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The dataset generation failed because of a cast error
Error code: DatasetGenerationCastError
Exception: DatasetGenerationCastError
Message: An error occurred while generating the dataset
All the data files must have the same columns, but at some point there are 7 new columns ({'embedding_model', 'distance', 'normalized', 'built_at', 'scann', 'source_jsonl', 'num_vectors'}) and 1 missing columns ({'text'}).
This happened while the json dataset builder was generating data using
hf://datasets/nimocodes/Viginiti_Octo/manifest.json (at revision 16475f7aabf26da16585a63e942a9e0af34a77d2)
Please either edit the data files to have matching columns, or separate them into different configurations (see docs at https://hf.co/docs/hub/datasets-manual-configuration#multiple-configurations)
Traceback: Traceback (most recent call last):
File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/builder.py", line 1831, in _prepare_split_single
writer.write_table(table)
File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/arrow_writer.py", line 644, in write_table
pa_table = table_cast(pa_table, self._schema)
File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/table.py", line 2272, in table_cast
return cast_table_to_schema(table, schema)
File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/table.py", line 2218, in cast_table_to_schema
raise CastError(
datasets.table.CastError: Couldn't cast
built_at: double
source_jsonl: string
num_vectors: int64
embedding_model: string
normalized: bool
distance: string
scann: struct<num_leaves: int64, leaves_to_search: int64, reorder: int64>
child 0, num_leaves: int64
child 1, leaves_to_search: int64
child 2, reorder: int64
to
{'text': Value('string')}
because column names don't match
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/src/services/worker/src/worker/job_runners/config/parquet_and_info.py", line 1456, in compute_config_parquet_and_info_response
parquet_operations = convert_to_parquet(builder)
File "/src/services/worker/src/worker/job_runners/config/parquet_and_info.py", line 1055, in convert_to_parquet
builder.download_and_prepare(
File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/builder.py", line 894, in download_and_prepare
self._download_and_prepare(
File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/builder.py", line 970, in _download_and_prepare
self._prepare_split(split_generator, **prepare_split_kwargs)
File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/builder.py", line 1702, in _prepare_split
for job_id, done, content in self._prepare_split_single(
File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/builder.py", line 1833, in _prepare_split_single
raise DatasetGenerationCastError.from_cast_error(
datasets.exceptions.DatasetGenerationCastError: An error occurred while generating the dataset
All the data files must have the same columns, but at some point there are 7 new columns ({'embedding_model', 'distance', 'normalized', 'built_at', 'scann', 'source_jsonl', 'num_vectors'}) and 1 missing columns ({'text'}).
This happened while the json dataset builder was generating data using
hf://datasets/nimocodes/Viginiti_Octo/manifest.json (at revision 16475f7aabf26da16585a63e942a9e0af34a77d2)
Please either edit the data files to have matching columns, or separate them into different configurations (see docs at https://hf.co/docs/hub/datasets-manual-configuration#multiple-configurations)Need help to make the dataset viewer work? Make sure to review how to configure the dataset viewer, and open a discussion for direct support.
text string |
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We present the Dark-ages Reionization and Galaxy-formation Observables from Numerical Simulations (DRAGONS) program and Tiamat, the collisionless N-body simulation program upon which DRAGONS is built. The primary trait distinguishing Tiamat from other large simulation programs is its density of outputs at high redshift... |
We illustrate this using standard relaxation metrics to establish two dynamical recovery time-scales: i) halos need ~1.5 dynamical times following formation, and ii) ~2 dynamical times following a major (3:1) or minor (10:1) merger to be relaxed. This is remarkably consistent across a wide mass range. Lastly, we use a ... |
Following cosmological recombination the baryonic gas filling the Universe became predominantly neutral. The fact that this gas is known to be mostly ionized today [Gunn:1965p2569] implies that the intergalactic medium (IGM) under went a significant reionization event at some early point in its history. This fact is re... |
The development of theoretical models that self-consistently include the physics of galaxy formation and intergalactic hydrogen will play a key role in understanding the nature of the first galaxies and in interpreting these observations. This paper is the first in a series describing the Dark-ages Reionization and Gal... |
Over the past decade the requirements for simulations aiming to address the structure of reionization and galaxy formation in the Epoch of Reionization (EoR) have been studied extensively. The consensus from previous N-body studies [Iliev:2007p2581, Zahn:2007p2570, McQuinn:2007p2582, Shin:2008p2583, Lee:2008p2584, Crof... |
In the cold neutral IGM prior to reionization, molecular cooling may proceed within minihalos with masses ~10^6 solar masses. However, the processes principally responsible for regulating galaxy formation are expected to be active in halos with virial temperatures greater than T_min ~ 10^4 K, above which atomic hydroge... |
At z~6 the dynamical time of a galactic disc falls below the lifetime of the least massive Type-II supernova progenitor (~4x10^7 yr). As a result, snapshots with a cadence of ~10^7 years are required to follow galaxy formation correctly during the EoR with a semi-analytic model. This interval is an order of magnitude s... |
We seek this understanding because of its potential impact on the structure of galactic halos, which is of fundamental importance to the physics of galaxy formation at any epoch, including the EoR. In particular, halo concentrations and angular momenta are generally believed to dictate the size and surface density of t... |
These studies have collectively established a set of criteria (which we refer to henceforth as standard relaxation criteria) capable (at low redshifts at least) of separating halos with disturbed structure from those with relaxed structure. These standard criteria consist of cuts on three metrics for each halo: the sep... |
At high redshifts where simulations predict that merger rates are very high, halos significantly less concentrated, and merger orbital properties quite different, the influence of dynamical state on halo structure may differ from local trends. It is unclear to what degree dynamical disturbance may play a role in the di... |
We will find that the standard relaxation criteria are effective at identifying systems that are recovering from their formation or from recent significant mergers. With this methodology properly validated at high redshift, we will subsequently perform a detailed analysis of the structure of both relaxed and unrelaxed ... |
Complementary high resolution hydrodynamics simulations called Smaug [already presented in][]{Duffy:2014p2561} will characterise the basic scaling relationships of early galaxy formation. There will then be a detailed comparison of Meraxes to the results of Smaug with suggested constraints of the semi-analytic model ba... |
At low redshifts at least, cuts on three metrics for quantifying the dynamical state of halos have found success at separating systems with disturbed structure from those with relaxed structure: the offset parameter (x_off), given by the displacement of the densest centre of a halo from its centre of mass; the virial r... |
Elevated values of the virial ratio are found prior to the dissipation of orbital energy following a merger. Lastly, elevated values of x_off are a natural result of the movement of a halo's dense core as it orbits the centre of mass of its system following even minor disturbances. The standard values for relaxed syste... |
Throughout our analysis we will measure intervals of time for a halo at redshift z in units of its dynamical time, which we take to be 10% of the Hubble time at that redshift. Times in this dimensionless system of units will be denoted by tau. At all redshifts, the Hubble time is tau=10 in this system. The three times ... |
Following 3:1 and 10:1 mergers, peak levels occur roughly one dynamical time after a merger begins with relaxed levels obtained at a merger age of ~2. Peak values of 0.2 and roughly 0.07 are reached following 3:1 and 10:1 mergers, suggesting that mergers are progressively less likely to excite the system above our x_of... |
Lastly, the substructure fraction shows a very simple and well defined behaviour following dynamical events. At formation, a wide range of values are seen about a distribution peak of ~0.2. A slow decline to baseline values follows. After merger events, the substructure fraction increases by expected amounts: 30% for 3... |
We conclude then that, of the three metrics we study here, the x_off statistic is the most effective single measure of dynamical state. It is sensitive to disturbances from mergers greater than approximately 10:1 and retains this sensitivity for approximately 2 dynamical times afterwards. The virial ratio is significan... |
These results suggest that following formation or mergers greater than 10:1, a small and fixed number of pericentric passages of the material disturbed at large radius in the merger remnant are required for relaxation. If this is the case, the mass independence of relaxation could be seen as a product of the fact that ... |
How then do the fractions of halos meeting these recovery criteria evolve with redshift? The distribution of all three dynamical ages evolves very little from z=15 to z=5. Over this redshift range, the distribution of formation ages is very narrow and peaked very close to our formation recovery timescale of 1.5. The ne... |
The situation is importantly different for minor mergers. In this case we find that halos experience minor mergers at rates which are much too rapid (on average) to permit dynamical relaxation between events. The narrow distribution of formation ages, broad distribution of merger ages and short times between 10:1 merge... |
The fractions of halos which meet these recovery criteria as a function of redshift is presented explicitly. Here we see the disappearance of halos with formation times less than 1.5 and the sustained low levels of halos having had sufficient time to recover from their most recent mergers. We have added to these plots ... |
This is likely the reason why our estimates of the recovered fraction exceeds the relaxed population at z<2. Taken together, we see that at high redshifts (z>5), the fraction of relaxed halos drops to levels of ~20% at all galactic masses. Combined with the rapid decline in the number density of halos with redshift at ... |
Doing so has yielded an interesting new insight into the dynamical lives of high-redshift galactic halos. There is a stark difference between the results from ROCKSTAR and SUBFIND. We can see clearly that while the halo appears relatively undisturbed with unremarkable substructure, it in fact consists primarily of two ... |
Substantial amounts of this gas will be stripped or rapidly coalesce into one hot halo, loosing its association with its original collisionless component while that material continues to orbit. This is the case with the Bullet Cluster for instance, albeit at a different mass scale and redshift. It is also the situation... |
A comparison of the evolving substructure fractions of FoF halos extracted from TinyTiamatW using Subfind to those obtained from ROCKSTAR as functions of the dynamical ages shows that while we see the familiar decline of f_sub following formation and mergers in the Subfind trees, the ROCKSTAR trees exhibit a much slowe... |
Substructure fractions are 50 to 60% at the highest masses in ROCKSTAR indicating that only around half of the mass in these systems is assigned to the most massive component of the system. This is a consequence of a very different splitting of the top level of the FoF group's substructure hierarchy. Suggestions of thi... |
Such differences may lead to significant systematics with mass in the evolution of merger trees which could masquerade as physical processes as diverse as mass dependancies in dust properties, photon escape fractions, feedback and cooling. A detailed account of how the cooling and feedback modelling of DRAGONS compares... |
We have introduced the Dark-ages Reionization and Galaxy-formation Observables from Numerical Simulations (DRAGONS) program and presented the Tiamat collisionless N-body simulation suite upon which it is constructed. The abundance of friends-of-friends (FoF) structures populating Tiamat is a good match to the universal... |
The distribution of formation times and times since major mergers maintain approximately these time-scales across all redshifts above z=5 while the time between minor mergers is typically significantly less. Relaxed fractions maintain levels of less than 20% at z>5 as a result. Using the GiggleZHR simulation we find th... |
This results in substructure fractions that are much higher for ROCKSTAR than for Subfind, with probable implications for semi-analytic models of galaxy formation at high redshift. Taken together, these results illustrate the dynamically violent circumstances under which galaxy formation proceeds in the early Universe.... |
We use high resolution N-Body simulations to study the concentration and spin parameters of dark matter haloes in the mass range between 10 to the power of 8 and 10 to the power of 11 solar masses per h and redshifts between 5 and 10, corresponding to the haloes of galaxies thought to be responsible for reionization. W... |
Our best-fit Einasto shape parameter, alpha, depends on peak height, nu, in a manner that is accurately described by the equation alpha equals 0.0070 times nu squared plus 0.1839. The distribution of the spin parameter, lambda, has a weak dependence on equilibrium state; lambda peaks at roughly 0.033 for our relaxed sa... |
The characteristics of DM haloes have been the subject of extensive research. Mass determines the overall size of the halo, but several other important parameters have also been identified. For example, using N-Body simulations [1997ApJ...490..493N] found that the density profiles of virialised haloes can be well descr... |
While the NFW profile is a common description, several recent studies [2004MNRAS.349.1039N, 2008MNRAS.388....2H, 2010MNRAS.402...21N] have shown that the density profiles of simulated haloes exhibit small but systematic deviations from the NFW equation. The Einasto profile [1965TrAlm...5...87E], provides a better appro... |
One approach relates the characteristic density to the past accretion history of the halo's main progenitor. [2002ApJ...568...52W], for example, calculated the mass assembly histories (MAHs) of simulated haloes and used a proportionality constant to relate the concentration to background density at the halo's time of f... |
[2007MNRAS.381.1450N] studied the z=0 c(M) relation in the Millennium simulation [2005Natur.435..629S], while [2011ApJ...740..102K] and [2012MNRAS.423.3018P] extended the analysis to z=6 using both the Millennium and Bolshoi simulations. In agreement with previous work, these authors each find a decline of concentratio... |
For example, [2012MNRAS.423.3018P] and [2014arXiv1407.4730D] find a high-mass upturn (above a few times 10 to the power of 10 solar masses per h) at z=5 amongst the full halo population. At similar masses, [2014arXiv1402.7073D], find a relation with a slightly positive slope, whereas [2015arXiv150506436H] report a weak... |
The effectiveness of these parameters in isolating relaxed DM haloes is further discussed in [2008MNRAS.387..536G] and [2012MNRAS.427.1322L]. A detailed study of these parameters with regard to dynamical relaxation at high redshift is provided by the first paper of the DRAGONS series, Poole et al. (2015b) (hereafter re... |
Most studies of the spin parameter have focused on the distribution of spins and its dependence on halo mass [2007MNRAS.376..215B, 2007MNRAS.381.1450N, 2008ApJ...678..621K, 2010crf..work...16M]. At any redshift, halo spins are distributed approximately log-normally, and peak at a lambda of approximately 0.03-0.04. At l... |
In Section 3 we present our concentration--mass relation and its redshift dependence, and in Section 4 the spin distribution, and its mass and redshift dependence. Finally, in Section 5 we summarise our main results. Our analysis focuses on DM haloes identified in three cosmological N-body simulations. These include a ... |
Cosmological parameters for each box were chosen to be consistent with the Planck 2015 data release [2015arXiv150201589P] (h, Omega_m, Omega_b, Omega_Lambda, sigma_8, n_s) = (0.678, 0.308, 0.0484, 0.692, 0.815, 0.968). The relevant numerical parameters are summarised in Table 1. A more detailed discussion of these simu... |
Haloes were identified in each simulation snapshot using Subfind [2001MNRAS.328..726S]. This produces two outputs: the first contains structures found by a friends-of-friends (FoF) algorithm (we adopt a linking length of 0.2 times the mean inter particle spacing); the second is obtained by dissecting each FoF group int... |
For each main halo, spherically-averaged density profiles were constructed in bins containing an equal number of particles. Only particles considered by Subfind to be bound to the central haloes were used. The number of bins was increased along with the number of halo particles. We imposed a minimum of 5 bins for the s... |
In defining our sample of equilibrium DM haloes we impose both dynamical and resolution criteria following the procedure established by [2007MNRAS.381.1450N], [2008MNRAS.387..536G] and [2012MNRAS.427.1322L]. The behaviour of these equilibrium diagnostics over the mass and redshift range probed by the Tiamat simulation ... |
[2007MNRAS.381.1450N] find that these restrictions provide a simple and physically motivated method to exclude haloes that are not well described by an NFW profile. In Paper I these parameters were also shown to be discriminate between haloes that have either recently doubled in mass, or suffered a major or minor merge... |
These sample cuts are designed to remove such systems and to keep transients out of our analysis as much as possible. For example, a halo which has just undergone a major merger may be comprised of two large, high density clumps, and consequently have a high x_off and poorly defined center. The density profile of such ... |
Caption: Concentration--mass relation of relaxed central haloes at z=5. Left and Right panels are the NFW and Einasto concentrations respectively. Inner shaded region denotes the bootstrapped 90 per cent confidence interval on the median. The outer shaded region shows the 68 per cent scatter. The line of best fit is fi... |
Caption: The same concentration mass relations for relaxed central haloes as shown in the previous figure, but now at z=7. Inner shaded region denotes the bootstrapped 90 per cent confidence interval on the median. The outer shaded region shows the 68 per cent scatter. The line is fit to the median and gives c_vir = 3.... |
The inner shaded region shows the bootstrapped 90 per cent confidence interval on the median for mass bins containing at least 20 haloes. The outer shaded area fills the 68 per cent scatter in individual concentration estimates. We find a weak trend of decreasing concentration with mass at z=5 for both NFW and Einasto ... |
The quoted errors are the 68 per cent confidence interval derived from the posterior distribution. We find intrinsic scatter in the c(M) relation of delta c_vir ~ 1.0 (or 20 per cent) for fits to both NFW and Einasto profiles. Best-fit power-law relations are provided in Table 2 for a range of redshifts. In addition to... |
In order to check for any subtle bias in our fits we have also constructed c(M) and alpha(nu) relations using the median density profiles obtained by stacking haloes in narrow mass bins. This smooths out any unique features of individual systems and allows for a robust estimate of the median structural properties of ha... |
However, the shape of our trend at redshift 5 is in qualitative disagreement with DM14, who find that a positive trend emerges at z=5 for both Einasto and NFW concentrations. We also find a higher normalization (about 25 per cent) than DM14 at ~10^10 solar masses per h. We do not speculate on the exact combination of t... |
Caption: Best fit values from the relaxed population for NFW-derived and Einasto-derived c(M) relations. N_sample denotes the number of haloes in the sample for Tiamat, MediTiamat, TinyTiamat. Fits and errors are the median and 68 per cent confidence interval using the MCMC package quoted previously. Caption: The Einas... |
Caption: Concentration-mass relation for relaxed haloes at z=5, but now with haloes containing >500 particles. The inner shaded region represents the bootstrapped median value and the outer region the 68 per cent scatter. The inclusion of haloes with particle number <5000 introduces more haloes with lower concentration... |
In Figures 6 and 7 we again present the c(M) relation but now relax the strict resolution and equilibrium criteria. Firstly, in Figure 6 we show the relation that results from lowering the minimum particle limit for a halo to 500 particles, while maintaining the relaxation criteria. Whereas our n_p > 5000 relation agre... |
Table 3 shows the best fit parameters for the full population of resolved haloes with n_p > 500 particles. In the left hand panel of Figure 7 we also plot the models of [2014arXiv1407.4730D] and [2012MNRAS.423.3018P]. [2014arXiv1407.4730D] use the phase space halo finder ROCKSTAR [2013ApJ...762..109B], and do not enfor... |
Our concentrations at these masses and redshifts are lower than those found by [2012MNRAS.423.3018P]. The delta c_vir ~ 1 difference likely originates from a combination of: a) the use of M_200 and c_200 in their definitions, b) the use of maximum circular velocity as a measure of concentration, which is shown in [2013... |
In Figure 8 we show the distribution of spin parameters for relaxed haloes in the Tiamat simulation for z=5. The mass range covered is now increased so that particle number n_p > 600 [2008ApJ...678..621K]. Rather than a log-normal, the solid black lines show the best-fitting function of [2007MNRAS.376..215B], which has... |
Both [2010crf..work...16M] and [2008ApJ...678..621K] fit a log-normal to their spin distribution, with best-fit parameters given by sigma_0= 0.57 (variance) and lambda_0 = 0.031 (mean), and sigma_0 = 0.53 and lambda_0 =0.035, respectively. Both have slightly higher spins overall. As found by [2007MNRAS.376..215B], the ... |
The existence of a small negative trend of spin parameter with mass at these redshifts is in qualitative agreement with [2008ApJ...678..621K], who find no trend at z=0-1 but an emerging trend at z=10. As noted, the virialised halo cut has an affect on our results. However, we find a small negative trend in both the ful... |
Caption: The spin-virial mass relation for the full population of haloes at z=5. For comparison fiducial results for relaxed haloes from [2011MNRAS.411..584M] are also shown. We used N-Body simulations to study concentrations and spins of DM haloes at z=5-10 and across the mass range 10^8 to 10^11 solar masses per h; t... |
Our best-fit concentration-mass relations at z=5 have a slightly negative slope that becomes more shallow towards z=9. Limiting our analysis to equilibrium haloes has a strong impact on the derived c(M) relation due to unrelaxed haloes having lower concentrations at all masses and redshifts. Haloes with larger center-o... |
Without imposing equilibrium cuts on our sample, the concentrations found in Tiamat have similar values to those reported by [2014arXiv1402.7073D], [2014arXiv1407.4730D] and [2015arXiv150506436H]. Concentrations of haloes in Tiamat are a factor of delta c_vir ~ 0.5-1 lower than reported by [2012MNRAS.423.3018P] and [20... |
Our best-fit power-law relation for relaxed haloes at z=5 is given, as is the relation for the full halo population. The growth of dark matter haloes drives high-z galaxy formation [2013ApJ...768L..37T], while the concentration and spin of haloes are key ingredients for semi-analytic models of galaxy formation [2006MNR... |
Correlations between black holes and their host galaxies provide insight into what drives black hole--host co-evolution. We use the Meraxes semi-analytic model to investigate the growth of black holes and their host galaxies from high redshift to the present day. Our modelling finds no significant evolution in the blac... |
Extensive low-redshift studies reveal a complex interplay between galaxies and the supermassive black holes that reside at their centres, with clear correlations observed between black hole mass and host bulge mass, total stellar mass, velocity dispersion and luminosity [Magorrian1998, Gebhardt2000, Merritt2001, Tremai... |
Observing high-redshift black hole--host correlations is fraught with difficulties. Host galaxies are hard to detect since they are often completely outshined by the AGN light, particularly in the rest-frame optical where common stellar mass estimators can be used [Zibetti2009, Taylor2011]. Subtracting the quasar light... |
In addition, the emission regions may not trace the spatial distribution of the stellar component of the galaxy, meaning that these dynamical masses may not be representative of the total stellar mass [Narayanan2009]. Determining the black hole masses of high-z quasars is also difficult, with emission-line based estima... |
For example, ALMA observations of five redshift z is approximately equal to 6 quasar hosts show black hole to dynamical mass ratios ranging from 10 to the power of -1.9 to 10 to the power of -1.5 [Wang2013]. Similar studies at redshift z is approximately equal to 4--7 [Maiolino2007, Riechers2008, Venemans2012] also giv... |
[Willott2017] suggest that since only the most massive z>6 black holes are observed, if the relation has a wide dispersion then one would expect to see a higher value due to the Lauer bias [Lauer2007]: since the luminosity function falls off rapidly at high masses, the most massive black holes occur more often as outli... |
A lack of evolution in the black hole--host relations is consistent with the findings of cosmological hydrodynamical simulations such as Horizon-AGN [Volonteri2016], which observes very little evolution in the black hole mass--stellar mass relation from redshift z=0 to 5, and BlueTides [Huang2018], which finds a black ... |
In this work we explore the evolution of the black hole--host relations with the Meraxes semi-analytic model [Mutch2016]. Meraxes is designed specifically to study galaxy formation and evolution at high redshifts, making it ideal for studying the evolution of black holes and their host galaxies. In this work we use Mer... |
Tiamat-125-HR is a low-redshift counterpart to Tiamat, running from redshift z=35 to z=0 with the same temporal resolution, but with a lower mass resolution (1080^3 particles of mass 1.33x10^8 per h solar masses) and larger box size of (125 per h Mpc)^3, more suited for low-redshift studies. Throughout this work, we us... |
In Meraxes, stars in galaxies reside in three components: an exponential disc, a spheroidal merger-driven bulge and a disc-like instability-driven bulge. Bulges grow through both galaxy-galaxy mergers and disc-instabilities. In Meraxes, we assume that galaxy mergers with merger ratio greater than 0.01 trigger a burst o... |
In our model we assume that the galaxy discs are thin, with an exponential surface density and flat rotation curve. Such discs become unstable if the disc mass is greater than the disc velocity squared times the scale radius divided by the gravitational constant, which equals the critical mass [Efstathiou1982, Mo1998].... |
We also assume that black holes grow in galaxy mergers, with the black holes in each galaxy merging together. Black holes accrete hot gas from the static hot gas reservoir around the galaxy, at a fraction of the Bondi-Hoyle accretion rate. We consider this fraction a free parameter, which adjusts the efficiency of radi... |
Black holes accrete cold gas from the galaxy, when triggered by either a galaxy-galaxy merger or a disc instability. During such an event, the black hole mass grows by a certain amount, where the virial velocity and a free parameter adjust the growth efficiency. For merger-triggered growth, we take the efficiency param... |
We calculate the bolometric luminosities of each black hole in the model following the Q17 method, which assumes Eddington luminosity for all accreting black holes, and self-consistently calculates the duty cycle. We consider the luminosities from both the quasar- and radio-modes of accretion. At high-redshifts the con... |
In M19 we calibrated the free parameters in Meraxes to match the observed stellar mass functions at redshift z=0--8, and the black hole--bulge mass relation at redshift z=0. Using this model, we find that the black hole mass function and quasar luminosity functions are much larger than predicted by the observations. In... |
We find that our results from the two simulations are generally consistent at redshift z is approximately equal to 2, with broad qualitative agreement at higher redshifts. We calibrate the free parameters in the model to match the observed stellar mass functions at redshift z=0--8, the [Shankar2009] and [Davis2014] bla... |
We note that all of these parameter sets produce very similar results. As a further check of the black hole population, we plot the black hole accretion rate density as a function of redshift for models with these different merger-driven black hole growth efficiencies. We find that the models with lower efficiencies gi... |
At redshift z=2 the model and the observations agree remarkably well. At redshift z>2 the model over-predicts the observed quasar X-ray luminosity function at intermediate luminosities, by up to ~0.7 dex at redshift z=4, while at redshift z<2 the model under-predicts the luminosity function at these luminosities. Our m... |
In addition to published uncertainties in the observations, it may also be the case that at higher redshifts X-ray AGN are more likely to be obscured, which is consistent with evidence from a range of X-ray observations [Treister2006, Vito2014, Buchner2015]. Thus we argue that the inability of our model to match the re... |
The black hole accretion rate density becomes significantly higher than the observations at redshift z<1, consistent with the quasar luminosities being overestimated at these redshifts. This excess black hole accretion is most likely a result of the model missing important physics required for modelling low-redshift ga... |
However, this causes the model to no longer match the observations at higher redshifts. Thus, some evolving Eddington ratio is necessary for Meraxes to accurately reproduce the redshift z<1 quasar UV luminosity function. We now use the model described to explore black hole growth. We investigate the redshift evolution ... |
Relative to the scatter in the relations, we see minimal evolution in both the black hole--bulge and black hole--total stellar mass relations from redshift z=0 to 6. This lack of evolution in the black hole--host mass relations is consistent with the findings of cosmological hydrodynamical simulations such as Horizon-A... |
The scatter decreases with increasing stellar mass. The median black hole mass to total stellar mass ratio as a function of redshift for galaxies with black hole mass > 10^6 solar masses shows no statistically-significant evolution out to redshift z is approximately equal to 8. This is consistent with current high reds... |
This is not consistent with the scenario proposed by [Peng2007] and [Jahnke2011], for example, where the black hole and galaxy growth is uncorrelated and the relationships are generated naturally within a merger driven galaxy evolution framework, due to a central-limit-like tendency. The median black hole mass to total... |
For a higher efficiency, the median black hole--stellar mass ratio decreases at redshifts z greater than or approximately equal to 6, instead of remaining constant with redshift. We investigate the cause of this high-redshift decrease in the black hole--host relation by considering the Eddington limit. Increasing the e... |
We consider the cumulative fraction of black hole mass formed through each of the mechanisms in our model: black hole seeding, merger-driven quasar-mode accretion, instability-driven quasar-mode accretion, radio-mode accretion and black hole--black hole coalescence in galaxy mergers. The merger-driven growth mode becom... |
We also consider the instantaneous growth fractions of black hole mass formed through each mechanism as a function of redshift. As discussed, the model produces unreliable black hole accretion rates at redshift z<1, and so we only consider these black hole growth rates at redshift z>1. The instability-driven growth mod... |
For example, [Koss2010] find that only 25 per cent of local, moderate luminosity X-ray AGN show signs of mergers, though the fraction is much higher for luminous AGN [Hong2015]. From redshift z from approximately 0.3 to 1.0, [Cisternas2010] find that the vast majority (>85 per cent) of X-ray selected AGN do not show si... |
Using an updated GALFORM model, [Griffin2019] found that accretion of hot gas dominates the growth of black holes at redshift z<2, with disc-instabilities dominant at higher redshifts. [Hirschmann2012] found that instability-driven black hole growth was required to reproduce AGN downsizing, and that while major mergers... |
The hydrodynamical simulation Horizon-AGN found that only ~35 per cent of black hole mass in local massive galaxies is directly attributable to merging, with the majority of black hole growth instead growing via secular processes [Martin2018]. The Magneticum Pathfinder Simulation also found that merger events are not t... |
Having a merger growth efficiency that is twice, six times or even 18 times larger than the instability-driven growth efficiency may have an effect on the conclusions outlined above. We find, as expected, that models with larger merger efficiencies result in more merger-driven growth. For a merger efficiency twice the ... |
A popular explanation for the black hole--host correlations is that major mergers drive the growth of both black holes and bulges [e.g.][Haehnelt2000, Croton2006b]. If this were the case, one would expect that black holes would only correlate with galaxy properties directly related to the merger process, such as bulge ... |
We plot the black hole mass--total stellar mass and black hole mass--bulge mass relation for disc-dominated and bulge-dominated galaxies at redshift z=0. Our simulated disc galaxies lie on the black hole mass--total stellar mass relation, but lie offset to the left of the black hole mass--bulge mass relation, as they h... |
This is consistent with our finding that the instability-driven mode is the dominant growth mechanism for black holes. We use the Meraxes semi-analytic model to investigate the evolution of black holes and their relations to their host galaxies. We find the following key predictions of our model: There is minimal stati... |
The instability-driven or secular quasar-mode growth is the dominant growth mechanism for black holes at all redshifts. The contribution from merger-driven quasar-mode growth only becomes significant at low redshift for black holes with mass greater than or approximately equal to 10^9 solar masses. Disc-dominated galax... |
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