winds, 100-200 km/s, keep baryons recycling and participating in galaxy formation, plenty of cool metals.

  9. REAL DATA NEW RESULTS!!: CIV Covering Fractions From COS-Dwarfs Thanks to RongmonBordoloi & Jason Tumlinson.

  10. ezw is the new vzw* CGM CGM CGM Energy-conserved feedback (ezw) where vwind ~ σ, η ~1/σ2where low-mass galaxies are suppressed more than momentum-conserved feedback (vzw): η ~ 1/σ. Missing baryons are ejected into the CGMs of these halos. *Let’s hope not.

  11. More Mass-Loading for Dwarfs Could Alter Stellar Assembly Histories vzw: η ~ 1/σ ezw: η ~ 1/σ2 Macc×fb Msfwind Msfcold 1Gyr 1Gyr 14 Gyrs 14 Gyrs Early winds suppress SF relative to baryon accretion rate. Returning winds that recycle on timescales of Gyrs add to late time stellar assembly, increasing late time specific SFR’s.

  12. Wind Recycling is Capable of sSFR Downsizing Wind recycling returns material back onto dwarf galaxies raising the sSFR’s for lower mass galaxies at late times (z=0).

  13. Mystery of Galaxy Formation May Be Solved “I think it's possible that Simone's dwarf SFH problem will disappear given the new wind model plus the new faint-end data which is steeper at high-z.” --RomeelDavé

  14. Diversity in Star Formation Histories is Possible Via Wind Recycling Cold Mode Hot Mode Wind Mode

  15. Diversity in Star Formation Histories is Possible Via Wind Recycling Cold Mode Hot Mode Wind Mode

  16. Summary Points • The shallow potential wells of low-mass halos are very sensitive testbeds for feedback processes affecting galaxy formation. • We are banking on finding a large fraction of the low-mass halo missing baryons in their local CGMs, where launched winds can re-participate in late galaxy formation. • Putting in 2-3 new, non-traditional parameters into SAMs (e.g. recyling parameters) should be able to divorce stellar assembly histories from dark matter accretion histories and reproduce most key observations of low-mass galaxy formation.

  17. New Tests for Galaxy Formation Models Patel et al. (2013)

  18. Are our simulations building the right galaxies in the right halos at the right time? Behroozi et al. 2012: star formation rate divided by baryon accretion rate for halos of various masses from z=8->0.

  19. Are our simulations building the right galaxies in the right halos at the right time? Behroozi et al. 2012: star formation rate divided by baryon accretion rate for halos of various masses from z=8->0.

  20. Are our simulations building the right galaxies in the right halos at the right time? Behroozi et al. 2012: star formation rate divided by baryon accretion rate for halos of various masses from z=8->0.

  21. Are our simulations building the right galaxies in the right halos at the right time? Behroozi et al. 2012: star formation rate divided by baryon accretion rate for halos of various masses from z=8->0.

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