Conveners
Galaxies
- Chien-Chou Chen (ASIAA)
Galaxies
- Ting-Wen Lan
The tidal disruptions of dwarf galaxies are thought to be the most important process in building diffuse stellar halos around galaxies. Multiple spectroscopic surveys seek to reconstruct major assembly events with chemical and dynamical information of stellar halo stars. In our recently published paper, we compute the number of progenitors that contribute to the accreted stellar halos of...
The volume of astronomical data is growing at an unprecedented rate. Directly interacting with and interpreting vast amounts of high-dimensional data, such as galaxy spectra, has become increasingly challenging. To address this big-data challenge, dimensionality reduction techniques are essential for uncovering underlying patterns hidden within a dataset. In this talk, I will demonstrate how...
It is generally believed that galaxies evolved from star-forming to quiescent over time, but the mechanism of how galaxies quench remains a question. Post-starburst galaxies (PSBs) are transitional galaxies that have rapid quenching recently, making them crucial for understanding galaxy quenching. In a theoretical model, it increased SFR during the early stage of galaxy merger. Then, massive...
The origin of dust and molecular gas observed outside of galaxies remains puzzling and poorly understood. Dust is expected to be rapidly destroyed via sputtering, suppressing the formation of molecular hydrogen. In addition, cool clouds should be dispersed via fluid instabilities within a few cloud-crushing times. To study this problem, we use a suite of cloud-crushing simulations featuring a...
How galaxies transition from star-forming to passive remains an open question. To shed light on this process, one can study the properties of the circumgalactic medium (CGM)—the site of gas inflow and outflow—around galaxies in transition, known as green valley galaxies. By doing so, we can better understand how gas flow processes drive galaxy transformation. In this talk, I will present our...
A gravitational field flux conservation and redistribution picture is proposed with generalizing the Integral Gauss's law of gravity at non-relativistic limit. 1/r dependence along with a disk thickness dependence of gravitational field and the flat rotation curves are obtained by a Gaussian surface with cylindrical symmetry,
where most of the gravitational flux lines are assumed to be...
We investigate the effect of resistivity on the dynamics of accretion flow using a global simulation model. Our approach involves employing a resistive magnetohydrodynamic model (Res-MHD) around spinning active galactic nuclei (AGNs). We conduct a comparative study of 2D and 3D resistive models surrounding black holes. In our analysis, we examine the dynamics of accretion flow while...
We present a detailed analysis of molecular gas in jet-interacting regions of NGC 1068 using ALMA archival data of CO(1-0) and CO(2-1) transitions. We identified a distinct feature where CO(1–0) shows redshifted absorption while CO(2–1) exhibits emission at the same location and velocity, observed consistently across several regions along the jet. Spectral profiles of CO(2–1) reveal redshifted...
Recently, the ASKAP POSSUM and MeerKAT surveys revealed an apparent lack of radio source counts in the Fornax galaxy cluster field. The sources in this patch of sky also appeared to be less polarised. These observations are peculiar and could be important signatures of depolarisation on galaxy cluster scales. In this work, we quantified the effects on polarisation of radio point sources behind...
Diffuse interstellar bands (DIBs) are weak, mysterious absorption features that have been detected ubiquitously in the Milky Way and other galaxies. However, their existence outside of galaxies remains unknown.
In this talk, I will present our study of searching for a DIB (DIB$\lambda4430$) outside of galaxies in the circumgalactic medium (CGM) environments. To this end, we make use of...
This study explores a possible solution to the Fermi paradox, which questions why we have not observed alien civilizations despite the vastness of the universe. Previous simulations by Zackrisson et al. (2015) suggested that a Kardashev-III type civilization, capable of harnessing the energy of an entire galaxy, could expand across 50% of the Milky Way (MW) in just 25 Myr. Similarly, Wright et...
One of the most powerful tools in the study of galaxies is the thermal emission of interstellar dust, which dominates their spectral energy distribution (SED) at far-infrared wavelengths. Using a dust emission model such as a modified blackbody, fits to the SED reveal the dust (and interstellar medium) column density and its temperature, making the dust SED a key tracer in Galactic and...
Multi-band observation of deep fields provides a unique scope to study different aspects of galaxy evolution by effectively detecting fainter sources in the distant universe. We utilize the angular resolution (~1.2 arcsec), sensitivity, and field of view of the Ultra-Violet Imaging Telescope (UVIT) onboard AstroSat to image several HST deep fields in the FUV and NUV bands. Combining UVIT...
