The Morphology of Galaxies from Classical Techniques to Deep Learning

Proposers: Sudhanshu Barway (IIA), Ajit Kembhavi (IUCAA), Sonali Sachdeva (KIAA-PKU), Smitha
Subramaniam (IIA), Kanak Saha (IUCAA) and Yogesh Wadadekar (NCRA)
The morphology of galaxies at different wavelengths is a very important indicator of their nature, possible origin, evolution since formation and influence of their environments. The objective of this workshop is to provide a comprehensive overview of various techniques adopted for the detection and measurement of morphology of galaxies at optical and near-IR wavelengths in the local and distant Universe, and some astrophysical consequences of these explorations. Experts from different institutes will illustrate the state-of-the-art techniques developed by them and others over the years for detection of morphological features through parametric and non-parametric methods. Also covered will be recent applications of Deep Learning techniques to the study of galaxy morphology. Implementation of various techniques to a large number of galaxies in a robust and automated manner, which is an important skill in the age of all-sky surveys, will be elaborated. The astrophysical insights provided by such morphological studies, including their correlation with stellar activity and environment will be discussed.

Morphology of galaxies has been examined in a detailed manner for a relatively small sample of galaxies and in a broad manner for large surveys like the SDSS. Advancement of instruments (HST/WFC3, MUSE etc.), surveys (BOSS, CANDELS, ASPECS, etc.) and data reduction techniques (like GALFIT, NoiseChisel and Deep Learning based algorithms) in the past decade, have generated ample evidence that intricately links morphology to the formative and evolutionary stages of galaxies. Morphology has been found to be directly correlated with stellar mass, halo mass, central SMBH mass, star formation, nuclear (AGN) activity, local environmental density and redshift of the galaxy to varying degrees.

Morphology of a galaxy is defined through various parameters which provide an insight into the distribution of different stellar populations, stellar mass, gas and dust inside the galaxy depending on the wavelengths probed and techniques adopted. It is important for astronomers to be aware of these techniques and possess the skill to utilise them in their respective field. This will help them extract a broader understanding of the physical processes involved. This skill is gaining critical importance as the wavelength and redshift range in which galaxies can be observed is expanding with recent and upcoming telescopes (ALMA, JWST etc.). It is also important to understand the main astrophysical results which have been inferred from these morphological studies, in combination with other properties like spectral energy distributions (SED). All these aspects will be summarised in the workshop through a series of talks, demonstrations and hands-on sessions.

Tentative schedule :

Time Title and Speaker
09:30-09:40 am Introduction (Sudhanshu Barway)
09:40-10:15 am Galaxy morphology - A perspective (Prof. Ajit Kembhavi)
10:15-11:00 am Galaxy kinematics in the era of IFU (Kanak Saha)
11:00-11:30 am Tea Break
11:30-12:00 noon Correlation of morphology with kinematics and stellar activity (SONALI SACHDEVA)
12:00-12:30 pm Bulge-disk decomposition for determination of galaxy morphology
(Yogesh Wadadekar)
12:30-01:00 pm Understanding galaxy evolution using scaling relations (Smitha Subramanian )
01:00-02:15 pm Lunch Break
02:15-03:00 pm Accessing the SDSS resources for galaxy science (Vivek M.)
03:00-03:45 pm Extraction of non-parametric measures of structure of galaxies (Sonali Sachdeva)
03:45-04:15 Tea Break
04:15-05:00 pm Introduction to deep learning and application to galaxy morphology (Ashish Mahabal)

The level of the workshop will be made suitable for researchers at all levels who need to acquire basic morphology measurement skills. It is expected that the participants will bring their own Linux based laptop with some basic software like IRAF, Python, etc. If some further software needs to be installed, participants will be informed before hand. Good audio-visual facilities, wifi with decent bandwidth and a number of power outlets will be required for conducting this workshop.

Expected Participants: The number of participants will be limited to 50 at the workshop.