RESEARCH

Our group at DAASE is working on resolving a few critical issues related to the galaxy formation and evolution process. Our primarily focus is concentrated on broadly two research areas. The first part focuses on the dark matter distribution in galaxies and tries to address the shortcomings of the Lambda-CDM model of cosmology. The second part focuses on gas and star formation and tries to understand how galaxies effectively use their gas reservoir to form stars and from where this gas comes.

Our group is also actively involved in cutting-edge instrumentation for new-generation radio telescopes. In our Digital Backend Group, we focus on developing state-of-the-art digital backends (e.g., receiver, beamformer, etc.) for radio telescopes using advanced computing platforms like FPGA and GPUS. The long-term ambition of this group is to support our own four-element interferometer (IIRI, IIT Indore Radio Interferometer) and develop indigenous technologies for next-generation instruments. Currently, we are working on developing a digital beam former for radio astronomy applications using FPGA.

Dark matter and the Lmbda-CDM

Despite immense success on large scales, the Lambda-CDM model of cosmology suffers several critical shortcomings on small galactic scales, e.g., the 'core-cusp' problem, the 'too big to fail' problem, the 'missing-satellite' problem, etc. All of these problems violate the predicted dark matter distributions in and around galaxies from a few kiloparsecs to a few hundred kiloparsecs. Our group is looking into some of these critical issues using observations of nearby galaxies. For example, we are addressing the long-standing missing satellite problem by analyzing observations of Compact High-Velocity Clouds. We are examining the dark matter distribution in dark matter deficient galaxies. The dark matter deficient galaxies are leading the front to challenge the Lambda-CDM. By inspectic the vertical structure of galactic disks, we are invesigating the non-sphericity of dark matter halos in galaxies. All these are open problems of astrophysics and directly challenge the working paradigm of modern cosmology.

Leo-T, a MW satellite galaxy, previously thought to be a CHVC

SDSS composit image of AGC 6438, a dark matter deficient galaxy

Vertical density profiles for different non-spherical dark matter halos in UGC 4148

Galaxy formation and evolution

In connection to galaxy formation and evolution, two significant issues persist to date despite several significant efforts. First, how do the galaxies acquire sufficient gas to sustain their prolonged star formation? Second, how the star formation physics, which acts at a microscopic scale, leads to global scaling relations at much larger scales in galaxies. We are addressing these pressing questions using extensive observations of nearby galaxies and sophisticated numerical modeling. In this regard, atomic Hydrogen (HI), in particular, serves as an excellent tracer of the physical activities and dynamics in galaxies. We perform deep HI/optical/UV observations of a large number of galaxies using different telescopes to trace the connection between gas and star formation in galaxies. Further, we have started a large campaign using the GMRT to detect AGNs in dwarf galaxies. These observations will unravel how feedback processes regulate the galaxy evolution process.

Signature of extra-planar atomic gas in NGC 1003

Regions of multi-component KS-law in NGC 6946

A rare atomic bar in the dwarf galaxy DDO 168

Instrumentation

We are also involved in developing digital backends for radio telescopes. Specifically, we make use of FPGA and GPUs, to build digital receivers for radio telescopes. We are currently working on an FPGA+GPU based correlator for IIT Indore Radio Interferometer (IIRI).

Software Development

Our lab develops scientific software and automated pipelines for radio interferometric data analysis, galaxy modeling, and next-generation instrumentation. The focus is on scalable, reproducible, and SKA-ready computational frameworks.

GARUDA
- GARUDA (Generic AI-based GMRT-Tuned Data Analysis Pipeline) is an end-to-end automated pipeline for radio data analysis and imaging. More information on GARUDA can be found here.
WSLIP
- This is a spectral analysis pipeline, which performs continuum subtraction, imaging, and produces moment maps. The UV manipulation is done using CASA modules, whereas the imaging is done by WSClean, and creating moment maps was done using SoFiA2. This is still a work in progress. More details will follow soon.
Antenna Configuration Optimization: EGMRT
- This code optimizes antenna configuration layout of an interferometric array using a random sampling method. Used to determine the antenna configurations for the EGMRT (Patra et al. 2019a, MNRAS, 483, 3, 3007).
diffsolve: Multi-component differential (Poisson’s-Boltzmann) equation solver
- Solves the Poisson’s-Boltzmann equation of hydrostatic equilibrium for multi-component galactic disks and produces a 3D dynamical model of the same. This is extensively used to study the structure of the atomic and molecular disks in galaxies (Patra 2020b, Patra 2020c, Patra 2019)
multigauss: Decomposing a spectrum into multiple Gaussian components
- Fully automated parallel routine to decompose line-of-sight HI spectra into multiple Gaussian components (Patra et al., 2016a, MNRAS, 456, 2467)
niso-solver: Non-isothermal hydrostatic equation (spherical) solver
- Solves the Poisson’s-Boltzmann equation of hydrostatic equation in a thermally supported ‘non-isothermal’ HI cloud. This is to identify satellite galaxies from the pool of Compact/Ultra-Compact High Velocity Clouds (Patra 2018b, MNRAS, 480, 4, 4369).

Dark matter and the Lmbda-CDM

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Galaxy formation and evolution

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Instrumentation and Software Development

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PEOPLE

Dr. Narendra Nath Patra

Principal Investigator

Dr. Narendra Nath Patra obtained his Ph.D. from the National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, under the guidance of Prof. Jayaram N. Chengalur. He did his first postdoc from NCRA-TIFR itself, where he worked on the proposed expansion of the Giant Meter-wave Radio Telescope (E-GMRT) and designed its antenna configuration. He then moved to the Raman Research Institute as a Pancharatnam Fellow in 2018. He joined the Department of Astronomy Astrophysics and Space Engineering of the Indian Institute of Technology in 2021 and established a Galaxy Research Group to investigate the process of galaxy formation and evolution. He also established the Digital Backend Lab at DAASE, which focuses on building digital receivers for radio telescopes. He is actively working on commissioning the four-element interferometer (IIRI) at IIT Indore.

Atharva Mirashi
3rd year PhD student
phd2301121001@iiti.ac.in

Radio Astronomy, Galaxy Dynamics in ΛCDM cosmology. Use multi-wavelength astronomy to look for dark matter distribution in galaxies and resolve small scale challenges of ΛCDM cosmology.

Keerthi K.
Third year PhD student
phd2301121009@iiti.ac.in

Understanding the evolution and dynamics of galaxies using IFU (optical), radio observations. Bar dynamics in galaxies, Tremaine-Weinberg method to estimate the pattern speed in galaxies.

Vatsal Garg
Second year PhD student
phd2401221005@iiti.ac.in

AGNs in dwarf galaxies, Radio continuum observation of dwarf galaxies, deep radio continuum surveys.

Ankur Sinha
Second year MS research student
ms2404121004@iiti.ac.in

Probing HI superdisk using radio observations. HI survey of nearby galaxies (GARCIA)

Aditya Sharma
Second year MSc student
msc2403121001@iiti.ac.in

Imaging galactic plane at low radio frequencies to investigate the progenotors of compact objects.

Soumya Gupta
First year MS Research student
ms2504121004@iiti.ac.in

Study the low-frequency continuum emission and search for the presence of non-thermal emission in star-forming regions in the Milky Way. Investigate the origin of the non-thermal emission and their effect on star-formation process (creating instability).