Context. Halos with masses in excess of the atomic limit are believed to be ideal environments which form heavy black hole seeds above 10 3 M ⊙ . In cases where H 2 fraction is suppressed, this expected lead reduced fragmentation gas and generation a top-heavy initial mass function. extreme can result formation massive seeds. Resolving scale resulting protostellar has, until now, not been robustly tested. Aims. We run zoom-in simulations atomically cooled halos suppressed assess whether they...

The Population III initial mass function (IMF) is currently unknown, but recent studies agree that fragmentation of primordial gas gives a broader IMF than the initially suggested singular star per halo. In this study we introduce sink particle mergers into Arepo, to perform first resolution for formation simulations and present run up densities 10-6g cm-3 hundreds years after particles. total number sinks formed increases with increasing creation density, without achieving numerical...

ABSTRACT Molecular hydrogen allows cooling in primordial gas, facilitating its collapse into Population III stars within halos. Lyman–Werner (LW) radiation from these can escape the halo and delay further star formation by destroying H2 other As cosmological simulations show that increasing background LW field strength increases average mass required for formation, we perform follow-up of selected halos to investigate knock-on effects this has on IMF. We follow 5 each J21 = 0, 0.01, 0.1...

Complex organic molecules (COMs) are widely detected in protostellar and protoplanetary systems, where they thought to have been inherited large part from earlier evolutionary phases. The chemistry of COMs these phases, namely starless prestellar cores, remains poorly understood, as models often struggle reproduce the observed gas-phase abundances species. We simulate formation a molecular cloud, cores within it, out diffuse interstellar medium, follow chemical evolution cloud material...

ABSTRACT Complex organic molecules (COMs) are widely detected in protostellar and protoplanetary systems, where they thought to have been inherited large part from earlier evolutionary phases. The chemistry of COMs these phases, namely starless prestellar cores, remains poorly understood, as models often struggle reproduce the observed gas-phase abundances species. We simulate formation a molecular cloud, cores within it, out diffuse interstellar medium, follow chemical evolution cloud...

ABSTRACT Population III (Pop III) stars form in groups due to the fragmentation of primordial gas. While uniform magnetic fields have been shown support against present-day star formation, it is unclear whether realistic k3/2 can same effect. We bypass issues associated with simulating turbulent dynamo by introducing a saturated field at equipartition velocity when central densities reach 10−13 g cm−3. test range sink particle creation from 10−10 10−8 Within tested, did not suppress gas and...

Much of what we know about molecular clouds, and by extension star formation, comes from line observations. Interpreting these correctly requires knowledge the underlying abundances. Simulations clouds typically only model species that are important for gas thermodynamics, which tend to be poor tracers denser material where stars form. We construct a framework post-processing simulations with full time-dependent chemical network, allowing us behaviour observationally-important not present in...

ABSTRACT Star formation activity in molecular clouds is often found to be correlated with the amount of material above a column density threshold ${\sim} 10^{22} \, {\rm cm}^{-2}$. Attempts connect this volume which star can occur are limited by fact that gas difficult reliably measure from observations. We post-process hydrodynamical simulations time-dependent chemical network, and investigate connection between commonly observed species activity. find many molecules widely assumed...

High redshift observations of 10$^9$ M$_\odot$ supermassive black holes (SMBHs) at $z \sim7$ and `Little Red Dots' that may host overmassive $z>4$ suggests the existence so-called heavy seeds (>1000 M$_\odot$) in early Universe. Recent work has suggested rapid assembly halos be key to forming enough Universe match such without need for extreme radiation fields or dark matter streaming velocities. We perform simulations BH seed formation 4 distinct idealised halo collapse scenarios; an...

Recent observations by the James Webb Space Telescope confirm existence of massive black holes ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mo>&gt;</mml:mo><mml:msup><mml:mn>10</mml:mn><mml:mn>6</mml:mn></mml:msup></mml:mrow></mml:math> ) beyond redshift display="inline"><mml:mrow><mml:mi>z</mml:mi><mml:mo>=</mml:mo><mml:mn>10</mml:mn></mml:mrow></mml:math>. However, their formation mechanism(s) still remain an open question. Light seed are one...

Advanced primordial chemistry networks have been developed to model the collapse of metal-free baryonic gas within gravitational well dark matter (DM) halos and its subsequent into Population III stars. At low densities 10$^{-26}$-10$^{-21}$ g cm$^{-3}$ (10$^{-3}$-10$^2$ cm$^{-3}$) is dependent on H$_2$ production, which a function compressional heating provided by DM potential. Once decouples from DM, temperature-density relationship follows established path dictated various chemical...

We present synthetic line observations of a simulated molecular cloud, utilising self-consistent treatment the dynamics and time-dependent chemical evolution. investigate emission from three most common CO isotopologues ($^{12}$CO, $^{13}$CO, C$^{18}$O) six supposed tracers dense gas (NH$_3$, HCN, N$_2$H$^+$, HCO$^+$, CS, HNC). Our simulation produces range intensities consistent with that observed in real clouds. The HCN-to-CO intensity ratio is relatively invariant column density, making...

ABSTRACT We present synthetic line observations of a simulated molecular cloud, utilizing self-consistent treatment the dynamics and time-dependent chemical evolution. investigate emission from three most common CO isotopologues (12CO, 13CO, C18O) six supposed tracers dense gas (NH3, HCN, N2H+, HCO+, CS, HNC). Our simulation produces range intensities consistent with that observed in real clouds. The HCN-to-CO intensity ratio is relatively invariant column density, making HCN (and chemically...

The formation of massive objects via gravitational collapse is relevant both for explaining the origin first supermassive black holes and in context star formation. Here, we analyze simulations pursued by different groups various environments, concerning holes, primordial stars, as well present-day stars. We focus particularly on regime small virial parameters, i.e., low ratios initial kinetic to energy, moderate Mach numbers, phase before feedback very efficient. compare outcomes under...

Recent observations by the James Webb Space Telescope confirm existence of massive black holes ($>10^6$ $\rm{M_{\odot}}$) beyond redshift $z=10$. However, their formation mechanism(s) still remain an open question. Light seed are one such pathway, forming as end stage metalfree (Population III) stars. can grow into long they accrete near Eddington limit for substantial periods or undergo several bursts super-Eddington accretion. In this work, our aim is to ascertain if light seeds in gas...

High-redshift observations of 10$^9$ M$_ supermassive black holes (SMBHs) at $z and `little red dots' that may host over-massive (BHs) $z&gt;4$ suggests the existence so-called heavy seeds (&gt;1000 in early Universe. Recent work has suggested rapid assembly halos be key to forming enough Universe match such observations, as high rate accretion into halo suppresses cooling ability H$_2$, allowing it quickly accrete up atomic limit 10$^7$ prior run-away collapse baryonic gas within its dark...

Molecular hydrogen allows cooling in primordial gas, facilitating its collapse into Population III stars within halos. Lyman-Werner (LW) radiation from these can escape the halo and delay further star formation by destroying H$_2$ other As cosmological simulations show that increasing background LW field strength increases average mass required for formation, we perform follow-up of selected halos to investigate knock-on effects this has on IMF. We follow 5 each $J_{21}$ = 0, 0.01 0.1...

Much of what we know about molecular clouds, and by extension star formation, comes from line observations. Interpreting these correctly requires knowledge the underlying abundances. Simulations clouds typically only model species that are important for gas thermodynamics, which tend to be poor tracers denser material where stars form. We construct a framework post-processing simulations with full time-dependent chemical network, allowing us behaviour observationally-important not present in...

Star formation activity in molecular clouds is often found to be correlated with the amount of material above a column density threshold $\sim 10^{22} \, {\rm cm^{-2}}$. Attempts connect this ${\it volume}$ which star can occur are limited by fact that volume gas difficult reliably measure from observations. We post-process hydrodynamical simulations time-dependent chemical network, and investigate connection between commonly-observed species activity. find many molecules widely assumed...

Advanced primordial chemistry networks have been developed to model the collapse of metal-free baryonic gas within gravitational well dark matter (DM) halos and its subsequent into Population III stars. At low densities 10^-26-10^-21 g cm-3 (10-3-10^2 cm-3) is dependent on H2 production, which a function compressional heating provided by DM potential. Once decouples from DM, temperature-density relationship follows established path dictated various chemical reactions until formation...

Halos with masses in excess of the atomic limit are believed to be ideal environments which form heavy black hole seeds above 10^3 Msun. In cases where H_2 fraction is suppressed this expected lead reduced fragmentation gas and generation a top initial mass function. extreme can result formation massive seeds. Resolving scale resulting protostellar has, until now, not been robustly tested. Cosmological simulations were performed moving mesh code Arepo using primordial chemistry network z =...