I am an astronomy PhD Student at the University of Victoria working with my supervisor Dr. Doug Johnstone and astronomer Dr. Nienke van der Marel. My research primarily uses the Atacama Large Millimeter/Submillimeter Array observations for studies of star and planet formation.
Accretion Variability in Embedded Protostars
The youngest protostars may have highly variable accretion rates due to disk instabilities or interactions with companions/planets in the disk. Using novel calibration strategires for millimeter observations with ALMA and JCMT, I aim to observe the accretion rate changes in protostars and understand the thermal and chemical effects they have on their surroundings.
Protoplanetary Disk Structures and Accretion Flow
ALMA has uncovered a diverse range of beautiful rings, gaps, and spirals in protoplanetary disks likely caused by forming planets, which may affect the flow of accreting gas towards their host protostars. With the aid of long-baseline ALMA observations and thermochemical modelling, I am quantifying how embedded planets may leave their imprint on the disk structure and accretion flow.
Optimizing ALMA Calibration and Data Analysis
The sensitivity and resolution provided by the 66 dishes of the ALMA have revolutionized our a view of the millimeter sky, however, robust calibration and optimal use of data from millimeter interferometers remains challenging. By developing new techniques for ALMA calibrating and imaging, my research pushes the limits of this powerful telescope to new heights.
You can find links to my published and accepted papers below. The above gallery image is a collection of stunning high-resolution ALMA observations of Transtion disks I reduced for my second paper with Dr. Nienke van der Marel.
- On the accuracy of the ALMA flux calibration in the time domain and across spectral windows (2020)
Francis, L., Johnstone, D., Herczeg, G., Hunter, T. R., & Harsono, D. AJ, 160, 270.
- Dust-depleted Inner Disks in a Large Sample of Transition Disks through Long-baseline ALMA Observations (2020)
Francis, L., & van der Marel, N. ApJ, 892, 111.
- Identifying Variability in Deeply Embedded Protostars with ALMA and CARMA (2019)
Francis, L., Johnstone, D., Dunham, M. M., Hunter, T. R., & Mairs, S. ApJ, 871, 149.
- The JCMT Transient Survey: Four Year Summary of Monitoring the Submillimeter Variability of Protostars (2021)
Lee, Y. et al. Arxiv, 2107.10750
- Dust traps and the formation of cavities in transition discs: a millimetre to sub-millimetre comparison survey (2021)
Norfolk, B. et al. MNRAS, 502, 5779
- ALMA Observations of the Asymmetric Dust Disk around DM Tau (2021)
Hashimoto, J. et al. ApJ 911, 5
- FAUST. II. Discovery of a Secondary Outflow in IRAS 15398-3359: Variability in Outflow Direction during the Earliest Stage of Star Formation? (2021)
Okoda, Y. et al. ApJ, 910, 11
- On the Diversity of Asymmetries in Gapped Protoplanetary Disks (2021)
van der Marel, N. et al. AJ, 161, 33
- FAUST I. The hot corino at the heart of the prototypical Class I protostar L1551 IRS5 (2020)
Bianchi, E. et al. MNRAS, 498, 87