Support of the astronomical research of the Cavendish Astrophysics Group

Lead Research Organisation: University of Cambridge
Department Name: Physics

Abstract

The Cavendish Astrophysics group's proposed research programme addresses many of the key science questions in contemporary astrophysics. Observational, instrumental, data analysis and theoretical work are all being pursued under the roof of the new Battcock Centre for Experimental Astrophysics, adjacent to the Institute of Astronomy and the Kavli Institute for Cosmology. Significant new areas of research have recently been brought in by the appointments of new senior staff, Profs. Roberto Maiolino, Didier Queloz and Chris Carilli, who are developing their research areas alongside and in collaboration with existing staff members. The growing area of exoplanet detection and characterisation is being pursued as part of the new Centre for Extra-Solar Planetary Science: this work includes the detection of new exo-planets using their radial velocity Doppler shift technique, measuring exoplanet atmosphere properties, and measuring the structure of protoplanetary discs to understand the formation and evolution mechanisms of exo-planet systems. This work will involve ALMA observations of the dust structures in protoplanetary discs around newly-formed stars. This work leads naturally into the problem of how stars themselves form in their protostellar discs: using their extensive expertise in submillimetre interferometry, the work will use ALMA to image the chemical and dynamical state of the gas deep in the potential wells of protostars where active accretion on to the star/disc system and jet generation is expected to occur. These high-resolution studies will be made possible for the first time by the commissioning on long baselines in ALMA during the course of this grant. In addition, the recent commissioning of e-MERLIN will allow the high-resolution measurement of the thermal radio emission from protostars, revealing the ionised accretion and outflow components close to the protostars. Together we expect these studies to help us understand the detailed physics of star formation and feedback on small physical scales. Beyond the Galaxy, the scientific focus is on the evolution of galaxies in the Universe through studies of their metallicity evolution; in particular we will prepare the ground for the use of guaranteed time on the James Webb Space Telescope (JWST) which is due for launch in this grant period. We will also continue work on the physics of galaxy clusters and how they evolve, and start an active involvement in an experiment aimed to detect the epoch of reionisation, the epoch when the Universe rapidly transitioned from neutral to ionised form. In parallel with these astrophysical studies, researchers will be pursuing blue-sky technical studies aimed at delivering new detection capabilities at optical, infrared and radio wavelengths.

Planned Impact

As well as our immediate scientific colleagues, our research will benefit a much wider community, spanning the commercial sector, policy makers in science and technology, and the wider public through our participation in specific educational outreach projects as well as more general engagement activities with the interested public.

Our experience in developing advanced experimental techniques to address the most pressing astrophysical problems has frequently led to much wider benefits than might have been anticipated. For example, our expertise in Bayesian data analysis which we have exploited in much of our cosmological work is now being utilised in the Oil and Gas exploration sector for geophysical inversion. Similarly, our proposed work on electromagnetic modeling of advanced radio astronomy receivers will likely benefit a much wider community of radio-frequency engineers than those focused on astronomy alone. The later stages of that work will be targeted towards utilising the newly developed modeling tool to explore the possible applications of Graphene and other new materials. While our focus will be on astronomy and space applications, the potential this work has to support new initiatives and possible commerical applications is likely to be large.

Our on-going work on low-noise detector characterization is a good example of a synergy between our astronomical research (as part of a wider UK collaboration) and the commerical interests of Selex, who fabricate the devices. Our aim is to guide their product development so that it both supports the UK's astrophysical goals, but also to provide a unique market advantage to Selex in the field of low-noise fast-readout infrared detectors. These have potential applications in many other arenas, for example in biological imaging studies, where the relative high transparency of tissue to infrared wavelenghts provides an important advantage.

Our proposed work on the Epoch of Reionization provides another example where our technical work will have wider societal contributions. The SKA-precursors we are participating in will clearly lead to major impacts on the local technical, economic and social climate, all benefiting the community in South Africa. Furthermore, there is likely to be significant technology transfer between SKA development activities and these nearer-term experiments, with implications for both significant UK and South African knowledge exchange.

In parallel with our technical activities, we will continue to support a wide range of outreach activities. Our staff and students regularly contribute to the very extensive programme of outreach activities organized at the Cavendish. In addition, our students and post-docs participate in regular tours of our observatory site. A key goal here is to inform the general public on both what we do, but also to explain the value of skilled research scientists in the non-academic environment as key players in the UKs knowledge base and innovation community.

Publications

10 25 50

publication icon
Aravena M (2016) A survey of the cold molecular gas in gravitationally lensed star-forming galaxies at z > 2 in Monthly Notices of the Royal Astronomical Society

publication icon
Barai P (2018) Quasar outflows at z = 6: the impact on the host galaxies in Monthly Notices of the Royal Astronomical Society

publication icon
Belfiore F (2017) SDSS-IV MaNGA - the spatially resolved transition from star formation to quiescence in Monthly Notices of the Royal Astronomical Society

publication icon
Belfiore F (2018) SDSS IV MaNGA - sSFR profiles and the slow quenching of discs in green valley galaxies in Monthly Notices of the Royal Astronomical Society

publication icon
Belfiore F (2016) Galaxy gas flows inferred from a detailed, spatially resolved metal budget in Monthly Notices of the Royal Astronomical Society

publication icon
Belfiore F (2016) SDSS IV MaNGA - spatially resolved diagnostic diagrams: a proof that many galaxies are LIERs in Monthly Notices of the Royal Astronomical Society

publication icon
Bing L (2019) Mildly suppressed star formation in central regions of MaNGA Seyfert galaxies in Monthly Notices of the Royal Astronomical Society

 
Description P5:
We have investigated the metallicity scaling relations (i.e. the relation between abundance of chemical elements and other galaxy properties, such as stellar and gas mass, and star formation rate) in local galaxies and as a function of redshift.
These have been investigated both for what concerns the integrated properties and spatially resolved properties. We have found that the chemical enrichment of galaxies can be described with relatively simple models of gas flows from/to the intergalactic medium.
The scaling relation have been extended to the gas content of galaxies and to the environment in which galaxies live.
We have investigated the spatial variation of metallicities (metallicity gradients) both in local and distant galaxies by using extensive multi-IFU surveys.
We have further investigated the differential metallicity between passive galaxies and their star forming progenitors to constrain the star formation quenching mechanism and timescale.
The physical properties of galactic outflows have been investigated in detail by exploiting multi-band observations.
Evidence for star formation in galactic outflows has been observationally characterised in detail.
The physical properties of the interstellar medium and kinematics/dynamics of galaxies close to the reionization have been investigated, revealing interesting similarities
with mature galaxies at lower redshifts, providing important constraints on the early formation mechanisms of galaxies.

P7:
Detailed simulation have been developed for the observations of the James Webb Space Telescope and its spectrograph NIRSpec, by also exploiting (as a guideline) recent observational results obtained us and collaborating teams.

We have contributed to the optimisation of the NIRSpec proposal tool (including the optimisation of the target allocations through the Micro Shutter Array) and to the optimisation of the pipeline.

Observing programmes of distant galaxies have been used to refine the planning of the GTO.

The GTO programme has been finalised and the latest version of the APTs has been submitted on 30th January 2018. We have led (or co-led) the plan of two major sub-programmes (integral field spectroscopy of distant galaxy and medium-deep multi-object observations).

P8:
We have run the detector (photon counting IR array) in cryogenic environment and characterised its read noise.
We have identified gain issues in the existing detector.
New tests on Mk13 Saphira arrays (in collaboration with Gert Finger, ESO) have shown strong evidence for photon-counting performance, the main goal of the grant-funded programme. These data are being analaysed for publication.
A new Saphira array is on order from Leonardo (formerly Selex).


P9
We have identified close-to-optimal fringe-tracking topologies for next generation optical/IR interferometer arrays

We have identified the optimal beam relay and delay line architectures for next generation optical/IR interferometer arrays. We have continued to investigate the best designs for the fringe-tracking beam combiners for the next generation of
optical/IR interferometer arrays with large (10-20) numbers
of telescopes.

P11:
We have developed an analysis pipeline using a physically based model and a fully Bayesian statistical frame work to analyse a large sample of 200 clusters of galaxies data sets in different wave-bands and to constrain their physical properties particularly, their total masses for the first time. We have developed a 'free-form' model for the radial profiles of physical properties, based on the 'nodal method' outlined above. This method has now been described in a paper submitted last year (available at arXiv:1705.10712) and is now in the final stages of review before publication.
Exploitation Route P5
The results obtained through our various observing programmes are providing important constraints to models of galaxy formation and evolution.
P7
Observations with JWST (which will take place in a few years) will provide a wealth of information on large sample of galaxies, which will be used
also by many other groups in UK and worldwide to investigate galaxy formation and evolution and to plan followup observations.
P9
We anticipate that our work on optimal array and sub-system designs
for high sensitivity optical/IR imaging interferometers will advise the
design of both the astronomical and defense sectors, as they move to assess the feasibility/efficacy of these telescopes for their activies over the next 5 years.
P11
Our single Bayesian tool for the physically-based, joint analysis of multi-waveband cluster observations can be and is being used by Astronomy community to constrain clusters physical parameters. Bayes_X, our Bayesian inference tool for the analysis of X-ray observations of galaxy clusters is also publically available at http://ccpforge.cse.rl.ac.uk/gf/project/bayesx/.
Sectors Other

 
Description P8: Findings are being used to inform design choices for Selex for their continued commercial development of their Saphira detectors. This is of economic use for all the markets they sell their detectors for. P9: The optimium array designs for interferometers to be used for Space Surveillance (in particular the imaging of GEO satellites) has been explored. This is of interest to the Aerospace, Defence and Marine sector.
First Year Of Impact 2015
Sector Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Manufacturing, including Industrial Biotechology,Other
Impact Types Economic,Policy & public services

 
Description KLEVER collaboration 
Organisation European Southern Observatory (ESO)
Country Germany 
Sector Charity/Non Profit 
PI Contribution This collaboration is associated with a Large Programme awarded by the European Southern Observatory exploiting 120 hours of observation with the KMOS instrument at the Very Large Telescope to obtain spatially resolved metallicity gradients, excitation diagram and kinematics in a sample of 150 galaxies (lensed and unlicensed) at z~1-2. Roberto Maiolino is the Co-PI of this programme. He has been in charge of co-leading the programme, planning the strategy and, together with his team, he has been processing, analysing and interpreting the results.
Collaborator Contribution The partners have been contributing in preparing the observations and processing the data.
Impact The first papers resulting from the analysis of the first set of data are being finalised and will be submitted for publication in the coming few months.
Start Year 2016
 
Description KLEVER collaboration 
Organisation National Institute for Astrophysics
Country Italy 
Sector Academic/University 
PI Contribution This collaboration is associated with a Large Programme awarded by the European Southern Observatory exploiting 120 hours of observation with the KMOS instrument at the Very Large Telescope to obtain spatially resolved metallicity gradients, excitation diagram and kinematics in a sample of 150 galaxies (lensed and unlicensed) at z~1-2. Roberto Maiolino is the Co-PI of this programme. He has been in charge of co-leading the programme, planning the strategy and, together with his team, he has been processing, analysing and interpreting the results.
Collaborator Contribution The partners have been contributing in preparing the observations and processing the data.
Impact The first papers resulting from the analysis of the first set of data are being finalised and will be submitted for publication in the coming few months.
Start Year 2016