Geneva Observatory, 10-12 Jan 2024
- (Pandya+ 2023) JWST CEERS "cigar" shaped high-z galaxies. Is the filamentary shape a signature of FDM or just expected high-z galaxy morphology (interacting, disks, etc)?
- Kimura+ (2021): stellar versus disk growth in simulations -> more mass in the disk after some time -> disk fragmentation
- Chon+ (2021): Flat IMF at low masses, suggesting an overabundance of massive stars
- Prole+ (2022): Studied the fragmentation differences with the sink density threshold
- Sugimura+ (2021?): It's difficult to grow stars above ~1000 Msun
- Cold flows can penerate to small radii (~0.01 r_vir) and forms a central disk. Most of the gas cools to 1000-3000 K and a small fraction enters the "zone of no return" that is warm (~10^4 K) but dense.
- When stellar feedback is included from a single Pop III star, the gas cloud re-collapses totally in the "zone of no return" and forms a SMS.
- The SMS IR radiation feedback destroys H-, preventing H2 cooling.
- A shell is launched from the SMS and part of it condenses. Claims that another SMS forms but then merges with the primary SMS.
- Maiolino+ (2023): Chandra detection of SMBH (GN-z11) at z ~ 11 with a mass of 1-3 x 10^6 Msun
- Lupi+ (2023): Finds that a heavy seed doesn't grow for 100-200 Myr and then grows from 10^5 to 10^8 Msun within 150 Myr (t_H ~ 650 Myr)
- Kimura+ (2023): Follow protostellar evolution for 150 yr (first 10 yr published in paper) after SMS birth in RHD simulations, studying the radius, luminosity, rotation, etc. of the protostar. They resolve the protostellar interior.
- ICs: BE turbulent sphere with a Mach number of 1 (constrained from Higashi+ 2021)
- Disk forms and fragments. Most of the fragments merge with the primary but has little effect on it.
- After 100 yr, the disk grows much more than the stars, consistent with their analytic model (Kimura+ 2021). The primary star is still bloated under a complex accretion history in 3D simulations, confirming the predictions from 1D calculations.
- They define the protostar where the pressure forces dominate over centrigual forces, which happens within 40 AU.
- 3D simulations have higher entropy (i.e. higher temperatures) in the cores than 1D calculations. The temperatures are about an order of magnitude higher than the 1D case.
- Toomre Q is on average above 1, but there always exists regions less than 1 (unstable)
- Rotational axis follows the AM vector of the accreting gas.
- Prole+ (2021?): No correlation between the sink particle mass and various halo properties and LW intensity.
- If the Pop III IMF is insensitive to J21 and halo mass, there should be a universal Pop III IMF.
- When studying atomic cooling halos, they found more fragmentation than minihalos, but massive stars still form.
- More massive star: R136 in the LMC. A binary of ~230 and ~170 Msun (Crowther+ 2010, 2016; Kalari+ 2022)
- Line-driven winds review (Vink 2022). dM/dt = f(Z, L, M, T_eff) = f(Gamma) =
$\kappa L / (4\pi c G M)$ , see Vink+ (2011). - As the star gets closer to the Eddington limit, the HeII lines transition from absorption to emission and become stronger with mass.
- Sabahit+ (2022, 2023) included this effect into MESA.
- GN-z11 has strong nitrogen lines. Can be explained by cWR stars (Kobayashi+ 2023); SMS (Charbonnell+ 2023), or VMS winds (Vink 2023).
- (Sabahit+ 2022; Higgins+ 2022) VMS mass is a strong function of mass, but zero-metallicity stars have much weaker winds. Iron provides the majority of the opacity.
- (Vink+ 2021; Winch+ 2024) Explaining 85 Msun BH from GW19XXXX with weaker line-driven winds in low-Z stars with MESA. The upper limit at low-Z is ~93 Msun.
- (Latif+ 2024) Radio emission from the first QSOs out to z~15, which can be correlated with detections with RST and Euclid.
- (Rossi+ 2021) Low-mass end: the lack of low-mass stars in UFDs sets a lower limit of the characteristic mass at 1 Msun, excluding the present-day IMF at a 99% confidence level. If no metal-free stars are observed by ELTs, then the characteristic mass lower limit increases to 5 Msun.
- (Vanni+ 2023) To explain CEMPs stars, need low-energy Pop III SNe, i.e. hypernovae with higher Fe and sub-solar [C/Fe] yields.
- (Koutsouridou+ 2023) NEFERTITI SAM code. They explored the effects of differing Pop III IMFs and SN energy distribution functions. The CEMP stars are most likely true 2nd generation stars enriched from Pop III low-energy SNe.
- (Pagnini+ 2023) Effects of an incomplete sampling of the IMF in low-mass galaxies.
- (Koutsouridou+ 2024) Chemical pollution from a massive PISN is required to explain a particular CEMP star (J1010+2358). They constrained the Pop III IMF's peak mass and slope to a linear relation bounded by m_ch/Msun = 191.16x - 132.44 and 143.21x - 225.94, where x is the slope.
- If the critical accretion rate (~0.04 Msun/yr) is surpassed, the model migrates to red within the KH time.
- (Nandal+ 2023) Chemical transport in Pop III stars. CNO can be transported to the outer layers.
- (Li+ 2021) SAM for QSO progenitors, including Pop III SF. Some of the most rare progenitors breach T = 10^4 K as early as z=50!
- (Toyouchi+ 2023) 3D RHD simulations of SMS formation. ICs from Wise+ (2019)! Finds that the final mass is 3e4 Msun with the star fluctuating between red and blue. Finds that the Pop III IMF can continue to 1e5 Msun with a slope of -1.3.
- (Toyouchi+ 2021) With a dust accretion disk, super-Eddington (up to 100) accretion rates are possible.
- (Inayoshi+ 2022ab) Post-processed 2D RHD simulations with CLOUDY to obtain time-dependent spectra and thus colors and detectability.
- (Klessen & Glover 2023) First stars review.
- (Schauer+ 2021) Analytic fit for Pop III minimum halo mass as a function of J_LW and streaming velocity.
- (Shu 1977; Girichidis+ 2011) The accretion rate depends on the number of Jeans masses in the collapsing system,
$dM/dt = m_0 c_s^3 / G$ , where$m_0 \propto A^{3/2}$ with$A \propto N_J^{2/3}$ so that$m_0 \propto N_J$ . - (Reinoso+ 2023) Showed that heavy BH seeds form through stellar mergers within clusters, not a single SMS. There are a few SMSs that grow to
$> 10^4 M_\odot$ .
- (Higgins+ 2023) Grid of MESA models between 50-500 Msun at solar metallicity, implementing the new Sabhahit+ (2022) wind model.
- This new model enhances the H- burning products of 14N, 20Ne, 23Na, and 26Al by a factor of 10 than the Vink (2001) model.
- The ejected mass of each isotope strongly depends on which burning phase the mass is lost, and therefore when the mass loss rates are high.
- (Li, Inayoshi+ 2024) High-z SMBH population
- (Inayoshi+ 2022a) Super-Eddington accretion simulation, showing that the HII region collapses and then forming a disk leading to super-Eddington accretion (~100 times)
- (Inayoshi+ 2022b) Post-processed the 2D simulations above with CLOUDY. Strong Balmer lines (EW = 1300A, 100A for alpha and beta). They made color-color (NIRCam + MIRI) predictions to detect these objects.
- (Inayoshi+ 2023) High-z TDE rates (>10 per year at z>4) with JWST/RST surveys. Can probe down to 10^5 Msun.
- (Marques+ 2020, 2021, 2022) Examples have very young (~10 Myr) populations with SFRs up to 1000 Msun/yr, high f_esc up to 0.9, large scale inflows, and strong stellar winds (strong & broad HeII 1640A lines)
- (Upadhyaya+ 2024) 13 UV-bright sources with intense HeII emission. Metallicities 0.2-0.6 Zsun. HeII emission caused by VMSs.
- (Martins & Palacios 2022) VMS stellar spectra library. NV absorption and HeII emission are good indicators of VMSs. SiIV 1393,1403 is also caused by supergiant VMSs.
- (Kobayashi & Ferrara 2023) Dual starburst model with standard IMF can explain the nitrogen abundances of GN-z11.
- The time spent at high N/O ratios is very short at ~1 Myr, showing that this phase is rare.
- PISNe have to be nearly absent because they produce large relative amounts of oxygen.
- (Volpato+ 2023) PARSEC stellar spectra models include Pop III stars.
- (Gieles+ 2018) SMS could form at the center of proto-GCs, which will last 2-5 Myr.
- (Martins+ 2020) Investigated spectral properties of SMS and SMS hosting clusters with different types of SMS masses / models
- (Kuruvanthodi+ 2023) Color-color selection rules for SMSs and found some candidates in the LEGUS catalog (M83 and NGC 628).
- Normal SSPs have the strongest Balmer breaks and EW(Hbeta) at the same age. SMSs have different spectral properties.
- Star-to-star abundance variations, anti-correlations (C-N, Na-O, Mg-Al) and correlations (N-Na, N-Al, Na-Al)
- (Ramirez+ in prep) When an accreting SMS reaches ~40 MK in the core, it remains between 40-70 MK for its lifetime.
- (Gieles+ 2018) SMSs form only above a critical stellar mass. In GCs and masstive star clusters, age and metallicity don't affect SMS formation. The more massive the cluster, the more extreme the variations.
- 30-70% of the GC stars (by mass) are 2nd generation GC stars. Percentage increases with cluster mass. If the SMS continues to accrete consuming H/He, the cluster remains He-poor, matching observations.
- Open questions: Mass accretion / loss (gas accretion, collisions, GR instability, etc); IMBHs; proton-rich GR-SNe; importance of galactic environment and feedback in a cosmological environment.
- (Ramirez+ in prep) Using MESA to produce SMS models. Convection models are important. MLT++local is the newest implementation (Jermyn+ 2023).
- SMS models are more blue than the models with standard convection models. In the latter phases, the star is fully convective.
- (Tazakkati+ in prep) Considers a Monte Carlo approach for normal-SMS stellar collisions, adding to the SMS mass and outer envelope.
- With a low accretion rate (1e-4 Msun/yr), only 10 collisions can destroy the SMS. However dM/dt = 1 Msun/yr, the SMS continues to grow and undergoes ~2000 collisions.
- Their SMS models between 300-2e4 Msun can explain GN-z11 and galactic GCs.
- (Tsiatsiou+ 2024) Uses GENEC for Pop III stellar evolution.
- (Charbonnel+ 2023; Senchyna+ 2023) SMS or proto-GC in GN-z11?
- (Pascale+ 2023; Maruqes+ 2023) Looking for lower-redshift analogs. Sunburst cluster at z=2.67 with Mstar ~ 10^7 Msun. [O/H] ~ 0.2 Zsun, supersolar N/O, normal C/O, high density/pressure ISM. Similar N/O ratio as GN-z11. Other examples: Lynx arc (z=3.36) and Mrk 996 (nearby peculiar WR galaxy), SMACS2031 (z=3.5)
- These objects are rare, compact, high density, and compatible with photo-ionization from stars.
- WR-scenario can explain C/O objects (WR galaxies) but not GCs (mass budget)
- SMS-scenario can reproduce abundance patterns in GCs, reaches very high N/O ratios, no mass budget problems (for GCs).
- Fate of the SMS: explosion (enrichment) or collapse (SMBH)? SN has small effect on the abundance ratios in GCs or possible IMBH formation (not found in GCs for >10^3 Msun).
Question: WR-scenario, why does the model starts at 1 Myr?