Publications (35)
Highly efficient broadband conversion of light polarization by composite retarders
S. S. Ivanov, A. A. Rangelov, N. V. Vitanov +2
Driving on an analogy with the technique of composite pulses in quantum physics, we propose highly efficient broadband polarization converters composed of sequences of ordinary ret…
Ionization driven molecular outflow in K3-50A
P. D. Klaassen, R. Galvan-Madrid, T. Peters +2
Whether high mass stars continue to accrete material beyond the formation of an HII region is still an open question. Ionized infall and outflow have been seen in some sources, but…
IRAS23385+6053: An embedded massive cluster in the making
R. Cesaroni, H. Beuther, A. Ahmadi +26
This study is part of the project ``CORE'', an IRAM/NOEMA large program consisting of observations of the millimeter continuum and molecular line emission towards 20 selected high-…
SILCC-Zoom: The dynamical and chemical evolution of molecular clouds
D. Seifried, S. Walch, P. Girichidis +6
We present 3D "zoom-in" simulations of the formation of two molecular clouds out of the galactic interstellar medium. We model the clouds - identified from the SILCC simulations -…
MUSCLE W49 : A Multi-Scale Continuum and Line Exploration of the Most Luminous Star Formation Region in the Milky Way. I. Data and The Mass Structure of the Giant Molecular Cloud
R. Galván-Madrid, H. B. Liu, Z. -Y. Zhang +9
The Multi-Scale Continuum and Line Exploration of W49 (MUSCLE W49) is a comprehensive gas and dust survey of the giant molecular cloud (GMC) of W49A, the most luminous star-formati…
Flickering of 1.3 cm Sources in Sgr B2: Towards a Solution to the Ultracompact HII Region Lifetime Problem
C. G. De Pree, T. Peters, M. -M. Mac Low +6
Accretion flows onto massive stars must transfer mass so quickly that they are themselves gravitationally unstable, forming dense clumps and filaments. These density perturbations…
Modelling the supernova-driven ISM in different environments
A. Gatto, S. Walch, M. -M. Mac Low +11
We use hydrodynamical simulations in a periodic box to model the impact of supernova (SN) explosions on the multi-phase interstellar medium (ISM) for initial de…
Flux Density Variations at 3.6 cm in the Massive Star-Forming Region W49A
C. G. De Pree, R. Galván-Madrid, W. M. Goss +8
A number of ultracompact H II regions in Galactic star forming environments have been observed to vary significantly in radio flux density on timescales of 10-20 years. Theory pred…
Core fragmentation and Toomre stability analysis of W3(H2O): A case study of the IRAM NOEMA large program CORE
A. Ahmadi, H. Beuther, J. C. Mottram +30
The fragmentation mode of high-mass molecular clumps and the properties of the central rotating structures surrounding the most luminous objects have yet to be comprehensively char…
Synthetic [CII] emission maps of a simulated molecular cloud in formation
A. Franeck, S. Walch, D. Seifried +10
The C ion is an important coolant of interstellar gas, and so the [CII] fine structure line is frequently observed in the interstellar medium. However, the physical and chemi…
Multi-wavelength modelling of the circumstellar environment of the massive proto-star AFGL 2591 VLA 3
F. A. Olguin, M. G. Hoare, K. G. Johnston +13
We have studied the dust density, temperature and velocity distributions of the archetypal massive young stellar object (MYSO) AFGL 2591. Given its high luminosity ($L=2 \times 10^…
Fragmentation, rotation and outflows in the high-mass star-forming region IRAS 23033+5951. A case study of the IRAM NOEMA large program CORE
F. Bosco, H. Beuther, A. Ahmadi +23
The formation process of high-mass stars (>8M) is poorly constrained, particularly, the effects of clump fragmentation creating multiple systems and the mechanism of mass a…
The sharp ALMA view of infall and outflow in the massive protocluster G31.41+0.31
M. T. Beltrán, V. M. Rivilla, R. Cesaroni +15
Context. To better understand the formation of high-mass stars, it is fundamental to investigate how matter accretes onto young massive stars, how it is ejected, and how all this d…
Kinematics and stability of high-mass protostellar disk candidates at sub-arcsecond resolution -- Insights from the IRAM NOEMA large program CORE
Aida Ahmadi, H. Beuther, F. Bosco +28
The fragmentation mode of high-mass molecular clumps and the accretion processes that form the most massive stars () are still not well understood. To this end,…
The SILCC project: III. Regulation of star formation and outflows by stellar winds and supernovae
A. Gatto, S. Walch, T. Naab +9
We study the impact of stellar winds and supernovae on the multi-phase interstellar medium using three-dimensional hydrodynamical simulations carried out with FLASH. The selected g…
Chemical complexity in high-mass star formation: An observational and modeling case study of the AFGL 2591 VLA 3 hot core
C. Gieser, D. Semenov, H. Beuther +30
We present a detailed observational and modeling study of the hot core VLA 3 in the high-mass star-forming region AFGL 2591, which is a target region of the NOrthern Extended Milli…
Fragmentation and disk formation during high-mass star formation: The IRAM NOEMA (Northern Extended Millimeter Array) large program CORE
H. Beuther, J. C. Mottram, A. Ahmadi +30
Aims: We aim to understand the fragmentation as well as the disk formation, outflow generation and chemical processes during high-mass star formation on spatial scales of individua…
Fragmentation in the massive G31.41+0.31 protocluster
M. T. Beltrán, V. M. Rivilla, R. Cesaroni +18
Context. ALMA observations at 1.4 mm and 0.2'' (750au) angular resolution of the Main core in the high-mass star forming region G31.41+0.31 have revealed a puzzling scenario: on th…
Substructures in the Keplerian disc around the O-type (proto)star G17.64+0.16
L. T. Maud, R. Cesaroni, M. S. N. Kumar +20
We present the highest angular resolution (20x15mas - 44x33au) Atacama Large Millimeter/sub-millimeter Array (ALMA) observations currently possible of the proto-O-star G17.64+0.16…
Evidence of Short Timescale Flux Density Variations of UC HII regions in Sgr B2 Main and North
C. G. De Pree, T. Peters, M. -M. Mac Low +6
We have recently published observations of significant flux density variations at 1.3 cm in HII regions in the star forming regions Sgr B2 Main and North (De Pree et al. 2014). To…
The CepA disk-outflow system at <=0.2'' or <=100au resolution
H. Beuther, C. Gieser, V. Aberham +21
Context: Although there has been significant progress, the physical properties and potential fragmentation of accretion disks around high-mass protostars remain poorly constrained.…
Accelerating infall and rotational spin-up in the hot molecular core G31.41+0.31
M. T. Beltrán, R. Cesaroni, V. M. Rivilla +20
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…
The SILCC (SImulating the LifeCycle of molecular Clouds) project: I. Chemical evolution of the supernova-driven ISM
S. K. Walch, P. Girichidis, T. Naab +7
The SILCC project (SImulating the Life-Cycle of molecular Clouds) aims at a more self-consistent understanding of the interstellar medium (ISM) on small scales and its link to gala…
Multi-scale view of star formation in IRAS 21078+5211: From clump fragmentation to disk wind
L. Moscadelli, H. Beuther, A. Ahmadi +23
In the massive star-forming region IRAS 21078+5211, a highly fragmented cluster (0.1~pc in size) of molecular cores is observed, located at the density peak of an elongated (1~pc i…
The physical and chemical structure of high-mass star-forming regions. Unraveling chemical complexity with the NOEMA large program "CORE"
C. Gieser, H. Beuther, D. Semenov +30
We use sub-arcsecond resolution (0.4) observations with NOEMA at 1.37 mm to study the dust emission and molecular gas of 18 high-mass star-forming regions. We combine the…
Enhancement in Thermally Generated Spin Voltage at Pd/NiFeO Interfaces by the Growth on Lattice-Matched Substrates
A. Rastogi, Z. Li, A. V. Singh +15
Efficient spin injection from epitaxial ferrimagnetic NiFeO thin films into a Pd layer is demonstrated via spin Seebeck effect measurements in the longitudinal geometry. Th…
Chasing discs around O-type (proto)stars - ALMA evidence for an SiO disc and disc wind from G17.64+0.16
L. T. Maud, R. Cesaroni, M. S. N. Kumar +28
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 (220G…
The evolution of young HII regions
P. D. Klaassen, K. G. Johnston, J. S. Urquhart +6
High-mass stars form in much richer environments than those associated with isolated low-mass stars, and once they reach a certain mass, produce ionised (HII) regions. The formatio…
Fragmentation and kinematics in high-mass star formation: CORE-extension targeting two very young high-mass star-forming regions
H. Beuther, C. Gieser, S. Suri +24
Context: The formation of high-mass star-forming regions from their parental gas cloud and the subsequent fragmentation processes lie at the heart of star formation research. Aims:…
Clustered star formation at early evolutionary stages. Physical and chemical analysis of the young star-forming regions ISOSS J22478+6357 and ISOSS J23053+5953
C. Gieser, H. Beuther, D. Semenov +20
We aim to characterize the physical and chemical properties of fragmented cores during the earliest evolutionary stages in the very young star-forming regions ISOSS J22478+6357 and…
Density distributions, magnetic field structures and fragmentation in high-mass star formation
H. Beuther, C. Gieser, J. D. Soler +19
Methods: Observing the large pc-scale Stokes I mm dust continuum emission with the IRAM 30m telescope and the intermediate-scale (<0.1pc) polarized submm dust emission with the Sub…
Unzipping graphene: Extendend defects by ion irradiation
S. Akcöltekin, H. Bukowska, T. Peters +6
Many of the proposed future applications of graphene require the controlled introduction of defects into its perfect lattice. Energetic ions provide one way of achieving this chall…
Disk fragmentation in high-mass star formation. High-resolution observations towards AFGL 2591-VLA 3
S. Suri, H. Beuther, C. Gieser +29
Increasing evidence suggests that, similar to their low-mass counterparts, high-mass stars form through a disk-mediated accretion process. At the same time, formation of high-mass…
Time-Variable Radio Recombination Line Emission in W49A
C. G. De Pree, D. J. Wilner, L. E. Kristensen +8
We present new Jansky Very Large Array (VLA) images of the central region of the W49A star-forming region at 3.6~cm and at 7~mm at resolutions of 0\farcs15 (1650 au) and 0\farcs04…
Young massive star cluster formation in the Galactic Centre is driven by global gravitational collapse of high-mass molecular clouds
A. T. Barnes, S. N. Longmore, A. Avison +19
Young massive clusters (YMCs) are the most compact, high-mass stellar systems still forming at the present day. The precursor clouds to such systems are, however, rare due to their…