# Magnus V. Persson's research while affiliated with Chalmers University of Technology and other places

## Publications (53)

Preprint
The nitrogen chemical evolution during star and planet formation is still not fully understood. Ammonia (NH$_3$) is a key specie in the understanding of the molecular evolution in star-forming clouds and nitrogen isotope fractionation. In this paper, we present high spatial resolution observations of multiple emission lines of NH$_3$ toward the pro...
Article
Context. Establishing the origin of the water D/H ratio in the Solar System is central to our understanding of the chemical trail of water during the star and planet formation process. Recent modeling suggests that comparisons of the D 2 O/HDO and HDO/H 2 O ratios are a powerful way to trace the chemical evolution of water and, in particular, deter...
Preprint
Full-text available
Establishing the origin of the water D/H ratio in the Solar System is central to our understanding of the chemical trail of water during the star and planet formation process. Recent modeling suggests that comparisons of the D$_2$O/HDO and HDO/H$_2$O ratios are a powerful way to trace the chemical evolution of water and, in particular, determine wh...
Article
Context. Water is a key molecule in the physics and chemistry of star and planet formation, but it is difficult to observe from Earth. The Herschel Space Observatory provided unprecedented sensitivity as well as spatial and spectral resolution to study water. The Water In Star-forming regions with Herschel (WISH) key program was designed to observe...
Article
Context. Far infrared cooling of excited gas around protostars has been predominantly studied in the context of pointed observations. Large-scale spectral maps of star forming regions enable the simultaneous, comparative study of the gas excitation around an ensemble of sources at a common frame of reference, therefore, providing direct insights in...
Preprint
Large scale spectral maps of star forming regions enable the comparative study of the gas excitation around an ensemble of sources at a common frame of reference, providing direct insights in the multitude of processes involved. In this paper we employ spectral-line maps to decipher the excitation, the kinematical and dynamical processes in NGC 133...
Article
Context: Low-mass protostars drive powerful molecular outflows that can be observed with millimetre and submillimetre telescopes. Various sulfuretted species are known to be bright in shocks and could be used to infer the physical and chemical conditions throughout the observed outflows. Aims: The evolution of sulfur chemistry is studied along the...
Article
Context. Water is a key volatile that provides insight into the initial stages of planet formation. The low water abundances inferred from water observations toward low-mass protostellar objects may point to a rapid locking of water as ice by large dust grains during star and planet formation. However, little is known about the water vapor abundanc...
Preprint
Water is a key volatile that provides insights into the initial stages of planet formation. The low water abundances inferred from water observations toward low-mass protostellar objects may point to a rapid locking of water as ice by large dust grains during star and planet formation. However, little is known about the water vapor abundance in new...
Article
We have conducted a survey of 328 protostars in the Orion molecular clouds with the Atacama Large Millimeter/submillimeter Array at 0.87 mm at a resolution of ~0.”1 (40 au), including observations with the Very Large Array at 9 mm toward 148 protostars at a resolution of ~0 08 (32 au). This is the largest multiwavelength survey of protostars at thi...
Article
Context. Low-mass protostars drive powerful molecular outflows that can be observed with millimetre and submillimetre telescopes. Various sulfuretted species are known to be bright in shocks and could be used to infer the physical and chemical conditions throughout the observed outflows. Aims. The evolution of sulfur chemistry is studied along the...
Preprint
Context. Low-mass protostars drive powerful molecular outflows that can be observed with mm and sub-mm telescopes. Various sulfuretted species are known to be bright in shocks and could be used to infer the physical and chemical conditions throughout the observed outflows. Aims. The evolution of sulfur chemistry is studied along the outflows driven...
Preprint
We have conducted a survey of 328 protostars in the Orion molecular clouds with ALMA at 0.87 mm at a resolution of $\sim$0.1" (40 au), including observations with the VLA at 9 mm toward 148 protostars at a resolution of $\sim$0.08" (32 au). This is the largest multi-wavelength survey of protostars at this resolution by an order of magnitude. We use...
Article
We present Atacama Large Millimeter/submillimeter Array (0.87 mm) and Very Large Array (9 mm) observations toward OMC-2 FIR4 and OMC-2 FIR3 within the Orion integral-shaped filament, thought to be two of the nearest regions of intermediate-mass star formation. We characterize the continuum sources within these regions on ~40 au (0."1) scales and as...
Article
Methanol is a key species in astrochemistry because it is the most abundant organic molecule in the interstellar medium and is thought to be the mother molecule of many complex organic species. Estimating the deuteration of methanol around young protostars is of crucial importance because it highly depends on its formation mechanisms and the physic...
Preprint
We present ALMA (0.87~mm) and VLA (9~mm) observations toward OMC2-FIR4 and OMC2-FIR3 within the Orion integral-shaped filament that are thought to be the nearest regions of intermediate mass star formation. We characterize the continuum sources within these regions on $\sim$40~AU (0\farcs1) scales and associated molecular line emission at a factor...
Article
Context. How water is delivered to planetary systems is a central question in astrochemistry. The deuterium fractionation of water can serve as a tracer for the chemical and physical evolution of water during star formation and can constrain the origin of water in Solar System bodies. Aims. The aim is to determine the HDO/H 2 O ratio in the inner w...
Preprint
The deuterium fractionation of water can serve as a tracer for the chemical and physical evolution of water during star formation and can constrain the origin of water in Solar System bodies. We determine the HDO/H$_2$O ratio in the inner warm gas toward three low-mass Class 0 protostars selected to be in isolated cores, i.e., not associated with a...
Article
Context. The relationship between outflow launching and the formation of accretion disks around young stellar objects is still not entirely understood, which is why spectrally and spatially resolved observations are needed. Recently, the Atacama Large Millimetre/sub-millimetre Array (ALMA) carried out long-baseline observations towards a handful of...
Preprint
Methanol is a key species in astrochemistry since it is the most abundant organic molecule in the ISM and is thought to be the mother molecule of many complex organic species. Estimating the deuteration of methanol around young protostars is of crucial importance because it highly depends on its formation mechanisms and the physical conditions duri...
Preprint
Context. The relationship between outflow launching and formation of accretion disks around young stellar objects is still not entirely understood, which is why spectrally and spatially resolved observations are needed. Recently, the Atacama Large Millimetre/sub-millimetre Array (ALMA) has carried out long-baseline observations towards a handful of...
Article
Context. The chemical composition of high-mass protostars reflects the physical evolution associated with different stages of star formation. In addition, the spatial distribution and velocity structure of different molecular species provide valuable information on the physical structure of these embedded objects. Despite an increasing number of in...
Preprint
The chemical composition of high-mass protostars reflects the physical evolution associated with different stages of star formation. In this study, the molecular inventory of the forming high-mass star AFGL 4176 is studied in detail at high angular resolution (~0.35 arcsec) using ALMA. This high resolution makes it possible to separate the emission...
Article
Recent measurements carried out at comet 67P/Churyumov–Gerasimenko (67P) with the Rosetta probe revealed that molecular oxygen, O₂, is the fourth most abundant molecule in comets. Models show that O₂ is likely of primordial nature, coming from the interstellar cloud from which our solar system was formed. However, gaseous O₂ is an elusive molecule...
Article
Context. One of the important questions of astrochemistry is how complex organic molecules, including potential prebiotic species, are formed in the envelopes around embedded protostars. The abundances of minor isotopologues of a molecule, in particular the D- and ¹³ C-bearing variants, are sensitive to the densities, temperatures and timescales ch...
Preprint
This paper presents a systematic survey of the deuterated and 13C isotopologues of a variety of oxygen-bearing complex organic molecules on Solar System scales toward the protostar IRAS 16293-2422B. We use the data from an unbiased molecular line survey between 329 and 363 GHz from the Atacama Large Millimeter/submillimeter Array (ALMA). The observ...
Preprint
Recent measurements carried out at comet 67P/C-G with the ${\it Rosetta}$ probe revealed that molecular oxygen, O$_2$, is the fourth most abundant molecule in comets. Models show that O$_2$ is likely of primordial nature, coming from the interstellar cloud from which our Solar System was formed. However, gaseous O$_2$ is an elusive molecule in the...
Article
Context . Complex organic molecules are readily detected in the inner regions of the gaseous envelopes of forming protostars. Their detection is crucial to understanding the chemical evolution of the Universe and exploring the link between the early stages of star formation and the formation of solar system bodies, where complex organic molecules h...
Preprint
Full-text available
Complex organic molecules are readily detected in the inner regions of the gaseous envelopes of forming protostars. In particular, molecules that contain nitrogen are interesting due to the role nitrogen plays in the development of life and the compact scales such molecules have been found to trace around forming protostars. The goal of this work i...
Article
Partitioning of elemental nitrogen in star-forming regions is not well constrained. Most nitrogen is expected to be partitioned among atomic nitrogen, molecular nitrogen (N2), and icy N-bearing molecules, such as ammonia (NH3) and N2. Atomic nitrogen is not directly observable in the cold gas. In this paper, we propose an indirect way to constrain...
Article
Full-text available
The evolutionary past of our Solar System can be pieced together by comparing analogous low-mass protostars with remnants of our Protosolar Nebula - comets. Sulphur-bearing molecules may be unique tracers of the joint evolution of the volatile and refractory components. ALMA Band 7 data from the large unbiased Protostellar Interferometric Line Surv...
Article
Context. Snowlines are key ingredients for planet formation. Providing observational constraints on the locations of the major snowlines is therefore crucial for fully connecting planet compositions to their formation mechanism. Unfortunately, the most important snowline, that of water, is very difficult to observe directly in protoplanetary disks...
Article
Full-text available
Searches for the prebiotically-relevant cyanamide (NH$_2$CN) towards solar-type protostars have not been reported in the literature. We here present the first detection of this species in the warm gas surrounding two solar-type protostars, using data from the Atacama Large Millimeter/Submillimeter Array Protostellar Interferometric Line Survey (PIL...
Article
Full-text available
Context. The enhanced degrees of deuterium fractionation observed in envelopes around protostars demonstrate the importance of chemistry at low temperatures, relevant in pre- and protostellar cores. Formaldehyde is an important species in the formation of methanol and more complex molecules. Aims. Here, we aim to present the first study of formalde...
Article
Full-text available
Organohalogens, a class of molecules that contain at least one halogen atom bonded to carbon, are abundant on the Earth where they are mainly produced through industrial and biological processes ¹. Consequently, they have been proposed as biomarkers in the search for life on exoplanets ². Simple halogen hydrides have been detected in interstellar s...
Article
One of the open questions in astrochemistry is how complex organic and prebiotic molecules are formed. Aims. Our aim is to start the process of compiling an inventory of oxygen-bearing complex organic molecules toward the solar-type Class 0 protostellar binary IRAS16293-2422 from an unbiased spectral survey with ALMA (PILS). Here we focus on the ne...
Article
Binary and multiple star systems are a frequent outcome of the star formation process, and as a result, almost half of all sun-like stars have at least one companion star. Theoretical studies indicate that there are two main pathways that can operate concurrently to form binary/multiple star systems: large scale fragmentation of turbulent gas cores...
Article
How protostars accrete mass is one of the fundamental problems of star formation. High column densities and complex kinematical structures make direct observations challenging and they only provide a snapshot. Chemical tracers provide an interesting alternative to characterise the infall histories of protostars. Previous observations of H13CO+ towa...
Article
The inner regions of the envelopes surrounding young protostars are characterised by a complex chemistry, with prebiotic molecules present on the scales where protoplanetary disks eventually may form. This paper introduces a systematic survey, "Protostellar Interferometric Line Survey (PILS)" of the Class 0 protostellar binary IRAS 16293-2422 using...
Article
(Abridged) The physical structure of deeply-embedded low-mass protostars (Class 0) on scales of less than 300 AU is still poorly constrained. Determining this is crucial for understanding the physical and chemical evolution from cores to disks. In this study two models of the emission, a Gaussian disk intensity distribution and a parametrized power...
Article
Full-text available
Glycolaldehyde is a key molecule in the formation of biologically relevant molecules such as ribose. We report its detection with the Plateau de Bure interferometer towards the Class 0 young stellar object NGC1333 IRAS2A, which is only the second solar-type protostar for which this prebiotic molecule is detected. Local thermodynamic equilibrium ana...
Article
Full-text available
Water plays a crucial role both in the interstellar medium and on Earth. To constrain its formation mechanisms and its evolution through the star formation process, the determination of the water deuterium fractionation ratios is particularly suitable. Previous studies derived HDO/H$_2$O ratios in the warm inner regions of low-mass protostars. We h...
Article
Full-text available
Context: The R CrA cloud hosts a handful of Class 0/I low-mass young stellar objects. The chemistry and physics at scales $>500$ AU in this cloud are dominated by the irradiation from the nearby Herbig Be star R CrA. The luminous large-scale emission makes it necessary to use high-resolution spectral imaging to study the chemistry and dynamics of t...
Article
(Abridged) The water deuterium fractionation (HDO/H$_2$O abundance ratio) has traditionally been used to infer the amount of water brought to Earth by comets. Measuring this ratio in deeply-embedded low-mass protostars makes it possible to probe the critical stage when water is transported from clouds to disks in which icy bodies are formed. We pre...
Article
(Abridged) Disks are observed around pre-main sequence stars, but how and when they form is still heavily debated. While disks around young stellar objects have been identified through thermal dust emission, spatially and spectrally resolved molecular line observations are needed to determine their nature. We present subarcsecond observations of du...
Article
Full-text available
Low-mass protostars have been suggested to show highly variable accretion rates through-out their evolution. Such changes in accretion, and related heating of their ambient envelopes, may trigger significant chemical variations on different spatial scales and from source-to-source. We present images of emission from C17O, H13CO+, CH3OH, C34S and C2...
Article
Stable rotationally supported disks (RSDs) are important for the star and planet formation process. The structure and stability of the RSDs are linked to the accretion process onto the star and the evolution of the protostellar system. Additionally, these disks are composed of infalling material that encounter a wide range of physical conditions. T...
Article
Water is an important molecule for our life on Earth, but its way from formation on the surfaces of dust grains to planets and the accompanying chemical processing are not well understood. Through evaporation in the warm inner regions of protostars, water brings complex organics and other species previously locked up in the ice into the gas phase....
Article
Measuring the water deuterium fractionation in the inner warm regions of low-mass protostars has so far been hampered by poor angular resolution obtainable with single-dish ground- and space-based telescopes. Observations of water isotopologues using (sub)millimeter wavelength interferometers have the potential to shed light on this matter. Observa...
Article
Water is present during all stages of star formation: as ice in the cold outer parts of protostellar envelopes and dense inner regions of circumstellar disks, and as gas in the envelopes close to the protostars, in the upper layers of circumstellar disks and in regions of powerful outflows and shocks. In this paper we probe the mechanism regulating...
Article
Although water is such an important molecule for our life here on earth, its way from the surface of dust grains to planets is not well understood. Studies of water in star forming regions show that it is the most abundant molecule in the surface ices on dust grains (e.g., Gibb et al. 2004), an important coolant (e.g., Watson et al. 2007), and thus...

## Citations

... Finally, models based on the "exclusive grain-surface" paradigm are unable to reproduce the observed abundance of several iCOMs (e.g. Coutens et al., 2016;Ligterink et al., 2018;Müller et al., 2016). ...
... formed, while CO freeze-out occurs after the temperature drops below 18 K in cold and dense cores (Bisschop et al. 2006). Thus, the ice structure can have two types of layers: inner H 2 O-dominated ice layer with a lower D/H ratio and outer CObased ice layer with a higher D/H ratio (Jensen et al. 2021). In addition, among COMs, the fractionation level also depends on the CO depletion timescale during core formation as well as the core density (Bergin 2014;Öberg & Bergin 2021) as the frozen CO on the grain surfaces can participate in the ice chemistry producing COMs. ...
... In particular, the search for Life in the Universe generally assumes the three following requirements: a) building block elements, i.e. molecules composed of the so-called CHNOPS elements (Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus and Sulphur, the major macromolecules building elements used by life); b) a source of free energy which can sustain thermodynamic disequilibria 5 and c) liquid water, acting as a universal solvent to life's reactions 6 . There is no lack of the first two ingredients in the cosmos 7,8 , and recent data suggest that water might be also abundant 9,10 . Here, we argue that the availability of transition metals is a strong constraint on the distribution of Life in the Universe, and should be systematically considered while selecting the most promising candidates for the search for extraterrestrial life. ...
... Water is also expected to be abundant in shocked regions associated with molecular outflows (Nisini et al. 2013;van Dishoeck et al. 2013van Dishoeck et al. , 2021Suutarinen et al. 2014;Dionatos et al. 2020). However, even in regions with high abundances of water, the P( 4 S) + H 2 O reaction is inefficient, the rate constant being ∼10 −50 cm 3 molecule −1 s −1 at temperatures in the 200-300 K range. ...
... been detected in the inner warm (100 K) regions (inner envelope and/or a disk), where water ice has sublimated, of several Class 0 sources at spatial scales of 100 au(Persson et al. 2012;Jensen et al. 2019).Harsono et al. (2020) reported nondetection of H O 2 ...
... are converted to physical lengths using HST's pixel size (0.12825 arcsec) and adopting the distance of 430.4 pc from Tobin et al. (2020). To find speeds, we divide by the time between epochs (11 yrs). ...
... More specifically, this article focuses on the southern filament of NGC 1333, which is composed of multiple structures with distinct systemic velocities and velocity gradients (e.g., Sandell & Knee 2001;Dhabal et al. 2018Dhabal et al. , 2019. The famous IRAS 4A system, a protostellar binary which drives two large-scale molecular outflows, is located on the west side of the filament (Choi 2005;Santangelo et al. 2015;De Simone et al. 2020;Taquet et al. 2020;Chuang et al. 2021). The filament joins an arc-like structure on the west which hosts other young protostars (the SVS13 and IRAS 2 systems). ...
... The ALMA 12-m array provides further spatial resolution of the continuum emission detected with the ACA 7-m array. The ALMA 12-m array also detected structures associated with continuum sources detected in previous works such as at 3 mm continuum sources detected by Kainulainen et al. (2017) andvan Terwisga et al. (2019) and 0.87 mm continuum sources detected by Tobin et al. (2019). The spatial resolution of our 1.3 mm continuum image obtained from the ALMA 12-m array is approximately three times higher than that of the 3 mm continuum in previous mosaic mapping observations (Kainulainen et al. 2017;van Terwisga et al. 2019). ...
... This D/H ratio can be different depending on the species. The fractionation of COMs tends to be higher than that of H 2 O (Persson et al. 2014;Taquet et al. 2019) because COMs would be formed on a grain surface after the CO freezes out: H 2 O ice can be formed on grain surfaces even before the dense core is Figure 13. Isotopic ratios of 13 CH 3 OH/ 12 CH 3 OH, CH 3 18 OH/CH 3 16 OH, and C 2 H 5 C 15 N/C 2 H 5 C 14 N as functions of N(H 2 ) (upper panels) and T ex (CH 3 OH) (lower panels). ...
... Because of the large range of physical scales that encompass the star formation process and the complex physical and chemical processes involved, ALMA users have conducted a vast array of observations including detailed observations of individual cores and protostars (e.g., Jensen et al. 2019;Ligterink et al. 2022;Ginsburg et al. 2019), comprehensive surveys of ensembles of sources (e.g., the Large Programs FAUST and IMF: Codella et al. 2021;Motte et al. 2022), and extensive mosaics of individual clouds and filaments in a variety of molecular species (e.g., Barnes et al. 2021;Lu et al. 2021;Yang et al. 2021). These observations have leveraged ALMA's unprecedented access to the full range of relevant Figure 17. ...