arXiv subjects

L. Podio

Publications and source records attributed to L. Podio.

At least 73 records · Page 4Linked to original sources

arXiv2020

Questioning the spatial origin of complex organic molecules in young protostars with the CALYPSO survey

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 resolution in a sample of 26 solar-type protostars, including 22 Class 0 and four Class I objects. Methanol is detected in 12 sources and tentatively in one source, which represents half of the sample. Eight sources (30%) have detections of at least three COMs. We find a strong chemical differentiation in multiple systems with five systems having one component with at least three COMs detected but the other component devoid of COM emission. The internal luminosity is found to be the source parameter impacting the most the COM chemical composition of the sources, while there is no obvious correlation between the detection of COM emission and that of a disk-like structure. A canonical hot-corino origin may explain the COM emission in four sources, an accretion-shock origin in two or possibly three sources, and an outflow origin in three sources. The CALYPSO sources with COM detections can be classified into three groups on the basis of the abundances of oxygen-bearing molecules, cyanides, and CHO-bearing molecules. These chemical groups correlate neither with the COM origin scenarii, nor with the evolutionary status of the sources if we take the ratio of envelope mass to internal luminosity as an evolutionary tracer. We find strong correlations between molecules that are a priori not related chemically (for instance methanol and methyl cyanide), implying that the existence of a correlation does not imply a chemical link. [abridged]

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arXiv2020

Searching for kinematic evidence of Keplerian disks around Class 0 protostars with CALYPSO

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 rotation. We used high-angular-resolution line observations obtained with the Plateau de Bure Interferometer as part of the CALYPSO large program. From $\mathrm{^{13}CO}$ ($J=2-1$), $\mathrm{C^{18}O}$ ($J=2-1$) and SO ($N_{j}=5_{6}-4_{5}$) moment maps, we find that seven sources show rotation about the jet axis at a few hundred au scales: SerpS-MM18, L1448-C, L1448-NB, L1527, NGC1333- IRAS2A, NGC1333-IRAS4B, and SVS13-B. We analyzed the kinematics of these sources in the $uv$ plane to derive the rotation profiles down to 50~au scales. We find evidence for Keplerian rotation in only two sources, L1527 and L1448-C. Overall, this suggests that Keplerian disks larger than 50 au are uncommon around Class 0 protostars. However, in some of the sources, the line emission could be optically thick and dominated by the envelope emission. Due to the optical thickness of these envelopes, some of the disks could have remained undetected in our observations.

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arXiv2020

Seeds of Life in Space (SOLIS) V. Methanol and acetaldehyde in the protostellar jet-driven shocks L1157-B0 and B1

Aim: In the past, observations of protostellar shocks have been able to set constraints on the formation route of formamide (NH2CHO), exploiting its observed spatial distribution and comparison with astrochemical model predictions. In this work, we follow the same strategy to study the case of acetaldehyde (CH3CHO). Method: To this end, we used the data obtained with the IRAM-NOEMA interferometer in the framework of the Large Program SOLIS to image the B0 and B1 shocks along the L1157 blueshifted outflow in methanol (CH3OH) and acetaldehyde line emission. Results: We imaged six CH3OH and eight CH3CHO lines which cover upper level energies up to 30 K. Both species trace the B0 molecular cavity as well as the northern B1 portion, i.e. the regions where the youngest shocks (1000 yr) occurred. The CH$_3$OH and CH$_3$CHO emission peaks towards the B1b clump, where we measured the following column densities and relative abundances: 1.3 x 10^16 cm-2 and 6.5 x 10-6 (methanol), and 7 x 10^13 cm-2 and 3.5 x 10-8 (acetaldehyde). We carried out a non-LTE LVG analysis of the observed CH3OH line: the average kinetic temperature and density of the emitting gas are Tkin = 90 K and nH2 = 4 x 10^5 cm-3, respectively. The CH3OH and CH3CHO abundance ratio towards B1b is 190, varying by less than a factor 3 throughout the whole B0-B1 structure. Conclusions: The comparison of astrochemical model predictions with the observed methanol and acetaldehyde spatial distribution does not allow to distinguish whether acetaldehyde is formed on the grain mantles or rather on the gas-phase, as its gas-phase formation, dominated by the reaction of ethyl radical (CH3CH2) with atomic oxygen, is very fast. Observations of acetaldehyde in younger shocks, e.g. 10^2 yr old, or/and of the ethyl radical, whose frequencies are not presently available, are necessary to settle the issue.

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arXiv2019

Investigating the nature of the extended structure around the Herbig star RCrA using integral field and high-resolution spectroscopy

We present a detailed analysis of the extended structure detected around the young and close-by Herbig Ae/Be star RCrA. This is a young triple system with an intermediate mass central binary whose separation is of the order of a few tens of the radii of the individual components, and an M-star companion at about 30 au. Our aim is to understand the nature of the extended structure by means of combining integral-field and high-resolution spectroscopy. We conducted the analysis based on FEROS archival optical spectroscopy data and adaptive optics images and integral-field spectra obtained with SINFONI and SPHERE at the VLT. The observations reveal a complex extended structure that is composed of at least two components: a non-uniform wide cavity whose walls are detected in continuum emission up to 400~au, and a collimated wiggling-jet detected in the emission lines of Helium and Hydrogen. Moreover, the presence of [FeII] emission projected close to the cavity walls suggests the presence of a slower moving wind, most likely a disk wind. The multiple components of the optical forbidden lines also indicate the presence of a high-velocity jet co-existing with a slow wind. We constructed a geometrical model of the collimated jet flowing within the cavity using intensity and velocity maps, finding that its wiggling is consistent with the orbital period of the central binary. The cavity and the jet do not share the same position angle, suggesting that the jet is itself experiencing a precession motion possibly due to the wide M-dwarf companion. We propose a scenario that closely agrees with the general expectation of a magneto-centrifugal-launched jet. These results build upon the extensive studies already conducted on RCrA.

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arXiv2019

VLA cm-wave survey of young stellar objects in the Oph A cluster: constraining extreme UV- and X-ray-driven disk photo-evaporation -- A pathfinder for Square Kilometre Array studies

Observations of young stellar objects (YSOs) in centimeter bands can probe the continuum emission from growing dust grains, ionized winds, and magnetospheric activity, which are intimately connected to the evolution of protoplanetary disks and the formation of planets. We have carried out sensitive continuum observations toward the Ophiuchus A star-forming region using the Karl G. Jansky Very Large Array (VLA) at 10 GHz over a field-of-view of 6$'$ with a spatial resolution of $θ_{maj}$ $\times$ $θ_{min}$ $\sim$ 0.4$''$ $\times$ 0.2$''$. We achieved a 5 $μ$Jy beam$^{-1}$ root-mean-square noise level at the center of our mosaic field of view. Among the eighteen sources we detected, sixteen are YSOs (three Class 0, five Class I, six Class II, and two Class III) and two are extragalactic candidates. We find that thermal dust emission generally contributes less that 30% of the emission at 10 GHz. The radio emission is dominated by other types of emission such as gyro-synchrotron radiation from active magnetospheres, free-free emission from thermal jets, free-free emission from the outflowing photo-evaporated disk material, and/or synchrotron emission from accelerated cosmic-rays in jet or protostellar surface shocks. These different types of emission could not be clearly disentangled. Our non-detections towards Class II/III disks suggest that extreme UV-driven photoevaporation is insufficient to explain the disk dispersal, assuming that the contribution of UV photoevaporating stellar winds to radio flux does not evolve with time. The sensitivity of our data cannot exclude photoevaporation due to X-ray photons as an efficient mechanism for disk dispersal. Deeper surveys with the Square Kilometre Array will be able to provide strong constraints on disk photoevaporation.

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arXiv2019

The SPHERE view of the jet and the envelope of RY Tau

Jets are rarely associated with pre-main-sequence intermediate-mass stars. Optical and near-IR observations of jet-driving sources are often hindered by the presence of a natal envelope. Jets around partly embedded sources are a useful diagnostic to constrain the geometry of the concealed protoplanetary disk. In fact, the jet-driving mechanisms are affected by both spatial anisotropies and episodic variations at the (sub-)au scale from the star. We obtained a rich set of high-contrast VLT/SPHERE observations from 0.6 micron to 2.2 micron of the young intermediate-mass star RY Tau. Given the proximity to the Sun of this source, our images have the highest spatial resolution ever obtained for an atomic jet. Optical observations in polarized light show no sign of the protoplanetary disk detected by ALMA. Instead, we observed a diffuse signal resembling a remnant envelope with an outflow cavity. The jet is detected in four spectral lines. The jet appears to be wiggling and its radial width increasing with the distance is complementary to the shape of the outflow cavity suggesting a strong jet/envelope interaction. Through the estimated tangential velocity, we revealed a possible connection between the launching time of the jet sub-structures and the stellar activity of RY Tau. RY Tau is at an intermediate stage toward the dispersal of the natal envelope. This source shows episodic increases of mass accretion/ejection similarly to other known intermediate-mass stars. The amount of observed jet wiggle is consistent with the presence of a precessing disk warp or misaligned inner disk that would be induced by an unseen planetary/sub-stellar companion at sub-/few-au scales. The high disk mass of RY Tau and of two other jet-driving intermediate-mass stars, HD163296 and MWC480, suggests that massive, full disks are more efficient at launching prominent jets.

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arXiv2019

MAORY science cases white book

MAORY is the Adaptive Optic (AO) module that will be installed at the E-ELT at the first light of the telescope. It will provide two different types of AO correction, a very high correction over a small FoV (diameter ~10 arcsec, SCAO mode) and a moderate and homogeneous correction over a wide FoV (diameter ~60 arcsec, MCAO mode). Here we present a first collection of science cases for MAORY feeding the E-ELT first light camera and spectrograph MICADO. Since the general science cases for E-ELT have already been developed elsewhere, here we focus on the design of specific observations, to explore the capabilities and observing modes of the system.

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arXiv2019

Organic molecules in the protoplanetary disk of DG Tau revealed by ALMA

Planets form in protoplanetary disks and inherit their chemical compositions. It is thus crucial to map the distribution and investigate the formation of simple organics, such as formaldehyde and methanol, in protoplanetary disks. We analyze ALMA observations of the nearby disk-jet system around the T Tauri star DG Tau in the o-H$_2$CO $3_{1,2}-2_{1,1}$ and CH$_3$OH $3_{-2,2}-4_{-1,4}$ E, $5_{0,5}-4_{0,4}$ A transitions at an unprecedented resolution of $\sim0.15"$, i.e., $\sim18$ au at a distance of 121 pc. The H$_2$CO emission originates from a rotating ring extending from $\sim40$ au with a peak at $\sim62$ au, i.e., at the edge of the 1.3mm dust continuum. CH$_3$OH emission is not detected down to an r.m.s. of 3 mJy/beam in the 0.162 km/s channel. Assuming an ortho-to-para ratio of 1.8-2.8 the ring- and disk-height-averaged H$_2$CO column density is $\sim0.3-4\times10^{14}$ cm$^{-2}$, while that of CH$_3$OH is $<0.04-0.7\times10^{14}$ cm$^{-2}$. In the inner $40$ au no o-H$_2$CO emission is detected with an upper limit on its beam-averaged column density of $\sim0.5-6\times10^{13}$ cm$^{-2}$. The H$_2$CO ring in the disk of DG Tau is located beyond the CO iceline (R$_{\rm CO}\sim30$ au). This suggests that the H$_2$CO abundance is enhanced in the outer disk due to formation on grain surfaces by the hydrogenation of CO ice. The emission peak at the edge of the mm dust continuum may be due to enhanced desorption of H$_2$CO in the gas phase caused by increased UV penetration and/or temperature inversion. The CH$_3$OH/H$_2$CO abundance ratio is $<1$, in agreement with disk chemistry models. The inner edge of the H$_2$CO ring coincides with the radius where the polarization of the dust continuum changes orientation, hinting at a tight link between the H$_2$CO chemistry and the dust properties in the outer disk and at the possible presence of substructures in the dust distribution.

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arXiv2018

ALMA polarimetric studies of rotating jet/disk systems

We have recently obtained polarimetric data at mm wavelengths with ALMA for the young systems DG Tau and CW Tau, for which the rotation properties of jet and disk have been investigated in previous high angular resolution studies. The motivation was to test the models of magneto-centrifugal launch of jets via the determination of the magnetic configuration at the disk surface. The analysis of these data, however, reveals that self-scattering of dust thermal radiation dominates the polarization pattern. It is shown that even if no information on the magnetic field can be derived in this case, the polarization data are a powerful tool for the diagnostics of the properties and the evolution of dust in protoplanetary disks.

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arXiv2018

Characterizing young protostellar disks with the CALYPSO IRAM-PdBI survey: large Class 0 disks are rare

Understanding the formation mechanisms of protoplanetary disks and multiple systems, and their pristine properties, is a key question for modern astrophysics. The properties of the youngest disks, embedded in rotating infalling protostellar envelopes, have largely remained unconstrained up to now. In the framework of the IRAM-PdBI CALYPSO survey, we have obtained sub-arcsecond observations of the dust continuum emission at 231 GHz and 94 GHz, for a sample of 16 solar-type Class 0 protostars. In an attempt to identify disk-like structures embedded at small scales in the protostellar envelopes, we model the dust continuum emission visibility profiles using both Plummer-like envelope models and envelope models including additional Gaussian disk-like components. Our analysis shows that in the CALYPSO sample, 11 of the 16 Class 0 protostars are better reproduced by models including a disk-like dust continuum component contributing to the flux at small scales, but less than 25% of these candidate protostellar disks are resolved at radii > 60 au. Including all available literature constraints on Class 0 disks at subarcsecond scales, we show that our results are representative: most (> 72% in a sample of 26 protostars) Class 0 protostellar disks are small and emerge only at radii < 60 au. Our multiplicity fraction at scales 100-5000 au is in global agreement with the multiplicity properties of Class I protostars at similar scales. We confront our observational constraints on the disk size distribution in Class 0 protostars to the typical disk properties from protostellar formation models. Because they reduce the centrifugal radius, and produce a disk size distribution peaking at radii <100 au during the main accretion phase, magnetized models of rotating protostellar collapse are favored by our observations.

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arXiv2018

The census of interstellar complex organic molecules in the Class I hot corino of SVS13-A

We present the first census of the interstellar Complex Organic Molecules (iCOMs) in the low-mass Class I protostar SVS13-A, obtained by analysing data from the IRAM-30m Large Project ASAI (Astrochemical Surveys At IRAM). They consist of an high-sensitivity unbiased spectral survey at the 1mm, 2mm and 3mm IRAM bands. We detected five iCOMs: acetaldehyde (CH$_3$CHO), methyl formate (HCOOCH$_3$), dimethyl ether (CH$_3$OCH$_3$), ethanol (CH$_3$CH$_2$OH) and formamide (NH$_2$CHO). In addition we searched for other iCOMs and ketene (H$_2$CCO), formic acid (HCOOH) and methoxy (CH$_3$O), whose only ketene was detected. The numerous detected lines, from 5 to 37 depending on the species, cover a large upper level energy range, between 15 and 254 K. This allowed us to carry out a rotational diagram analysis and derive rotational temperatures between 35 and 110 K, and column densities between $3\times 10^{15}$ and $1\times 10^{17}$ cm$^{-2}$ on the 0."3 size previously determined by interferometric observations of glycolaldehyde. These new observations clearly demonstrate the presence of a rich chemistry in the hot corino towards SVS13-A. The measured iCOMs abundances were compared to other Class 0 and I hot corinos, as well as comets, previously published in the literature. We find evidence that (i) SVS13-A is as chemically rich as younger Class 0 protostars, and (ii) the iCOMs relative abundances do not substantially evolve during the protostellar phase.

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arXiv2018

SPHERE / ZIMPOL high resolution polarimetric imager. I. System overview, PSF parameters, coronagraphy, and polarimetry

We describe the Zurich Imaging Polarimeter (ZIMPOL), the visual focal plane subsystem of the SPHERE "VLT planet finder", which pushes the limits of current AO systems to shorter wavelengths, higher spatial resolution, and much improved polarimetric performance. We provide new benchmarks for the performance of high contrast instruments, in particular for polarimetric differential imaging. We have analyzed SPHERE/ZIMPOL point spread functions and measure the peak surface brightness, the encircled energy, and the full width half maximum (FWHM) for different wavelengths, atmospheric conditions, star brightness, and instrument modes. Coronagraphic images are described and analized and the performance for different coronagraphs is compared with tests for the binary alpha Hyi with a separation of 92 mas and a contrast of 6 mag. For the polarimetric mode we made the instrument calibrations using zero polarization and high polarization standard stars and here we give a recipe for the absolute calibration of polarimetric data. The data show a small <1 mas but disturbing differential polarimetric beam shifts, which can be explained as Goos-Hähnchen shifts from the inclined mirrors, and we discuss how to correct this effect. The polarimetric sensitivity is investigated with non-coronagraphic and deep, coronagraphic observations of the dust scattering around the symbiotic Mira variable R Aqr. SPHERE/ZIMPOL achieves imaging performances in the visual range with unprecedented characteristics, in particular very high spatial resolution and very high polarimetric contrast. This instrument opens up many new research opportunities for the detailed investigation of circumstellar dust, in scattered and therefore polarized light, for the investigation of faint companions, and for the mapping of circumstellar Halpha emission.

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arXiv2018

Water and interstellar complex organics associated with the HH 212 protostellar disc - On disc atmospheres, disc winds, and accretion shocks

The HH 212 protostellar system, in Orion B, has been mapped thanks to ALMA-Band 7 Cycle 1 and Cycle 4 observations of dueterated water (HDO) and acetaldehyde (CH$_3$CHO) emission with an angular resolution down to $\sim$0.15 arcsec (60 au). Many emission lines due to 14 CH$_3$CHO and 1 HDO transitions at high excitation ($E_{\rm u}$ between 163 K and 335 K) have been imaged in the inner $\sim$ 70 au region. The local thermal equilibrium analysis of the CH$_3$CHO emission leads to a temperature of 78$\pm$14 K and a column density of 7.6$\pm$3.2 $\times$ 10$^{15}$ cm$^{-2}$, which, when $N_{\rm H_2}$ of 10$^{24}$ cm$^{-2}$ is assumed, leads to an abundance of $X_{\rm CH_3CHO}$ $\simeq$ 8 $\times$ 10$^{-9}$. The large velocity gradient analysis of the HDO emission also places severe constraints on the volume density, n$_{\rm H_2}$ $\geq$ 10$^8$ cm$^{-3}$. The line profiles are 5--7 km s$^{-1}$ wide, and CH$_3$CHO and HDO both show a $\pm$ 2 km s$^{-1}$ velocity gradient over a size of $\sim$ 70 au (blue-shifted emission towards the north-west and red-shifted emission towards the south-east) along the disc equatorial plane, in agreement with what was found so far using other molecular tracers. The kinematics of CH$_3$CHO and HDO are consistent with the occurrence of a centrifugal barrier, that is, the infalling envelope-rotating disc ring, which is chemically enriched through low-velocity accretion shocks. The emission radius is $\sim$ 60 au, in good agreement with what was found before for another interstellar complex organic molecule such as NH$_2$CHO. We support a vertical structure for the centrifugal barrier, suggesting the occurrence of two outflowing, expanding, and rotating rings above and below (of about 40-45 au) the optically thick equatorial disc plane. It is tempting to speculate that these rings could probe the basis of a wind launched from this region.

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arXiv2018

Astrochemical evolution along star formation: Overview of the IRAM Large Program ASAI

Evidence is mounting that the small bodies of our Solar System, such as comets and asteroids, have at least partially inherited their chemical composition from the first phases of the Solar System formation. It then appears that the molecular complexity of these small bodies is most likely related to the earliest stages of star formation. It is therefore important to characterize and to understand how the chemical evolution changes with solar-type protostellar evolution. We present here the Large Program "Astrochemical Surveys At IRAM" (ASAI). Its goal is to carry out unbiased millimeter line surveys between 80 and 272 GHz of a sample of ten template sources, which fully cover the first stages of the formation process of solar-type stars, from prestellar cores to the late protostellar phase. In this article, we present an overview of the surveys and results obtained from the analysis of the 3 mm band observations. The number of detected main isotopic species barely varies with the evolutionary stage and is found to be very similar to that of massive star-forming regions. The molecular content in O- and C- bearing species allows us to define two chemical classes of envelopes, whose composition is dominated by either a) a rich content in O-rich complex organic molecules, associated with hot corino sources, or b) a rich content in hydrocarbons, typical of Warm Carbon Chain Chemistry sources. Overall, a high chemical richness is found to be present already in the initial phases of solar-type star formation.

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arXiv2018

A search for Cyanopolyynes in L1157-B1

We present here a systematic search for cyanopolyynes in the shock region L1157-B1 and its associated protostar L1157-mm in the framework of the Large Program "Astrochemical Surveys At IRAM" (ASAI), dedicated to chemical surveys of solar-type star forming regions with the IRAM 30m telescope. Observations of the millimeter windows between 72 and 272 GHz permitted the detection of HC$_3$N and its $^{13}$C isotopologues, and HC$_5$N (for the first time in a protostellar shock region). In the shock, analysis of the line profiles shows that the emission arises from the outflow cavities associated with L1157-B1 and L1157-B2. Molecular abundances and excitation conditions were obtained from analysis of the Spectral Line Energy Distributions under the assumption of Local Thermodynamical Equilibrium or using a radiative transfer code in the Large Velocity Gradient approximation. Towards L1157mm, the HC$_3$N emission arises from the cold envelope ($T_{rot}=10$ K) and a higher-excitation region ($T_{rot}$= $31$ K) of smaller extent around the protostar. We did not find any evidence of $^{13}$C or D fractionation enrichment towards L1157-B1. We obtain a relative abundance ratio HC$_3$N/HC$_5$N of 3.3 in the shocked gas. We find an increase by a factor of 30 of the HC$_3$N abundance between the envelope of L1157-mm and the shock region itself. Altogether, these results are consistent with a scenario in which the bulk of HC$_3$N was produced by means of gas phase reactions in the passage of the shock. This scenario is supported by the predictions of a parametric shock code coupled with the chemical model UCL_CHEM.

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arXiv2017

Nitrogen oxide in protostellar envelopes and shocks: the ASAI survey

The high-sensitivity of the IRAM 30-m ASAI unbiased spectral survey in the mm-window allows us to detect NO emission towards both the Class I object SVS13-A and the protostellar outflow shock L1157-B1. We detect the hyperfine components of the $^2Π_{\rm 1/2}$ $J$ = 3/2 $\to$ 1/2 (at 151 GHz) and the $^2Π_{\rm 1/2}$ $J$ = 5/2 $\to$ 3/2 (250 GHz) spectral pattern. The two objects show different NO profiles: (i) SVS13-A emits through narrow (1.5 km s$^{-1}$) lines at the systemic velocity, while (ii) L1157-B1 shows broad ($\sim$ 5 km s$^{-1}$) blue-shifted emission. For SVS13-A the analysis leads to $T_{\rm ex}$ $\geq$ 4 K, $N(\rm NO)$ $\leq$ 3 $\times$ 10$^{15}$ cm$^{-2}$, and indicates the association of NO with the protostellar envelope. In L1157-B1, NO is tracing the extended outflow cavity: $T_{\rm ex}$ $\simeq$ 4--5 K, and $N(\rm NO)$ = 5.5$\pm$1.5 $\times$ 10$^{15}$ cm$^{-2}$. Using C$^{18}$O, $^{13}$C$^{18}$O, C$^{17}$O, and $^{13}$C$^{17}$O ASAI observations we derive an NO fractional abundance less than $\sim$ 10$^{-7}$ for the SVS13-A envelope, in agreement with previous measurements towards extended PDRs and prestellar objects. Conversely, a definite $X(NO)$ enhancement is measured towards L1157-B1, $\sim$ 6 $\times$ 10$^{-6}$, showing that the NO production increases in shocks. The public code UCLCHEM was used to interpret the NO observations, confirming that the abundance observed in SVS13-A can be attained in an envelope with a gas density of 10$^5$ cm$^{-3}$ and a kinetic temperature of 40 K. The NO abundance in L1157-B1 is reproduced with pre-shock densities of 10$^5$ cm$^{-3}$ subjected to a $\sim$ 45 km s$^{-1}$ shock.

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arXiv2017

ALMA discovery of a rotating SO/SO$_2$ flow in HH212. A possible MHD disk wind?

We wish to constrain the possible contribution of a magnetohydrodynamic disk wind (DW) to the HH212 molecular jet. We mapped the flow base with ALMA Cycle 4 at 0.13"$\sim$ 60 au resolution and compared these observations with synthetic DW predictions. We identified, in SO/SO$_2$, a rotating flow that is wider and slower than the axial SiO jet. The broad outflow cavity seen in C$^{34}$S is not carved by a fast wide-angle wind but by this slower agent. Rotation signatures may be fitted by a DW of a moderate lever arm launched out to $\sim$ 40 au with SiO tracing dust-free streamlines from 0.05-0.3 au. Such a DW could limit the core-to-star efficiency to $\leq$50%.

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arXiv2017

Seeds Of Life In Space (SOLIS): The organic composition diversity at 300--1000 au scale in Solar-type star forming regions

Complex organic molecules have been observed for decades in the interstellar medium. Some of them might be considered as small bricks of the macromolecules at the base of terrestrial life. It is hence particularly important to understand organic chemistry in Solar-like star forming regions. In this article, we present a new observational project: SOLIS (Seeds Of Life In Space). This is a Large Project at the IRAM-NOEMA interferometer, and its scope is to image the emission of several crucial organic molecules in a sample of Solar-like star forming regions in different evolutionary stage and environments. Here, we report the first SOLIS results, obtained from analysing the spectra of different regions of the Class 0 source NGC1333-IRAS4A, the protocluster OMC-2 FIR4, and the shock site L1157-B1. The different regions were identified based on the images of formamide (NH2CHO) and cyanodiacetylene (HC5N) lines. We discuss the observed large diversity in the molecular and organic content, both on large (3000-10000 au) and relatively small (300-1000 au) scales. Finally, we derive upper limits to the methoxy fractional abundance in the three observed regions of the same order of magnitude of that measured in few cold prestellar objects, namely ~10^-12-10^-11 with respect to H2 molecules.

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