Galaxy Structure & Dynamics
Research Group at the MPIA
Galaxy Structure and Dynamics
The research in our group focuses on understanding the dynamical structure and evolution of stellar systems. In nearby galaxies and stellar clusters, we look for the 'fossil records' of their formation by constructing realistic dynamical models that fit their photometric and spectroscopic observations in detail. The latter include integral-field spectroscopy, observed motions and properties of individual stars, as well as (strong) gravitational lensing observations.
Our individual research interests are listed below - for information, see group members' websites or try reading some of our recent papers.
Group Members
Group Leader
Postdocs
- Dr. Laura Watkins
- dynamical models of resolved stellar systems
- dynamical models of host-satellite systems
- Milky Way halo substructures using RR Lyraes
- watkins@mpia.de
- Dr. Mariya Lyubenova
- stellar kinematics of nearby galaxies in the CALIFA Survey
- stellar population and kinematics of globular and nuclear clusters
- near-IR spectral properties of stellar populations
- TP-AGB stars influence on the near-IR spectra of galaxies and stellar population models
- lyubenova@mpia.de
- Dr. Remco van den Bosch
- triaxial Schwarzschild models
- HET massive galaxy survey
- super-massive black holes
- bosch@mpia.de
PhD students
- Akin Yildirim
- super-massive black holes and dark matter halos in compact early-type galaxies
- lensing and dynamics in the Einstein Cross
- yildirim@mpia.de
- Alex Büdenbender
- dark matter and fossil records in the Solar Neighbourhood
- Axisymmetric Jeans models and Schwarzschild models using SEGUE
- buedenbender@mpia.de
- Athanasia Tsatsi
- Dynamical structure and evolution of elliptical galaxies
- tsatsi@mpia.de
- Paolo Bianchini
- Stellar dynamics in quasi-relaxed stellar systems
- Internal dynamics of globular cluster in the era of Extremely Large Telescopes
- bianchini@mpia.de
- Robert Singh
- the true nature of LINERs in the CALIFA Survey: weak AGN or strong stars?
- singh@mpia.de
- Ronald Läsker
- super-massive black holes and their host galaxies in the nearby universe
- laesker@mpia.de
- Sladjana Nikolić
- integral view of shocks in supernovae remnants (SN1006 & Tycho) and classical novae (FH Ser)
- nikolic@mpia.de
- Vesselina Kalinova
- total (including dark) matter distribution of nearby galaxies from the CALIFA Survey, and spiral galaxies observed with the SAURON-IFU
- kalinova@mpia.de
Masters students
- Wilma Trick
- Determining the total and dark matter distribution in the spiral galaxy SDSS J1331+3638 via strong gravitational lensing and dynamical modeling.
- trick@mpia.de
Collaborations
- Close collaborators and regular visitors:
- Mark den Brok (Utah)
- Jesús Falcón Barroso (IAC, Tenerife)
- Agnieszka Rys (IAC, Tenerife)
- Larger collaborations:
- CALIFA Survey
- SFB881
- SAURON Project
- Meeting organisation committees:
- 3rd CALIFA Busy Week - Haus der Astronomie - 11-15 June 2012
- Dynamics meets kinematic tracers - Ringberg Castle - 10-14 April 2012
Publications
Follow these links to a complete list of refereed and non-refereed publications from members in the group, while some recent publications (kept up to date by ADS) are given here:
Recent publications
- The complex nature of the nuclear star cluster in FCC 277
- Lyubenova, van den Bosch, Côté, Kuntschner, van de Ven, Ferrarese, Jordán, Infante, and Peng (2013)
- 3D view on Virgo and field dwarf elliptical galaxies: late-type origin and environmental transformations
- Ryś, Falcón-Barroso, and van de Ven (2013)
- The VIRUS-P Exploration of Nearby Galaxies (VENGA): Survey Design, Data Processing, and Spectral Analysis Methods
- Blanc, Weinzirl, Song, Heiderman, Gebhardt, Jogee, Evans, van den Bosch, Luo, Drory, Fabricius, Fisher, Hao, Kaplan, Marinova, Vutisalchavakul, and Yoachim (2013)
- Aperture corrections for disk galaxy properties derived from the CALIFA survey. Balmer emission lines in spiral galaxies
- Iglesias-Páramo, Vílchez, Galbany, Sánchez, Rosales-Ortega, Mast, García-Benito, Husemann, Aguerri, Alves, Bekeraité, Bland-Hawthorn, Catalán-Torrecilla, de Amorim, de Lorenzo-Cáceres, Ellis, Falcón-Barroso, Flores, Florido, Gallazzi, et al. (2013)
- An Integral View of Fast Shocks Around Supernova 1006
- Nikolić, van de Ven, Heng, Kupko, Husemann, Raymond, Hughes, and Falcón-Barroso (2013)
- The complex nature of the nuclear star cluster in FCC 277
- Lyubenova, van den Bosch, Côté, Kuntschner, van de Ven, Ferrarese, Jordán, Infante, and Peng (2013)
- A census of orbital properties of the M31 satellites
- Watkins, Evans, and van de Ven (2013)
- ALMA follows streaming of dense gas down to 40 pc from the supermassive black hole in NGC1097
- Fathi, Lundgren, Kohno, Piñol-Ferrer, Martín, Espada, Hatziminaoglou, Imanishi, Izumi, Krips, Matsushita, Meier, Nakai, Sheth, Turner, van de Ven, and Wiklind (2013)
- The Mass-Metallicity relation explored with CALIFA: I. Is there a dependence on the star formation rate?
- Sanchez, Rosales-Ortega, Jungwiert, Iglesias-Paramo1, Vilchez, Marino, Walcher, Husemann, Mast, Monreal-Ibero, Cid Fernandes, Perez, Gonzalez Delgado, Garcia-Benito, Galbany, van de Ven, Jahnke, Flores, Bland-Hawthorn, Lopez-Sánchez, et al. (2013)
- Virgo cluster and field dwarf ellipticals in 3D - I. On the variety of stellar kinematic and line-strength properties
- Ryś, Falcón-Barroso, and van de Ven (2013)
- The flattening of globular clusters: internal rotation or velocity anisotropy?
- Bianchini, Varri, Bertin, and Zocchi (2013)
- The Evolution of Galaxies Resolved in Space and Time: A View of Inside-out Growth from the CALIFA Survey
- Pérez, Cid Fernandes, González Delgado, García-Benito, Sánchez, Husemann, Mast, Rodón, Kupko, Backsmann, de Amorim, van de Ven, Walcher, Wisotzki, Cortijo-Ferrero, and collaboration6 (2013)
- The VIRUS-P Exploration of Nearby Galaxies (VENGA): The X CO Gradient in NGC 628
- Blanc, Schruba, Evans, Jogee, Bolatto, Leroy, Song, van den Bosch, Drory, Fabricius, Fisher, Gebhardt, Heiderman, Marinova, Vogel, and Weinzirl (2013)
- CALIFA, the Calar Alto Legacy Integral Field Area survey. II. First public data release
- Husemann, Jahnke, Sánchez, Barrado, Bekerait*error*ė, Bomans, Castillo-Morales, Catalán-Torrecilla, Cid Fernandes, Falcón-Barroso, García-Benito, González Delgado, Iglesias-Páramo, Johnson, Kupko, López-Fernandez, Lyubenova, Marino, Mast, Miskolczi, et al. (2013)
- Formation and evolution of dwarf early-type galaxies in the Virgo cluster. II. Kinematic scaling relations
- Toloba, Boselli, Peletier, Falcón-Barroso, van de Ven, and Gorgas (2012)
- An over-massive black hole in the compact lenticular galaxy NGC1277
- van den Bosch, Gebhardt, Gültekin, van de Ven, van der Wel, and Walsh (2012)
- Constraining the Galactic potential via action-based distribution functions for mono-abundance stellar populations
- Ting, Rix, Bovy, and van de Ven (2012)
- The stretching of Hercules
- Deason, Belokurov, Evans, Watkins, and Fellhauer (2012)
- Chemo-orbital evidence from SDSS/SEGUE G-type dwarf stars for a mixed origin of the Milky Way's thick disc
- Liu and van de Ven (2012)
- The Gravitational Potential Near the Sun From SEGUE K-dwarf Kinematics
- Zhang, Rix, van de Ven, Bovy, Liu, and Zhao (2012)
Positions & Projects
PostDoc and PhD positions
The MPIA is currently accepting applications for a number of positions within the Galaxies and Cosmology department, including positions in our group. Please see this site for more information and to apply.
MSc and BSc students
Various aspects of the research projects below, and of the research in our group in general, are well-suited for a bachelor or master project in astronomy, physics or computer science.
Follow the links for a brief description per project, but please contact any member of the group or send an e-mail to dynamics@mpia.de for further information and other projects and topics related to the research in our group.
Projects
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- Lensing and dynamics
- Lensing and dynamics
- Gravitational lensing is the deflection of light from distant sources by the gravitational fields of intervening objects, while kinematics are the motions of stars or gas in the gravitational potential of an object. This means that both luminous tracers are sensitive to the total mass distribution, including possible dark matter, which can be recovered after subtracting the luminous matter.
The main goal of the project is to arrive an efficient method to fit lens and dynamical models -- individually as well as combined -- to the upcoming abundant gravitational lensing and kinematic data-sets. The method will enable robust and unbiased measurements of the total (including dark) matter density in galaxies at different redshifts, which in turn will provide important constraints on galaxy formation as well as cosmological models. - Shape of dark matter halos
- Shape of dark matter halos
- The concordance cold dark matter cosmological model predicts that galaxies are embedded in extended dark matter halos with a close to universal density distribution. While many studies have focused on the radial profile and in particular the predicted inner cusp, very few have considered the predicted triaxial shape of the dark matter density. Although dark matter itself is invisible, its mass affects the kinematics of luminous tracers; in particular, the triaxial shape is expected to cause non-circular motions in the observed gas velocity fields.
The main goal of this project is to investigate these effects of triaxiality and use non-circular motions observed in gas velocity fields of galaxies to constrain the shape of their dark matter halo. - Made-to-measure N-body method
- Made-to-measure N-body method
- The made-to-measure N-body method (hereafter M2M) introduced by Syer & Tremaine (1996) is closely related to Schwarzschild's orbit-superposition approach. Whereas in Schwarzschild's approach orbits are first integrated and then superimposed, in the M2M method these two steps are merged: trajectories are integrated and then particle weights adapted at the same time until some constraints are satisfied, such as an optimal fit to observational data. The advantage of the M2M method is that not only the particle weights can be adjusted, but also the particle distribution as a whole might evolve. This enables one to investigate stability and to efficiently adapt mass distributions which can be asymmetric and contain rotating components.
The main goal of the project is to complement our orbit-based modeling tools with the M2M particle-based method, and use the additional flexibility to also investigate galaxies such as the Milky Way with a rotating bar and a warped outer disk. - Stars around black holes
- Stars around black holes
- Since all large galaxies are believed to contain a central black hole (BH), these BHs are expected to undergo merging along with the galaxies themselves. Dynamical modeling tools such as our triaxial implementation of Schwarzschild's orbit superposition method, not only allows the measurement of the mass of such (merged) BHs, but also of the surrounding orbital structure. Aside from the large galaxies, we can also fit such dynamical models to kinematic measurements in dwarf galaxies and even globular clusters to establish whether they also contain a central (intermediate-mass) BH.
The main goal of this project is to use these studies to help understand the important scaling relation between BH masses and the host galaxy properties, from the high-mass to low-mass end. - Feeding the centers of galaxies
- Feeding the centers of galaxies
- A still open question is how the gas, that is needed to feed a central black hole and create an active galactic nucleus (AGN), is brought in from larger scales. Whereas bars are able to efficiently transport gas from the outer parts of a galaxy inward, the gas typically stalls at a radius well outside the inner hundred parsec. However, the continued dynamical friction may induce non-axisymmetric perturbations, such as nuclear spirals, along which the gas can move further inward. Unfortunately, the resulting deviations in the gas density are typically to weak for direct imaging and the obscuration due to assumed associated dust often leads to unclear or even missed detections. At the same time, the perturbations induce significant non-circular motions in the gas, so that velocity fields provide a cleaner way to detect the perturbations and even constrain the gas inflow velocity.
The main goal of the project is to use gas velocity fields of (spiral) galaxies to quantify mass inflow rate from larger scales down to the central black hole. - Close encounters in dense environments
- Close encounters in dense environments
- Shocks are present wherever matter is accelerated past the sound speed of the medium they are propagating through. A class of astrophysical shocks that is relatively simple to interpret are the so-called "Balmer-dominated shocks traditionally observed as limb-brightened optical fillaments around historical supernova remnants. The are characterized by strong hydrogen emission lines with a narrow (~10 km/s) and broad (~1000 km/s) component. By measuring the broad-line width and broad-to-narrow line intensity, we can constrain the shock velocity and electron-to-proton temperature immediately behind the shock front. Next, combining these measurements with the sometimes coincident non-thermal (X-ray and radio) emission observed, provides a rare opportunity to study cosmic ray accelaration in partially-neutral media. Moreover, we can constrain the geometry of the ambient magnetic field by measuring non-Gaussian components in the broad line caused by pick-up protons. Clearly, these measurements require high-quality spectroscopy of the narrow and curved shock fronts which moreover might overlap each other in projection along the line-of-sight.
The main goal of the project is to use the unqiue capability of high-spatial resolution intergral-field spectrographs to accurately trace and isolate shocks, allowing a careful analysis of shocks and their ambient medium.