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Christopher Codella

Christopher Codella

Doctor of Philosophy

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384
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Publications

Publications (384)
Article
We present sensitive NH 3 (1,1)–(7,7) line images from the Karl G. Jansky Very Large Array toward successive shocks, which are associated with the blueshifted outflow lobe driven by the compact protobinary system L1157. Within a projection distance of 0.1 pc, our observations not only trace the quiescent and cold gas in the flattened envelope, but...
Article
The ALMA interferometer, with its unprecedented combination of high-sensitivity and high-angular resolution, allows for (sub-)mm wavelength mapping of protostellar systems at Solar System scales. Astrochemistry has benefited from imaging interstellar complex organic molecules in these jet-disk systems. Here we report the first detection of methanol...
Preprint
The ALMA interferometer, with its unprecedented combination of high-sensitivity and high-angular resolution, allows for (sub-)mm wavelength mapping of protostellar systems at Solar System scales. Astrochemistry has benefited from imaging interstellar complex organic molecules in these jet-disk systems. Here we report the first detection of methanol...
Preprint
Planetary systems such as our own are formed after a long process where matter condenses from diffuse clouds to stars, planets, asteroids, comets and residual dust, undergoing dramatic changes in physical and chemical state in less than a few million years. Several studies have shown that the chemical composition during the early formation of a Sol...
Preprint
Full-text available
Methanol is a ubiquitous species commonly found in the molecular interstellar medium. It is also a crucial seed species for the building-up of the chemical complexity in star forming regions. Thus, understanding how its abundance evolves during the star formation process and whether it enriches the emerging planetary system is of paramount importan...
Preprint
Full-text available
We present sensitive $\rm NH_3$ (1,1)--(7,7) line images from the Karl G. Jansky Very Large Array toward successive shocks, which are associated with the blueshifted outflow lobe driven by the compact protobinary system L1157. Within a projection distance of 0.1 pc, our observations not only trace the quiescent and cold gas in the flattened envelop...
Preprint
Full-text available
Protostellar jets are an important agent of star formation feedback, tightly connected with the mass-accretion process. The history of jet formation and mass-ejection provides constraints on the mass accretion history and the nature of the driving source. We want to characterize the time-variability of the mass-ejection phenomena at work in the Cla...
Article
Context. One of the biggest unsolved mysteries of modern astrochemistry is understanding chemical formation pathways in the interstellar medium (ISM) and circumstellar environments. The detections (or even nondetections) of molecules composed of low-abundance atomic species (such as S, P, Si, and Mg) may help to constrain chemical pathways. Thioace...
Article
Full-text available
Context. Protostellar jets are an important agent of star formation feedback, tightly connected with the mass-accretion process. The history of jet formation and mass ejection provides constraints on the mass accretion history and on the nature of the driving source. Aims. We characterize the time-variability of the mass-ejection phenomena at work...
Article
Full-text available
The huge variety of planetary systems discovered in recent decades likely depends on the early history of their formation. In this contribution, we introduce the FAUST Large Program which focuses specifically on the early history of solar-like protostars and their chemical diversity at scales of ∼ 50 au, where planets are expected to form. In parti...
Preprint
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Hot corinos are compact regions around solar-mass protostellar objects that are very rich in interstellar complex organic molecules (iCOMs). They are believed to represent the very early phases of our Solar System's birth, which was very likely also characterized by rich organic chemistry. While most of the studied hot corinos are either isolated o...
Article
Context. One of the biggest unsolved mysteries of modern astrochemistry is understanding chemical formation pathways in the interstellar medium (ISM) and circumstellar environments. The detections (or even nondetections) of molecules composed of lowabundance atomic species (such as S, P, Si, and Mg) may help to constrain chemical pathways. Thioacet...
Preprint
Full-text available
Thioacetamide (CH3CSNH2) is the sulfur analog to acetamide (CH3CONH2) and it is a viable candidate to search for in astronomical environments specifically toward regions where other S-bearing molecules have been found and, if possible, that also contain a detection of CH3CONH2. If detected, it would not only continue to expand the view of molecular...
Preprint
Full-text available
The huge variety of planetary systems discovered in recent decades likely depends on the early history of their formation. In this contribution we introduce the FAUST Large Program, which focuses specifically on the early history of Solar-like protostars and their chemical diversity at scales of $\sim$ 50 au, where planets are expected to form. In...
Preprint
Full-text available
Class I protostars are a bridge between Class 0 protostars, and Class II protoplanetary disks. Recent studies show gaps and rings in the dust distribution of disks younger than 1 Myr, suggesting that planet formation may start already at the Class I stage. To understand what chemistry planets will inherit, it is crucial to characterize the chemistr...
Preprint
Planet-forming disks are not isolated systems. Their interaction with the surrounding medium affects their mass budget and chemical content. In the context of the ALMA-DOT program, we obtained high-resolution maps of assorted lines from six disks that are still partly embedded in their natal envelope. In this work, we examine the SO and SO$_2$ emis...
Article
Context. Recent results in astrochemistry have revealed that some molecules, such as interstellar complex organic species and deuterated species, can serve as valuable tools in the investigation of star-forming regions. Sulphuretted species can also be used to follow the chemical evolution of the early stages of a Sun-like star formation process. A...
Preprint
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Aims: The goal is to obtain a census of S-bearing species using interferometric images, towards SVS13-A, a Class I object associated with a hot corino rich in interstellar complex organic molecules. Methods: We used data at 3mm and 1.4mm obtained with IRAM-NOEMA in the framework of the Large Program SOLIS. Results: We imaged the spatial distributio...
Article
Full-text available
HCN and its isomer HNC play an important role in molecular cloud chemistry and the formation of more complex molecules. We investigate here the impact of protostellar shocks on the HCN and HNC abundances from high-sensitivity IRAM 30m observations of the prototypical shock region L1157-B1 and the envelope of the associated Class 0 protostar, as a p...
Preprint
Full-text available
HCN and its isomer HNC play an important role in molecular cloud chemistry and the formation of more complex molecules. We investigate here the impact of protostellar shocks on the HCN and HNC abundances from high-sensitivity IRAM 30m observations of the prototypical shock region L1157-B1 and the envelope of the associated Class 0 protostar, as a p...
Article
We have observed the very low-mass Class 0 protostar IRAS 15398−3359 at scales ranging from 50 to 1800 au, as part of the Atacama Large Millimeter/Submillimeter Array Large Program FAUST. We uncover a linear feature, visible in H_{2}CO, SO, and C^{18}O line emission, which extends from the source in a direction almost perpendicular to the known act...
Article
Aims. As a part of the CALYPSO Large Program, we aim to constrain the properties of protostellar jets and outflows by searching for corresponding emission in a sample of 21 Class 0 protostars covering a broad range of internal luminosities ( L int from 0.035 L ⊙ to 47 L ⊙ ). Methods. We analyzed high angular (~0.′′5–1.′′0) resolution IRAM Plateau d...
Preprint
As a part of the CALYPSO large programme, we constrain the properties of protostellar jets and outflows in a sample of 21 Class 0 protostars with internal luminosities, Lint, from 0.035 to 47 Lsun. We analyse high angular resolution (~0.5"-1") IRAM PdBI observations in CO (2-1), SO ($5_6-4_5$), and SiO (5-4). CO (2-1), which probes outflowing gas,...
Article
We present an overview of the ALMA chemical survey of disk-outflow sources in Taurus (ALMA-DOT), a campaign devoted to the characterization of the molecular emission from partly embedded young stars. The project is aimed at attaining a better understanding of the gaseous products delivered to planets by means of high-resolution maps of the assorted...
Article
Context. The isotopic ratio of nitrogen presents a wide range of values in the Solar System: from ~140 in meteorites and comets to 441 in the solar wind. In star-forming systems, we observe even a higher spread of ~150–1000. The origin of these differences is still unclear. Aims. Chemical reactions in the gas phase are one of the possible processes...
Preprint
The isotopic ratio of nitrogen presents a wide range of values in the Solar System and in star forming system whose origin is still unclear. Chemical reactions in the gas phase are one of the possible processes that could modify the $^{14}$N/$^{15}$N ratio. We aim at investigating if and how the passage of a shock wave in the interstellar medium, c...
Article
Context. Planets form in protoplanetary disks and inherit their chemical composition. It is therefore crucial to understand the molecular content of protoplanetary disks in their gaseous and solid components. Aims. We aim to characterize the distribution and abundance of molecules in the protoplanetary disk of DG Tau and to compare them with its du...
Preprint
Context. The process of mass accretion in the earliest phases of star formation is still not fully understood: Does the accretion rate smoothly decline with the age of the protostar or are there short, intermittent accretion bursts? Aims. We aim to explore whether or not the observed C$^{18}$O and N$_2$H$^+$ emission pattern towards the VeLLO IRAM...
Article
Context. Planet formation starts around Sun-like protostars with ages ≤1 Myr, but the chemical compositions of the surrounding discs remains unknown. Aims. We aim to trace the radial and vertical spatial distribution of a key species of S-bearing chemistry, namely H 2 CS, in protoplanetary discs. We also aim to analyse the observed distributions in...
Preprint
Full-text available
Aims: To trace the radial and vertical spatial distribution of H2CS, a key species of the S-bearing chemistry, in protoplanetary disks. To analyse the observed distributions in light of the H2CS binding energy, in order to discuss the role of thermal desorption in enriching the gas disk component. Methods: In the context of the ALMA chemical survey...
Preprint
Planets form in protoplanetary disks and inherit their chemical composition. It is therefore crucial to understand the disks molecular content. We aim to characterize the distribution and abundance of molecules in the disk of DG Tau. In the context of the ALMA chemical survey of Disk-Outflow sources in Taurus (ALMA-DOT) we analyse ALMA observations...
Article
Full-text available
Context. The process of mass accretion in the earliest phases of star formation is still not fully understood: does the accretion rate smoothly decline with the age of the protostar or are there short, intermittent accretion bursts? The latter option would also yield the possibility for very low-luminosity objects (VeLLOs) to be precursors of solar...
Article
The study of hot corinos in solar-like protostars has been so far mostly limited to the Class 0 phase, hampering our understanding of their origin and evolution. In addition, recent evidence suggests that planet formation starts already during Class I phase, which therefore represents a crucial step in the future planetary system chemical compositi...
Article
The chemical composition of planets is inherited from that of the natal protoplanetary disk at the time of planet formation. Increasing observational evidence suggests that planet formation occurs in less than 1−2 Myr. This motivates the need for spatially resolved spectral observations of young Class I disks, as carried out by the ALMA chemical su...
Preprint
The chemical composition of planets is inherited from the one of protoplanetary disks at the time of their formation. Increasing observational evidence suggests that planet formation occurs in less than $1-2$ Myr. This motivates the need for spatially resolved spectral observations of young Class I disks, as carried out by the ALMA-DOT campaign in...
Preprint
The study of hot corinos in Solar-like protostars has been so far mostly limited to the Class 0 phase, hampering our understanding of their origin and evolution. In addition, recent evidence suggests that planet formation starts already during Class I phase, which, therefore, represents a crucial step in the future planetary system chemical composi...
Article
Full-text available
Context. The interstellar complex organic molecules (iCOMs) are C-bearing molecules containing at least six atoms; two main proposals for their formation are suggested: a direct formation in the icy mantle of the dust grains and formation through the reaction in gas phase of released grain mantle species. The shocked gas along outflows driven by lo...
Article
Full-text available
Context. Contrary to what is expected from models of Galactic chemical evolution, the isotopic fractionation of silicon (Si) in the Galaxy has recently been found to be constant. This finding calls for new observations, also at core scales, to re-evaluate the fractionation of Si. Aims. L1157-B1 is one of the outflow-shocked regions along the blue-s...
Preprint
Aims: A unique environment to study how interstellar Complex Organic Molecules (iCOMs) can be formed is the shocked gas along low-mass protostellar outflows, as the dust mantles composition is sputtered into the gas phase. The chemical richness in these environments has been so far studied only in the L1157 blue shifted outflow. Methods: To underst...
Article
Context. Large millimeter interferometers (ALMA, NOEMA, SMA), with their high spectral resolution and sensitivity, are revealing a growing number of rotating outflows, which are suggested to trace magneto-centrifugal disk winds (MHD DWs). However, the angular momentum flux that they extract and its impact on disk accretion are not yet well quantifi...
Article
We present observations of SO and SO2 lines toward the shocked regions along the L1157 chemically rich outflow, taken in the context of the Seeds of Life in Space IRAM Northern Extended Millimeter Array Large Program, and supported by data from the Submillimeter Array and IRAM-30 m telescope at 1.1–3.6 mm wavelengths. We simultaneously analyze, for...
Preprint
L1157-B1 is one of the outflow shocked regions along the blue-shifted outflow driven by the Class 0 protostar L1157-mm, and is an ideal laboratory to study the material ejected from the grains in very short timescales, i.e. its chemical composition is representative of the composition of the grains. We imaged $^{28}$SiO, $^{29}$SiO and $^{30}$SiO J...
Preprint
We present observations of SO and $\rm SO_2$ lines toward the shocked regions along the L1157 chemically rich outflow, taken in the context of the Seeds Of Life In Space IRAM-NOrthern Extended Millimeter Array Large Program, and supported by data from Submillimeter Array and IRAM-30 m telescope at 1.1--3.6 mm wavelengths. We simultaneously analyze,...
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
Large millimeter interferometers are revealing a growing number of rotating outflows, which are suggested to trace magneto-centrifugal disk winds (MHD DWs). However, their impact on disk accretion is not yet well quantified. Here we identify systematic biases in retrieving the true launch zone, magnetic lever arm, and angular momentum flux of an MH...
Article
We show the first interferometric maps of the 14N/15N ratio obtained with the Atacama Large Millimeter Array (ALMA) towards the Solar-like forming protocluster OMC–2 FIR4. We observed N2H+, 15NNH+, N15NH+ (1–0), and N2D+(2–1) from which we derive the isotopic ratios 14N/15N and D/H. The target, OMC–2 FIR4, is one of the closest analogues of the env...
Article
The chemical composition of planets is determined by the distribution of the various molecular species in the protoplanetary disk at the time of their formation. To date, only a handful of disks have been imaged in multiple spectral lines with high spatial resolution. As part of a small campaign devoted to the chemical characterization of disk-outf...
Article
Aims. The Seeds Of Life In Space IRAM/NOEMA large program aims at studying a set of crucial complex organic molecules in a sample of sources with a well-known physical structure that covers the various phases of solar-type star formation. One representative object of the transition from the prestellar core to the protostar phases has been observed...
Article
Full-text available
Context. Understanding the initial properties of star forming material and how they affect the star formation process is a key question. The infalling gas must redistribute most of its initial angular momentum inherited from prestellar cores before reaching the central stellar embryo. Disk formation has been naturally considered as a possible solut...
Preprint
The chemical composition of planets is inherited by the distribution of the various molecular species in the protoplanetary disk at thetime of their formation. As of today, only a handful of disks has been imaged in multiple spectral lines with high spatial resolution. As part of a small campaign devoted to the chemical characterization of disk-out...
Preprint
The SOLIS (Seeds Of Life In Space) IRAM/NOEMA Large Program aims at studying a set of crucial complex organic molecules in a sample of sources, with well-known physical structure, covering the various phases of Solar-type star formation. One representative object of the transition from the prestellar core to the protostar phases has been observed t...
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
We show the first interferometric maps of the 14N/15N ratio obtained with the Atacama Large Millimeter Array (ALMA) towards the Solar-like forming protocluster OMC-2 FIR4. We observed N2H+, 15NNH+, N15NH+ (1-0), and N2D+ (2-1), from which we derive the isotopic ratios 14N/15N and D/H. The target is one of the closest analogues of the environment in...
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...
Article
Full-text available
Context. Complex organic molecules (COMs) have been detected in a few Class 0 protostars but their origin is not well understood. While the usual picture of a hot corino explains their presence as resulting from the heating of the inner envelope by the nascent protostar, shocks in the outflow, disk wind, the presence of a flared disk, or the intera...
Preprint
Full-text available
Complex organic molecules (COMs) have been detected in a few Class 0 protostars but their origin is not well understood. Going beyond studies of individual objects, we want to investigate the origin of COMs in young protostars on a statistical basis. We use the CALYPSO survey performed with the IRAM PdBI to search for COMs at high angular resolutio...
Preprint
Full-text available
[abridged] Understanding how the infalling gas redistribute most of its initial angular momentum inherited from prestellar cores before reaching the stellar embryo is a key question. Disk formation has been naturally considered as a possible solution to this "angular momentum problem". However, how the initial angular momentum of protostellar cores...
Preprint
Full-text available
The formation of protoplanetary disks is not well understood. To understand how and when these disks are formed, it is crucial to characterize the kinematics of the youngest protostars at a high angular resolution. Here we study a sample of 16 Class 0 protostars to measure their rotation profile at scales from 50 to 500~au and search for Keplerian...