arXiv subjects

L. Testi

Publications and source records attributed to L. Testi.

At least 109 records · Page 6Linked to original sources

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

Wideband 67-116 GHz cryogenic receiver development for ALMA Band 2

The Atacama Large Millimeter/sub-millimeter Array (ALMA) is already revolutionising our understanding of the Universe. However, ALMA is not yet equipped with all of its originally planned receiver bands, which will allow it to observe over the full range of frequencies from 35-950 GHz accessible through the Earth's atmosphere. In particular Band 2 (67-90 GHz) has not yet been approved for construction. Recent technological developments in cryogenic monolithic microwave integrated circuit (MMIC) high electron mobility transistor (HEMT) amplifier and orthomode transducer (OMT) design provide an opportunity to extend the originally planned on-sky bandwidth, combining ALMA Bands 2 and 3 into one receiver cartridge covering 67-116 GHz. The IF band definition for the ALMA project took place two decades ago, when 8 GHz of on-sky bandwidth per polarisation channel was an ambitious goal. The new receiver design we present here allows the opportunity to expand ALMA's wideband capabilities, anticipating future upgrades across the entire observatory. Expanding ALMA's instantaneous bandwidth is a high priority, and provides a number of observational advantages, including lower noise in continuum observations, the ability to probe larger portions of an astronomical spectrum for, e.g., widely spaced molecular transitions, and the ability to scan efficiently in frequency space to perform surveys where the redshift or chemical complexity of the object is not known a priori. Wider IF bandwidth also reduces uncertainties in calibration and continuum subtraction that might otherwise compromise science objectives. Here we provide an overview of the component development and overall design for this wideband 67-116 GHz cryogenic receiver cartridge, designed to operate from the Band 2 receiver cartridge slot in the current ALMA front end receiver cryostat.

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arXiv2018

Characterising the high-mass star forming filament G351.776--0.527 with Herschel and APEX dust continuum and gas observations

G351.776-0.527 is among the most massive, closest, and youngest filaments in the inner Galactic plane and therefore it is an ideal laboratory to study the kinematics of dense gas and mass replenishment on a large scale. In this paper, we present far-infrared (FIR) and submillimetre wavelength continuum observations combined with spectroscopic C$^{18}$O (2-1) data of the entire region to study its temperature, mass distribution, and kinematics. The structure is composed of a main elongated region with an aspect ratio of $\sim 23$, which is associated with a network of filamentary structures. The main filament has a remarkably constant width of 0.2 pc. The total mass of the network (including the main filament) is $\geq 2600$ M$_\odot$, while we estimate a mass of $\sim 2000$ M$_\odot$ for the main structure. Therefore, the network harbours a large reservoir of gas and dust that could still be accreted onto the main structure. From the analysis of the gas kinematics, we detect two velocity components in the northern part of the main filament. The data also reveal velocity oscillations in C$^{18}$O along the spine in the main filament and in at least one of the branches. Considering the region as a single structure, we find that it is globally close to virial equilibrium indicating that the entire structure is approximately in a stable state.

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arXiv2018

High-Resolution ALMA Observations of HD100546: Asymmetric Circumstellar Ring, and Circumplanetary Disk Upper Limits

We present long baseline Atacama Large Millimeter/submillimeter Array (ALMA) observations of the 870$\,μ$m dust continuum emission and CO (3-2) from the protoplanetary disk around the Herbig Ae/Be star HD 100546, which is one of the few systems claimed to have two young embedded planets. These observations achieve a resolution of 4 au (3.8 mas), an rms noise of 66$μ$Jy/beam, and reveal an asymmetric ring between $\sim$20-40 au with largely optically thin dust continuum emission. This ring is well fit by two concentric and overlapping Gaussian rings of different widths and a Vortex. In addition, an unresolved component is detected at a position consistent with the central star, which may trace the central inner disk ($<$2au in radius). We report a lack of compact continuum emission at the positions of both claimed protoplanets. We use this result to constrain the circumplanetary disk (CPD) mass and size of 1.44M$_{\rm Earth}$ and 0.44au in the optically thin and thick regime, respectively, for the case of the previously directly imaged protoplanet candidate at $\sim$55 au (HD100546 b). We compare these empirical CPD constraints to previous numerical simulations. This suggests that HD100546 b is inconsistent with several planet accretion models, while gas-starved models are also still compatible. We estimate the planetary mass as 1.65 M$_J$ by using the relation between planet, circumstellar, and circumplanetary masses derived from numerical simulations. Finally, the CO integrated intensity map shows a possible spiral arm feature that would match the spiral features identified in Near-Infrared scattered light polarized emission, which suggests a real spiral feature in the disk surface that needs to be confirmed with further observations.

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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 ALMA Lupus protoplanetary disk survey: evidence for compact gas disks and molecular rings from CN

The cyanide radical CN is abundant in protoplanetary disks, with line fluxes often comparable to those of $^{13}$CO. It is known to be sensitive to UV irradiation of the upper disk atmosphere, with models predicting ring-shaped emission. We seek to characterize the CN emission from 94 Class II disks in the Lupus star forming region, compare it to observations in other regions, and interpret our observations with a grid of models. The CN emission morphology is discussed for two primordial disks, Sz 71 and Sz 98, and modeled in more detail. ALMA observed CN N=3-2 in Lupus disks down to sensitivities better than previous surveys. Models constructed with the physico-chemical code DALI are used to study the integrated fluxes of the disks and resolved emission of CN in disks without (dust) substructures. We find that CN N=3-2 is bright, and detected in 38% of sources, but its disk-integrated flux is not strongly correlated to either $^{13}$CO or continuum flux. Compared to pre-ALMA single-dish surveys, no significant difference in the CN flux distributions in Lupus and Taurus-Auriga is found, although $ρ$ Ophiuchus disks may be fainter on average. We find ring-shaped CN emission with peak radii of ~50 AU in two resolved disks. We conclude that a large fraction of sources is faint in CN; only exponential gas surface density cutoffs at $R_{c} \leq 15$ AU can reconcile observations with models. This is the first observational evidence of such a compact gas disk population in Lupus. Absolute intensities and the emission morphology of CN are reproduced by DALI models without the need for any continuum substructure; they are unrelated to the CO snowline location. These observations and the successful modeling of these rings provide a new probe of the structure and conditions in disks, and particularly their incident UV radiation field, if disk size is determined by the data.

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arXiv2018

Chasing discs around O-type (proto)stars - ALMA evidence for an SiO disc and disc wind from G17.64+0.16

We present high angular resolution 0.2 arcsec continuum and molecular emission line Atacama Large Millimeter/sub-millimeter Array (ALMA) observations of G17.64+0.16 in Band 6 (220GHz) taken as part of a campaign in search of circumstellar discs around (proto)-O-stars. At a resolution of 400au the main continuum core is essentially unresolved and isolated from other strong and compact emission peaks. At a resolution of 400au the main continuum core is essentially unresolved and isolated from other strong and compact emission peaks. We detect SiO (5-4) emission that is marginally resolved and elongated in a direction perpendicular to the large-scale outflow seen in the 13CO (2-1) line using the main ALMA array in conjunction with the Atacama Compact Array (ACA). Morphologically, the SiO appears to represent a disc-like structure. Using parametric models we show that the position-velocity profile of the SiO is consistent with the Keplerian rotation of a disc around an object between 10-30Mo in mass, only if there is also radial expansion from a separate structure. The radial motion component can be interpreted as a disc wind from the disc surface. Models with a central stellar object mass between 20 and 30Mo are the most consistent with the stellar luminosity (100000 Lo) and indicative of an O-type star. The H30a millimetre recombination line (231.9GHz) is also detected, but spatially unresolved, and is indicative of a very compact, hot, ionised region co-spatial with the dust continuum core. Accounting for all observables, we suggest that G17.64 is consistent with a O-type young stellar object in the final stages of protostellar assembly, driving a wind, but that has not yet developed into a compact HII region. The existance and detection of the disc in G17.64 is likely related to its isolated and possibly more evolved nature, traits which may underpin discs in similar sources.

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arXiv2018

Feedback from massive stars at low metallicities: MUSE observations of N44 and N180 in the Large Magellanic Cloud

We present MUSE integral field data of two HII region complexes in the Large Magellanic Cloud (LMC), N44 and N180. Both regions consist of a main superbubble and a number of smaller, more compact HII regions that formed on the edge of the superbubble. For a total of 11 HII regions, we systematically analyse the radiative and mechanical feedback from the massive O-type stars on the surrounding gas. We exploit the integral field property of the data and the coverage of the HeII$λ$5412 line to identify and classify the feedback-driving massive stars, and from the estimated spectral types and luminosity classes we determine the stellar radiative output in terms of the ionising photon flux $Q_{0}$. We characterise the HII regions in terms of their sizes, morphologies, ionisation structure, luminosity and kinematics, and derive oxygen abundances via emission line ratios. We analyse the role of different stellar feedback mechanisms for each region by measuring the direct radiation pressure, the pressure of the ionised gas, and the pressure of the shock-heated winds. We find that stellar winds and ionised gas are the main drivers of HII region expansion in our sample, while the direct radiation pressure is up to three orders of magnitude lower than the other terms. We relate the total pressure to the star formation rate per unit area, $Σ_{SFR}$, for each region and find that stellar feedback has a negative effect on star formation, and sets an upper limit to $Σ_{SFR}$ as a function of increasing pressure.

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arXiv2018

Accelerating infall and rotational spin-up in the hot molecular core G31.41+0.31

As part of our effort to search for circumstellar disks around high-mass stellar objects, we observed the well-known core G31.41+0.31 with ALMA at 1.4 mm with an angular resolution of~0.22" (~1700 au). The dust continuum emission has been resolved into two cores namely Main and NE. The Main core, which has the stronger emission and is the more chemically rich, has a diameter of ~5300 au, and is associated with two free-free continuum sources. The Main core looks featureless and homogeneous in dust continuum emission and does not present any hint of fragmentation. Each transition of CH3CN and CH3OCHO, both ground and vibrationally excited, as well as those of CH3CN isotopologues, shows a clear velocity gradient along the NE-SW direction, with velocity linearly increasing with distance from the center, consistent with solid-body rotation. However, when comparing the velocity field of transitions with different upper level energies, the rotation velocity increases with increasing energy of the transition, which suggests that the rotation speeds up towards the center. Spectral lines towards the dust continuum peak show an inverse P-Cygni profile that supports the existence of infall in the core. The infall velocity increases with the energy of the transition suggesting that the infall is accelerating towards the center of the core, consistent with gravitational collapse. Despite the monolithic appearance of the Main core, the presence of red-shifted absorption, the existence of two embedded free-free sources at the center, and the rotational spin-up are consistent with an unstable core undergoing fragmentation with infall and differential rotation due to conservation of angular momentum. Therefore, the most likely explanation for the monolithic morphology is that the large opacity of the dust emission prevents the detection of any inhomogeneity in the core.

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arXiv2018

High-contrast imaging of HD 163296 with the Keck/NIRC2 L'-band vortex coronograph

We present observations of the nearby (D$\sim$100\,pc) Herbig star HD~163296 taken with the vortex coronograph at Keck/NIRC2 in the L' band (3.7~$μ$m), to search for planetary mass companions in the ringed disc surrounding this pre-main sequence star. The images reveal an arc-like region of scattered light from the disc surface layers that is likely associated with the first bright ring detected with ALMA in the $λ$=1.3mm dust continuum at $\sim$65~au. We also detect a point-like source at $\sim$0\farcs5 projected separation in the North-East direction, close to the inner edge of the second gap in the millimetre images. Comparing the point source photometry with the atmospheric emission models of non-accreting giant planets, we obtain a mass of 6--7~M$_J$ for a putative protoplanet, assuming a system age of 5~Myr. Based on the contrast at a 95\% level of completeness calculated on the emission-free regions of our images, we set upper limits for the masses of giant planets of 8--15~M$_J$, 4.5--6.5~M$_J$ and 2.5-4.0~M$_J$ at the locations of the first, second and third gap in the millimetre dust continuum, respectively. Further deep, high resolution thermal IR imaging of the HD~163296 system are warranted, to confirm the presence and nature of the point source and to better understand the structure of the dust disc.

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arXiv2018

V1094 Sco: a rare giant multi-ringed disk around a T Tauri star

A wide variety of ring-like dust structures has been detected in protoplanetary disks, but their origin and frequency are still unclear. We characterize the structure of an extended, multi-ringed disk discovered serendipitously in the ALMA Lupus disk survey and put it in the context of the Lupus disk population. ALMA observations in Band 6 at 234 GHz and Band 7 at 328 GHz at 0.3" resolution toward the K6 star V1094 Sco in Lupus III are presented, and its disk structure is analyzed. The spectral index $α_{mm}$ is determined in the inner 150 AU of the disk. The ALMA continuum data show a very extended disk with two gap/ring pairs. The gaps are located at 100 AU and 170 AU, the bright rings at 130 AU and 220 AU. Continuum emission is detected out to a 300 AU distance, similar to IM Lup but a factor of 5 larger than typically found for Lupus disks at this sensitivity and resolution. The bright central region of the disk (within 35 AU) is possibly optically thick at 1 mm wavelengths, and has a brightness temperature of only 13 K. The spectral index increases between the inner disk and the first ring, at the location of the first gap. Due to the low temperature of the disk midplane, snow lines can be excluded as the drivers behind the ring and gap formation in this disk. Disks the size of V1094 Sco are rare, and only 2.1+-1.5% of disks in Lupus show continuum emission beyond 200 AU. Possible connections between the large primordial disk population, transition disks, and exoplanets are discussed.

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arXiv2018

Homogeneous Analysis of the Dust Morphology of Transition Disks Observed with ALMA: Investigating dust trapping and the origin of the cavities

We analyze the dust morphology of 29 transition disks (TDs) observed with ALMA at (sub-) millimeter-emission. We perform the analysis in the visibility plane to characterize the total flux, cavity size, and shape of the ring-like structure. First, we found that the $M_{\rm{dust}}-M_\star$ relation is much flatter for TDs than the observed trends from samples of class II sources in different star forming regions. This relation demonstrates that cavities open in high (dust) mass disks, independent of the stellar mass. The flatness of this relation contradicts the idea that TDs are a more evolved set of disks. Two potential reasons (not mutually exclusive) may explain this flat relation: the emission is optically thick or/and millimeter-sized particles are trapped in a pressure bump. Second, we discuss our results of the cavity size and ring width in the context of different physical processes for cavity formation. Photoevaporation is an unlikely leading mechanism for the origin of the cavity of any of the targets in the sample. Embedded giant planets or dead zones remain as potential explanations. Although both models predict correlations between the cavity size and the ring shape for different stellar and disk properties, we demonstrate that with the current resolution of the observations, it is difficult to obtain these correlations. Future observations with higher angular resolution observations of TDs with ALMA will help to discern between different potential origins of cavities in TDs.

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arXiv2018

ALMA Survey of Lupus Protoplanetary Disks II: Gas Disk Radii

We present ALMA Band 6 observations of a complete sample of protoplanetary disks in the young (1-3 Myr) Lupus star-forming region, covering the 1.33 mm continuum and the 12CO, 13CO, and C18O J=2-1 lines. The spatial resolution is 0.25 arcsec with a medium 3-sigma continuum sensitivity of 0.30 mJy, corresponding to M_dust ~ 0.2 M_earth. We apply "Keplerian masking" to enhance the signal-to-noise ratios of our 12CO zero-moment maps, enabling measurements of gas disk radii for 22 Lupus disks; we find that gas disks are universally larger than mm dust disks by a factor of two on average, likely due to a combination of the optically thick gas emission as well as the growth and inward drift of the dust. Using the gas disk radii, we calculate the dimensionless viscosity parameter, alpha_visc, finding a broad distribution and no correlations with other disk or stellar parameters, suggesting that viscous processes have not yet established quasi-steady states in Lupus disks. By combining our 1.33 mm continuum fluxes with our previous 890 micron continuum observations, we also calculate the mm spectral index, alpha_mm, for 70 Lupus disks; we find an anti-correlation between alpha_mm and mm flux for low-mass disks (M_dust < 5), followed by a flattening as disks approach alpha_mm = 2, which could indicate faster grain growth in higher-mass disks, but may also reflect their larger optically thick components. In sum, this work demonstrates the continuous stream of new insights into disk evolution and planet formation that can be gleaned from unbiased ALMA disk surveys.

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arXiv2018

Nitrogen fractionation in high-mass star-forming cores across the Galaxy

The fractionation of nitrogen (N) in star-forming regions is a poorly understood process. To put more stringent observational constraints on the N-fractionation, we have observed with the IRAM-30m telescope a large sample of 66 cores in massive star-forming regions. We targeted the (1-0) rotational transition of HN$^{13}$C, HC$^{15}$N, H$^{13}$CN and HC$^{15}$N, and derived the $^{14}$N/$^{15}$N ratio for both HCN and HNC. We have completed this sample with that already observed by Colzi et al. (2018), and thus analysed a total sample of 87 sources. The $^{14}$N/$^{15}$N ratios are distributed around the Proto-Solar Nebula value with a lower limit near the terrestrial atmosphere value ($\sim$272). We have also derived the $^{14}$N/$^{15}$N ratio as a function of the Galactocentric distance and deduced a linear trend based on unprecedented statistics. The Galactocentric dependences that we have found are consistent, in the slope, with past works but we have found a new local $^{14}$N/$^{15}$N value of $\sim$400, i.e. closer to the Prosolar Nebula value. A second analysis was done, and a parabolic Galactocentric trend was found. Comparison with Galactic chemical evolution models shows that the slope until 8 kpc is consistent with the linear analysis, while the flattening trend above 8 kpc is well reproduced by the parabolic analysis.

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arXiv2018

The fragmentation properties of massive protocluster gas clumps: an ALMA study

Fragmentation of massive dense molecular clouds is the starting point in the formation of rich clusters and massive stars. Theory and numerical simulations indicate that the population of the fragments (number, mass, diameter, separation) resulting from the gravitational collapse of such clumps is probably regulated by the balance between the magnetic field and the other competitors of self-gravity, in particular turbulence and protostellar feedback. We have observed 11 massive, dense and young star-forming clumps with the Atacama Large Millimeter Array (ALMA) in the thermal dust continuum emission at $\sim 1$~mm with an angular resolution of 0.25 arcseconds with the aim of determining their population of fragments. We find fragments on sub-arcsecond scales in 8 out of the 11 sources. The ALMA images indicate two different fragmentation modes: a dominant fragment surrounded by companions with much smaller mass and size, and many ($\geq 8$) fragments with a gradual change in masses and sizes. On average, the largest number of fragments is found towards the warmer and more massive clumps. Also, the warmer clumps tend to form fragments with larger mass and size. To understand the role of the different physical parameters to regulate the final population of the fragments, we have simulated the collapse of a massive clump of $100$ and $300$ M$_{\odot}$ having different magnetic support. The simulations indicate that: (1) fragmentation is inhibited when the initial turbulence is low, independent of the other physical parameters. (2) a filamentary distribution of the fragments is favoured in a highly magnetised clump. We conclude that the clumps that show many fragments distributed in a filamentary-like structure are likely characterised by a strong magnetic field, while the others are possible also in a weaker magnetic field.

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arXiv2018

Rings and gaps in the disc around Elias 24 revealed by ALMA

We present Atacama Large Millimeter/sub-millimeter Array (ALMA) Cycle 2 observations of the 1.3 mm dust continuum emission of the protoplanetary disc surrounding the T Tauri star Elias 24 with an angular resolution of $\sim 0.2"$ ($\sim 28$ au). The dust continuum emission map reveals a dark ring at a radial distance of $0.47"$ ($\sim 65$ au) from the central star, surrounded by a bright ring at $0.58"$ ($\sim 81$ au). In the outer disc, the radial intensity profile shows two inflection points at $0.71"$ and $0.87"$ ($\sim 99$ and $121$ au respectively). We perform global three-dimensional smoothed particle hydrodynamic gas/dust simulations of discs hosting a migrating and accreting planet. Combining the dust density maps of small and large grains with three dimensional radiative transfer calculations, we produce synthetic ALMA observations of a variety of disc models in order to reproduce the gap- and ring-like features observed in Elias 24. We find that the dust emission across the disc is consistent with the presence of an embedded planet with a mass of $\sim 0.7\, \mathrm{M_{\mathrm{J}}}$ at an orbital radius of $\sim$ 60 au. Our model suggests that the two inflection points in the radial intensity profile are due to the inward radial motion of large dust grains from the outer disc. The surface brightness map of our disc model provides a reasonable match to the gap- and ring-like structures observed in Elias 24, with an average discrepancy of $\sim$ 5% of the observed fluxes around the gap region.

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arXiv2017

ALMA continuum observations of the protoplanetary disk AS 209. Evidence of multiple gaps opened by a single planet

The paper presents new high angular resolution ALMA 1.3 mm dust continuum observations of the protoplanetary system AS 209 in the Ophiuchus star forming region. The dust continuum emission is characterized by a main central core and two prominent rings at $r = 75\,$au and $r = 130\,$au intervaled by two gaps at at $r = 62\,$au and $r = 103\,$au. The two gaps have different widths and depths, with the inner one being narrower and shallower. We determined the surface density of the millimeter dust grains using the 3D radiative transfer disk code \textsc{dali}. According to our fiducial model the inner gap is partially filled with millimeter grains while the outer gap is largely devoid of dust. The inferred surface density is compared to 3D hydrodynamical simulations (FARGO-3D) of planet-disk interaction. The outer dust gap is consistent with the presence of a giant planet ($M_{\rm planet} \sim 0.8\,M_{\rm Staturn}$); the planet is responsible for the gap opening and for the pile-up of dust at the outer edge of the planet orbit. The simulations also show that the same planet can give origin to the inner gap at $r = 62\,$au. The relative position of the two dust gaps is close to the 2:1 resonance and we have investigated the possibility of a second planet inside the inner gap. The resulting surface density (including location, width and depth of the two dust gaps) are in agreement with the observations. The properties of the inner gap pose a strong constraint to the mass of the inner planet ($M_{\rm planet} < 0.1\,M_{\rm J}$). In both scenarios (single or pair of planets), the hydrodynamical simulations suggest a very low disk viscosity ($α< 10^{-4}$). Given the young age of the system (0.5 - 1 Myr), this result implies that the formation of giant planets occurs on a timescale of $\lesssim$ 1\,Myr.

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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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