Project Overview

Within two of the deepest and most-well-studied fields in the sky, ~50 strong radio sources were identified that had no infrared (IR) or optical counterparts, down to a very faint level. Named “Infrared-Faint Radio Sources” (IFRSs), and related to the class of optically-invisible radio sources, follow up of these objects has found no IR down to extremely sensitive levels (< 1 uJy), and has found evidence to suggest they’re very distant active galactic nuclei. Similar brighter IFRSs samples have confirmed their extreme distances at redshifts 1 < z < 5, and more recent examples have been found at similar extreme redshifts via ALMA CO observations. However, the redshift range of the original and most extreme IFRSs, with no optical or IR counterparts, remain a mystery, and their potential high redshift status presents interesting implications for standard models of hierarchical black hole growth.

Aims

This project aims to explore the optical/IR properties of the most extreme IFRSs, and confirm their redshift range.

Objectives

The objectives of this project would be: 
- Search for optical/IR counterparts of IFRSs using recent observations, such as JWST and Euclid, within deep fields, such as the CDFS and ELAIS-S1 fields 
- Gather new observations of IFRSs within deep fields, such ALMA observations of CO, and optical/IR spectroscopy from JWST 
- Compare the most extreme IFRSs to their brighter and more well-known counterparts, aiming to determine whether they’re a related or continuous distribution of the same class of object 
- Identify any new selection criteria for finding high-redshift radio sources.

Significance 

Any properties uncovered in optical/IR, or redshifts measured of these extreme IFRSs, will be the first of their kind, helping to determine their nature. If confirmed as very numerous high-redshift AGN, this presents challenges against current models for the formation of supermassive black holes in the early universe. Determining new methods for finding high-redshift radio sources is crucial for understanding the early universe, and for providing background sources against which HI absorption can be identified at high redshift. This project also opens up the possibility to lead projects on prominent telescopes, such as ALMA and JWST.

The successful candidate will join an active group working on high redshift AGN, which is embedded within the Curtin Institute of Radio Astronomy (CIRA), and includes three members of the supervisory panel. New data within several deep fields already exists, so the first part of the project is ready to go. Support will be given when submitting new observing proposals, both internally within this group, and externally via various collaborations, connections and networks. 

Data processing requirements are not expected to be significant, and can be met on any number of existing machines or facilities to which the candidate will be granted access, including single dedicated machines, national facilities, and commercial providers. In particular, support will be given by the Australian SKA Regional Centre.  

This research will help to grow this CIRA research group, and will expand the expertise of CIRA in the area of multi-wavelength astronomy. There will be plenty of opportunity to present results at international and domestic conferences through funding from Curtin.

• Future Students

• Faculty of Science & Engineering
  • Science courses
  • Engineering courses

• Higher Degree by Research

• Australian Citizen
• Australian Permanent Resident
• New Zealand Citizen
• Permanent Humanitarian Visa
• International Student

• Merit Based

The annual scholarship package, covering both stipend and tuition fees, amounts to approximately $70,000 per year.

In 2024, the RTP stipend scholarship offers $35,000 per annum for a duration of up to three years. Exceptional progress and adherence to timelines may qualify students for a six-month completion scholarship.

Selection for these scholarships involves a competitive process, with shortlisted applicants notified of outcomes by November 2024.

1

All applicable HDR courses.

We are looking for a self-motivated PhD candidate with excellent organisation, problem-solving and project management skills. Candidates with strong quantitative skills, including familiarity with python and astronomy are desired for this project. Must be eligible to enrol in PhD programs at Curtin.

 

Please send your CV, academic transcripts and brief rationale why you want to join this research project via the HDR expression of interest form to the project lead researcher, listed below. 

You must be enrolled in a Higher Degree by Research Course at Curtin University by March 2025.

Project Lead: Dr Jordan Collier