Searcharxiv⌕ Search

arXiv subjects

Stefan Meingast

Publications and source records attributed to Stefan Meingast.

At least 19 recordsLinked to original sources
arXiv2026

The dispersal law of young star clusters: free expansion -- A Gaia/eROSITA census of Orion and Sco--Cen

We measure how young star clusters disperse over time in the two nearest star-forming complexes. Our sample comprises 44 \texttt{SigMA}-\textit{Gaia}-defined clusters in Orion and 31 in Sco--Cen, with isochronal ages of 2--25\,Myr. We extend each cluster's census with \textit{eROSITA}-selected young stars that share its parallax and motion and lie within the distance they could have traveled ballistically since birth. By 10--30\,Myr, about one in three former cluster stars lies outside the cluster's cataloged boundary. Across both complexes and the full age range, we find that (1) the half-member radius increases linearly with age, $\rfifty \simeq \sigbirth t$, (2) the velocity dispersion shows no measurable evolution, and (3) all studied clusters are unbound. These results support free expansion. Young clusters in Orion and Sco-Cen emerge unbound from their birth clouds and coast at their birth velocity dispersion without significant relaxation or a characteristic dispersal timescale. We further show that memberships defined by density contrast preferentially omit the fastest stars, making the same clusters appear to expand more slowly ($\propto t^{0.6}$), cool with age, and approach equilibrium.

astro-ph.GA↗
arXiv2026

A comprehensive cluster census of Orion. An application of the Significance Mode Analysis (SigMA) algorithm

Precise astrometric surveys and modern clustering algorithms are working in step to transform our view of star-forming regions. By revealing a much richer substructure than previously accessible, they pave the way for reconstructing star formation histories by accurately resolving and age-dating individual sub-populations. The Orion star-forming complex is the best-studied stellar nursery in the solar neighborhood and the nearest one currently forming massive stars. Even so, a comprehensive characterization of its substructure, including a homogeneous age mapping and extinction analysis, is still incomplete. Here, we present the most complete census of stellar populations across the Orion complex from the newest version of the SigMA algorithm and outline our additions and improvements to the algorithm that have extended its usage to distant (>300 pc) regions. We separate the Orion complex into 47 co-spatial and co-moving stellar groups comprising 11,996 reliable members, with ages ranging from 1.5 to 25 Myr. To evaluate the statistical robustness of each group, we derive cluster persistence values and individual membership probabilities for each source from 10 independent clustering repetitions. Our group memberships agree well with the literature, but SigMA consistently finds a factor of ~2-3 more members. In particular, it resolves more very young populations, such as NGC 2024, RV Orionis, B30, NGC 1977, NGC 2068, and NGC 2071, than previous algorithms. In addition to recovering 28 known clusters and three groups previously classified as substructures, we present 16 new co-eval substructure candidates of the Orion star-forming complex. This work builds up a new high-resolution time-resolved picture of Orion. This spatio-temporal map allows us to relate its stellar content to the surrounding ISM and paves the way for a detailed analysis of its star formation history in the future.

astro-ph.GA↗
arXiv2026

The First Glimpse of Water Ice Absorption Map in the Milky Way

Interstellar ice plays a key role in the thermal evolution of the interstellar medium and in astrochemical pathways, yet its large-scale distribution remains poorly constrained. We use ALLWISE and 2MASS photometry to estimate water ice absorption in the $\Wi$/WISE band by correcting the observed colors for reddening and intrinsic stellar colors. This allows us to construct a first Milky Way water ice map. By varying input parameters, we test the stability of the method and identify the extinction law as the dominant source of uncertainty. Using synthetic photometry, we also quantify how different physical and observational parameters influence the $\Wi$ band water ice absorption. The strong correlation between the measurement from photometric method and spectroscopic water ice abundance confirms that the $\Wi$ band signature originates from the 3 $\mu$m ice feature. We present the relationship between ice absorption in $\Wi$ band and water ice optical depth from theory and observations. Finally, we provide a preliminary Milky Way-scale map of water ice distribution.

astro-ph.GA↗
arXiv2025

Kinematics of young stellar objects in NGC 2024 based on infrared proper motions

The most recently formed young stellar objects (YSOs) in active star forming regions are excellent tracers of their parent cloud motion. Their positions and dynamics provide insight into cluster formation and constrain kinematic decoupling timescales between stars and gas. However, because of their strong extinction and young age, embedded YSOs are mainly visible at infrared wavelengths and thus absent from astrometric surveys such as Gaia. We measured the proper motions of 6,769 sources toward the NGC 2024 cluster in the Flame Nebula using multi-epoch near-infrared observations from three ESO public surveys: VISIONS, VHS, and the VISTA/VIRCAM science verification program. Cross-validation of our results with Gaia using optically visible stars shows excellent agreement, with uncertainties on the same order of magnitude. For 362 YSO candidates identified from the literature, we derived proper motions on the order of <5 mas/yr with mean measurement uncertainties of ~0.22 mas/yr. This is the first homogeneous proper motion measurement of this quality for more than half of these stars. For Class I and flat-spectrum sources, our results provide a >13-fold increase in available proper motion measurements. We analyzed the positional and kinematic differences between YSO classes and confirmed a previously reported inside-out age segregation from younger to older stars, likely driven by an outward movement of older stars. No evidence of prolonged hierarchical assembly was found. Instead, the results support a rapid (<1 Myr) cluster collapse. This scenario also accounts for the observed slightly higher 1D velocity dispersion of Class I sources relative to Class flat objects. YSO radial velocities generally align with the gas velocities measured from 12CO(3-2), HNC(1-0), HCN(1-0), and show a weaker correlation with N_2H+(1-0). Some Class II and III objects appear to be already decoupling.

astro-ph.GA↗
arXiv2025

Toward the fabric of the Milky Way I. The density of disk streams from a local $250^3$ pc$^3$ volume

We studied 12 disk streams found in a 250$^3$ pc$^3$ volume in the solar neighborhood, which we define as coeval and comoving stellar structures with aspect ratios greater than 3:1. Using Gaia Data Release 3 data and the advanced clustering algorithms SigMA and Uncover, we identified and characterized these streams beyond the search volume, doubling, on average, their known populations. We estimate the number density of disk streams to be $\approx 820$ objects / kpc$^3$ (for $|Z| < 100$ pc), or surface densities of $\approx 160$ objects / kpc$^2$. These estimates surpass N-body estimates by one to two orders of magnitude and challenge the prevailing understanding of their destruction mechanisms. Our analysis reveals that these 12 disk streams are dynamically cold with 3D velocity dispersions between 2 and 5 km s$^{-1}$, exhibit narrow sequences in the Hertzsprung-Russell diagram, and are highly elongated with average aspect ratios of 7:1, extending up to several hundred parsecs. We find evidence suggesting that one of the disk streams, currently embedded in the Scorpius-Centaurus association, is experiencing disruption, likely due to the primordial gas mass of the association.

astro-ph.GA↗
arXiv2025

Mapping water ice with infrared broadband photometry

Interstellar ices play a fundamental role in the physical and chemical evolution of molecular clouds and star-forming regions, yet their large-scale distribution and abundance remain challenging to map. In this work, I present the ice color excess method, which parametrizes the peak optical depth ($τ_{3.0}^{\mathrm{max}}$) of the prominent 3$μ$m absorption feature, which is predominantly caused by the presence of solid H$_2$O. The method builds on well-established near-infrared color excess techniques and uses widely available infrared broadband photometry. Through detailed evaluation of passband combinations and a comprehensive error analysis, I construct the ice color excess metric $Λ(W_1 - I_1)$. This parameter emerges as the optimal choice that minimizes systematic errors while leveraging high-quality, widely available photometry from Spitzer and WISE data archives. To calibrate the method, I compile from the literature a sample of stars located in the background of nearby molecular clouds, for which spectroscopically measured optical depths are available. The empirical calibration yields a remarkably tight correlation between $τ_{3.0}^{\mathrm{max}}$ and $Λ(W_1 - I_1)$. This photometric technique opens a new avenue for tracing the icy component of the interstellar medium on Galactic scales, providing a powerful complement to spectroscopic surveys and enabling new insights into the environmental dependence of the formation and evolution of icy dust grains.

astro-ph.GA↗
arXiv2024

The physical properties of Cluster Chains

We explore the kinematics and star formation history of the Scorpius Centaurus (Sco-Cen) OB association following the initial identification of sequential, linearly aligned chains of clusters. Building upon our characterization of the Corona Australis (CrA) chain, we now analyze two additional major cluster chains that exhibit similar characteristics: the Lower Centaurus Crux (LCC) and Upper Scorpius (Upper Sco) chains. All three cluster chains display distinct sequential patterns in 1) the 3D spatial distribution, 2) age, 3) velocity, and 4) mass. The Upper-Sco chain is the most massive and complex cluster chain, possibly consisting of two or more overlapping subchains. We discuss the possible formation of cluster chains and argue for a scenario where feedback from the most massive star formation episode 15 Myr ago initiated the formation of these spatio-temporal cluster sequences. Our results identify cluster chains as a distinct type of stellar structure with well-defined physical properties, formed in environments capable of sustaining stellar feedback over timescales of 5-10 Myr. We find that around 40% of the stellar population in Sco-Cen formed due to triggered star formation, with 35% forming along the three cluster chains. We conclude that cluster chains could be common structures in OB associations, particularly in regions that have similar natal environments as Sco-Cen. Beyond their significance for star formation and stellar feedback, they appear to be promising laboratories for chemical enrichment and the transport of elements from one generation to the next in the same star-forming region.

astro-ph.GA↗
arXiv2024

Most nearby young star clusters formed in three massive complexes

Efforts to unveil the structure of the local interstellar medium and its recent star formation history have spanned the past seventy years. Recent studies utilizing precise data from space astrometry missions have revealed nearby, newly formed star clusters with connected origins. Nonetheless, mapping young clusters across the entire sky back to their natal regions has been hindered by a lack of clusters with precise radial velocity data. Here we show that 155 out of 272 (57 percent) high-quality young clusters within one kiloparsec of the Sun arise from three distinct spatial volumes. This conclusion is based upon the analysis of data from the third Gaia release and other large-scale spectroscopic surveys. Currently dispersed throughout the Solar Neighborhood, their past positions over 30 Myr ago reveal that these families of clusters each formed in one of three compact, massive star-forming complexes. One of these families includes all of the young clusters near the Sun -- the Taurus and Sco-Cen star-forming complexes. We estimate that over 200 supernovae were produced from these families and argue that these clustered supernovae produced both the Local Bubble and the largest nearby supershell GSH 238+00+09, both of which are clearly visible in modern three-dimensional dust maps.

astro-ph.GA↗
arXiv2024

An empirical isochrone archive for nearby open clusters

The ages of star clusters and co-moving stellar groups contain essential information about the Milky Way. Their special properties make them excellent tracers of galactic structure and key components to unlocking its star formation history. Yet, even though the importance of stellar population ages has been widely recognized, their determination remains a challenging task often associated with highly model-dependent and uncertain results. We propose a new approach to this problem, which relies on empirical isochrones of known clusters extracted from high-quality observational data. These purely observation-based data products open up the possibility of relative age determination, free of stellar evolution model assumptions. For the derivation of the empirical isochrones, we used a combination of the statistical analysis tool principal component analysis for preprocessing and the supervised machine learning method support vector regression for curve extraction. To improve the statistical reliability of our result, we defined the empirical isochrone of a color-magnitude diagram (CMD) of a cluster as the median calculated from a set of bootstrapped curves. We provide empirical isochrones in all Gaia DR2 and DR3 color combinations for 83 nearby clusters, paving the way for a relative comparison between individual stellar populations based on an age-scaling ladder of empirical isochrones of known clusters. Due to the precision of the available observational data, we report accurate lower main sequence empirical isochrones for many clusters in our sample, which are of special interest as this region is known to be especially complex to model. We validate our results by comparing the extracted empirical isochrones to cluster ages in the literature. We also investigate the added information that empirical isochrones covering the lower main sequence can provide on two case studies.

astro-ph.GA↗
arXiv2023

The star formation history of the Sco-Cen association. Coherent star formation patterns in space and time

We reconstruct the star formation history of the Sco-Cen OB association using a novel high-resolution age map of the region. We develop an approach to produce robust ages for Sco-Cen's recently identified 37 stellar clusters using the SigMA algorithm. The Sco-Cen star formation timeline reveals four periods of enhanced star formation activity, or bursts, remarkably separated by about 5 Myr. Of these, the second burst, which occurred about 15 million years ago, is by far the dominant, and most of Sco-Cen's stars and clusters were in place by the end of this burst. The formation of stars and clusters in Sco-Cen is correlated but not linearly, implying that more stars were formed per cluster during the peak of the star formation rate. Most of the clusters that are large enough to have supernova precursors were formed during the 15 Myr period. Star and cluster formation activity has been continuously declining since then. We have clear evidence that Sco-Cen formed from the inside out and contains 100-pc long chains of contiguous clusters exhibiting well-defined age gradients, from massive older clusters to smaller young clusters. These observables suggest an important role for feedback in forming about half of Sco-Cen stars, although follow-up work is needed to quantify this statement. Finally, we confirm that the Upper-Sco age controversy discussed in the literature during the last decades is solved: the nine clusters previously lumped together as Upper-Sco, a benchmark region for planet formation studies, exhibit a wide range of ages from 3 to 19 Myr.

astro-ph.SR↗
arXiv2023

The Solar Neighborhood in the Age of Gaia

Most of what we know about the formation of stars, and essentially everything we know about the formation of planets, comes from observations of our solar neighborhood within 2 kpc of the Sun. Before 2018, accurate distance measurements needed to turn the 2D Sky into a faithful 3D physical picture of the distribution of stars, and the interstellar matter that forms them, were few and far between. Here, we offer a holistic review of how, since 2018, data from the Gaia mission are revealing previously unseen and often unexpected 3D distributions of gas, dust, and young stars in the solar neighborhood. We summarize how new extinction-based techniques yield 3D dust maps and how the density structure mapped out offers key context for measuring young stars' 3D positions from Gaia and VLBI. We discuss how a subset of young stars in Gaia with measured radial velocities and proper motions is being used to recover 3D cloud motion and characterize the internal dynamics of individual star-forming regions. We review relationships between newly-identified clusters and streams of young stars and the molecular interstellar medium from which they evolve. The combination of these measures of gas and stars' 3D distribution and 3D motions provides unprecedented data for comparison with simulations and reframes our understanding of local star formation in a larger Galactic context. This new 3D view of our solar neighborhood in the age of Gaia shows that star-forming regions once thought to be isolated are often connected on kiloparsec scales, causing us to reconsider models for the arrangement of gas and young stars in galaxies.

astro-ph.GA↗
arXiv2023

VISIONS: The VISTA Star Formation Atlas -- I. Survey overview

VISIONS is an ESO public survey of five nearby (d < 500 pc) star-forming molecular cloud complexes that are canonically associated with the constellations of Chamaeleon, Corona Australis, Lupus, Ophiuchus, and Orion. The survey was carried out with VISTA, using VIRCAM, and collected data in the near-infrared passbands J, H, and Ks. With a total on-sky exposure time of 49.4 h VISIONS covers an area of 650 deg$^2$, and it was designed to build an infrared legacy archive similar to that of 2MASS. Taking place between April 2017 and March 2022, the observations yielded approximately 1.15 million images, which comprise 19 TB of raw data. The observations are grouped into three different subsurveys: The wide subsurvey comprises shallow, large-scale observations and has visited the star-forming complexes six times over the course of its execution. The deep subsurvey of dedicated high-sensitivity observations has collected data on the areas with the largest amounts of dust extinction. The control subsurvey includes observations of areas of low-to-negligible dust extinction. Using this strategy, the VISIONS survey offers multi-epoch position measurements, is able to access deeply embedded objects, and provides a baseline for statistical comparisons and sample completeness. In particular, VISIONS is designed to measure the proper motions of point sources with a precision of 1 mas/yr or better, when complemented with data from VHS. Hence, VISIONS can provide proper motions for sources inaccessible to Gaia. VISIONS will enable addressing a range of topics, including the 3D distribution and motion of embedded stars and the nearby interstellar medium, the identification and characterization of young stellar objects, the formation and evolution of embedded stellar clusters and their initial mass function, as well as the characteristics of interstellar dust and the reddening law.

astro-ph.GA↗
arXiv2023

VISIONS: The VISTA Star Formation Atlas -- II. The data processing pipeline

The VISIONS public survey provides large-scale, multiepoch imaging of five nearby star-forming regions at subarcsecond resolution in the near-infrared. All data collected within the program and provided by the European Southern Observatory (ESO) science archive are processed with a custom end-to-end pipeline infrastructure to provide science-ready images and source catalogs. The data reduction environment has been specifically developed for the purpose of mitigating several shortcomings of the bona fide data products processed with software provided by the Cambridge Astronomical Survey Unit (CASU), such as spatially variable astrometric and photometric biases of up to 100 mas and 0.1 mag, respectively. At the same time, the resolution of coadded images is up to 20% higher compared to the same products from the CASU processing environment. Most pipeline modules are written in Python and make extensive use of C extension libraries for numeric computations, thereby simultaneously providing accessibility, robustness, and high performance. The astrometric calibration is performed relative to the Gaia reference frame, and fluxes are calibrated with respect to the source magnitudes provided in the Two Micron All Sky Survey (2MASS). For bright sources, absolute astrometric errors are typically on the order of 10 to 15 mas and fluxes are determined with subpercent precision. Moreover, the calibration with respect to 2MASS photometry is largely free of color terms. The pipeline produces data that are compliant with the ESO Phase 3 regulations and furthermore provides curated source catalogs that are structured similarly to those provided by the 2MASS survey.

astro-ph.IM↗
arXiv2022

Significance Mode Analysis (SigMA) for hierarchical structures. An application to the Sco-Cen OB association

We present a new clustering method, Significance Mode Analysis (SigMA), to extract co-spatial and co-moving stellar populations from large-scale surveys such as ESA Gaia. The method studies the topological properties of the density field in the multidimensional phase space. We validate SigMA on simulated clusters and find that it outperforms competing methods, especially in cases where many clusters are closely spaced. We apply the new method to Gaia DR3 data of the closest OB association to Earth, Scorpio-Centaurus (Sco-Cen), and find more than 13,000 co-moving young objects, with about 19% of these having a sub-stellar mass. SigMA finds 37 co-moving clusters in Sco-Cen. These clusters are independently validated by their narrow HRD sequences and, to a certain extent, by their association with massive stars too bright for Gaia, hence unknown to SigMA. We compare our results with similar recent work and find that the SigMA algorithm recovers richer populations, is able to distinguish clusters with velocity differences down to about 0.5 km s$^{-1}$, and reaches cluster volume densities as low as 0.01 sources/pc$^3$. The 3D distribution of these 37 coeval clusters implies a larger extent and volume for the Sco-Cen OB association than typically assumed in the literature. Additionally, we find the association to be more actively star-forming and dynamically more complex than previously thought. We confirm that the star-forming molecular clouds in the Sco-Cen region, namely, Ophiuchus, L134/L183, Pipe Nebula, Corona Australis, Lupus, and Chamaeleon, are part of the Sco-Cen The application of SigMA to Sco-Cen demonstrates that advanced machine learning tools applied to the superb Gaia data allows to construct an accurate census of the young populations, to quantify their dynamics, and to reconstruct the recent star formation history of the local Milky Way.

astro-ph.GA↗
arXiv2021

Extended stellar systems in the solar neighborhood -- V. Discovery of coronae of nearby star clusters

In this paper, we present a novel view on the morphology and the dynamical state of 10 prominent, nearby ($\leq$ 500 pc), and young ($\sim$30-300 Myr) open star clusters with Gaia DR2: $α\,$Per, Blanco 1, IC 2602, IC 2391, Messier 39, NGC 2451A, NGC 2516, NGC 2547, Platais 9, and the Pleiades. We introduce a pioneering member identification method that is informed by cluster bulk velocities and deconvolves the spatial distribution with a mixture of Gaussians. Our approach enables inferring the clusters' true spatial distribution by effectively filtering field star contaminants while at the same time mitigating the impact of positional errors along the line of sight. This first application of the method reveals the existence of vast stellar coronae, extending for $\gtrsim\,$100 pc and surrounding the, by comparison tiny and compact, cluster cores. The coronae and cores form intertwined, co-eval, and co-moving extended cluster populations, each encompassing tens of thousands of cubic parsec and stretching across tens of degrees on the sky. Our analysis shows that the coronae are gravitationally unbound but largely comprise the bulk of the populations' stellar mass. Most systems are in a highly dynamic state, showing evidence of expansion and sometimes simultaneous contraction along different spatial axes. The velocity field of the extended populations for the cluster cores appears asymmetric but is aligned along a spatial axis unique to each cluster. The overall spatial distribution and the kinematic signature of the populations are largely consistent with the differential rotation pattern of the Milky Way. This finding underlines the important role of global Galactic dynamics to the fate of stellar systems. Our results highlight the complexity of the Milky Way's open cluster population and call for a new perspective on the characterization and dynamical state of open clusters.

astro-ph.GA↗
arXiv2021

The $ρ$ Oph region revisited with Gaia EDR3

Context. Young and embedded stellar populations are important probes of the star formation process. Paradoxically, we have a better census of nearby embedded young populations than the slightly more evolved optically visible young populations. The high accuracy measurements and all-sky coverage of Gaia data are about to change this situation. Aims. This work aims to construct the most complete sample to date of YSOs in the $ρ$ Oph region. Methods. We compile a catalog of 1114 Ophiuchus YSOs from the literature and crossmatch it with the Gaia EDR3, Gaia-ESO and APOGEE-2 surveys. We apply a multivariate classification algorithm to this catalog to identify new, co-moving population candidates. Results. We find 191 new high-fidelity YSO candidates in the Gaia EDR3 catalog belonging to the $ρ$ Oph region. The new sources appear to be mainly Class III M-stars and substellar objects and are less extincted than the known members. We find 28 previously unknown sources with disks. The analysis of the proper motion distribution of the entire sample reveals a well-defined bimodality, implying two distinct populations sharing a similar 3D volume. The first population comprises young stars' clusters around the $ρ$ Ophiuchi star and the main Ophiuchus clouds (L1688, L1689, L1709). In contrast, the second population is older ($\sim$ 10 Myr), dispersed, has a distinct proper motion, and is possibly from the Upper Sco group. The two populations are moving away from each other at about 4.1 km/s, and will no longer overlap in about 4 Myr. Finally, we flag 17 sources in the literature as impostors, which are sources that exhibit large deviations from the average distance and proper motion properties of the $ρ$ Oph population. Our results show the importance of accurate 3D space and motion information for improved stellar population analysis. (Abridged)

astro-ph.SR↗
arXiv2021

Evidence for Radial Expansion at the Core of the Orion Complex with Gaia EDR3

We present a phase-space study of two stellar groups located at the core of the Orion complex: Briceño-1 and Orion Belt Population-near (OBP-near). We identify the groups with the unsupervised clustering algorithm, Shared Nearest Neighbor (SNN), which previously identified twelve new stellar substructures in the Orion complex. For each of the two groups, we derive the 3D space motions of individual stars using Gaia EDR3 proper motions supplemented by radial velocities from Gaia DR2, APOGEE-2, and GALAH DR3. We present evidence for radial expansion of the two groups from a common center. Unlike previous work, our study suggests that evidence of stellar group expansion is confined only to OBP-near and Briceño-1 whereas the rest of the groups in the complex show more complicated motions. Interestingly, the stars in the two groups lie at the center of a dust shell, as revealed via an extant 3D dust map. The exact mechanism that produces such coherent motions remains unclear, while the observed radial expansion and dust shell suggest that massive stellar feedback could have influenced the star formation history of these groups.

astro-ph.GA↗
arXiv2020

3D dynamics of the Orion cloud complex -- Discovery of coherent radial gas motions at the 100-pc scale

We present the first study of the 3D dynamics of the gas in the entire southern Orion cloud complex. We used the parallaxes and proper motions of YSOs from Gaia DR2 as a proxy for gas distance and proper motion, and the gas radial velocities from archival CO data, to compute the space motions of the different star-forming clouds in the complex, including subregions in Orion A, Orion B, and two outlying cometary clouds. From the analysis of the clouds' orbits in space and time, we find that they were closest about 6 Myr ago and are moving radially away from roughly the same region in space. This coherent 100-pc scale radial motion supports a scenario where the entire complex is reacting to a major feedback event, which we name the Orion-BB (big blast) event. This event, which we tentatively associate with the recently discovered Orion X stellar population, shaped the distribution and kinematics of the gas we observe today, although it is unlikely to have been the sole major feedback event in the region. We argue that the dynamics of most of the YSOs carry the memory of the feedback-driven star formation history in Orion and that the majority of the young stars in this complex are a product of large-scale triggering, which can raise the star formation rate by at least an order of magnitude, as for the head of Orion A (the Integral Shape Filament). Our results imply that a feedback, compression, and triggering process lies at the genesis of the Orion Nebula Cluster and NGC2023/2024 in Orion B, thus confirming broadly the classical feedback-driven scenario proposed in Elmegreen & Lada (1977). The space motions of the well-known young compact clusters, $σ$ Orionis and NGC 1977, are consistent with this scenario. A momentum estimate suggests that the energy of a few to several supernovae is needed to power the coherent 3D gas motion we measure in this paper.

astro-ph.SR↗