Roberto Galvan-Madrid
(ESO-Garching)
21/10/2013, 09:00
The Multi-Scale Continuum and Line Exploration of W49 (MUSCLE W49) is a comprehensive gas and dust survey of the parental giant molecular cloud (GMC) of W49A, the most luminous ($L \sim 10^{7.3} L_{sun}$) star-formation region in the Milky Way. The project has multiple components that cover the entire GMC at different scales and angular resolutions. We present results from observations with...
Tigran Arshakian
(Universität zu Köln)
21/10/2013, 09:00
We develop a wavelet-based cross-correlation (WCC) method to study the correlation between characteristic structures in molecular clouds as a function of scale. The method compares a pair of maps observed in different tracers, at different wavelenghts or in different velocity ranges. Advantages of the WCC: (i) it allows to measure the correlation coefficient and structural offset between two...
László Szücs
(Universität Heidelberg, ZAH, ITA)
21/10/2013, 09:00
Carbon monoxide molecule (CO) and its isotopes are frequently used as tracers of column
density in studies of the dense interstellar medium. The most abundant CO isotope,
$^{12}$CO, is usually optically thick in intermediate and high density regions and so
provides only a lower limit for the column density. In these regions, less abundant
isotopes are used, such as $^{13}$CO. To relate...
Dr
David Hubber
(Excellence Cluster Universe)
21/10/2013, 09:00
We present GANDALF, a new hybrid SPH and N-body code for combined star formation, planet formation and star cluster studies. GANDALF is written in C++ to perform the main hydrodynamic and gravitational computations. GANDALF also includes a python library to allow interactive simulations and visualisation. Initial conditions can also be generated inside python allowing simple control of setting...
Jeong-Gyu Kim
(Seoul National University)
21/10/2013, 09:00
The neutral component of the interstellar medium (ISM) is segregated
into the cold neutral medium (CNM) and warm neutral medium (WNM) as
a result of thermal instability. It was found that the CNM--WNM
evaporation interface, across which the CNM undergoes thermal
expansion, is linearly unstable to corrugational disturbances, in
complete analogy with the Darrieus-Landau instability (DLI)...
Andy Pon
(University of Leeds)
21/10/2013, 09:00
Molecular clouds exhibit large linewidths, which are usually interpreted as being due to supersonic turbulence. This turbulence plays a key role in many theories of star formation, as it is believed to help support and fragment molecular clouds. Current numerical MHD simulations show that the turbulent energy of a molecular cloud dissipates on the order of a crossing time, but do not...
Robertas Aluzas
(School of Physics and Astronomy, University of Leeds)
21/10/2013, 09:00
The interstellar medium (ISM) is highly structured and inhomogeneous. Density enhancements (clouds) that occupy a small volume fraction can dominate the mass fraction. The interaction between clouds and flows is a key process affecting the behaviour and evolution of the ISM, with implications for star formation and galaxy evolution. For instance, dense clouds may be destroyed by a flow, while...
Jonathan Heiner
(CRyA, UNAM Morelia)
21/10/2013, 09:00
Cold, self-absorbing atomic hydrogen can be seen as absorption features in the broader HI profile. However, unless emission of molecular gas (typically CO) at the same velocity as the absorption feature is detected, it is not always possible to distinguish between self-absorption and the lack of HI emission. Ideally one would want to dispense with the need to detect molecular emission, since...
Jonathan Smoker
(European Southern Observatory (VLT))
21/10/2013, 09:00
We describe a search for tiny-scale structure in the interstellar medium using archive twin-epoch measurements of resolution 42,000 and 120,000 towards hundreds of stars. Our aim is to discover more examples of time-variation in the interstellar medium and determine if they can be explained by varying physical conditions, the statistical properties of the ISM, or by ""real"" structures such as...
Catherine McEvoy
(Queen's University Belfast)
21/10/2013, 09:00
The tiny scale structure (from 1 AU to 1 pc) of the ISM is generally poorly understood. High resolution optical spectroscopic observations, both new and archival, have been used to delve into this tiny structure to see just how ubiquitous it is and to try to understand what causes such variation to occur.
Interstellar absorption lines from a selection of 96 O and B type stars spectra,...
Simon Bihr
(Max Planck Institute for Astronomy)
21/10/2013, 09:00
How do molecular clouds form from the diffuse atomic interstellar medium? To address this and further questions we are conducting the THOR survey, a galactic plane survey (l = 15 to 60dec and b = -1 to +1dec) of the 21cm HI line, four OH lines, and 20 recombination lines as well as the continuum from 1 to 2 GHz at a spatial resolution of ~20arcsec. We got granted 110 hours at the VLA in...
Ji-hyun Kang
(Korea Astronomy and Space Science Institute)
21/10/2013, 09:00
Turbulence study of the neutral hydrogen gas associated with supernova remnants (SNRs) has not been done so far, in spite of the fact that many HI surveys have been used to characterize the turbulent interstellar medium. This is mainly because the shocked HI emission of SNRs is difficult to be distinguished from the ambient HI emission in the Galactic Plane. We notice that some expanding HI...
Juan Camilo Ibañez
(ZAH/ITA)
21/10/2013, 09:00
Studying how self-gravitating turbulence in the interstellar medium determines the morphology, density profile and velocity dispersion of dense molecular clouds is key to understand the initial conditions of star formation. We use the Flash adaptive mesh refinement magnetohydrodynamics code to perform three-dimensional numerical simulations of a vertical column of the interstellar medium...
Lukas Konstandin
(Institut für Theoretische Astrophysik, Heidelberg)
21/10/2013, 09:00
Observations reveal that supersonic turbulence is prevalent in star forming clouds. The density and velocity field within these clouds indicate complex, chaotic, and filamentary structures, where turbulent motions interact with shocks. Therefore, understanding the properties of turbulence is a prerequisite for developing a comprehensive theory of star formation in the ISM. We study a set of...
Ralf Klessen
(ZAH/ITA, University of Heidelberg)
21/10/2013, 09:15
Dr
Stefanie Walch
(Max-Planck-Institut für Astrophysik)
21/10/2013, 09:55
review talk
Kazunari Iwasaki
(Nagoya University)
21/10/2013, 11:05
contributed talk
Nonlinear evolution of bistable interstellar medium is investigated using two-dimensional simulations with a realistic cooling rate, heat conduction, and physical viscosity. The calculation is performed in periodic boundary conditions without any external forcing. As the initial condition, spatially uniform unstable gas under thermal equilibrium is considered. At the initial stage, the...
Evangelia Ntormousi
(SAp/CEA Saclay)
21/10/2013, 11:20
contributed talk
Recent observational results have shown that local interstellar filaments follow a thickness distribution which is surprisingly narrowly peaked at 0.1 pc for a wide range of column densities. This fact is pertinent to the study of interstellar gases as a fingerprint of the physical mechanisms acting on that scale.
But what can create structure of a characteristic size when both gravity and...
Peter Scicluna
(ESO)
21/10/2013, 11:35
contributed talk
The spatial distribution of dust has significant influence on the observed extinction curve. As a result, when observing anisotropic, clumpy or turbulent environments the aperture may contain a wealth of unresolved structure. Hence, observations only probe an effective optical depth and effective extinction curve. In order to elucidate and quantify the impact of unresolved structure we perform...
Hans Zinnecker
(Deutsches SOFIA Institut)
21/10/2013, 11:50
contributed talk
I will present a short summary of the status of SOFIA, the Stratospheric Observatory for Infrared Astronomy. SOFIA has been deployed to the Southern Hemisphere in July 2013 and completed 9 successful flights out of Christchurch, New Zealand. Some amazing results from from these FIR observations with GREAT are emerging, including detection of the 2.5 THz OH and 2.7 THz HD ground state...
Joao Alves
(University of Vienna)
21/10/2013, 12:05
review talk
Understanding how matter is organized inside a molecular
cloud is key to understand where and how stars form. In this talk we summarize the main results from our ongoing program on NIR extinction on nearby molecular clouds, complemented with recent Herschel archival data. Our sample comprises all the nearby molecular cloud complexes in their entirety, from Pipe Nebula to the Orion complex,...
Nicola Schneider
(LAB Bordeaux)
21/10/2013, 14:15
contributed talk
Doris Arzoumanian
(IAS Orsay)
21/10/2013, 14:30
contributed talk
Herschel dust continuum images have revealed the ubiquity of filaments in the interstellar medium (ISM) and their fundamental role in the star formation process. Planck dust polarization observations trace the magnetic field structure of the ISM.
Filamentary structures are formed by the interplay of interstellar turbulence, gravity and magnetic field. What is the role of these various...
Gesa Bertrang
(ITAP, University of Kiel)
21/10/2013, 14:45
contributed talk
The influence of magnetic fields on the star-forming process is still under debate. A very good environment to study this influence is given in low-mass star-forming regions, so-called Bok globules. These objects are less affected by other processes, such as large-scale turbulences. The magnetic field strength and structure in the dense inner regions of these globules can be determined by...
Jouni Kainulainen
(Max-Planck-Institute for Astronomy)
21/10/2013, 15:00
contributed talk
Supersonic turbulence has a profound impact on the density structure of the cold interstellar medium (ISM). Consequently, observations of the ISM density structure can be used to constrain the fundamental properties of turbulence. However in practice, connecting the observed density structure to theoretical predictions is greatly hampered by the inability of observations to probe the wide...
Rowan Smith
(ZAH/ITA University of Heidelberg)
21/10/2013, 15:15
contributed talk
Filaments are seen throughout the ISM, from long filamentary IRDCs to individual filamentary sites of star formation. Using the moving mesh code AREPO we can investigate filament formation on all scales, as the unique combination of a Lagrangian mesh with a Riemann solver results in an extremely accurate treatment of shocks and discontinuities. I will describe how filamentary molecular clouds...
Patrick Hennebelle
(SAp/CEA Saclay)
21/10/2013, 16:30
review talk
Paul Clark
(ZAH/ITA, University of Heidelberg)
21/10/2013, 17:00
contributed talk
To date, numerical studies of the IMF have adopted initial conditions that are very dense -- often comparable to the densities of individual prestellar cores that are observed in giant molecular clouds (GMCs). These calculations, which start in the regime where the gas and dust are already strongly coupled, can say nothing about conditions we observe in nearby star-forming regions. In...
Jo Barnes
(University of St Andrews)
21/10/2013, 17:15
contributed talk
We investigate 3D photoionisation models of the Diffuse Ionised Gas (DIG). Our simulations show that in a supernova-driven, turbulent magnetised medium photons from OB stars in the Galactic plane are able to travel many kiloparsecs and reach heights required to ionise the DIG. To reach these heights photons travel through ?bubbles? evacuated by supernovae close to the midplane of the...
Prof.
Edith Falgarone
(LERMA/LRA Ecole Normale Supérieure)
21/10/2013, 17:30
The diffuse interstellar medium has long been known to harbor a remarkable molecular richness, that cannot be understood in the framework of state-of-the-art UV-driven chemistry. Absorption spectroscopy performed with Herschel/HIFI reveals unexpected large abundances of small hydrides that are the building blocks of interstellar chemistry in the diffuse medium. Because they are so abundant...
Matthew Bate
(University of Exeter)
22/10/2013, 09:00
review talk
Paula Stella Teixeira
(University of Vienna, Department of Astrophysics)
22/10/2013, 09:40
contributed talk
It is well established for several decades that filamentary structures are very common in star forming molecular clouds. Observational studies of how these structures evolve and fragment to form cores (and subsequently stars) may ultimately lead us to better understand how the core mass function (CMF) and stellar initial mass function (IMF) are assembled. The fragmentation of these filamentary...
Enrique Vazquez-Semadeni
(CRyA, UNAM)
22/10/2013, 09:55
contributed talk
I present results from numerical simulations and an analytical model of the
formation and gravitational collapse of giant molecular clouds (GMCs). The
clouds develop a network of filaments at various scales, whose physical
properties we compare with recent observations. Simulations including
ionizing stellar feedback show that its effect is the destruction of the
local star-forming...
Katharine Johnston
(MPIA, Heidelberg)
22/10/2013, 10:10
contributed talk
The massive infrared dark cloud G0.253+0.016 projected 45pc from the Galactic centre contains 10^5 Msun of dense gas whilst being mostly devoid of observed star formation tracers. To scrutinise the gas properties of G0.253+0.016, we have carried out a concerted SMA and IRAM 30m study of this enigmatic cloud in dust continuum, CO isotopologues as low-density tracers, as well as CH3OH and SiO as...
Cornelia Jäger
(Laboratory Astrophysics Group of the Max Planck Institute for Astronomy)
22/10/2013, 10:55
review talk
Holger Kreckel
(MPIK, Heidelberg)
22/10/2013, 11:35
contributed talk
As an ever increasing number of molecules are observed in interstellar space, accurate laboratory data on their formation and destruction processes will be required to understand interstellar reaction networks. Astrochemical models have identified ion-molecule reactions as one of the drivers for the buildup of molecules in space. On the other hand, dissociative recombination with free...
Andreas Wolf
(MPIK, Heidelberg)
22/10/2013, 11:50
contributed talk
Low energy collisions of electrons with atomic and molecular ions are among the most basic microscopic interactions in the interstellar medium. Electron-ion recombination limits the abundance of charged atoms molecules and, as dissociative recombination of molecular ions, produces neutral radical fragments for gas phase reaction chains. Moreover, electron impact excitation can influence...
Simon Glover
(ZAH/ITA University of Heidelberg)
22/10/2013, 12:05
review talk
Thomas Henning
(MPIA Heidelberg)
22/10/2013, 14:05
review talk
Marta Alves
(Institut d'Astrophysique Spatiale (IAS))
22/10/2013, 14:35
contributed talk
The Planck all-sky survey has opened a new window in our understanding of interstellar dust emission in extending to sub-millimetre wavelengths and microwave frequencies the detailed mapping of dust emission provided by past infrared missions. Such a wide frequency coverage allows us to probe the spectral energy distribution (SED) of large and cold dust grains, which are the bulk of the dust...
Henrik Beuther
(MPIA)
22/10/2013, 14:50
contributed talk
The interstellar medium (ISM) is mainly comprised of ionized, neutral atomic and molecular gas. One of the most important constituents of these phases is carbon in its ionized/neutral/molecular form (C^+, C^0 and CO). However, until recently a coherent analysis of the different phases at adequate resolution (Jeans length ~0.2pc) is lacking. We therefore conducted at study of the spectral lines...
Bastian Gundlach
(Institut für Geophysik und extraterrestrischer Physik, TU Braunschweig)
22/10/2013, 15:05
contributed talk
Grain growth by coagulation of ice and dust particles has been postulated and observed in the densest and coldest interstellar clouds. Thus, we have performed laboratory experiments in order to simulate inter-particle collisions in these environments. The experiments were used to measure the sticking threshold of micrometer-sized water ice particles for different grain sizes, velocities, and...
Ralf Siebenmorgen
(ESO)
22/10/2013, 15:20
contributed talk
We present a model for the diffuse interstellar dust that explains the observed wavelength-dependence of extinction, emission, linear and circular polarisation of light. The model is set up with a small number of parameters. It consists of a mixture of amorphous carbon and silicate grains with sizes from the molecular domain of 0.5 up to about 500nm. Dust grains with radii larger than 6nm are...
Svitlana Zhukovska
(Max Planck Institute for Astronomy)
22/10/2013, 16:05
contributed talk
Dust grains are indispensable part of the matter cycle, which plays an important role in many physical processes in the ISM. Interstellar dust content is determined by the interplay between dust formation by stars, destruction in the ISM and dust growth by mantle accretion in the ISM. The relative importance of these processes depends on both the stage of galactic evolution and metallicity...
Adam Leroy
(NRAO Charlottesville)
22/10/2013, 16:20
review talk
Diederik Kruijssen
(MPA Garching)
22/10/2013, 17:00
contributed talk
Galactic star formation (SF) relations are known to develop substantial scatter or even change form when considered below a certain spatial scale. I will quantify how this behaviour should be expected due to the incomplete statistical sampling of independent star-forming regions. Other included limiting factors are the incomplete sampling of SF tracers from the stellar initial mass function...
Sarah Ragan
(Max Planck Institute for Astronomy)
22/10/2013, 17:15
contributed talk
The question of how high-mass stars form relies fundamentally on the initial conditions. Due to the large distances to high-mass star-forming complexes and their precursors known as infrared-dark clouds (IRDCs), high-angular resolution is required to resolve individual cores. With the advent of Herschel, we now have access to the wavelength regime in which the cold dust comprising the clouds...
Javier A. Rodon
(ESO)
22/10/2013, 17:30
contributed talk
Rodón, J. A. (1): Beuther, H. (2): Zhang, Q. (3): Schilke, P. (4)
(1) European Southern Observatory; (2) Max-Planck Institut für Astronomie; (3) Harvard-Smithsonian Center for Astrophysics; (4) Universität zu Köln
In the last decade, we have started to spatially resolve the small gas and dust condensations in high-mass star-forming regions that will eventually become a massive star or...
Amelia Stutz
(MPIA)
22/10/2013, 17:45
contributed talk
Understanding how the gas environment within molecular clouds
influences the properties of protostars is a key step towards
understanding the physical factors that control star formation. We
report on analysis of the connection between molecular cloud
environment and protostellar properties using the Herschel Orion
Protostar Survey (HOPS), a large multi-observatory survey of
protostars...
Phil Cigan
(New Mexico Tech)
23/10/2013, 09:00
Many FIR studies target systems that have typical or enhanced abundances of heavy elements, but what is the picture for the low-metallicity regime? We present a comparison of HI and [CII] observations for five extremely metal-poor dwarf galaxies from the LITTLE THINGS survey. The galaxies we discuss have 12+log(O/H) = 7.4 - 7.8, some of the lowest-metallicity galaxies observed in [CII]. Our...
Mykola Petrov
(University of Vienna)
23/10/2013, 09:00
The galactic evolution is dominated by gas dynamics which can include gas infall and outflows, galactic fountains, and more and can be understandable due to differences in dynamics, thermal energies and element abundances of the gas phases. To follow the chemical and temporal evolution of galaxies it is necessary to model the gasdynamics combined with stellar dynamics, the star-gas energy and...
Deidre Hunter
(Lowell Observatory)
23/10/2013, 09:00
Metallicity is not a passive result of galaxy evolution, but a crucial driver. Dwarf galaxies are low in heavy elements, which has consequences for the ability to form cold, dense clouds that form stars. Molecular cores shrink and atomic envelopes grow in star-forming clouds as the metallicity drops (Bolatto et al. 2011). For this reason, CO had not been detected at log(O/H)+12 < 8.0 (Schruba...
Stefan Ohm
(Dept of Physics and Astronomy, University of Leicester)
23/10/2013, 09:00
Westerlund 1 (Wd 1) is the most massive stellar cluster in the Galaxy and associated with an extended region of TeV emission. Here we report the results of a search for GeV $\gamma$-ray emission in this region. The analysis is based on ~4.5 years of Fermi-LAT data and reveals significantly extended emission which we model as a Gaussian, resulting in a best-fit sigma of $\sigma$_S = $(0.475 \pm...
Nalin Vutisalchavakul
(University of Texas at Austin)
23/10/2013, 09:00
Combining several large scale Galactic plane surveys, we studied the gas distribution and star formation activities in part of the Galactic plane. Star formation rates were determined from infrared data obtained from WISE and Spitzer surveys. The Bolocam Galactic Plane Survey provided the data of 1.1mm dust continuum and dense gas tracers, while the Galactic Ring Survey provided the data of...
Oleg Egorov
(Sternberg Astronomical Institute of Lomonosow Moscow State University)
23/10/2013, 09:00
We present observations and analysis of two dwarf Irr galaxies in M81 group - IC 2574 and Holmberg II. Their 21 cm images of these galaxies show multiple shell-like structures with sizes up to 1-2 kpc, so-called supergiant shells (SGS), most probably created by stellar feedback from several generations of stars. According to modern understanding the SGS expansion triggers new bursts of star...
Emeric Bron
(LUTH - Observatoire de Paris/Université Paris Diderot)
23/10/2013, 09:00
The process of H2 formation on dust grains is the first step in the increase in chemical complexity leading to the multitude of molecules revealed by the latest generation of telescopes. It controls the transition from atomic to molecular gas and the resulting molecular chemistry through the central role of H2 in the chemical network. The formation rate in a diffuse medium has been inferred...
Mr
Alessandro Ballone
(USM/MPE, Garching)
23/10/2013, 09:00
A. Ballone, M. Schartmann, A. Burkert, S. Gillessen, R. Genzel, T.K.
Fritz, F. Eisenhauer, O Pfuhl, T. Ott
The origin of the dense gas cloud "G2" discovered in the Galactic Center
(Gillessen et al. 2012) is still a debated puzzle.
G2 might be a diffuse cloud or the result of an outflow from an invisible
star embedded in it. I will present the first attempt of detailed
simulations of...
Jennifer Schober
(ZAH / Uni Heidelberg)
23/10/2013, 09:00
Magnetic fields influence many processes in the ISM strongly. In the primordial ISM they are usually not considered, as they are assumed not to be dynamically important yet. In the presence of turbulence, however, the small-scale dynamo can amplify weak seed fields by randomly stretching, twisting and folding the field lines. The details of this process depend on the nature of turbulence, i.e....
Adam Ritchey
(University of Washington)
23/10/2013, 09:00
We present a detailed analysis of the physical conditions in shocked interstellar clouds along two lines of sight through the Vela supernova remnant using new high-resolution HST/STIS spectra acquired at FUV wavelengths. From the relative populations of collisionally-excited fine-structure levels in C I and O I, we derive unique solutions for the gas density and kinetic temperature in discrete...
Maximilian Brunner
(USM/LMU)
23/10/2013, 09:00
In galaxies stars are formed from a reservoir of cold molecular gas. For star formation to continue this reservoir has to be fueled with extragalactic material or else the gas is depleted. In this project we use the SPH-code GADGET to simulate a spiral galaxy that is constantly fed with new gas at a rate of five solar masses per year. We find that the star formation rate tries to adjust to the...
Mordecai-Mark Mac Low
(AMNH New York)
23/10/2013, 09:00
review talk
Adam Ginsburg
(University of Colorado, Boulder / European Southern Observatory)
23/10/2013, 09:00
Turbulence is one of the primary processes governing star formation. Many recent theories have determined the overall star formation rate of gas and even the shape of the initial mass function based purely on turbulent initial conditions. The key property governing star formation rates is the density distribution of the gas, which determines how much gas is above some "critical density" for...
Katharina Fierlinger
(LMU)
23/10/2013, 09:00
Amnart Sukom
(The Graduate University for Advanced Studies)
23/10/2013, 09:00
We present first wide-field deep near-infrared imaging polarimetry (15'x60') of the Orion A Integral Shape Filament obtained with SIRPOL, simultaneous JHKs imaging polarimeter on the IRSF telescope. Most derived magnetic field orientations from aperture polarimetry are perpendicular to the elongation of the ISF. The extended H-band polarization pattern confirms the hourglass shaped structure...
Joanne Dawson
(CSIRO Astronomy and Space Science)
23/10/2013, 09:40
contributed talk
I will examine the role of large-scale stellar feedback in the formation of new molecular clouds. The theoretical context for this is the compression, cooling and fragmentation of the atomic medium in turbulent shocks and flows, of which the ubiquitous ""supershells"" formed by multiple supernovae and stellar winds are one example. I will first report CO(J=1-0) and HI 21cm observations of the...
James Dale
(Excellence Cluster Universe, Garching b. München)
23/10/2013, 09:55
contributed talk
On the scale of galactic disks, supernovae are likely to be the most important form of stellar feedback on the ISM. However, the environment in which the supernovae explode is likely to have been strongly modified by the action of other kinds of feedback, particularly the earlier photoionization and winds from the exploding stars.
I will present SPH simulations of a parameter space of giant...
Matthias Gritschneder
(Univ California, Santa Cruz)
23/10/2013, 10:10
contributed talk
We study the evolution of molecular clouds under the influence of ionizing radiation. First, we propose that the Pipe Nebula is an HII region swept up by the B2 star theta Ophiuchi. We propose the nebula is currently containing a three phase medium. By means of analytical calculations, we are able to show that the current size, mass and pressure of the region can be explained in this...
Andrea Gatto
(MPA)
23/10/2013, 10:25
contributed talk
Turbulence is believed to be a crucial component of the interstellar medium's energetic budget. However, its origin and injection scales are still a matter of debate. Following e.g. Mac Low & Klessen (2004), energy injection from Supernova explosions is able to generate and maintain the observed level of turbulence in the ISM, at least in ""normal"" star-forming galaxies. In addition, a...
Thomas Peters
(Institut für Theoretische Physik, Universität Zürich)
23/10/2013, 11:10
contributed talk
H II regions are important signatures of star formation, play an important role in destroying the parental molecular clouds in which stars form, and, while still in the ultracompact phase, give insight into the process of high-mass star formation. I will present simulations that consistently follow the gravitational collapse of a massive molecular cloud, the subsequent build-up and...
Eric Keto
(Harvard-Smithsonian Center for Astrophysics)
23/10/2013, 11:25
contributed talk
HII regions are the clearest sign of the formation of the most massive stars, and ionization feedback could be responsible for a number of other phenomena observed in the ISM. For example, the general field of turbulence is suspected to be driven, at least in part, by the expansion of HII regions. Ionization feedback may also be responsible, along with stellar winds, for the bubbles seen...
Prof.
Thomas Preibisch
(USM/LMU)
23/10/2013, 11:40
contributed talk
The Carina Nebula constitutes the closest galactic analog of a giant extragalactic HII region. The combination of its large population of very massive stars and its moderate distance of 2.3 kpc makes it an ideal target for detailed studies of small-scale phenomena of the stellar feedback on the surrounding clouds in a starburst-like environment. In the last few years, we have performed several...
Dominique Meyer
(Argelander Institut fur Astronomie, Bonn)
23/10/2013, 11:55
contributed talk
Observations of stellar wind bow shocks can be used to constrain stellar, circumstellar and interstellar medium (ISM) properties. This presentation aims at introducing a grid of two-dimensional hydrodynamical simulations of wind-ISM interaction of massive runaway stars. This explores the combined effects of space velocities (ranging from 20 to 70 km/s) and initial masses (ranging from 10 to 40...
Jonathan Mackey
(AIfA, Uni. Bonn)
23/10/2013, 12:10
contributed talk
At least 25 per cent of massive stars are ejected from their parent cluster, becoming runaways or exiles, travelling with often-supersonic space velocities through the interstellar medium (ISM). Their H II regions can strongly impact the structure of the ISM: the overpressurised H II region imparts kinetic energy and momentum to the ISM; it compresses and/or evaporates dense clouds; and it can...
Ellen Zweibel
(University of Wisconsin)
24/10/2013, 09:00
review talk
Richard Crutcher
(University of Illinois)
24/10/2013, 09:30
review talk
Francois Boulanger
(Institut d'Astrophysique Spatiale)
24/10/2013, 10:00
contributed talk
The Planck satellite has completed the first whole sky map of dust polarization in emission. The data is revealing a new sky we have started to explore. The observations have the sensitivity and angular resolution to image dust polarization over the whole sky. For the first time, we have the data needed to characterize the structure of the Galactic magnetic field and its coupling with...
Alex Hill
(CSIRO Astronomy & Space Science)
24/10/2013, 10:15
contributed talk
High velocity clouds (HVCs) observed around the Milky Way trace the interaction between the Galactic disk and halo and may provide fuel for star formation in the disk. However, hydrodynamic work suggests that HVCs should not be able to survive passage through the Galactic halo as far as observed. We present an analysis of Faraday rotation observations which we have used to measure magnetic...
Stefan Reißl
(Christian-Albrechts-Universität zu Kiel, Institut für Theoretische Physik und Astrophysik)
24/10/2013, 11:00
contributed talk
Magnetic fields in the interstellar medium (ISM) critically affect many astrophysical processes in various environments and scales, such as the collapse of molecular clouds, the formation of jets, and accretion of matter through circumstellar disks. However, vital questions still remain unanswered due to an apparently complex structure of the magnetic field on various scales and so far rather...
91.
The far-infrared - radio correlation: Star formation and magnetic field amplification in the ISM
Dominik Schleicher
(Institut für Astrophysik Göttingen)
24/10/2013, 11:15
contributed talk
The presence of magnetic fields is well-established in the interstellar medium of galaxies, which can be probed via the far-infrared - radio correlation even at high redshift. The latter corresponds to a correlation between the star formation rate and the magnetic field strength in galaxies. In this talk, I will show how such a correlation can be obtained as a result of turbulent magnetic...
Alberto Bolatto
(University of Maryland)
24/10/2013, 11:30
review talk
Andreas Burkert
(USM/LMU)
24/10/2013, 12:00
review talk
Brent Groves
(MPIA)
24/10/2013, 14:00
contributed talk
In the local universe the mass of gas in galaxies is usually measured through the combination of the 21cm HI line, tracing the atomic gas, and the CO sub-millimeter lines that trace the molecular interstellar medium (ISM). However, the dust infrared continuum provides another tracer of the ISM mass, through two paths; the correlation of dust and gas mass, and the association of the total IR...
Manuel Behrendt
(MPE, Garching)
24/10/2013, 14:15
contributed talk
We perform high resolution hydrodynamical simulations of gas-rich disks to get a better understanding of the origin and peculiar properties of the dominating structures in z=2 massive disk galaxies. Their structure is irregular, they have highly turbulent motions and high gas fractions of 30-80%. Stars form with enormous rates of a factor of 10-100 higher than in the Milky Way. The star...
Maria Kapala
(Max Planck Institute for Astronomy)
24/10/2013, 14:30
contributed talk
The [CII] 158 micron line is typically the brightest emission line from star-forming galaxies and arises from both the ionized and neutral phases of the ISM. As a strong line it has been suggested both as a tracer of star-formation and a diagnostic of the ISM, but first we must distinguish the ISM phases it arises from and understand how it is excited.
To address these issues we have...
Jin Koda
(Stony Brook University)
24/10/2013, 14:45
contributed talk
I will discuss the formation and evolution of giant molecular clouds (GMCs) in spiral galaxies. The evolution appears quite different between the molecule-rich and atom-rich galaxies. GMCs exist almost exclusively along HI spiral arms and filaments in atom-rich galaxies, suggesting that they form and finish their short lifetimes within the HI arms. However, in molecular-rich galaxies, GMCs are...
Dr
Martin Krause
(Max-Planck-Institut für extraterrestrische Physik)
24/10/2013, 15:00
contributed talk
With sizes from below 100 pc to just above 1kpc, superbubbles are structuring the ISM on scales in between the larger scale spiral arms and the smaller, turbulent molecular cloud scales. With 3D hydrodynamics simulation of the entire stellar evolution of and the interaction between an ensemble of massive stars we are able to explain at least some of the apparent width of observed bubbles...
Ute Lisenfeld
(Universidad Granada)
24/10/2013, 15:15
contributed talk
In galaxy collisions gas and stars can be torn out of the parent galaxies, giving rise to tails and bridges of gas and to intergalactic star forming region of different sizes. These regions are ideal to study the conditions for the onset of star formation in very simple environments which are different from those in spiral galaxies.
I will describe and compare the molecular gas properties...
Andreas Schruba
(MPE, Garching)
24/10/2013, 16:00
contributed talk
I summarize first results from a large CARMA survey to image CO(1-0) emission at high sensitivity and resolution (20pc, 1km/s) in the nearby Andromeda galaxy (M31). This survey augments a new extensive set of multi-wavelength data including Hubble, Spitzer, Herschel, VLA photometry and spectroscopy that provide an unprecedented knowledge of the stars, dust, and gas in M31. We are able to...
Rahul Shetty
(ZAH/ITA, University of Heidelberg)
24/10/2013, 16:15
contributed talk
The star formation rate is observed to be strongly correlated with the gas surface density. This correlation is well described as a power-law with index N, now known as the Kennicutt-Schmidt (KS) relationship. Previous efforts have inferred N=1.5 when considering both resolved observations of galaxies as well as unresolved starbursting systems. More recently, analysis of resolved observations...
Javier Zaragoza-Cardiel
(Instituto de Astrofísica de Canarias)
24/10/2013, 16:30
contributed talk
We have used interacting galaxies to explore the properties of high luminosity star forming zones. With the GHaFaS Fabry-Perot spectrometer on the 4.2m William Herschel Telescope (La Palma) we have used Halpha emission to obtain complete 2D mapping in surface brightness, velocity, and velocity dispersion of 8 paris of interecting galaxies. The detailed kinematics reveal global features such as...
Steven Longmore
(Liverpool John Moores University)
24/10/2013, 16:45
Timothy Davis
(ESO)
24/10/2013, 17:25
contributed talk
The centres of early-type galaxies are extreme environments, with strong radiation fields from old stars, high metallicities, alpha-enhancements, deep potential wells, and a high incidence of AGN. It has been shown in recent years that despite these extreme conditions a sizeable proportion of these galaxies have a cold ISM, with atomic/molecular gas and dust reservoirs. We have carried out a...
Vladimir Dogiel
(P.N.Lebedev Institute of Physics)
24/10/2013, 17:40
contributed talk
We investigate the origin of the diffuse 6.4~keV line emission and the source of H$_2$ ionization in the diffuse molecular gas of the Galactic center (GC) region. We showed that Fe atoms are most likely ionized by X-ray photons emitted by Sgr~A$^\ast$ during a previous period of flaring activity of the supermassive black hole. The H$_2$ molecules of the diffuse gas can not be ionized by...
Tsuyoshi Inoue
(Aoyama Gakuin University)
25/10/2013, 09:00
review talk
Sabrina Casanova
(MPIK, Heidelberg)
25/10/2013, 09:40
contributed talk
We solve the transport equations of cosmic rays inside a molecular cloud assuming an arbitrary energy and space dependent diffusion coefficient. Cosmic rays penetrating the cloud produce gamma-ray emission through pp collisions with the ambient gas. For small diffusion coefficients inside the cloud we expect the gamma-ray spectrum from the cloud to be harder than the Galactic diffuse emission...
Philipp Girichidis
(MPA Garching)
25/10/2013, 09:55
contributed talk
We explore the impact of cosmic rays (CR) on the structure of the ISM, the turbulence in the Galactic disk, and how/to what extent cosmic rays drive Galactic outflows. We include the production of cosmic rays in SN remnants in a stratified box and follow the coupled system of gas and cosmic ray fluid self-consistently in three-dimensional adaptive mesh refinement simulations. The coupled...
Miwa Goto
(USM/LMU)
25/10/2013, 10:10
contributed talk
Cosmic ray is a unique place that high-energy astrophysics meets low-energy chemistry. The ion molecule H3+ is the best chemical probe of the cosmic ray ionization rate, because of the simplicity of the chemical process. Meanwhile, a new gamma-ray observation identified a point like source near Sgr A*. To produce the gamma-ray flux discovered by HESS collaboration by a neutral pion decay, one...
Ruizhi Yang
(Purple Mountain Observatory)
25/10/2013, 10:25
contributed talk
We report the results of our study on the energy spectra and absolute fluxes of cosmic rays (CRs) in the Local Galaxy based on three-year $\gamma$-ray observations of ten nearby giant molecular clouds (GMCs) belongs to the Gould Belt, with the Fermi Large Area Telescope (LAT). The $\gamma$-ray signals obtained with high statistical significance allow the determination of $\gamma$-ray spectra...
Linda Tacconi
(MPE, Garching)
25/10/2013, 11:10
review talk
Avishai Dekel
(The Hebrew University)
25/10/2013, 11:40
review talk
Muhammad Latif
(Institute for Astrohphysics, Göttingen)
25/10/2013, 12:10
contributed talk
Supermassive black holes have been observed even at redshift 7, their formation and growth need to be highly efficient in order to obtain final masses of more than 10^9 solar. Theoretical models suggest the formation of their seeds in dark matter halos with virial temperatures above 10^4 K at z~15, as such halos may cool efficiently via atomic hydrogen. At the same time, in order to avoid...
Dr
Thorsten Naab
(MPA)
25/10/2013, 12:25
contributed talk
Outflows and the structure of the ISM in high-redshift galaxies
Recent observations of high-redshift galaxies indicate that the conditions in their ISM are distinctively different to local galaxies. High formation rates of stars embedded in an extremely dense and highly turbulent interstellar medium with high molecular gas fractions and strong gas outflows are ubiquitous. We present new...
Silke Andree
(1. Physikalisches Institut, Universität zu Köln)
Poster
Photon-dominated regions (PDRs), in which the interstellar far-UV radiation field determines the energy balance and the chemistry of the ISM, form the interface between HII regions and molecular clouds. PDR emission dominates the infrared and sub-millimetre spectra in star forming regions.
To understand the interplay between far-UV radiation and star formation in molecular clouds it is ...
Gary Ferland
(Univ of Kentucky)
contributed talk
The 2013 release of the plasma simulation code Cloudy, described in arXiv:1302.4485, includes significantly improved gas and grain physics. I compare these predictions with existing models of a variety of objects, and "universal" fitting formulate for gas cooling rates. Large differences are present.
Jonathan Braithwaite
(University of Bonn)
Poster
From pulsar scintillations we infer the presence of density variations in the ISM, and there are reasons to believe that the effect is caused mainly by sheet-like structures. It has been suggested that these may be current sheets. I present arguments from basic MHD theory that this is exactly what we should expect, as well as results from simple simulations of decaying turbulence which...
Dominik Bomans
(Astronomical Institute of the Ruhr-University Bochum)
Poster
Galactic outflows and winds are key ingredients for the birth and live of galaxies in the intergalactic medium. Via outflows the halos of galaxies are structured, heated, and enriched with heavy elements. Galactic outflows may also major drivers of the turbulence of halo gas. Using integral field spectroscopy data from the ongoing CALIFA survey (observing a statistically well defined sample of...
Tuhin Ghosh
(Institut d'Astrophysique Spatiale)
Poster
Planck has mapped the polarization of the sky emission at microwave frequencies with unprecedented sensitivity. We use the data to characterise the frequency dependence of Galactic polarization.
We make use of the cross-correlation analysis which is an established method to characterise the spectral properties of Galactic emission at microwave frequencies. We take the Planck 353 GHz HFI...
Saman Moradian Jahoudbejari
(University of Guilan)
contributed talk
The sudden, intense outburst and explosion of gamma ray in the depths of the universe is known as GRB (Gamma Ray Burst).This phenomenon was known for decades as one of mysterious astronomical phenomena. Today it has been known that some of these explosions are relevant with supernovae, and other related to magnetars(which is a type of neutron star with a very strong magnetic field).Discovery...
Stefano Bovino
(Institut für Astrophysik, Georg-August Universität Göttingen)
Poster
The study of the ISM includes a large set of processes and phenomena that needs an accurate modeling and which are often CPU-demanding: chemistry, cooling, heating, dust evolution, photochemistry, and many others. To cope with these we developed a package, named KROME, which is designed to manage the chemistry and the related phenomena with ease. It consists of a Python pre-processor that...
Archana Soam
(Aryabhatta Research Institute of Observational Sciences (ARIES))
Poster
In our study we tried to undersatnd the importance of magnetic field in the very low mass star formation in Bok Globules using optical polarisation techniques. We have studied the starless, prestellar and star forming cores to see the change in magnetic field at different evolutionary stages. We have also also observed cometary globule LBN437 (Gal96-15) extending the previous work done by...
Marissa Rosenberg
(Leiden Observatory)
contributed talk
(Ultra) Luminous Infrared Galaxies ((U)LIRGs) are galaxies exhibiting an extremely high infrared luminosity and may be the evolutionary transition phase between starburst galaxies and QSOs. Understanding the heating and cooling mechanisms in these galaxies give us insight to the driving mechanisms that fuel this transition. Molecular emission lines play a crucial role in the cooling of...
Martin Ilgner
(University Observatory Munich)
Poster
The evolution of the ISM and of the IGM is strongly influenced by the fraction of ionizing radiation which escapes young massive clusters and galaxies. Results obtained by recent computational models indicate a wide range of values for the escape fraction. However, since these models were primarily designed to test single aspects they forecast tendencies rather than presenting a coherent...
Poster
Poster
Poster
Poster
Jan Forbrich
(University of Vienna/Smithsonian)
contributed talk
A few years ago, extinction mapping provided us with a first detailed look at the starless core population of the Pipe Nebula, a molecular cloud at a distance of only 130 pc. Using sensitive mid-infrared Spitzer observations, we showed that its star formation rate is very low, in an interesting contrast to the Rho Oph region next door or Taurus, two clouds in a similar mass range. Here, we ...
Stefanie Walch
(Max-Planck-Institute for Astrophysics)
contributed talk
Molecular clouds are cold, dense, and turbulent filamentary structures that condense out of the multi-phase interstellar medium. They are also the sites of star formation. The minority of new-born stars is massive, but these stars are particularly important for the fate of their parental molecular clouds. I will present results from high-performance, three-dimensional simulations that show the...
Ged Kitchener
(Centre for Astrophysics Research, University of Hertfordshire)
contributed talk
We present a 6-cm radio continuum (RC) survey with the JVLA in C-configuration of the LITTLE THINGS sample of 39 local, gas-rich dwarf galaxies, and explore the radio continuum - Far Infrared (RC-FIR) relation in such systems. We generate images with a resolution of 3? and an rms noise of ~5muJy/beam, and detect significant emission in about half of our sample. We double the luminosity range...
Yu Gao
(Purple Mountain Observatory)
contributed talk
We first show that the disk-averaged surface star formation rate (SFR) density has the tightest linear correlation with that of the dense molecular gas (traced by HCN), not the molecular gas (H2) or total gas (HI+H2). This is consistent with the tight FIR-HCN correlation established globally for both dense cores and star-forming galaxies near and far. The Kennicutt-Schmidt law that relates the...
