A5012270663- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Atmospheric Ozone and Climate
- Molecular Spectroscopy and Structure
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- Atomic and Molecular Physics
- Advanced Combustion Engine Technologies
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Advanced Chemical Physics Studies
- Earthquake Detection and Analysis
- Solar and Space Plasma Dynamics
- Advanced Physical and Chemical Molecular Interactions
- Theoretical and Computational Physics
- SAS software applications and methods
- Scientific Research and Discoveries
Chalmers University of Technology
2020-2024
University College London
2017-2019
European Southern Observatory
2019
University of Palermo
2018
We report the first detection of phosphorus monoxide ion (PO + ) in interstellar medium. Our unbiased and very sensitive spectral survey toward G+0.693–0.027 molecular cloud covers four different rotational transitions this molecule, two which ( J = 1–0 2–1) appear free contamination from other species. The fit performed, assuming local thermodynamic equilibrium conditions, yields a column density N =(6.0 ± 0.7) × 10 11 cm −2 . resulting abundance with respect to hydrogen is 4.5 –12 PO...
The low dust temperatures (<14 K) of Planck Galactic cold clumps (PGCCs) make them ideal targets to probe the initial conditions and very early phase star formation. "TOP-SCOPE" is a joint survey program targeting ∼2000 PGCCs in J = 1–0 transitions CO isotopologues ∼1000 850 μm continuum emission. objective surveys (SMT 10 m, KVN 21 NRO 45 m) statistically study occurring during formation evolution molecular clouds, across wide range environments. observations, data analysis, example science...
Observations carried out toward starless and pre-stellar cores have revealed that complex organic molecules are prevalent in these objects, but it is unclear what chemical processes involved their formation. Recently, has been shown organics preferentially produced at an intermediate-density shell within the L1544 core radial distances of ~4000 au with respect to center. However, spatial distribution only inferred this remains unknown whether species present a similar behaviour other cores....
We present the first release of data and compact-source catalogue for JCMT Large Program SCUBA-2 Continuum Observations Pre-protostellar Evolution (SCOPE). SCOPE consists 850-um continuum observations 1235 Planck Galactic Cold Clumps (PGCCs) made with Submillimetre Common-User Bolometer Array 2 on James Clerk Maxwell Telescope. These are at an angular resolution 14.4 arcsec, significantly improving upon 353-GHz 5 arcmin, allowing a 3528 compact sources in 558 PGCCs. find that detected PGCCs...
Abstract We study the astrochemical diagnostics of isolated massive protostar G28.20-0.05. analyze data from Atacama Large Millimeter/submillimeter Array 1.3 mm observations with a resolution 0.″2 (∼1000 au). detect emission wealth species, including oxygen-bearing (e.g., H 2 CO, CH 3 OH, OCH ), sulfur-bearing (SO , S), and nitrogen-bearing HNCO, NH CHO, C CN, 5 CN) molecules. discuss their spatial distributions, physical conditions, correlation between different possible chemical origins....
ABSTRACT Infrared dark clouds (IRDCs) are potential hosts of the elusive early phases high mass star formation (HMSF). Here, we conduct an in-depth analysis fragmentation properties a sample 10 IRDCs, which have been highlighted as some best candidates to study HMSF within Milky Way. To do so, obtained set large mosaics covering these IRDCs with Atacama Large Millimeter/submillimeter Array (ALMA) at Band 3 (or mm). These observations angular resolution (∼3 arcsec; ∼0.05 pc), and continuum...
Recent observations of the pre-stellar core L1544 and younger starless L1498 have revealed that complex organic molecules (COMs) are enhanced in gas phase toward their outer intermediate-density shells. Our goal is to determine level chemical complexity L1517B, which seems than L1498, compare it with other two previously studied cores see if there a evolution within cores. We carried out 3 mm high-sensitivity positions L1517B core: core's centre position where methanol emission peaks (at...
ABSTRACT Supernova remnants (SNRs) contribute to regulate the star formation efficiency and evolution of galaxies. As they expand into interstellar medium (ISM), transfer vast amounts energy momentum that displace, compress, heat surrounding material. Despite extensive work in galaxy models, it remains be observationally validated what extent molecular ISM is affected by interaction with SNRs. We use first results ESO–ARO Public Spectroscopic Survey SHREC investigate shock between SNR IC443...
Abstract The origin of the stellar initial mass function (IMF) and how it may vary with galactic environment is a matter debate. Certain star formation theories involve close connection between IMF core (CMF), so important to measure this CMF in range Milky Way locations. Here we study three Galactic center clouds: G0.253+0.016 (“The Brick”), Sagittarius B2-Deep South field (Sgr B2-DS), C C). We use Atacama Large Millimeter/submillimeter Array 1 mm continuum images identify cores as peaks...
Abstract We present ∼8–40 μ m SOFIA-FORCAST images of seven regions “clustered” star formation as part the SOFIA Massive Star Formation Survey. identify a total 34 protostar candidates and build their spectral energy distributions (SEDs). fit these SEDs with grid radiative transfer models based on turbulent core accretion (TCA) theory to derive key protostellar properties, including initial mass, M c , clump environment mass surface density, Σ cl current * . also carry out empirical graybody...
Infrared-Dark Clouds (IRDCs) are cold, dense regions of high (optical and infrared) extinction, believed to be the birthplace high-mass stars stellar clusters. The physical mechanisms leading formation these IRDCs not completely understood it is thus important study their molecular gas kinematics chemical content search for any signature process. Using 30m-diameter antenna at Instituto de Radioastronom\'ia Milim\'etrica, we have obtained emission maps tracers (H$^{13}$CO$^{+}$ HN$^{13}$C)...
Abstract Magnetohydrodynamic (MHD) shocks are violent events that inject large amounts of energy in the interstellar medium dramatically modifying its physical properties and chemical composition. Indirect evidence for presence such has been reported from especial chemistry detected toward a variety astrophysical shocked environments. However, internal structure these remains unresolved since their expected spatial scales too small to be measured with current instrumentation. Here we report...
Context. Massive stars have an impact on their surroundings from early in formation until the end of lives. However, very little is known about formation. Episodic accretion may play a crucial role process, but only handful observations reported such events occurring massive protostars. Aims. We aim to investigate outburst event high-mass star-forming region S255IR where protostar NIRS3 recently underwent outburst. follow evolution this source both photometry and morphology its surroundings....
Abstract Magnetic fields may play a crucial role in setting the initial conditions of massive star and cluster formation. To investigate this, we report SOFIA-HAWC+ 214 μ m observations polarized thermal dust emission high-resolution GBT-Argus C 18 O(1-0) toward Infrared Dark Cloud (IRDC) G28.37+0.07. Considering local dispersion B -field orientations, produce map strength IRDC, which exhibits values between ∼0.03 1 mG based on refined Davis–Chandrasekhar–Fermi method proposed by Skalidis...
Abstract An important issue in the chemistry of interstellar ices is role dust materials. In this work, we study effect an amorphous water-rich magnesium silicate deposited onto ZnSe windows on chemical evolution ultraviolet-irradiated methanol ices. For comparison, also irradiate similar bare windows. Silicates are produced at relatively low temperatures exploiting a sol–gel technique. The composition synthesized material reflects forsterite stoichiometry. Si–OH groups and carbonates...
Infrared Dark Clouds (IRDCs) are very dense and highly extincted regions that host the initial conditions of star stellar cluster formation. It is crucial to study kinematics molecular content IRDCs test their formation mechanism ultimately characterise these conditions. We have obtained high-sensitivity Silicon Monoxide, SiO(2-1), emission maps toward six IRDCs, G018.82$-$00.28, G019.27+00.07, G028.53$-$00.25, G028.67+00.13, G038.95$-$00.47 G053.11+00.05 (cloud A, B, D, E, I J,...
Abstract The stellar initial mass function (IMF) is fundamental for many areas of astrophysics, but its origin remains poorly understood. It may be inherited from the core (CMF) or arise as a result more chaotic, competitive accretion. Dense, gravitationally bound cores are seen in molecular clouds and some observations have suggested that CMF similar shape to IMF, though translated higher masses by factor ∼3. Here we measure 28 dense clumps within 3.5 kpc likely central regions massive...
We present $\sim10-40\,\mu$m SOFIA-FORCAST images of 11 isolated protostars as part the SOFIA Massive (SOMA) Star Formation Survey, with this morphological classification based on 37 $\mu$m imaging. develop an automated method to define source aperture size using gradient its background-subtracted enclosed flux and apply build spectral energy distributions (SEDs). fit SEDs radiative transfer models, developed within framework turbulent core accretion (TCA) theory, estimate key protostellar...
Supernova remnants (SNRs) may regulate star formation in galaxies. For example, SNR-driven shocks form new molecular gas or compress pre-existing clouds and trigger the of stars. To test this scenario, we measure deuteration $N_2H^+$, $D_{frac}^{N_2H^+}$, a well-studied tracer pre-stellar cores, across Infrared Dark Cloud (IRDC) G034.77-00.55, known to be experiencing shock interaction with SNR W44. We use N$_2$H$^+$ N$_2$D$^+$ J=1-0 single pointing observations obtained 30m antenna at...
Nitrogen is one of the most abundant elements in Universe and its 14N/15N isotopic ratio has potential to provide information about initial environment which our Sun formed. Recent findings suggest that Solar System may have formed a massive cluster since presence short-lived radioisotopes meteorites can only be explained by influence supernova. The aim this project determine towards sample cold, dense cores at stages their evolution. We observed J=1-0 transitions HCN, H13CN, HC15N, HN13C...
Context. Infrared dark clouds (IRDCs) are cold, dense regions of the interstellar medium (ISM) that likely to represent initial conditions for massive star and cluster formation. It is thus important study physical chemical IRDCs provide constraints inputs theoretical models these processes. Aims. We aim determine astrochemical conditions, especially cosmic ray ionisation rate (CRIR) age, in different IRDC G28.37+00.07 by comparing observed abundances multiple molecules molecular ions with...
We report high-resolution 1.3~mm continuum and molecular line observations of the massive protostar G28.20-0.05 with ALMA. The image reveals a ring-like structure 2,000~au radius, similar to morphology seen in archival 1.3~cm VLA observations. Based on its spectral index associated H$30\alpha$ emission, this mainly traces ionised gas. However, there is evidence for $\sim30$~M$_{\odot}$ dusty gas near main mm peak one side ring, as well adjacent regions within 3,000~au. A virial analysis...
To study the early phases of massive star formation, we present ALMA observations SiO(5-4) emission and VLA 6 cm continuum towards 32 Infrared Dark Cloud (IRDC) clumps, spatially resolved down to $\lesssim 0.05$ pc. Out detect SiO in 20 11 them is relatively strong likely tracing protostellar outflows. Some outflows are collimated, while others less ordered. For six strongest outflows, estimate basic outflow properties. In our entire sample, where there emission, find 1.3 mm infrared nearby,...
Evidence that the chemical characteristics around low- and high-mass protostars are similar has been found: notably, a variety of carbon-chain species complex organic molecules (COMs) form both types. On other hand, compositions intermediate-mass (IM) ($2 M_ odot < m_* <8 $) have not studied with large samples. In particular, it is unclear extent to which them. We aim obtain sample IM protostars, focusing particularly on species. also derive rotational temperatures HC$_5$N confirm...
Context . Massive stars play important roles throughout the universe; however, their formation remains poorly understood. Observations of jets and outflows in high-mass star-forming regions, as well surveys young stellar object (YSO) content, can help test theoretical models massive star formation. Aims We aim at characterizing region AFGL 5180 near-infrared (NIR), identifying relating these to sub-mm/mm sources, surveying overall YSO surface number density compare models. Methods Broad-...