Research of the Infrared/Submillimeter Group at MPE

Research of the Infrared and Submillimeter Group is focused on the fields of evolution of galaxies and galactic nuclei, including the center of our own galaxy and starburst phenomena as well as studies of the dense interstellar medium in star- and planet-forming regions. See this link for a list of highly cited IR group papers, with at least 100 citations.

Galactic nuclei

The Galactic Center Project (see also dedicated Galactic Center page)

Our own Galactic Center provides an essential laboratory for studying the black hole paradigm, and for a detailed characterization of a (comparatively small) nuclear stellar cluster. Since 1992, we have used diffraction-limited infrared imaging to study the stellar dynamics of the central parsec and the influence of the central black hole. Infrared spectroscopy characterizes the stellar population evolving in an environment that is unique in our galaxy. Flared near-infrared emission that we detected in 2003 is an unrivaled way to probe the immediate vicinity of the black hole. Recently, interferometry with GRAVITY reached scales with important general relativistic effects.

Key publications:

  • Detection of orbital motions near the last stable circular orbit of the massive black hole SgrA*, GRAVITY collaboration et al. A&A 618, L10 (2018)
  • Detection of the gravitational redshift in the orbit of the star S2 near the Galactic Centre massive black hole, GRAVITY collaboration et al. A&A 615, L15 (2018)
  • A gas cloud on its way towards the supermassive black hole at the Galactic Centre, S. Gillessen et al. Nature 481, 51 (2012)
  • The Galactic Center massive black hole and nuclear star cluster, R. Genzel et al., Reviews of Modern Physics 82, 3121 (2010)
  • Monitoring Stellar Orbits Around the Massive Black Hole in the Galactic Center, S. Gillessen et al., ApJ 692, 1075 (2009)
  • The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics, and Formation, T. Paumard et al. ApJ 641, 1011 (2006)
  • Near-infrared flares from accreting gas around the supermassive black hole at the Galactic Centre, R. Genzel et al., Nature 425, 934 (2003)
  • A star in a 15.2-year orbit around the supermassive black hole at the centre of the Milky Way, R. Schödel et al., Nature 419, 694 (2002)
  • Stellar proper motions in the central 0.1pc of the Galaxy, A. Eckart & R. Genzel, MNRAS 291, 219 (1997)
  • SWS Observations of the Galactic Center, D. Lutz et al., A&A 315, L269 (1996)
  • The Nuclear Cluster of the Milky Way: Star Formation and Velocity Dispersion in the Central 0.5 Parsec, A. Krabbe et al., ApJ 447, L95 (1995)

Ultraluminous Infrared Galaxies and QSOs (see also SHINING page)

The population of Ultraluminous Infrared Galaxies (ULIRGs) plays a key role in scenarios for the formation of Quasars and of elliptical galaxies, and as possible local analogues to high redshift sources above the star forming sequence. We have tested the energy sources of ULIRGs and QSOs using ISO, Spitzer and Herschel mid-and far-infrared spectroscopy and near-infrared imaging spectroscopy.

Key publications:

  • Massive molecular outflows and negative feedback in ULIRGs observed by Herschel-PACS. E. Sturm et al., ApJ 733, L16 (2011)
  • Spitzer Quasar and ULIRG Evolution Study (QUEST). I. The Origin of the Far-Infrared Continuum of QSOs, M. Schweitzer et al. ApJ 649, 79 (2006)
  • What Powers Ultraluminous IRAS Galaxies?, R. Genzel et al., ApJ 498, 579 (1998)

The Structure of AGN (see also AGN page)

Several open questions concerning active galactic nuclei and their environment are best addressed by our tools of high spatial resolution near-infrared spectroscopy, near-infrared and mm interferometry and mid-infrared spectroscopy. Among others, projects have dealt with characterization of cirumnuclear starbursts, distribution and dynamics of circumnuclear gas, and the properties of the obscuring material. Recent work has focused on spatially resolving the BLR and hot dust on sub-pc scales through a large program with GRAVITY.

Key publications:

  • Spatially resolved rotation of the broad-line region of a quasar at sub-parsec scale, GRAVITY collaboration et al. Nature 563, 657 (2018)
  • A Close Look at Star Formation around Active Galactic Nuclei, R. Davies et al. ApJ 671, 1388 (2007)
  • The relation between AGN hard X-ray emission and mid-infrared continuum from ISO spectra: Scatter and unification aspects, D. Lutz et al., A&A 418, 465 (2004)
  • 2.5-45μm SWS spectroscopy of the Circinus Galaxy, A. Moorwood et al., A&A 315, L109 (1996)

Evolution of Galaxies

Dynamics and Evolution of Massive High Redshift Galaxies (see also dedicated SINS/KMOS3D page)

Determining the evolution of massive galaxies with redshift is a key long term goal in studying galaxy evolution and a crucial test for current models. We are studying large samples representing several categories of high redshift galaxies using integral field spectroscopy with SINFONI and KMOS at the VLT. We are obtaining spatially resolved measures in order to determine structure, dynamics, metallicity, excitation sources, and outflow properties of these galaxies that are frequently found to be clumpy turbulent disks.

Key publications:

  • The KMOS3D Survey: Demographics and Properties of Galactic Outflows at z = 0.6 - 2.7, N.M. Förster Schreiber et al. 2019, ApJ, in press (arXiv 1807.04738)
  • Strongly baryon-dominated disk galaxies at the peak of galaxy formation ten billion years ago, R. Genzel et al. Nature 543, 397 (2017)
  • The KMOS3D Survey: Design, First Results, and the Evolution of Galaxy Kinematics from 0.7<z<2.7, E. Wisnioski et al. ApJ 799, 209 (2015)
  • The SINS/zC-SINF Survey of z ~ 2 Galaxy Kinematics: Evidence for Powerful Active Galactic Nucleus-Driven Nuclear Outflows in Massive Star-Forming Galaxies, N.M. Förster Schreiber et al. ApJ 787, 28 (2014)
  • The SINS/zC-SINF Survey of z ~ 2 Galaxy Kinematics: Evidence for Gravitational Quenching, R. Genzel et al. ApJ 785, 75 (2014)
  • The SINS Survey of z ~ 2 Galaxy Kinematics: Properties of the Giant Star-forming Clumps, R. Genzel et al. ApJ 733, 101 (2011)
  • The SINS Survey: SINFONI Integral Field Spectroscopy of z ~ 2 Star-forming Galaxies, N.M. Förster Schreiber et al. ApJ 706, 1364 (2009)
  • The rapid formation of a large rotating disk galaxy three billion years after the Big Bang, R. Genzel et al., Nature 442, 786 (2006)
  • SINFONI Integral Field Spectroscopy of z ~ 2 UV-selected Galaxies: Rotation Curves and Dynamical Evolution, N.M. Förster Schreiber et al. ApJ 645, 1062 (2006)

The role of molecular gas in galaxy evolution

Continuing technological progress in particular at the IRAM Plateau de Bure NOEMA interferometer enables study of the cosmic evolution of molecular gas content both in the ‘equilibrium growth’ of normal galaxies and in rare merger events. We have started to address these issues targeting submm sources and Lyman Break galaxies, and obtained major advances in characterizing normal high redshift galaxies.

Key publications:

  • PHIBSS: Unified Scaling Relations of Gas Depletion Time and Molecular Gas Fractions, L. Tacconi et al. ApJ 853, 179 (2018)
  • The Metallicity Dependence of the CO → H2 Conversion Factor in z≥1 Star-forming Galaxies, R. Genzel et al., ApJ 746, 69 (2012)
  • High molecular gas fractions in normal massive star-forming galaxies in the young Universe, L. Tacconi et al., Nature 463, 781 (2010)
  • A study of the gas-star formation relation over cosmic time, R. Genzel et al., MNRAS 407, 2091 (2010)
  • Submillimeter Galaxies at z ~ 2: Evidence for Major Mergers and Constraints on Lifetimes, IMF, and CO-H2 Conversion Factor, L. Tacconi et al. ApJ 680, 246 (2008)


The Nature of High Redshift Infrared Sources (see also PEP page)

Surveys at mid-infrared and (sub)mm wavelengths with ISO, SCUBA, MAMBO, Spitzer and Herschel have uncovered populations of massively star forming galaxies at high redshift that constitute a major part of the total cosmic star forming activity and a key phase in the evolution of massive galaxies. We are studying the nature of these objects in the context of the evolution of massive galaxies

Key publications:

  • The evolution of the dust temperatures of galaxies in the SFR-M plane up to z ∼ 2, B. Magnelli et al., A&A 561, A86 (2014)
  • The mean star formation rate of X-ray selected active galaxies and its evolution from z ~ 2.5: results from PEP-Herschel, D. Rosario et al. A&A 545, A45 (2012)
  • Galaxy Structure and Mode of Star Formation in the SFR-Mass Plane from z ~ 2.5 to z ~ 0.1, S. Wuyts et al. ApJ 742, 96 (2011)
  • Building the cosmic infrared background brick by brick with Herschel/PEP, S. Berta et al., A&A 532, A49 (2011)
  • A Mid-Infrared Spectroscopic Study of Submillimeter Galaxies: Luminous Starbursts at High Redshift, E. Valiante et al. ApJ 660, 1060 (2007)

Studies of star- and planet formation and the dense interstellar medium

Structure and evolution of protoplanetary disks

Most young pre-main sequence stars are surrounded by disks of gas and dust out of which planets can form. We are carrying out a number of combined observations-modeling projects to understand their physical and chemical structure using submillimeter data from ALMA, complemented by infrared spectroscopy with VLT-CRIRES, Herschel and soon JWST-MIRI. Of particular interest are the transitional disks with large inner holes, which are at the crucial stage in between the gas-rich and debris-disk phases when planet formation appears to be actively taking place. ALMA now allows to resolve both the gas and the dust in detail and reveal clues to their origin. In addition, large surveys of disks are carried out to characterize the disk population.

Key publications:

Water and organic molecules in star-forming regions

Water is one of the most abundant and important molecules in star- and planet-forming regions: as a major reservoir of oxygen, a gas coolant and (as ice) assisting planet formation. Both water and complex organic molecules gas are directly associated with the biology of living organisms on Earth. We are using ALMA, NOEMA, Herschel HIFI and PACS, VLT and soon JWST-MIRI to observe water and organic molecules towards a large sample of protostars, covering a wide range of masses and luminosities -from the lowest to the highest mass protostars-, and a large range of evolutionary stages -from the first stages of clouds prior to collapse to the last stages represented by pre-main sequence stars surrounded by protoplanetary disks. A suite of molecular excitation and radiative transfer tools has been developed. The data reveal the physics and chemistry of hot cores and dense irradiated shocks in protostars and allow to probe the water reservoir of gas and ice from clouds to disks.

Key publications:

Resolving the gas-star cycle in nearby galaxies at molecular cloud scale

To understand the growth and evolution of galaxies requires understanding of the physics that regulate the gas-star cycle within galaxies. Employing state-of-the-art instrumentation in several legacy-type surveys (of a few hundred hours each), a complete observational view on the gas-star cycle at scales (few pc - 20pc) of individual star-forming molecular clouds have been obtained using ALMA, NOEMA, CARMA, VLA and HST. Such studies are key to relate the detailed but small-scale studies inside our Milky Way to the full but poorly resolved galaxy population in the local Universe and in determining how galactic properties and galaxy evolution are regulated by the small-scale process of star formation and vice versa.

Key publications:

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