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Daniela Carollo

Research Assistant Professor
Astrophysics

Laurea in Physics, University of Turin, Italy
Ph.D. Astrophysics, Australian National University

Email: dcaroll1@nd.edu
Office phone: 574-631-8653
Office: 334 Nieuwland Science Hall

Dr. Carollo’s Web Page

Research Interests

Daniela Carollo's research interests fall into the area of Near Field Cosmology or Galactic Archaeology, in which numerous details (kinematics, dynamics, and metal abundances) of various stellar components in the MilkyWay (and eventually, other Local Group galaxies) are examined and used to unveil their past history.

This approach is particularly suitable for our own galaxy. Indeed, the Milky Way is a unique laboratory, as it is the one large galaxy where it is possible to analyze the full space motions and chemical compositions of its stellar populations based on individual stars.

She is also interested in exploring the intergalactic metals at high redshift (z > 5), in particular the identification of chemical signatures also present in the most metal poor stars of the Milky Way.

Important Discoveries

-- The discovery of the dual halo structure of the Milky Way, inner- and outer-halo. By using a set of calibration stars from the Sloan Digital Sky Survey (SDSS), it was demonstrated that the halo of the Milky Way comprises at least two smooth components, an inner- and an outer-halo, which possess different chemical composition as well as distinct spatial distributions, kinematic and orbital parameters. This discovery represents a milestone in the comprehension of the Galaxy formation and has given a strong hint to the idea of galactic mergers, already proposed few decades ago.

-- The demonstration that the stellar halo populations differ also in other chemical properties (other than the content of metals), i.e. the amount of carbon present in the atmosphere of metal poor stars (Carbon-Enhanced Metal Poor: CEMP). Indeed the outer halo population has two times more CEMP stars than the inner halo.

-- The demonstration that the CEMP stars in the outer halo belong mostly to the class of CEMP-no stars (no neutron capture elements), while the inner halo exhibit a larger fraction of another important category of objects, the CEMP-s stars (high amount of neutron capture elements). CEMP-s and CEMP-no stars have different progenitors: intermediate-mass stars in a binary system for the CEMP-s (over-production of neutron-capture elements), and massive stars not in a binary system in case of the CEMP-no. This implies that the progenitors of CEMP stars in the halo components were different: massive stars for the outer halo and intermediate-mass stars in case of the inner halo.

Large Survey Projects

-- GALAH (Galactic Archaeology with HERMES) survey: large high-resolution spectroscopic survey using the newly commissioned High Efficiency and Resolution Multi-Element Spectrograph (HERMES) on the Anglo-Australian Telescope (Australia, http://www.mso.anu.edu.au/galah/home.html). The goal of the survey is to unravel the formation and evolutionary history of the Milky Way, using fossil remnants of ancient star formation events which have been disrupted and are now dispersed throughout the Galaxy.

-- SkyMapper: SkyMapper is a state-of-the-art automated wide-field survey telescope sited in Siding Spring Observatory in central NSW (Australia). SkyMapper’s mission is to robotically create the first comprehensive digital survey of the entire southern sky. The result will be a massively detailed record of more than a billion stars and galaxies.

-- APOGEE-2: The APO Galaxy Evolution Experiment 2 (APOGEE-2) which is obtaining high-resolution near-infrared spectroscopy of several hundred thousand stars in the Milky Way.

-- OzDes (Australian Dark Energy Survey): OzDES is the leading source of spectroscopy for the Dark Energy Survey. The survey will use the Anglo-Australian Telescope during a five year observing program designed to measure the redshifts of tens of thousands of galaxies and obtain spectra of supernovae and other transients. The galaxy redshifts will be used to make the most detailed measurement of the Universe’s expansion history ever and will lead to a better understanding of the physics behind the acceleration of the Universe.

Publications (Link to ADS)