Empirical Constraints Research Articles

A Correlated Multi-Pixel Inversion Approach for Aerosol Remote Sensing

Aerosol retrieval algorithms used in conjunction with remote sensing are subject to ill-posedness. To mitigate non-uniqueness, extra constraints (in addition to observations) are valuable for stabilizing the inversion process. This paper focuses on the imposition of an empirical correlation constraint on the retrieved aerosol parameters. This constraint reflects the empirical dependency between different aerosol parameters, thereby reducing the number of degrees of freedom and enabling accelerated computation of the radiation fields associated with neighboring pixels. A cross-pixel constraint that capitalizes on the smooth spatial variations of aerosol properties was built into the original multi-pixel inversion approach. Here, the spatial smoothness condition is imposed on principal components (PCs) of the aerosol model, and on the corresponding PC weights, where the PCs are used to characterize departures from the mean. Mutual orthogonality and unit length of the PC vectors, as well as zero sum of the PC weights also impose stabilizing constraints on the retrieval. Capitalizing on the dependencies among aerosol parameters and the mutual orthogonality of PCs, a perturbation-based radiative transfer computation scheme is developed. It uses a few dominant PCs to capture the difference in the radiation fields across an imaged area. The approach is tested using 27 observations acquired by the Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) during multiple NASA field campaigns and validated using collocated AERONET observations. In particular, aerosol optical depth, single scattering albedo, aerosol size, and refractive index are compared with AERONET aerosol reference data. Retrieval uncertainty is formulated by accounting for both instrumental errors and the effects of multiple types of constraints.

Constraining Metallicity-dependent Mixing and Extra Mixing Using [C/N] in Alpha-rich Field Giants

Abstract Internal mixing on the giant branch is an important process which affects the evolution of stars and the chemical evolution of the galaxy. While several mechanisms have been proposed to explain this mixing, better empirical constraints are necessary. Here, we use [C/N] abundances in 26,097 evolved stars from the SDSS-IV/APOGEE-2 Data Release 14 to trace mixing and extra mixing in old field giants with −1.7 < [Fe/H] < 0.1. We show that the APOGEE [C/N] ratios before any dredge-up occurs are metallicity dependent, but that the change in [C/N] at the first dredge-up is metallicity independent for stars above [Fe/H] ∼ −1. We identify the position of the red giant branch (RGB) bump as a function of metallicity, note that a metallicity-dependent extra mixing episode takes place for low-metallicity stars ([Fe/H] < −0.4) 0.14 dex in log g above the bump, and confirm that this extra mixing is stronger at low metallicity, reaching Δ[C/N] = 0.58 dex at [Fe/H] = −1.4. We show evidence for further extra mixing on the upper giant branch, well above the bump, among the stars with [Fe/H] < −1.0. This upper giant branch mixing is stronger in the more metal-poor stars, reaching 0.38 dex in [C/N] for each 1.0 dex in log g. The APOGEE [C/N] ratios for red clump (RC) stars are significantly higher than for stars at the tip of the RGB, suggesting additional mixing processes occur during the helium flash or that unknown abundance zero points for C and N may exist among the RC sample. Finally, because of extra mixing, we note that current empirical calibrations between [C/N] ratios and ages cannot be naively extrapolated for use in low-metallicity stars specifically for those above the bump in the luminosity function.

Intuition, intelligence, data compression

The main goal of my paper is to argue that data compression is a necessary condition for intelligence. One key motivation for this proposal stems from a paradox about intuition and intelligence. For the purposes of this paper, it will be useful to consider playing board games—such as chess and Go—as a paradigm of problem solving and cognition, and computer programs as a model of human cognition. I first describe the basic components of computer programs that play board games, namely value functions and search functions. I then argue that value functions both play the same role as intuition in humans and work in essentially the same way. However, as will become apparent, using an ordinary value function is just a simpler and less accurate form of relying on a database or lookup table. This raises our paradox, since reliance on intuition is usually considered to manifest intelligence, whereas usage of a lookup table is not. I therefore introduce another condition for intelligence that is related to data compression. This proposal allows that even reliance on a perfectly accurate lookup table can be nonintelligent, while retaining the claim that reliance on intuition can be highly intelligent. My account is not just theoretically plausible, but it also captures a crucial empirical constraint. This is because all systems with limited resources that solve complex problems—and hence, all cognitive systems—need to compress data.

In-medium properties of a $ \Xi$ΞN interaction derived from chiral effective field theory

The in-medium properties of a baryon-baryon interaction for the strangeness $S=-2$ sector derived within chiral effective field theory up to next-to-leading order are investigated. The considered $\Xi N$ interaction is in line with available empirical constraints on the $\Lambda\Lambda$ $S$-wave scattering length and on $\Xi N$ elastic and inelastic cross sections. In particular, there are no near-threshold bound states in the $\Xi N$ system. A conventional $G$-matrix calculation for this interaction is performed and reveals that the single-particle potential of the $\Xi$-hyperon in nuclear matter is moderately attractive as suggested by recent experimental evidence for the existence of $\Xi$-hypernuclei.

Rates of Dynamic Recrystallization in Geologic Materials

AbstractGrain size reduction via dynamic recrystallization (DRX) is intimately related to the softening of crystalline materials under an applied stress, and plays a role in numerous geodynamic processes that involve strain‐weakening feedbacks. Despite its importance, few studies have provided empirical constraints on the rates of DRX and grain size reduction. Here we examine DRX rates using the Johnson‐Mehl‐Avrami‐Kolmogorov theory for phase transformation kinetics. Our analysis uses a compilation of published and newly‐derived DRX data from experimental studies on a wide range of geologic and engineering materials. We find that DRX rates are strongly dependent on the homologous temperature at which deformation occurs, with DRX occurring over a broad range of shear strains (0.01 < γ < 200), and more rapidly with increasing homologous temperature. Moreover, the experimental data can be described by a single fit to a modified form of the Avrami equation that incorporates homologous temperature dependence, implying that, to first order, DRX rates are largely material independent. We also examine the influence of stress, deformation work rate, crystal orientation, and initial grain size on DRX rates and compare DRX data from experimental and natural conditions. Overall, we show that microstructures can evolve over long transient intervals, and provide a framework for determining DRX kinetics from empirical data, which can ultimately be incorporated into geodynamic models of grain size evolution in the Earth.

Probing Galactic Halos with Fast Radio Bursts

The precise localization (<1'') of multiple fast radio bursts (FRBs) to z>0.1 galaxies has confirmed that the dispersion measures (DMs) of these enigmatic sources afford a new opportunity to probe the diffuse ionized gas around and in between galaxies. In this manuscript, we examine the signatures of gas in dark matter halos (aka halo gas) on DM observations in current and forthcoming FRB surveys. Combining constraints from observations of the high velocity clouds, OVII absorption, and the DM to the Large Magellanic Cloud with hydrostatic models of halo gas, we estimate that our Galactic halo will contribute ${\rm DM}_{\rm MW,halo} \approx 50-80 \rm pc/cm^{-3}$ from the Sun to 200 kpc independent of any contribution from the Galactic ISM. Extending analysis to the Local Group, we demonstrate that M31's halo will be easily detected by high-sample FRB surveys (e.g. CHIME) although signatures from a putative Local Group medium may compete. We then review current empirical constraints on halo gas in distant galaxies and discuss the implications for their DM contributions. We further examine the DM probability distribution function of a population of FRBs at z >> 0 using an updated halo mass function and new models for the halo density profile. Lastly, we illustrate the potential of FRB experiments for resolving the baryonic fraction of halos by analyzing simulated sightlines through the CASBaH survey. All of the code and data products of our analysis are available at https://github.com/FRBs.

High-resolution ALMA Observations of HD 100546: Asymmetric Circumstellar Ring and Circumplanetary Disk Upper Limits

Abstract We present long-baseline Atacama Large Millimeter/submillimeter Array observations of the 870 μm dust continuum emission and CO (3–2) from the protoplanetary disk around the Herbig Ae/Be star HD 100546, which is one of the few systems claimed to have two young embedded planets. These observations achieve a resolution of 4 au (3.8 mas), an rms noise of 66 μJy beam−1, and reveal an asymmetric ring between ∼20 and 40 au with largely optically thin dust continuum emission. This ring is well fit by two concentric and overlapping Gaussian rings of different widths and a Vortex. In addition, an unresolved component is detected at a position consistent with the central star, which may trace the central inner disk (&lt;2 au in radius). We report a lack of compact continuum emission at the positions of both claimed protoplanets. We use this result to constrain the circumplanetary disk (CPD) mass and size of 1.44 M ⊕ and 0.44 au in the optically thin and thick regimes, respectively, for the case of the previously directly imaged protoplanet candidate at ∼55 au (HD 100546 b). We compare these empirical CPD constraints to previous numerical simulations. This suggests that HD 100546 b is inconsistent with several planet accretion models, while gas-starved models are also still compatible. We estimate the planetary mass as 1.65 M J using the relation between planet, circumstellar, and circumplanetary masses derived from numerical simulations. Finally, the CO-integrated intensity map shows a possible spiral arm feature that could match the spiral features identified in near-infrared scattered light polarized emission, which suggests a real spiral feature in the disk surface that needs to be confirmed with further observations.

Effects of hadron–quark phase transition on properties of neutron stars

We investigate the possible scenario of deconfinement of hyperon rich hadronic matter to quark matter at high densities and the resulting hybrid star (HS) properties are analyzed. In the relativistic mean-field framework, we construct the equation of state (EoS) of hadronic matter using the effective chiral model while the pure quark matter is described using the MIT bag model. We revisit the hyperon puzzle and analyze the possibility of hadron–quark phase transition with proper choice of the bag constant. In static condition the maximum mass of the resultant HSs are in good agreement with the recent observational bounds on the same from high mass pulsars such as PSR J1614−2230 and PSR J0348+0432. On invoking the phenomenon of phase transition, the radius of canonical mass (R1.4) and value of R1.6 predicted by the model lie within the range prescribed from binary neutron star merger detected by the LIGO-Virgo collaboration in 2017. The surface redshift obtained for the HSs also satisfy the constraints from pulsars RX J0 720.4-3125 and 1E 1 207.4-5209. It is worth noting that unlike several other works, we add no modifications to the original form of the Bag model to satisfy these recent observational and empirical constraints on NS properties. We also discuss the rotational aspects of the HSs by calculating the properties like rotational mass, radius, energy density, moment of inertia at different angular velocities. The maximum bound on rotational frequency from the rapidly rotating pulsars like PSR B1937+21 and PSR J1748−2446ad are satisfied with the HS configuration. We also test the universality of our hybrid EoS in terms of normalized moment of inertia.

Mode Changing and Giant Pulses in the Millisecond Pulsar PSR B1957+20

Abstract Many radio pulsars have stable pulse profiles, but some exhibit mode changing where the profile switches between two or more quasi-stable modes of emission. So far, these effects had only been seen in relatively slow pulsars, but we show here that the pulse profile of PSR B1957+20, a millisecond pulsar, switches between two modes, with a typical time between mode changes of only 1.7 s (or ∼1000 rotations), the shortest observed to date. The two modes differ in both intensity and polarization, with relatively large differences in the interpulse and much more modest ones in the main pulse. We find that the changes in the interpulse precede those in the main pulse by ∼25 ms, placing an empirical constraint on the timescale over which mode changes occurs. We also find that the properties of the giant pulses emitted by PSR B1957+20 are correlated with the mode of the regular emission: their rate and the rotational phase at which they are emitted both depend on mode. Furthermore, the energy distribution of the giant pulses emitted near the main pulse depends on mode as well. We discuss the ramifications for our understanding of the radio emission mechanisms as well as for pulsar timing experiments.

On the Impact of Helium Content on the RR Lyrae Distance Scale

Abstract We constructed new sets of He-enhanced (Y = 0.30, Y = 0.40) nonlinear, time-dependent convective hydrodynamical models of RR Lyrae (RRL) stars covering a broad range in metal abundances (Z = 0.0001–0.02). The increase in He content from the canonical value (Y = 0.245) to Y = 0.30–0.40 causes a simultaneous increase in stellar luminosity and in pulsation period. To investigate the dependence of the RRL distance scale on the He abundance, we computed new optical (RI) and near-infrared (JHK) Period–luminosity–metallicity–helium relations. Interestingly enough, the increase in He content causes a minimal change in the coefficients of both period and metallicity terms, since canonical and He-enhanced models obey similar PLZ relations. On the contrary, the classical B- and V-band mean magnitude metallicity relations and the R-band PLZ relation display a significant dependence on the He content. The He-enhanced models are, at fixed metal content, 0.2–0.5 mag brighter than canonical ones. This variation is only marginally affected by evolutionary effects. The quoted distance diagnostics once calibrated with trigonometric parallaxes (Gaia) will provide the opportunity to estimate the He content of field and cluster RRLs. Moreover, the use of either spectroscopic or photometric metal abundances will pave the way to new empirical constraints on the universality of the helium-to-metal enrichment ratio in old (t ≳ 10 Gyr) stellar tracers.

Terminal settling velocity of a single sphere in drilling fluid

The accurate prediction of terminal settling velocity of solid spheres in non-Newtonian liquids is important for various fluid-particle systems such as slurry pipelines, separation processes, hole-cleaning in drilling operations, and mineral processing. The standard practice for the prediction involves an implicit procedure that requires repeated iterations using Newtonian correlations. Wilson et al. developed an explicit method that allows direct (noniterative) prediction of the velocity in non-Newtonian liquids. Although very useful, the original Wilson model has an empirical constraint that limits its application. In this study, experiments are performed to measure the terminal settling velocity of precision spheres in Newtonian liquid (water) and non-Newtonian drilling fluids (Flowzan solutions). The Herschel–Bulkley three parameter model satisfactorily modeled the non-Newtonian rheology. Experimental data and similar measurements available in the literature are presented in this paper. The data exhibited the standard relationship between the drag coefficient and the Reynolds number. The original Wilson model was tested for these data points and was modified in this study to address its limitations. Consequently, it was observed that the modified version yielded more accurate results than the original model. Its prediction was especially better when the value of corresponding Reynolds number was more than 10.

First empirical constraints on the low Hα mass-loss rates of magnetic O-stars

AbstractA small subset of Galactic O-stars possess surface magnetic fields that alter the outflowing stellar wind by magnetically confining it. Key to the magnetic confinement is that it induces rotational modulation of spectral lines over the full EM domain; this allows us to infer basic quantities, e.g., mass-loss rate and magnetic geometry. Here, we present an empirical study of the Hα line in Galactic magnetic O-stars to constrain the mass fed from the stellar base into the magnetosphere, using realistic multi-dimensional magnetized wind models, and compare with theoretical predictions. Our results suggest that it may be reasonable to use mass-feeding rates from non-magnetic wind theory if the absolute mass-loss rate is scaled down according to the amount of wind material falling back upon the stellar surface. This provides then some empirical support to the proposal that such magnetic O-stars might evolve into heavy stellar-mass black holes (Petit et al.2017).

The Developmental Trajectory of the Operational Momentum Effect.

Mental calculation is thought to be tightly related to visuospatial abilities. One of the strongest evidence for this link is the widely replicated operational momentum (OM) effect: the tendency to overestimate the result of additions and to underestimate the result of subtractions. Although the OM effect has been found in both infants and adults, no study has directly investigated its developmental trajectory until now. However, to fully understand the cognitive mechanisms lying at the core of the OM effect it is important to investigate its developmental dynamics. In the present study, we investigated the development of the OM effect in a group of 162 children from 8 to 12 years old. Participants had to select among five response alternatives the correct result of approximate addition and subtraction problems. Response alternatives were simultaneously presented on the screen at different locations. While no effect was observed for the youngest age group, children aged 9 and older showed a clear OM effect. Interestingly, the OM effect monotonically increased with age. The increase of the OM effect was accompanied by an increase in overall accuracy. That is, while younger children made more and non-systematic errors, older children made less but systematic errors. This monotonous increase of the OM effect with age is not predicted by the compression account (i.e., linear calculation performed on a compressed code). The attentional shift account, however, provides a possible explanation of these results based on the functional relationship between visuospatial attention and mental calculation and on the influence of formal schooling. We propose that the acquisition of arithmetical skills could reinforce the systematic reliance on the spatial mental number line and attentional mechanisms that control the displacement along this metric. Our results provide a step in the understanding of the mechanisms underlying approximate calculation and an important empirical constraint for current accounts on the origin of the OM effect.

From ocean to mantle: new evidence for U-cycling with implications for the HIMU source and the secular Pb isotope evolution of Earth's mantle

Of the isotopically distinctive mantle domains, the so-called HIMU (“high-μ”; μ = 238U/204Pb) source is the most extreme, and its genesis continues to be debated. We report very strong U enrichment at unchanged Th concentrations in Cretaceous oceanic serpentinites with exceptionally high 206Pb/204Pb (reaching 56) but unchanged 208Pb/204Pb. Similar, but less extreme, features are found in 1.9 billion years old altered oceanic crust (AOC). Forward modelling demonstrates that mantle, if metasomatised by supercritical liquids derived from AOC and serpentinites, evolves to the HIMU Pb isotope signatures, while satisfying experimental and empirical constraints on subduction zone element processing. By contrast, no model solutions for the conventional proposal of the HIMU source representing residual igneous altered oceanic crust can be reconciled with 208Pb/204Pb, strengthening the need for a paradigm shift regarding HIMU OIB genesis. Over time, the net U addition to the convecting mantle via deeply subducted serpentinite has expressed itself as the so-called second terrestrial Pb isotope paradox, or kappa conundrum.

Optimized chiral N2LO interactions in nuclear matter

We employ modern two- and three-nucleon interactions derived in chiral perturbation theory (ChPT) at next to-next-to leading order (N2LO), to calculate the energy per particle of symmetric nuclear matter and pure neutron matter in the framework of the microscopic Brueckner-Hartree-Fock approach. In particular, we present results concerning two optimized versions at N2LO of chiral potentials ( $ \mathrm{N2LO}_{opt}$ ), fitted to properties of light nuclei. We also employ the recently developed $\mathrm{N2LO}_{sat}$ interaction which has been calculated at the same order of ChPT but fitted in a very different way compared with the $\mathrm{N2LO}_{opt}$ interactions. We find that using these potentials, in general, it is not possible to reproduce all the saturation properties of nuclear matter. In particular the behaviour of the symmetry energy ( $E_{sym}$ predicted by the interactions considered is quite soft. This is shown comparing our results with the empirical constraints on $E_{sym}$ obtained from the data analysis of the excitation energies of isobaric analog states in nuclei and from experimental data of the neutron skin thickness of heavy nuclei. We finally confront our results with similar calculations performed by other research groups using nuclear chiral interactions at various order of ChPT and employing different many-body methods.

Contrasting accessory mineral behavior in minimum-temperature melts: Empirical constraints from the Himalayan metamorphic core

Medium-grained leucogranite in the Tama Kosi region of the Nepalese Himalayan Metamorphic Core yields a relatively narrow range of monazite 208Pb/232Th dates with a dominant population at ~21.0 Ma inferred to represent crystallization of an early plutonic phase. In contrast, the pegmatitic portion of the same intrusive complex, that cross-cuts the medium-grained leucogranite, contains zircon, monazite and xenotime that each display near-identical age spectra, recording semi-continuous (re-)crystallization from 27.5 Ma to 21.0 Ma, followed by a ~2 m.y. hiatus then further (re-)crystallization between 19.4 and 18.6 Ma. The “gap” in pegmatite dates corresponds well to the crystallization age of the older leucogranite, whereas the end of accessory phase growth in the pegmatite coincides with the onset of regional-scale cooling. Detailed textural, trace element and thermochronologic data indicate that the range of zircon, monazite and xenotime dates recorded in the pegmatite reflect inherited components that underwent semi-continuous (re-)crystallization during metamorphism and/or anatexis in the source region(s), whereas dates younger than the hiatus indicate accessory phase recrystallization, related to both fluid influx and a concomitant increase in temperature. In contrast, the lack of an inherited component(s) in the medium-grained leucogranite phase is inferred to be a result of complete dissolution during partial melting. A model is proposed in which influx of heat and H2O-rich fluids associated with early leucogranite emplacement temporarily delayed zircon and monazite and xenotime crystallization, respectively. These data highlight the importance of measuring spatially resolved dates, trace elements and textural patterns from multiple accessory minerals combined with model constraints to better understand the often-complex crystallization history of anatectic melts in collisional orogens.

An uncertainty principle for star formation – II. A new method for characterizing the cloud-scale physics of star formation and feedback across cosmic history

The cloud-scale physics of star formation and feedback represent the main uncertainty in galaxy formation studies. Progress is hampered by the limited empirical constraints outside the restricted environment of the Local Group. In particular, the poorly-quantified time evolution of the molecular cloud lifecycle, star formation, and feedback obstructs robust predictions on the scales smaller than the disc scale height that are resolved in modern galaxy formation simulations. We present a new statistical method to derive the evolutionary timeline of molecular clouds and star-forming regions. By quantifying the excess or deficit of the gas-to-stellar flux ratio around peaks of gas or star formation tracer emission, we directly measure the relative rarity of these peaks, which allows us to derive their lifetimes. We present a step-by-step, quantitative description of the method and demonstrate its practical application. The method's accuracy is tested in nearly 300 experiments using simulated galaxy maps, showing that it is capable of constraining the molecular cloud lifetime and feedback time-scale to $<0.1$ dex precision. Access to the evolutionary timeline provides a variety of additional physical quantities, such as the cloud-scale star formation efficiency, the feedback outflow velocity, the mass loading factor, and the feedback energy or momentum coupling efficiencies to the ambient medium. We show that the results are robust for a wide variety of gas and star formation tracers, spatial resolutions, galaxy inclinations, and galaxy sizes. Finally, we demonstrate that our method can be applied out to high redshift ($z\lesssim4$) with a feasible time investment on current large-scale observatories. This is a major shift from previous studies that constrained the physics of star formation and feedback in the immediate vicinity of the Sun.

A quantitative model of paleowind reconstruction using subsurface lacustrine longshore bar deposits – An attempt

The paleo-atmospheric flow field is an important component of climate. However, the difficulty of constraining paleowind fields using geological information hinders quantification of paleo-atmospheric conditions. In this paper, it is proposed that the geometric characteristics of lacustrine longshore bars, widespread in both modern and ancient shallow lakes, can be used as proxies for paleowind fields. The self-organizational model of longshore bar formation indicates that bar geometry and dimensions are determined by breaking waves. Accordingly, a simple geometric model is proposed that incorporates empirical constraints, including: 1) the ratio of paleowater depths between bar crest and adjacent landward trough is constant, and 2) the bar landward slope reaches the angle of repose. The model suggests that the parameters longshore bar thickness (t), topographic slope of the bar-basement (α) and paleo-fetch of the basin (F) are sufficient to constrain paleowave conditions, and hence, based on wave statistics and wind-wave relationships, paleowind conditions. The method is then applied to an ancient example, the Dongying Depression in East China, to determine wind direction and strength during part of the Eocene (~45.0–44.2 Ma). The results show that contemporaneous northerly and southeasterly winds existed, with highest wind speeds of 6.9–13.5 m s−1 and 7.5–18.2 m s−1, respectively. These findings provide a new perspective on delineating paleowind conditions. Error analyses reveal that for a sufficiently large lake (fetch exceeding 30 km), calculation errors will be small to negligible, if longshore bar thickness is determined as precisely as possible. The method is applicable only for bars whose formation conforms to the self-organizational model.

First Observation of the Submillimeter Polarization Spectrum in a Translucent Molecular Cloud

Abstract Polarized emission from aligned dust is a crucial tool for studies of magnetism in the ISM, but a troublesome contaminant for studies of cosmic microwave background polarization. In each case, an understanding of the significance of the polarization signal requires well-calibrated physical models of dust grains. Despite decades of progress in theory and observation, polarized dust models remain largely underconstrained. During its 2012 flight, the balloon-borne telescope BLASTPol obtained simultaneous broadband polarimetric maps of a translucent molecular cloud at 250, 350, and 500 μm. Combining these data with polarimetry from the Planck 850 μm band, we have produced a submillimeter polarization spectrum, the first for a cloud of this type. We find the polarization degree to be largely constant across the four bands. This result introduces a new observable with the potential to place strong empirical constraints on ISM dust polarization models in a previously inaccessible density regime. Compared to models by Draine &amp; Fraisse, our result disfavors two of their models for which all polarization arises due only to aligned silicate grains. By creating simple models for polarized emission in a translucent cloud, we verify that extinction within the cloud should have only a small effect on the polarization spectrum shape, compared to the diffuse ISM. Thus, we expect the measured polarization spectrum to be a valid check on diffuse ISM dust models. The general flatness of the observed polarization spectrum suggests a challenge to models where temperature and alignment degree are strongly correlated across major dust components.

Nuclear matter calculations with chiral interactions

Using two-nucleon and three-nucleon interactions derived in the framework of chiral perturbation theory (ChPT) with and without the explicit Δ isobar contributions, we calculate the energy per particle of symmetric nuclear matter and pure neutron matter employing the microscopic Brueckner–Hartree–Fock approach. Specifically, we present nuclear matter calculations using the new fully local in coordinate-space two-nucleon interaction at the next-to-next-to-next-to-leading-order (N3LO) of ChPT with Δ isobar intermediate states (N3LOΔ) recently developed by Piarulli et al. [1] supplemented with a local N2LO three-nucleon interaction with explicit Δ isobar degrees of freedom. We show that for this combination of two- and three-nucleon interactions it is possible to obtain a good saturation point of symmetric nuclear matter. We also calculate the nuclear symmetry energy and compare our results with the available empirical constraints on this quantity.