2019/05/21 by Sonali Sachdeva, Rupjyoti Gogoi, Kanak Saha +2
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics #Bulge #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Physics #Redshift #Star formation #Stellar mass #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stz1417
published as Monthly Notices of the Royal Astronomical Society, 2019, Volume 487, Issue 2, p.1795-1807 · 15 pages, 10 figures, accepted for publication in MNRAS
arxiv created 2019/05/21 · openalex publication_date 2019/05/22 · arxiv updated 2019/06/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present combined evolution of morphological and stellar properties of galaxies on the two sides of z = 2 (2.0 < z < 4.0 and 1.5 < z < 2.0) in CDFS, with ground-based spectroscopic redshifts. We perform bulge-disc decomposition on their images in J and H filters, from the 3DHST Legacy Survey obtained using HST/WFC3. Combining morphological information with stellar properties, we provide a detailed account of the formation/growth of discs and spheroids around z ∼ 2. The fraction of two-component (bulge+disc) systems increases from 46 per cent for z > 2 to 70 per cent for z < 2, compensating for the fall in population of pure discs and pure spheroids. All quiescent outliers of our full sample on the main sequence, are two-component systems, belonging to the lower redshift range (z < 2). The doubling of stellar mass of two-component systems and decrease in their SFR by the same factor, suggests that mechanisms involved in morphological transformations are also responsible for the quenching of their star formation activity. Interestingly, while there is substantial increase in the size (2.5 times) and mass (5 times) of pure discs, from z > 2 to z < 2, pure spheroids maintain roughly the same values. Additionally, while bulge hosting discs witness an expansion in scale length (1.3 times), their bulge sizes as well as bulge to total light ratio see no evolution, suggesting that z ∼ 2 is pre-dominantly a disc formation period.