Somnath Dutta

About Me

Welcome to my personal webpage

I am an astronomer, employed as a scientist at the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) in Taiwan. My research is mainly focused on the understanding the insight of the star and planet formation processes. For that purpose, I usually utilize various telescope facilities based on ground to sky at different wavelengths (mainly sub-millimeter, infrared, optical, radio) data collected from telescopes. My recent focus has been on studying protostellar jets at early stage of stellar accretion process using observations from the ALMA telescopes, which led to insights of observational characteristics of jets and their association with stellar accretion and planet formation processes. I study the dust and molecular line emission originating from the protoplanetary disk, and model the structures to identify potential substructures associated with planet formation. Additionally, I am interested in the installation, calibration, and data processing of very-large baseline interferometry (VLBI) and I am supporting the BURSTT VLBI project, which aims to detect and localize Fast Radio Bursts (FRBs).

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Publications: ADS link!

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Research

Project I: Protostellar Jets/Outflows and Planet Formation
Outflows and jets are the most intriguing characteristics of protostars during the accretion process. They remove excess angular momentum from the disk surface, allowing accreting material to fall onto the star surface. The origin and characteristics are still unclear. High-resolution and high-sensitivity observations with Atacama Large Millimeter Array - ALMA in the submillimeter wavelength provides a robust opportunity to explore the characteristics of the jets. Observations of statistically significant jets allow drawing a comprehensive picture of the jet's characteristics. A few AU scale observations with higher velocity resolution allow to measure jet rotation as well as jet-launching radius (ref: ALMASOP project; Dutta et al. 2020; 2022a; 2022b & 2024 )

Planets are thought to form within protoplanetary disks at their very early evolutionary stage. Observations and simulations have indicated possible signs of planet formation within these disks. However, the exact process and timeline for the beginning of their formation are not yet fully understood, and further detailed investigation is needed. We are working on the emission from the dust continuum and molecular line within the disk, and model the structures to identify potential substructures associated with planet formation.

Dense Cores, Molecular Outflow and Jets, the Birth Places of Stars and Planets
Dense cores are incredible targets for investigating the initial condition of star formation, jet morphology, chemical evolution, and planet formation. To explore multiple goals, we have been investigating a set of dense cores. Slide (1) displays the location of such dense cores in the Orion molecular Cloud Complex. Slide (2) presents examples of continuum emission of different kinds of dense cores. Slide (3) shows examples of outflow emission of already formed protostars within dense cores. Slide (4) shows the chemical composition of Hot corinos within dense cores. Slide (5) displays molecular jets and associated knots for two stars, one of them is the most evolved protostar with a molecular jet. Slide (6) is one of the youngest molecular jets. Molecular jets could be monopolar or bipolar. Slide (7) provides some examples of monopolar jets. Slide (8) shows some examples of bipolar jets.	(1) (2) (3) (4) (5) (6) (7) (8) Previous Next
Copyright© Dutta et al. 2020 ; Dutta et al. 2022a ; Dutta et al. 2022b & Dutta et al. 2024

Project II: Radio Instrumentation and Data processing
First Radio Burst (FRB) has been a topic of immense attraction for the last few years due to the challenges of their detection and localization. Recently, the Taiwanese FRB community launched a new radio telescope, Bustling Universe Radio Survey Telescope in Taiwan (BURSTT) , dedicated for detection and localization of FRBs. Due the technical challenges, I am interested in their localization using very large baseline interferometric (VLBI) observations. There are several outrigger stations of the BURSTT projects as a part of VLBI observations Lin et al. 2022. I am involved in the installation, calibration and data processing of the telescope with out the BURSTT collaboration. I am particularly leading one BURSTT outrigger station at Raman Research Institute (RRI), Bangalore, India.

Project III: Formation of Young Star Cluster
The formation of the star cluster is a topic of considerable interest since most stars in our Galaxy form in groups within clustered environments. Several environmental conditions can breed young clusters. As molecular clouds are often composed of HIIregions, bubbles, and dense filamentary structures , understanding what shapes the molecular clouds to be dense and massive enough to form a young cluster is therefore of great interest. Additionally, the initial cloud configuration decides the future location of cluster formation. Therefore, the exact role of environment on the star and star cluster formation of a cloud can only be thoroughly understood by tracing various components of the interstellar medium (ISM) through multiwavelength observations. We utilize multiwavelength (sub-millimeter, radio 1.4 GHz, infrared, optical) observed data to explore the star and star cluster formation (Ref: (Dutta et al. 2015, 2018b )

Molecular clouds: Formation of Massive Stars, HII regions, Star Cluster Formation
Slide (1) displays an example of star cluster 2282. Slide (2) presents example of star forming molecular cloud G108.37-01.06. Slide (3) optical spectra of massive stars. Slide (4) shows the methods of young stellar objects detection. Slide (5) shows the spacial ditribution of young stars and morphology of the filaments associated with the molecular cloud.	(1) (2) (3) (4) (5) Previous Next
Copyright© Dutta et al. 2015 & Dutta et al. 2018

Project IV: Time-Series photometry of young objects
Photometric variability is a ubiquitous characteristic of young stars. In a binary system, two components eclipse one another periodically, resulting in a change in the apparent brightness of the system. Furthermore, various temporal phenomena such as flare-like activity on the corona, circumstellar disc extinction due to disc asymmetry, variable accretion rates, etc., can lead to aperiodic variability of young stars. Potentially, variability explores the young stars in the field population. We performed optical monitoring of young star clusters with optical telescopes 2m HCT, India 1.3m DFOT, India; 1.04-m ST, India) to explore the variability characteristics of the young stars (ref: Dutta et al. 2018a & Dutta et al. 2019.

Optical Photometric Variable Protostars
Slide (1) displays our optical observations of star forming cluster NGC 2282. Slide (2) presents RMS deviation of candidate variable stars in NGC 2282 region. Slide (3) a few example variable ligh curves. Slide (4) shows some example phase light curves of young stars. Slide (5) shows a tentative correlation between surrounding material and amplitude of rotation. Slide (6) is our observed optical image of Cyg OB7 star forming region. Slide (7) rms deviation of candidate variable stars in Cyg OB7. Slide (8) shows observed light curves of the stars.	(1) (2) (3) (4) (5) (6) (7) (8) Previous Next
Copyright© Dutta et al. 2018a & Dutta et al. 2019

Publications

1. The First Ka-band (26.1–35 GHz) Blind Line Survey toward Orion KL; Liu, X., Liu, T., Shen, Z., including Dutta S., et al., The Astrophysical Journal Supplement Series, 271, 3 (2024)
2. The Giant Molecular Cloud G148.24+00.41: gas properties, kinematics, and cluster formation at the nexus of filamentary flows; Rawat, V., Samal, M. R., Walker, D. L., including Dutta S., et al., Monthly Notices of the Royal Astronomical Society, 528, 2199 (2024)
3. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Molecular Jets and Episodic Accretion in Protostars; Dutta S., Lee, C.-F., Johnstone, D., et al., The Astronomical Journal, 167, 72 (2024)
4. Understanding the relative importance of magnetic field, gravity, and turbulence in star formation at the hub of the giant molecular cloud G148.24+00.41; Rawat, V., Samal, M. R., Eswaraiah, C., including Dutta S., et al., Monthly Notices of the Royal Astronomical Society, 528, 1460 (2024)
5. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Discovery of an Extremely Dense and Compact Object Embedded in the Prestellar Core G208.68-19.92-N2; Hirano, N., Sahu, D., Liu, S.-Y., including Dutta S., et al., The Astrophysical Journal, 961, 123 (2024)
6. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): The Warm-envelope Origin of Hot Corinos; Hsu, S.-Y., Liu, S.-Y., Johnstone, D., including Dutta S., et al., The Astrophysical Journal, 956, 120 (2023)
7. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): A Forming Quadruple System with Continuum "Ribbons" and Intricate Outflows; Luo, Q.-. yi ., Liu, T., Lee, A. T., including Dutta S., et al., The Astrophysical Journal, 952, L2 (2023)
8. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Density Structure of Centrally Concentrated Prestellar Cores from Multiscale Observations; Sahu, D., Liu, S.-Y., Johnstone, D., including Dutta S., et al., The Astrophysical Journal, 945, 156 (2023)
9. A Q-band Line Survey toward Orion KL Using the Tianma Radio Telescope; Liu, X., Liu, T., Shen, Z., including Dutta S., et al., The Astrophysical Journal Supplement Series, 263, 13 (2022)
10. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Evidence for a Molecular Jet Launched at an Unprecedented Early Phase of Protostellar Evolution; Dutta S., Lee, C.-F., Hirano, N., et al., The Astrophysical Journal, 931, 130 (2022)
11. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): How Do Dense Core Properties Affect the Multiplicity of Protostars?; Luo, Q.-. yi ., Liu, T., Tatematsu, K., including Dutta S., et al., The Astrophysical Journal, 931, 158 (2022)
12. Nobeyama Survey of Inward Motions toward Cores in Orion Identified by SCUBA-2; Tatematsu, K., Yeh, Y.-T., Hirano, N., including Dutta S., et al., The Astrophysical Journal, 931, 33 (2022)
13. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Deriving Inclination Angle and Velocity of the Protostellar Jets from Their SiO Knots; Jhan, K.-S., Lee, C.-F., Johnstone, D., including Dutta S., et al., The Astrophysical Journal, 931, L5 (2022)
14. ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions - VIII. A search for hot cores by using C<SUB>2</SUB>H<SUB>5</SUB>CN, CH<SUB>3</SUB>OCHO, and CH<SUB>3</SUB>OH lines; Qin, S.-L., Liu, T., Liu, X., including Dutta S., et al., Monthly Notices of the Royal Astronomical Society, 511, 3463 (2022)
15. ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions - V. Hierarchical fragmentation and gas dynamics in IRDC G034.43+00.24; Liu, H.-L., Tej, A., Liu, T., including Dutta S., et al., Monthly Notices of the Royal Astronomical Society, 510, 5009 (2022)
16. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): A Hot Corino Survey toward Protostellar Cores in the Orion Cloud; Hsu, S.-Y., Liu, S.-Y., Liu, T., including Dutta S., et al., The Astrophysical Journal, 927, 218 (2022)
17. A Comprehensive Study of the Young Cluster IRAS 05100+3723: Properties, Surrounding Interstellar Matter, and Associated Star Formation; Yadav, R. K., Samal, M. R., Semenko, E., including Dutta S., et al., The Astrophysical Journal, 926, 16 (2022)
18. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Detection of a Dense SiO Jet in the Evolved Protostellar Phase; Dutta S., Lee, C.-F., Johnstone, D., et al., The Astrophysical Journal, 925, 11 (2022)
19. The JCMT Transient Survey: Four-year Summary of Monitoring the Submillimeter Variability of Protostars; Lee, Y.-H., Johnstone, D., Lee, J.-E., including Dutta S., et al., The Astrophysical Journal, 920, 119 (2021)
20. Planck Galactic Cold Clumps at High Galactic Latitude-a Study with CO Lines; Xu, F., Wu, Y., Liu, T., including Dutta S., et al., The Astrophysical Journal, 920, 103 (2021)
21. Molecular Cloud Cores with High Deuterium Fractions: Nobeyama Mapping Survey; Tatematsu, K., Kim, G., Liu, T., including Dutta S., et al., The Astrophysical Journal Supplement Series, 256, 25 (2021)
22. Spectroscopic and Photometric Monitoring of a Poorly Known Highly Luminous OH/IR Star: IRAS 18278+0931; Ghosh, S., Mondal, S., Das, R., & Dutta S., The Astronomical Journal, 161, 198 (2021)
23. Sustaining Star Formation in the Galactic Star Cluster M 36?; Panja, A., Chen, W. P., Dutta S., et al., The Astrophysical Journal, 910, 80 (2021)
24. Fast photometric variability of very low mass stars in IC 348: detection of superflare in an M dwarf; Ghosh, S., Mondal, S., Dutta S., et al., Monthly Notices of the Royal Astronomical Society, 500, 5106 (2021)
25. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Detection of Extremely High-density Compact Structure of Prestellar Cores and Multiple Substructures Within; Sahu, D., Liu, S.-Y., Liu, T., including Dutta S., et al., The Astrophysical Journal, 907, L15 (2021)
26. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP). II. Survey Overview: A First Look at 1.3 mm Continuum Maps and Molecular Outflows; Dutta S., Lee, C.-F., Liu, T., et al., The Astrophysical Journal Supplement Series, 251, 20 (2020)
27. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP). I. Detection of New Hot Corinos with the ACA; Hsu, S.-Y., Liu, S.-Y., Liu, T., including Dutta S., et al., The Astrophysical Journal, 898, 107 (2020)
28. Census of the Young Stellar Population in the Galactic H II Region Sh2-242; Panja, A., Mondal, S., Dutta S., et al., The Astronomical Journal, 159, 153 (2020)
29. Characterization of pre-main sequence population in HII region Sh2-242; Panja, A., Mondal, S., Dutta S., et al., Bulletin de la Societe Royale des Sciences de Liege, 88, 270 (2019)
30. Rotation rates of pre-main sequence stars: role of circumstellar disk; Dutta S., Mondal, S., Joshi, S., & Das, R., Bulletin de la Societe Royale des Sciences de Liege, 88, 103 (2019)
31. Optical photometric variable stars towards Cygnus OB7; Dutta S., Mondal, S., Joshi, S., & Das, R., Monthly Notices of the Royal Astronomical Society, 487, 1765 (2019)
32. The Planck Cold Clump G108.37-01.06: A Site of Complex Interplay between H II Regions, Young Clusters, and Filaments; Dutta S., Mondal, S., Samal, M. R., & Jose, J., The Astrophysical Journal, 864, 154 (2018)
33. Phase-dependent Photometric and Spectroscopic Characterization of the MASTER-Net Optical Transient J212444.87+321738.3: An Oxygen-rich Mira; Ghosh, S., Mondal, S., Das, R., including Dutta S., et al., The Astronomical Journal, 155, 216 (2018)
34. Optical photometric variable stars towards the Galactic H II region NGC 2282; Dutta S., Mondal, S., Joshi, S., et al., Monthly Notices of the Royal Astronomical Society, 476, 2813 (2018)
35. The young cluster NGC 2282: a multiwavelength perspective; Dutta S., Mondal, S., Jose, J., et al., Monthly Notices of the Royal Astronomical Society, 454, 3597 (2015)

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