arXiv subjects

Q. Zhang

Publications and source records attributed to Q. Zhang.

At least 19 recordsLinked to original sources

arXiv2026

Magnetic fields in Massive Star-Forming Regions (MagMaR). VIII. Magnetic field overrun by gravity in GGD 27's accretion streamers

Context. Accretion streamers connected to protostellar disks and/or envelopes are thought to transport material across several thousand of au. Whether the motions of the gas comprising these streamers are dominated by gravity, large scale external turbulence or the action of magnetic fields is still under scrutiny. Aims. The aim of this work is to understand the role of the magnetic fields in the star-formation processes, in particular the role that magnetic forces have in potentially leading flows of gas and the accretion onto the envelopes and disks orbiting protostars. Methods. First, we try to identify the large-scale accretion streamers toward the high-mass Young Stellar Object GGD 27-MM1 and fit their trajectories using the so-called Mendoza's model, a modification of the classical model of pure gravitational infalling motion of fluid particles in a potential well. Second, we estimate the strength of the magnetic field associated with the streamers. Then, we determine if the streamers are dominated by magnetic or centrifugal forces. Results. Inspecting the Atacama Large Millimeter/submillimeter Array (ALMA) H$_2$CO cube we were able to identify four accretion streamers spreading up to $\sim$7,000 au and fit their trajectories in the position-position-velocity space. The polarized continuum emission reveals a good alignment of the magnetic field and the trajectory of the streamers. Using the Davis-Chandrasekhar-Fermi method, we derive estimates for the magnetic field strength, find that the streamers are sub-alfv\'enic, and discuss (after estimating energy terms for turbulence, ordered motions, magnetic forces and gravity) a possible qualitative scenario in which, the gravitational well of the GGD 27-MM1 protostar dominates streamer gas motions over turbulence and magnetic forces at distances of $\sim 3,000$ au.

astro-ph.SR↗

arXiv2026

Magnetic Fields in Massive Star-forming Regions (MagMaR). VII. On the dynamical importance of B-fields in massive protocluster W33 A

Magnetic fields (B-fields) are likely important in massive protocluster formation, but their role remains poorly constrained. We present 1.2 mm ALMA full-polarization observations of W33 A, a massive star-forming region at 2.4 kpc, with an angular resolution of 0.3 arcsec (730 au). The region is resolved into 20 dense cores and 9 filaments. The plane-of-sky B-field, inferred from linearly polarized dust emission, shows diverse structures: two nearly perpendicular large-scale components oriented northwest-southeast (NW-SE) and northeast-southwest (NE-SW), and two localized features toward the millimeter peaks MM1 and MM2. The NW-SE component could be shaped by a molecular outflow. The NE-SW component is coherent along the main filaments F1, F-Main, and Tail, all of which show trans-Alfvenic turbulence. In F-Main, the line mass exceeds the turbulent critical value, implying that magnetic support is required to prevent radial collapse and suppress fragmentation. In F1 and Tail, turbulence alone can support the gas against gravity, although B-fields may provide additional support. Toward MM1, the B-field follows a spiral-like infalling streamer traced by CH3CN. The trans-Alfvenic state of the accreting gas suggests efficient magnetic damping of turbulence and a magnetically regulated, laminar accretion flow feeding the core. Toward MM2, the B-field shows an hourglass morphology fitted by parabolic curves. Two independent methods give a consistent field strength of about 8.1(1.9) mG, and virial analysis indicates that the B-field is dynamically important in delaying collapse of MM2. Within a single protocluster, B-fields can stabilize filaments, regulate accretion, and delay core collapse, highlighting their diverse dynamic role in high-mass star formation.

astro-ph.GA↗

arXiv2026

ALMAGAL IX. The chemical complexity of AG318.9477-00.1960: A line-identification template for ALMAGAL

We present a detailed molecular line analysis of one of the most chemically rich cores in the ALMAGAL sample, the high-mass core~9 in the AG318.9477-00.1960 clump (AG318-c9), located at a heliocentric distance of \sim 10.4\,\rm kpc. We further assessed whether the emission of selected COMs, that is, ethylene glycol ((CH_2OH)_2; EG), glycolaldehyde (CH_2(OH)CHO; GA), and methyl formate (CH_3OCHO; MF), can be used to trace the innermost regions of hot molecular cores (HMCs). We analysed ALMA Band~6 observations (\sim 217-221GHz). Spectral line identification and local thermodynamic equilibrium modelling were performed using the software MADCUBA. We derived the physical parameters, including the column density (N), excitation temperature (Tex), velocity, line width, and molecular abundances relative to H_2, for all detected species. The chemical inventory of AG318-c9 was compared with that of the HMC G31.41+0.31 (G31). In addition, we performed a pixel-by-pixel analysis of EG, GA, and MF to generate spatially resolved N and Tex maps and corresponding radial profiles.

astro-ph.GA↗

arXiv2026

ALMAGAL VIII. Early phases of triggered star formation in source AG286.0716$-$1.8229

Several theoretical and observational studies have shown that new waves of triggered star-formation can be induced by the feedback from newly formed massive protostars, due to the expansion of H II regions. We used the millimeter dust continuum data of the ALMAGAL survey and the Anderson et al. 2014 catalog of H II regions and selected one ALMAGAL source for ALMA follow-up observations. In fact, in source AG286.0716$-$1.8229 six cores were detected at a resolution of $\sim7600$ au, but only two at a higher resolution. The 4 cores not detected at higher resolution are prestellar core candidates. We used archival data from the SMGPS and RACS to confirm whether an H II region is present in the field. We observed the source with with ALMA in Band 4, covering the emission of DCO$^+$ (2$-$1), N$_2$D$^+$ (2$-$1), DCN (2$-$1), and CH$_3$CCH (9$-$8), to estimates whether these cores are in an early phase of the star-formation process. The new Band 4 continuum image revealed three cores outside of the ALMAGAL field of view, for a total of 9 cores in the region, 8 of which are located along an arch of radius $\sim0.75$ pc. We have derived a spectral index between -0.14 and -0.4, in the frequency range of 0.8-1.6 GHz for the candidate H II region, which is consistent with optically thin free-free emission. Using plausible temperature ranges, based on the information from chemical tracers and the dust continuum, we derived mass ranges for the cores ($\sim2-16\,$M$_{\odot}$) and ranges for the virial parameter ($\sim0.3-5$). All the cores along the arch have virial parameters $\lesssim$2, with only one exception. Comparing the typical separation and mass of the cores with those expected in the case of the collect and collapse scenario and with the thermal Jean length and mass, the best agreement is found with the characteristic scales in the case of triggered star formation.

astro-ph.GA↗

arXiv2026

The converging gas flow around the infrared dark cloud G28.3

Aims: The G28.37+0.07 star-forming region is a prototypical infrared dark cloud (IRDC) located at the interface of a converging gas flow. This study characterizes the properties of this dynamic gas flow. Methods: Combining data from the Northern Extended Millimeter Array (NOEMA) with single-dish data from the IRAM30m observatory, we mapped large spatial scales (~81pc^2) at high angular resolution (7.0''x2.6'' corresponding ~2.3x10^4au or ~0.1pc) down to core scales. The spectral setup in the 3mm band covers many spectral lines as well as the continuum emission. Results: The data reveal the proposed west-east converging gas flow in all observed dense gas tracers. We estimate a mass-flow rate along that flow around 10^-3M_sun/yr. Comparing these west-east flow rates to infall rates toward sources along the line of sight, the gas flow rates are roughly a factor of 25 greater than than those along the line of sight. This confirms the dominance of longitudinal motions along the converging gas flow in G28.37. For comparison, in the main north-south IRDC formed by the west-east converging gas flow, infall rates along the line of sight are about an order of magnitude greater than those along the west-east flow. In addition to the kinematic analysis, a comparison of CH_3CN-derived gas temperatures with Herschel-derived dust temperatures typically show higher gas temperatures toward high-density sources. We discuss whether mechanical heating from the conversion of the flow's kinetic energy into thermal energy may explain some of the observed temperature differences. Conclusions: The differences between flow rates along the converging flow, perpendicular to it, and toward the sources at the IRDC center indicate that at the interfaces of converging gas flows - where most of the active star formation takes place - originally more directed gas flows can convert into multidirectional infall motions.

astro-ph.GA↗

arXiv2026

Interaction of the central jet with the surrounding gas in the protostellar outflow from IRAS 04166+2706

$Context.$ The outflow from the Class 0 protostar IRAS 04166+2706 (hereafter IRAS 04166) contains a remarkably symmetric jet-like component of extremely high-velocity (EHV) gas. $Aims.$ We studied the IRAS 04166 outflow and investigated the relation between its EHV component and the slower outflow gas. $Methods.$ We mosaicked the CO(2--1) emission from the IRAS 04166 outflow using the 12m and the Compact Arrays of ALMA. We also developed a ballistic toy model of the gas ejected laterally from a jet to interpret the data. $Results.$ In agreement with previous observations, the ALMA data show that the slow outflow component is distributed in two opposed conical lobes and has a shear-flow pattern with velocity increasing toward the axis. The EHV gas consists of a series of arc-like condensations that span the full width of the conical lobes and merge with their walls, suggesting that the fast and slow outflow components are physically connected. In addition, position--velocity diagrams along the outflow axis show finger-like extensions that connect the EHV emission with the origin of the diagram, as if part of the EHV gas had been decelerated by its interaction with the low-velocity outflow. A ballistic model can reproduce these finger-like extensions assuming that the EHV gas consists of jet material that has been ejected laterally over a short period of time and has transferred part of its momentum to the surrounding shear flow. $Conclusions.$ The EHV gas in the IRAS 04166 outflow seems to play a role in the acceleration of the slower gas component. The presence of similar finger-like extensions in the position-velocity diagrams of other outflows suggests that this process may be occurring in other systems, even if the EHV component is not seen because it has an atomic composition.

astro-ph.GA↗

arXiv2026

Formal Modeling and Verification of Grover's Algorithm

Grover's algorithm relies on the superposition and interference of quantum mechanics, which is more efficient than classical computing in specific tasks such as searching an unsorted database. Due to the high complexity of quantum mechanics, the correctness of quantum algorithms is difficult to guarantee through traditional simulation methods. By contrast, the fundamental concepts and mathematical structure of Grover's algorithm can be formalized into logical expressions and verified by higher-order logical reasoning. In this paper, we formally model and verify Grover's algorithm in the HOL Light theorem prover. We focus on proving key properties such as the unitarity of its oracle and diffusion operators, the monotonicity of the success probability with respect to the number of iterations, and an exact expression for the optimal iteration count. By analyzing a concrete application to integer factorization, we demonstrate the practicality and prospects of our work.

quant-ph↗

arXiv2025

ALMAGAL VI. The spatial distribution of dense cores during the evolution of cluster-forming massive clump

High-mass stars and star clusters form from the fragmentation of massive dense clumps driven by gravity, turbulence, and magnetic fields. The ALMAGAL project observed $\sim1000$ clumps at $\sim$1000\,au resolution, enabling a statistically significant characterization of this process across a large range of clump physical parameters and evolutionary stages. In this work, we investigated the spatial distribution of dense cores in the 514 massive, potentially cluster-forming, clumps hosting at least 4 cores, to trace fragmentation's initial conditions and early evolution. We used quantitative descriptors, evaluated against the clump bolometric luminosity-to-mass ratio as an indicator of evolution. Core separations were measured with the minimum spanning tree method (MST) and compared with the Jeans gravitational fragmentation theory. We used the $Q$ parameter and the mass segregation ratio, $\Lambda_{MSR}$, to evaluate whether cores have specific arrangements or differences depending on their masses. ALMAGAL cores are usually arranged in elliptical groups with an axis ratio $e\sim2.2$, but $e\geq$5 is also observed. A single characteristic core separation per clump is found in $\sim76$% of cases, but signatures of multiple fragmentation lengths not rare. Typical core separations are compatible with the clump-averaged thermal Jeans length, $\lambda^{th}_{J}$, though a population, typical of low-fragmented/young clumps, has wider separations with $l\approx3\times\lambda^{th}_{J}$. The core separation decreases on average from $l\sim22000$ au in younger systems to $l\sim7000$ au in more evolved ones. Cores are typically distributed in fractal-type subclusters, with centrally concentrated patterns appearing only at later stages, but without a progressive evolutionary transition. Finally, mass segregation is found in 110 systems, with its occurrence increasing with evolution.

astro-ph.GA↗

arXiv2025

ALMAGAL V. Relations between the core populations and the parent clump physical properties

Context. The fragmentation of massive molecular clumps into smaller, potentially star-forming cores plays a key role in the processes of high-mass star formation. The ALMAGAL project offers high-resolution data to investigate these processes across various evolutionary stages in the Galactic plane. Aims. This study aims at correlating the fragmentation properties of massive clumps, obtained from ALMA observations, with their global physical parameters (e.g., mass, surface density, and temperature) and evolutionary indicators (such as luminosity-to-mass ratio and bolometric temperature) obtained from Herschel observations. It seeks to assess whether the cores evolve in number and mass in tandem with their host clumps, and to determine the possible factors influencing the formation of massive cores (M > 24M_\odot). Methods. We analyzed the masses of 6348 fragments, estimated from 1.4 mm continuum data for 1007 ALMAGAL clumps. Leveraging this unprecedentedly large data set, we evaluated statistical relationships between clump parameters, estimated over about 0.1 pc scales, and fragment properties, corresponding to scales of a few 1000 au, while accounting for potential biases related to distance and observational resolution. Our results were further compared with predictions from numerical simulations. Results. The fragmentation level correlates preferentially with clump surface density, supporting a scenario of density-driven fragmentation, whereas it does not show any clear dependence on total clump mass. Both the mass of the most massive core and the core formation efficiency show a broad range and increase on average by an order of magnitude in the intervals spanned by evolutionary indicators such as clump dust temperature and the luminosity-to-mass ratio. This suggests that core growth continues throughout the clump evolution, favoring clump-fed over core-fed theoretical scenarios.

astro-ph.GA↗

arXiv2025

Pulse shape simulation for the reduced charge collection layer in p-type high-purity germanium detectors

$P$-type high-purity germanium (HPGe) detectors are widely used across many scientific domains, and current data analysis methods have served well in many use cases. However, applications like low-background experiments that search for rare physics, such as dark matter, neutrinoless double-beta decay, and coherent elastic neutrino-nucleus scattering, could profit a lot from a more detailed understanding of the detector response close to the surface. The outer $n^+$ electrode of the $p$-type HPGe detector forms a layer with reduced charge collection, and events originating here can be a critical background source in such experiments. If the difference in detector pulse shape between detector surface and bulk events is known, it can be used to identify and veto these background events. However, a faithful simulation of the detector response in this surface region is difficult and has not been available as a standard method so far. We present a novel three-dimensional pulse shape simulation method for this reduced charge collection (RCC) layer. We have implemented this method as a new feature in the open-source simulation package \emph{SolidStateDetectors$.$jl} and show a validation of the numerical simulation results with analytical calculations. An experimental study using a $p$-type HPGe detector also validates our approach. The current implementation supports $p$-type HPGe detectors of fairly arbitrary geometry, but is easily adaptable to $n$-type detectors by adjusting the impurity density profile of the layer. It should also be adaptable to other semiconductor materials in a straightforward fashion.

physics.ins-det↗

arXiv2025

First results from ALPPS: a sub-Alfv\'enic streamer in SVS13A

We present the first results from the ALMA Perseus Polarization Survey (ALPPS), focusing on the magnetic field in the SVS13A circumbinary disk. The dataset includes full-Stokes dust continuum observations at $\sim0\farcs3$ and 870 $\mu$m, as well as molecular line emission from C$^{17}$O$(J=3 \rightarrow 2)$ at $\sim0\farcs3$, C$^{18}$O$(J=2 \rightarrow 1)$ at $\sim0\farcs2$, and DCN$(J=3 \rightarrow 2)$ at $\sim0\farcs1$ angular resolution. Our observations resolve both a previously identified dust spiral and an infalling streamer, capturing their spatial and kinematic structures. The streamer is traced from scales $>300$ au down to the circumbinary disk. Using alignment measure (AM) maps and histograms that compare the orientations of the plane-of-sky magnetic field with local intensity and velocity gradients, we find that the AM distribution peaks at a value of 1. This AM peak strongly suggests alignment between the field and the dust total intensity emission, as well as between the field and the gas velocity, which in turn suggests grain alignment by magnetic fields. From our data, we derive a magnetic field strength, B$_{\mathrm{pos}} \sim 1.1 \pm 0.6$\, mG, and a kinetic to magnetic energy ratio of $0.5 \pm 0.4$, suggesting magnetic dominance. We also produced a map of the Alfv\'enic Mach number, finding $\mathcal{M}_{\rm A} < 1$ along the streamer, consistent with sub-Alfv\'enic infalling motions. Therefore, the field is likely facilitating the inflow of material from the envelope onto the disk by constraining movement across the field lines. This represents the first detection of a magnetically sub-Alfv\'enic infalling streamer in a protostellar system.

astro-ph.GA↗

arXiv2025

ALMA-IMF XX: Core fragmentation in the W51 high-mass star-forming region

We present a study of core fragmentation in the W51-E and W51-IRS2 protoclusters in the W51 high-mass star-forming region. The identification of core fragmentation is achieved by the spatial correspondence of cores and compact sources which are detected in the short (low resolution) and the long baseline (high resolution) continuum images with the Atacama Large Millimeter/submillimeter Array (ALMA) in Bands 3 (3 mm) and 6 (1.3 mm), respectively. We characterize the compact sources found in the long baseline image, and conclude that the compact sources are pre/protostellar objects (PPOs) that are either prestellar dust cores or dust disks or envelopes around protostars. The observed trend of core fragmentation in W51 is that (i) massive cores host more PPOs, (ii) bright PPOs are preferentially formed in massive cores, (iii) equipartition of flux between PPOs is uncommon. Thermal Jeans masses of parent cores are insufficient to explain the masses of their fragments, and this trend is more prominent at high-mass cores. We also find that unfragmented cores are large, less massive, and less dense than fragmented cores.

astro-ph.GA↗

arXiv2025

First Demonstration of Resonant Pitch-Angle Scattering of Relativistic Electrons by Externally-Launched Helicon Waves

Helicon waves satisfying the normal wave-particle cyclotron resonance are observed to limit the growth and maximum energy of relativistic electrons (REs) in low-density Ohmic DIII-D tokamak plasmas. Following the application of helicon waves, pitch-angle scattering of high-energy REs causes an increase in both synchrotron and electron-cyclotron emissions. The hard x-ray emission, a proxy for the RE population, ceases to grow; and energy-resolved hard x-ray measurements also show a striking decrease in the number of high-energy REs (above the resonance at approximately \SI{8}{MeV}) to below the noise floor. This occurs despite the toroidal electric field remaining high enough to drive exponential RE growth in the absence of helicon waves. These results open new directions for limiting the maximum energy of RE populations in laboratory and fusion plasmas.

physics.plasm-ph↗

arXiv2025

ALMAGAL IV. Morphological comparison of molecular and thermal dust emission using the histogram of oriented gradients (HOG) method

The study of molecular line emission is crucial to unveil the kinematics and the physical conditions of gas in star-forming regions. Our aim is to quantify the reliability of using individual molecular transitions to derive physical properties of the bulk of the H2 gas, looking at morphological correlations in their overall integrated molecular line emission with the cold dust. For this study we selected transitions of H2CO, CH$_3$OH, DCN, HC$_3$N, CH$_3$CN, CH$_3$OCHO, SO, and SiO and compared them with the 1.38 mm dust continuum emission at different spatial scales in the ALMAGAL sample, that observed a total of 1013 targets covering all evolutionary stages of the high-mass star-formation process and different conditions of clump fragmentation. We used the method of the histogram of oriented gradients (HOG) implemented in the tool astroHOG to compare the morphology of integrated line emission with maps of the 1.38 mm dust continuum emission. Moreover, we calculated the Spearman's correlation coefficient, and compared it with our astroHOG results. Only H$_2$CO, CH$_3$OH, and SO show emission on spatial scales comparable with the diffuse continuum emission. However, from the HOG method, the median correlation of the emission of each of these species with the continuum is only $\sim$24-29%. In comparison with the dense fragments these molecular species still have low values of correlation. On the other hand DCN, HC$_3$N, CH$_3$CN, and CH$_3$OCHO show a good correlation with the dense dust fragments, above 60%. The worst correlation is seen with SiO, both with the extended continuum emission and with compact sources. From the comparison of the results of the HOG method and the Spearman's correlation coefficient, the HOG method gives much more reliable results than the intensity-based coefficient in estimating the level of similarity of the emission morphology.

astro-ph.GA↗

arXiv2025

Mountain pass solution to the Br\'{e}zis-Nirenberg problem with logarithmic perturbation

In this paper we give a positive answer to the conjecture raised by Hajaiej et al. (J. Geom. Anal., 2024, 34(6): No. 182, 44 pp) on the existence of a mountain pass solution at positive energy level to the Br\'{e}zis-Nirenberg problem with logarithmic perturbation. To be a little more precise, by taking full advantage of the local minimum solution and some very delicate estimates on the logarithmic term and the critical term, we prove that the following problem \begin{eqnarray*} \begin{cases} -\Delta u= \lambda u+\mu|u|^2u+\theta u\log u^2, &x\in\Omega,\\ u=0, &x\in\partial\Omega \end{cases} \end{eqnarray*} possesses a positive mountain pass solution at positive energy level, where $\Omega\subset \mathbb{R}^4$ is a bounded domain with smooth boundary $\partial\Omega$, $\lambda\in \mathbb{R}$, $\mu>0$ and $\theta<0$. A key step in the proof is to control the mountain pass level around the local minimum solution from above by a proper constant to ensure the local compactness. Moreover, this result is also extended to three-dimensional and five-dimensional cases.

math.AP↗

arXiv2025

An attempt to determine the magnetic field configuration in the planetary nebula K 3-35 with ALMA

We examined dust polarisation within the planetary nebula (PN) K 3-35 using the Atacama Large Millimeter/Submillimeter Array (ALMA). This investigation aimed to identify and trace the magnetic field within the PN, as it potentially plays a crucial role in shaping this bipolar nebula. Our findings include a marginal detection of the polarised region and low fractional polarisation (peaking at 1.4%). Assuming a certain level of validity, we observed well-organised dust grains aligned along the equatorial plane of the PN, indicating a magnetic field alignment with the outflows. The limited polarisation detection at submillimeter wavelengths in this PN and others may be attributed to a pronounced optical depth. However, our K 3-35 analysis with the code DUSTY does not seem to support this idea. We also modelled the SED of K3-35, and our best-fit models included a mixture of silicates and amorphous carbon. The grains of amorphous carbon are less susceptible to alignment with the magnetic field, which could, at least partially, explain the observed low polarisation. The models presented in this article should be considered preliminary, and a more advanced approach is needed for a more complete interpretation of the results.

astro-ph.SR↗

arXiv2025

ALMAGAL I. The ALMA evolutionary study of high-mass protocluster formation in the Galaxy. Presentation of the survey and early results

Fundamental questions about the physics responsible for fragmenting molecular parsec-scale clumps into cores of ~1000 au are still open, that only a statistically significant investigation with ALMA is able to address: what are the dominant agents that determine the core demographics, mass, and spatial distribution as a function of the physical properties of the hosting clumps, their evolutionary stage and the different Galactic environments in which they reside? To what extent extent is fragmentation driven by clumps dynamics or mass transport in filaments? With ALMAGAL we observed the 1.38 mm continuum and lines toward more than 1000 dense clumps in our Galaxy, with M>500M_sun, surface density > 0.1 g/cm2 and d<7.5 kpc. The ACA and two 12-m array setups were used to deliver a minimum resolution of ~1000 au over the entire sample distance range. The sample covers all evolutionary stages from infrared dark clouds (IRDCs) to HII regions from the tip of the Galactic bar to the outskirts of the Galaxy. The spectral setup includes several molecular lines to trace the multiscale physics and dynamics of gas, notably CH3CN, H2CO, SiO, CH3OH, DCN, HC3N, SO etc. We present an initial overview of the observations and the early science product and results, with a first characterization of the morphological properties of the continuum emission. We use "perimeter-versus-area" and convex hull-versus-area metrics to classify the different morphologies. More extended and morphologically complex shapes are found toward clumps that are relatively more evolved and have higher surface densities.

astro-ph.GA↗

arXiv2025

ALMAGAL II. The ALMA evolutionary study of high-mass protocluster formation in the Galaxy. ALMA data processing and pipeline

The ALMAGAL Large Program has observed 1017 high-mass star-forming regions distributed throughout the Galaxy, sampling different evolutionary stages and environmental conditions. In this work, we present the acquisition and processing of the ALMAGAL data. The main goal is to set up a robust pipeline that generates science-ready products, with a good and uniform quality across the whole sample. ALMAGAL observations were performed with the Atacama Large Millimeter/submillimeter Array (ALMA). Each field was observed in three different telescope arrays, being sensitive to spatial scales ranging from 1000 au up to 0.1 pc. The spectral setup allows sensitive imaging of the continuum emission at 219 GHz, and it covers multiple molecular spectral lines observed in four different spectral windows that span about 4 GHz in frequency coverage. We have designed a Python-based processing workflow to calibrate and image these observational data. This ALMAGAL pipeline includes an improved continuum determination, suited for line-rich sources; an automatic self-calibration process that improves the dynamical range of the final images; and the combination of data from different telescope arrays to produce science-ready, fully combined images. The fully combined products have spatial resolutions in the range 800-2000 au, and mass sensitivities in the range 0.02-0.07 Mo. We also present a first analysis of the spectral line information included in the ALMAGAL setup, and its potential for future scientific studies. As an example, specific spectral lines at 1000 au scales resolve the presence of multiple outflows in clusters and will help us to search for disk candidates around massive protostars. Moreover, the broad frequency bands provide information on the chemical richness of the different cluster members, which can be used to study the chemical evolution during the formation process of star clusters.

astro-ph.GA↗