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 characterisation 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 characterises the stellar population evolving in an environment that is unique in our Galaxy. Flared near-infrared emission that we detected in 2003 is a unique way to probe the immediate vicinity of the black hole.

Key publications:

  • 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)
  • SINFONI in the Galactic Center: Young Stars and Infrared Flares in the Central Light-Month, F. Eisenhauer et al., ApJ 628, 246 (2005)
  • 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 infrared sources. 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. Dynamical studies using near-infrared spectroscopy and mm interferometry probe the evolution from ULIRGs to (disky) ellipticals and their evolutionary connection to QSOs.

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)
  • Ultraluminous Infrared Galaxies: QSOs in Formation? L. Tacconi et al., ApJ 580, 73 (2002)
  • Ultraluminous Infrared Mergers: Elliptical Galaxies in Formation? R. Genzel et al., ApJ 563, 527 (2001)
  • The Nature and Evolution of Ultraluminous Infrared Galaxies: A Mid-Infrared Spectroscopic Survey, D. Lutz et al., ApJ, 505, L103 (1998)
  • What Powers Ultraluminous IRAS Galaxies?, R. Genzel et al., ApJ 498, 579 (1998)
  • Near-infrared line imaging of NGC 6240 - Collision shock and nuclear starburst, P. van der Werf et al., ApJ 405, 522 (1993)

Nearby AGN and Black Holes (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, 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. In quiescent objects, we are probing for the dynamical signature of non-active black holes using high spatial and spectral resolution near-infrared spectroscopy.

Key publications:

  • A Close Look at Star Formation around Active Galactic Nuclei, R. Davies et al. ApJ 671, 1388 (2007)
  • The Star-forming Torus and Stellar Dynamical Black Hole Mass in the Seyfert 1 Nucleus of NGC 3227, R. Davies et al. ApJ 646, 754 (2006)
  • 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)
  • Infrared imaging and spectroscopy of NGC 7469, R. Genzel et al., ApJ 444, 129 (1995)
  • The nature of the dense obscuring material in the nucleus of NGC 1068, L. Tacconi et al., ApJ 426, L77 (1994)

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 evolution of metallicity and metallicity gradients from z=2.7-0.6 with KMOS3D, E. Wuyts et al. ApJ in press (2016, arXiv:1603.01139)
  • The angular momentum distribution and baryon content of star forming galaxies at z~1-3, A. Burkert et al. ApJ in press (2016, arXiv:1510.03262)
  • 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)
  • Evidence for Wide-spread Active Galactic Nucleus-driven Outflows in the Most Massive z ~ 1-2 Star-forming Galaxies, R. Genzel et al. ApJ 796, 7 (2014)
  • 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 targetting submm sources and Lyman Break galaxies, and obtained major advances in characterizing normal high redshift galaxies.

Key publications:

  • Combined CO and Dust Scaling Relations of Depletion Time and Molecular Gas Fractions with Cosmic Time, Specific Star-formation Rate, and Stellar Mass, R. Genzel et al., ApJ 800, 20 (2015)
  • Phibss: Molecular Gas Content and Scaling Relations in z ~ 1-3 Massive, Main-sequence Star-forming Galaxies, L. Tacconi et al., ApJ 768, 74 (2013)
  • 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)
  • High Resolution Millimeter Imaging of Submm Galaxies, L. Tacconi et al., ApJ, 640, 228 (2006)
  • Molecular Gas in the lensed Lyman Break Galaxy cB58, A. Baker et al., ApJ 604, 125 (2004)
  • Spatially Resolved Millimeter Interferometry of SMM J02399-0136: A Very Massive Galaxy at z = 2.8, R. Genzel et al., ApJ 584, 663 (2003)


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 now 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 carrying out several projects aiming at 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 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:

  • Survey of cold water lines in protoplanetary disks: indications of systematic volatile depletion, F. Du et al. 2017, ApJ, 842, A98
  • The ALMA Protostellar Interferometric Line Survey (PILS). First results from an unbiased submillimeter wavelength line survey of the Class 0 protostellar binary IRAS 16293-2422 with ALMA, J.K. Jorgensen et al. 2016, A&A, 595, A117
  • The deuterium fractionation of water on solar-system scales in deeply-embedded low-mass protostars, M.V. Persson, J.K. Jorgensen, E.F. van Dishoeck, D. Harsono, 2014, A&A, 563, A74
  • Water in Star-forming Regions with the Herschel Space Observatory (WISH). I. Overview of key program and first results, E.F. van Dishoeck et al., 2011, PASP, 123, 138

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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