Research Projects

“Reserve your right to think, for even to think wrongly is better than not to think at all.” – Hypatia

Long-Deep Eclipses in ZTF & Beyond

Recently I have been very excited about the prospect of deep diving in the world of slow-time domain astronomy. More specifically, I’m interested in what can we learn about stellar evolution from the lens of slowly evolving stellar variability. The study of century-long photometric variability has already shown to be fruitful of exotic and extreme stellar binaries that challenge our understanding. I’m passionate on compiling both modern and archival TD photometry on the discovery and characterization of deep-long stellar variability. This project is currently being mentored by my advisor Professor James Davenport.

alt text (Example of a long-period-deep stellar variable discovered from the Gaia Alert Archive in unison with the Zwicky Transient Facility)

Characterizing Periodic Signals in the LSST Era

I currently work under my advisor Professor Eric Bellm on behalf of the Vera C. Rubin Observatory Data Management group at the University of Washington. I am broadly interested in transient alert processing with a focus on calculating and characterizing alert light curve moments and statistical properties as a tool for transient classification.

Currently I am involved in understanding and testing the period-finding capabilities that will be possible with the Legacy Survey of Space and Time (LSST) survey during the first few years during the alert processing generation. Currently, we are working with a series of in-house and known LSST-like-cadence light curves of periodic variables. We are interested in addressing broad questions such as completeness, accuracy, and period significance scoring. The findings and conclusions of this study will be publicly available in the LSST Data Management Technotes-221.

Type-II Supernovae in the Local Universe with the Zwicky Transient Facility

(Paper coming soon on ArXiv!)

Over the last year and a half, I have been working as a post-baccalaureate research student and support researcher for the Zwicky Transient Facility (ZTF) survey under Professor Mansi Kasliwal and Ph.D. student Kishalay De. My research at Caltech aims to broadly understand the synthesis of supernovae populations in the local universe using data from the ZTF survey. I am a contributing member of the Census of the Local Universe (CLU) ZTF experiment that aims to spectroscopically classify all supernovae within 200 Mpc.

alt text (Tzanidakis et al. 2020 - Science images of type II SNe discovered by the ZTF CLU experiment.)

During my time at Caltech, I have been fascinated with the intrinsic rates of type II supernovae. Recent evidence suggests that type II supernova are amongst the most common type of supernovae (Arcavi et al. 2017). However, due to their large spread in luminosity and limited supernovae spectroscopic follow-up resources, it becomes challenging to constraint the faint end of the luminosity function.

Controlled experiments such as the ZTF CLU (De et al.2020) make it possible to answer this question by, specifically, focusing on the nearby universe and achieving spectroscopic completeness up to r~20 mag. In my most recent paper (link coming soon!), we present the largest spectroscopically complete sample of type II supernovae to date. The analysis utilizes a flexible parametric lightcurve model to model lightcurves via a Bayesian approach. We provide a detailed luminosity function in the ZTF-gri bands, analyze the lightcurve characteristics, and provide a useful discussion on future type II luminosity functions and estimates of rates.

(Stay tuned for the details!)

alt text (Tzanidakis et al. 2021 - Modeling type II lightcurves using parametric lightcurve models)

Galactic Archeology: Tomography of the Galactic Disk

During my undergraduate degree alongside with my mentors and collaborators, I was very fortunate to be involved in researching the shape of the Milky Way’s disk. The fascinating field of Galactic Archeology gives astronomers the opportunity to glimpse into the evolving past of our own galaxy, and ultimately understand the underlying physics that has produced the bulk motion and positions of stars in the Milky Way.

Alongside with an amazing community of collaborators, and publications I was a key contributor to suggest that the disk of the Milky Way is oscillating. Why is this a big deal? This points to a series of very important questions such as what are the driving forces of such large-scale oscillations? One plausible scenario described by our publication suggests that dwarf satellite galaxies are able to kick-out stats from the Disk, causing radial oscillating-like features.

alt text

(data visualization: Tzanidakis A., Laporte C. et al. 2018) This animation shows the N-body simulations described by Laporte et al. 2018, and show the dynamic interaction between the a Milky-Way like galaxy interacting with the Sagittarius dwarf satellite galaxy.

alt text

(data visualization: Tzanidakis A., Laporte C. et al. 2018) N-body simulation of the Milky Way’s disk after Sagittarius has passed through the disk. This visual demonstrates that the oscillations of the Galactic disk perhaps permeate radially across the entire disk.

If you would like to learn more about our research, please find some relevant publications here.