A5013404053- Astrophysics and Star Formation Studies
- Molecular Spectroscopy and Structure
- Atmospheric Ozone and Climate
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Advanced Chemical Physics Studies
- Quantum and electron transport phenomena
- Gamma-ray bursts and supernovae
- Semiconductor Quantum Structures and Devices
- Solar and Space Plasma Dynamics
- Magnetic confinement fusion research
- Advanced Thermodynamic Systems and Engines
- Atmospheric aerosols and clouds
- Geophysics and Sensor Technology
- Chemical and Physical Properties of Materials
- Physics of Superconductivity and Magnetism
- Advanced Measurement and Metrology Techniques
- Planetary Science and Exploration
- High-pressure geophysics and materials
- Atomic and Molecular Physics
- Calibration and Measurement Techniques
- Spacecraft and Cryogenic Technologies
- Quantum, superfluid, helium dynamics
Chalmers University of Technology
1998-2023
Sahlgrenska University Hospital
2017
Leiden University
2013-2017
Leiden Observatory
2016
University of Copenhagen
2012-2014
Natural History Museum Aarhus
2012-2014
University of Liverpool
2011
astroquery is a collection of tools for requesting data from databases hosted on remote servers with interfaces exposed the internet, including those web pages but without formal application program interfaces. These are built Python requests package, which used to make HTTP requests, and astropy, provides most parsing functionality. modules generally attempt replicate page interface provided by given service as closely possible, making transition browser-based command-line interaction easy....
The inner regions of the envelopes surrounding young protostars are characterised by a complex chemistry, with prebiotic molecules present on scales where protoplanetary disks eventually may form. This paper introduces systematic survey, "Protostellar Interferometric Line Survey (PILS)" Class 0 protostellar binary IRAS 16293-2422 using Atacama Large Millimeter/submillimeter Array (ALMA). survey covers full frequency range from 329 to 363 GHz (0.8 mm) additional targeted observations at 3.0...
One of the open questions in astrochemistry is how complex organic and prebiotic molecules are formed. Aims. Our aim to start process compiling an inventory oxygen-bearing toward solar-type Class 0 protostellar binary IRAS16293-2422 from unbiased spectral survey with ALMA (PILS). Here we focus on new detections ethylene oxide (c-C$_2$H$_4$O), acetone (CH$_3$COCH$_3$), propanal (C$_2$H$_5$CHO). Methods. With ALMA, surveyed range 329 363 GHz at 0.5$"$ (60 AU diameter) resolution. Using a...
The evolutionary past of our Solar system can be pieced together by comparing analogous low-mass protostars with remnants Protosolar Nebula – comets. Sulphur-bearing molecules may unique tracers the joint evolution volatile and refractory components. ALMA Band 7 data from large unbiased Protostellar Interferometric Line Survey are used to search for S-bearing in outer disc-like structure, ∼60 au IRAS 16293–2422 B, compared on 67P/Churyumov–Gerasimenko (67P/C–G) stemming ROSINA (Rosetta...
Context . Complex organic molecules are readily detected in the inner regions of gaseous envelopes forming protostars. Their detection is crucial to understanding chemical evolution Universe and exploring link between early stages star formation solar system bodies, where complex have been found abundance. In particular, that contain nitrogen interesting due role plays development life compact scales such trace around Aims The goal this work determine inventory one family nitrogen-bearing...
Abstract We have conducted a survey of 328 protostars in the Orion molecular clouds with Atacama Large Millimeter/submillimeter Array at 0.87 mm resolution ∼0.″1 (40 au), including observations Very 9 toward 148 ∼0.″08 (32 au). This is largest multiwavelength this by an order magnitude. use dust continuum emission and to measure disk radii masses Class 0, I, flat-spectrum protostars, characterizing evolution these properties protostellar phase. The mean for are <?CDATA...
(Abridged) Disks are observed around pre-main sequence stars, but how and when they form is still heavily debated. While disks young stellar objects have been identified through thermal dust emission, spatially spectrally resolved molecular line observations needed to determine their nature. We present subarcsecond of gas toward four Class I low-mass in Taurus. The 13CO C18O J=2-1 transitions at 220 GHz were with the Plateau de Bure Interferometer a spatial resolution ~0.8'' analyzed using...
Formamide (NH$_2$CHO) has previously been detected in several star-forming regions and is thought to be a precursor for different prebiotic molecules. Its formation mechanism still debated, however. Observations of formamide, related species their isopotologues may provide useful clues the chemical pathways leading formation. The Protostellar Interferometric Line Survey (PILS) represents an unbiased high angular resolution sensitivity spectral survey low-mass protostellar binary IRAS...
[abridged] The enhanced degrees of deuterium fractionation observed in envelopes around protostars demonstrate the importance chemistry at low temperatures, relevant pre- and protostellar cores. formaldehyde is an important species formation methanol more complex molecules. Here, we present first study deuteration on small scales prototypical low-mass protostar IRAS 16293-2422 using high spatial spectral resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations. Numerous...
Context: The R CrA cloud hosts a handful of Class 0/I low-mass young stellar objects. chemistry and physics at scales $>500$ AU in this are dominated by the irradiation from nearby Herbig Be star CrA. luminous large-scale emission makes it necessary to use high-resolution spectral imaging study dynamics inner envelopes discs protostars. Aims: We aim better understand structure regions these protostars and, particular, interplay between presence discs. Methods: Using Atacama Large...
This paper presents a systematic survey of the deuterated and 13C isotopologues variety oxygen-bearing complex organic molecules on Solar System scales toward protostar IRAS 16293-2422B. We use data from an unbiased molecular line between 329 363 GHz Atacama Large Millimeter/submillimeter Array (ALMA). The observations probe 60 AU where most have sublimated off dust grains are present in gas-phase. can be divided into two groups with one group, simpler species, showing D/H ratio...
Low-mass protostars have been suggested to show highly variable accretion rates through-out their evolution. Such changes in accretion, and related heating of ambient envelopes, may trigger significant chemical variations on different spatial scales from source-to-source. We present images emission C17O, H13CO+, CH3OH, C34S C2H toward the low-mass protostar IRAS 15398-3359 0.5" (75 AU diameter) with Atacama Large Millimeter/submillimeter Array (ALMA) at 340 GHz. The resolved that H13CO+ is...
Context. Water is present during all stages of star formation: as ice in the cold outer parts protostellar envelopes and dense inner regions circumstellar disks, gas close to protostars, upper layers disks powerful outflows shocks. Because its key importance understanding origin our own solar system, following evolution water way planet-forming disk a fundamental task research formation astrochemistry.
[Abridged] We present spectroscopic observations in H$_{2}$O, CO and related species with \textit{Herschel} HIFI PACS, as well ground-based follow-up the JCMT APEX CO, HCO$^{+}$ isotopologues, of a sample 49 nearby ($d<$500\,pc) candidate protostars. These data are used to study outflow envelope properties these sources. also compile their continuum SEDs order constrain physical properties. Water emission is dominated by shocks associated outflow, rather than cooler, slower entrained...
Despite their importance in the star formation process, measurements of magnetic field strength proto-planetary discs remain rare. While linear polarisation dust and molecular lines can give insight into structure, only observations circular produced by Zeeman splitting provide a direct measurement strenghts. One most promising probes strengths is paramagnetic radical CN. Here we present first Atacama Large Millimeter/submillimeter Array (ALMA) CN disc TW~Hya. The indicate an excellent...
Searches for the prebiotically-relevant cyanamide (NH$_2$CN) towards solar-type protostars have not been reported in literature. We here present first detection of this species warm gas surrounding two protostars, using data from Atacama Large Millimeter/Submillimeter Array Protostellar Interferometric Line Survey (PILS) IRAS 16293-2422 B and observations IRAM Plateau de Bure Interferometer NGC1333 IRAS2A. furthermore detect deuterated $^{13}$C isotopologues NH$_2$CN B. This is NHDCN...
Measuring the water deuterium fractionation in 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 isotopologues using (sub)millimeter wavelength interferometers have potential to shed light on this matter. toward IRAS 16293-2422 5(3,2)-4(4,1) transition H2-18O at 692.07914 GHz from Atacama Large Millimeter/submillimeter Array (ALMA) as well 3(1,3)-2(2,0) 203.40752...
(Abridged) The water deuterium fractionation (HDO/H$_2$O abundance ratio) has traditionally been used to infer the amount of brought Earth by comets. Measuring this ratio in deeply-embedded low-mass protostars makes it possible probe critical stage when is transported from clouds disks which icy bodies are formed. We present sub-arcsecond resolution observations HDO combination with H$_2^{18}$O PdBI toward three NGC 1333-IRAS 2A, IRAS 4A-NW, and 4B. resulting HDO/H$_2$O...
Glycolaldehyde is a key molecule in the formation of biologically relevant molecules such as ribose. We report its detection with Plateau de Bure interferometer toward Class 0 young stellar object NGC 1333 IRAS2A, which only second solar-type protostar for this prebiotic detected. Local thermodynamic equilibrium analyses glycolaldehyde, ethylene glycol (the reduced alcohol glycolaldehyde), and methyl formate most abundant isomer glycolaldehyde) were carried out. The relative abundance to...
The chemical composition of high-mass protostars reflects the physical evolution associated with different stages star formation. In this study, molecular inventory forming AFGL 4176 is studied in detail at high angular resolution (~0.35 arcsec) using ALMA. This makes it possible to separate emission inner hot envelope and disk around from that its cool outer envelope. addition, sensitivity ALMA identify weak optically thin lines allows for many isotopologues be detected, providing a more...
Context. How water is delivered to planetary systems a central question in astrochemistry. The deuterium fractionation of can serve as tracer for the chemical and physical evolution during star formation constrain origin Solar System bodies. Aims. aim determine HDO/H 2 O ratio inner warm gas toward three low-mass Class 0 protostars selected be isolated cores, i.e., not associated with any cloud complexes. Previous sources which have been established were all part larger star-forming...
Context. Low-mass protostars drive powerful molecular outflows that can be observed with mm and sub-mm telescopes. Various sulfuretted species are known to bright in shocks could used infer the physical chemical conditions throughout outflows. Aims. The evolution of sulfur chemistry is studied along driven by NGC1333-IRAS4A protobinary system located Perseus cloud constrain processes at work shocks. Methods. We various transitions from OCS, CS, SO, SO$_2$ towards 1.3, 2, 3mm bands using IRAM...