Research at CASM encompasses a wide array of areas, including cosmology, black holes, stars, galaxies and planets. Our members are involved in international research projects such as the European Space Agency's Euclid mission and projects involved with the James Webb Space Telescope.
Equally interesting and important – particularly with the planned launch of the LISA observatory in the mid-2030's is the existence of intermediate mass black holes (IMBHs). These are black holes typically with masses in the range 1,000 – 1,000,000 times the mass of the Sun. These objects should populate less massive (so-called dwarf galaxies) and may also be the progenitors of the SMBHs. Observations of IMBHs are difficult – IMBHs are inherently less luminous than their more massive cousins and may also be located off-nuclear i.e. they may not necessarily be located at galactic centres making their detection even more challenging. Understanding the population demographics of IMBHs is hugely important in terms of predicting merger rates for LISA and for understanding the origin of SMBHs.
People
Observations of galaxies across cosmic time have shown that the star-formation rate peaked at a redshift of ~1.5, well before galaxies with the metal content of the Milky Way existed. However, observational studies have predominantly been on young stellar objects (YSOs) in solar metallicity Milky Way star-forming regions. It is essential to investigate/understand differences in the star-formation process for planet harbouring stars such as our Sun at lower metallicities when the Universe was most actively forming stars. The group works on observations of star forming regions in the low metallicity Magellanic Clouds with the JWST.
The Microwave Kinetic Inductance Detector (MKID) research group is developing novel superconducting detector arrays for applications in astronomy and cosmology. The current project is funded under Science Foundation Ireland’s Frontier for the Future programme (Grant number - 21/FFP-P/10213). The detector technology relies upon the kinetic inductance principle, and employs frequency-division multiplexing (FDM) for their readout. The extremely small superconducting bandgap in certain materials allows for inherent energy resolution in each pixel of an array of MKIDs at UV/optical/near-IR wavelengths, which opens the door to many interesting astronomical science targets. In more detail, our current work lies in the following areas:
People
The accretion and outflow phases are important stages in the formation of a star and the accretion disks in which planets may eventually form are also widely studied. However, not all the mass in a star forming region will go into making stars. Typically 5 % will form the sub-stellar brown dwarfs. Brown dwarfs are the so-called “failed stars”, that never manage to reach masses, and therefore temperatures, high enough for hydrogen fusion to occur. The BD mass range lies just below the normal hydrogen burning mass limit and as such, brown dwarfs are the link between stars and planets. The question of how brown dwarfs form is still an open one in the field of star formation and an important step towards understanding this came when it was found that brown dwarfs were strong accretors, had accretion disks and could drive outflows.
The expertise of Dr. Emma Whelan’s group is in high angular resolution spectroscopic observations of outflow and accretion activity in young stars and brown dwarfs. The group is particularly interested in the question of how angular momentum is removed from a young star and how the jets and winds launched from young stars impact future planet formation. Related to this is the question of how early in the lifetime of a star planet formation begins. The group also investigates how outflow and accretion activity compares in brown dwarfs and young stars. They are involved in several projects on these topics. Dr. Whelan mainly works with the instruments of the European Southern Observatory’s Very Large Telescope and most recently the JWST. She also has experience in the radio and X-ray regimes and is very much focussed on the arrival of the European Southern Observatory’s Extremely Large Telescope.
People
Our research seeks to understand the properties of matter at extremely high temperatures and densities, such as could be found in the first millisecond of the Big Bang, in supernova explosions, and in neutron stars and neutron star mergers. At these temperatures and densities, quarks and gluons rather than hadrons (protons, neutrons, pions etc) are the relevant degrees of freedom.
Through computer simulations of the theory of strong interactions (quantum chromodynamics) we study the thermodynamic and transport properties of matter and the properties of whatever particles exist in these conditions, and aim to relate these to what can be observed for example in the structure of neutron stars and their cooling.
Research on the cosmic microwave background (CMB) is led by Dr Créidhe O’Sullivan and Dr Neil Trappe. The CMB is relic radiation from the Big Bang and contains very faint temperature and polarization features, or anisotropies, imprinted on it in the early Universe. The European Space Agency’s Planck satellite, a space mission dedicated to the study of CMB anisotropies, measured the temperature anisotropies to fundamental limits. These anisotropies were caused by structures forming in the early Universe and so provided some of our most important constraints on models of cosmology and fundamental physics. The standard model of cosmology, the ΛCDM model, with just 6 cosmological parameters, continues to give an excellent fit to CMB data and has passed all tests since it was developed more than three decades ago. Planck has placed stringent constraints on our models of the early Universe and its large-scale structure and yet questions remain, in particular how fluctuations in the early Universe were first generated. The theory of Inflation, considered an extension to the Big Bang theory, provides a mechanism for generating small departures from uniformity that can seed formation of subsequent structures. According to Inflation, the Universe underwent a brief period of exponential expansion 10-36 seconds after the Big Bang. The basic inflationary paradigm is accepted by most physicists because of its ability to solve fine-tuning problems of big bang cosmology as well as explain the origin of large-scale structure. Despite these successes however, we have as yet no proof for inflation. If Inflation is correct, then gravitational waves produced in the very early Universe will imprint a very faint polarization pattern on the CMB, known as the primordial B-modes. The next ambitious goal for CMB astronomy is to detect and map this polarization signature.
As well as the CMB anisotropies, the absolute CMB frequency spectrum is a second key observable to challenge the accepted standard cosmological model. Departures from a blackbody spectrum, i.e., spectral distortions, encode information about the thermal history of the Universe from the early stages (with primordial distortions due to inflation and cosmological recombination lines) up until today.
Current projects include:
QUBIC
The Q & U Bolometric Interferometer for Cosmology (QUBIC) is a novel ground-based telescope that is designed to measure very faint B-mode polarisation fluctuations, a goal that demands exquisite sensitivity and control of instrumental systematic errors since the signal is expected to be extremely small, of the order of a few tens of nK. QUBIC exploits a very promising technique to do this – bolometric interferometry combined with spectral imaging.
BISOU
BISOU (Balloon Interferometer for Spectral Observations of the Universe) is a study of the viability of a balloon-borne spectrometer, a pathfinder for a future space mission dedicated to the measurements of the CMB spectral distortions, while consolidating the instrumental concept and improving the readiness of some of its key sub-systems. The BISOU concept is based on a Fourier Transform Spectrometer (FTS), covering a spectral range from about 90 GHz to 2 THz, adapted from previous mission proposals such as PIXIE and FOSSIL.