News related to my reaserch activity from 2018 and onwords



Converging filaments of G148 GMC @ Herschel
Clouds more massive than about 10^5 Msun are potential sites of massive (10^4 Msun) cluster formation. In a recent work, using various observational metrics, we discuss the cluster formation mechanisms and cluster forming potential of the Giant Molecular Cloud (GMC) G148.24+00.41. Comparing our results with the models of star cluster formation, we conclude that the GMC has the potential to form a star cluster in the mass range ∼ 2000–3000 Msun through dynamical hierarchical collapse and assembly of both gas and stars. For details, see Rawat et al. 2023.
Posted March 09th, 2024

Proper motion vectors of Tr-37 members @ GAIA
In a recent work, using Gaia-DR3 data and machine learning tools, we identified members of Tr-37 young cluster over 7.1 degree^2 area. Doing kinematic analysis, we find that cluster members are expanding at a rate of 1.1 km/s, which is found to be slower compared to the expansion velocity, ~5 km/s, of the molecular gas in the complex. We discussed that this slow expansion of the cluster is likley due to the fact that most of the cluster members are still bound and the cluster is still not significantly dynamically evolved. For details, see Das et al. 2023.
Posted March 3rd, 2023

G208Walma @ ALMA
The first hydrostatic core (FHSC) is the first object to form at the centre of a collapsing prestellar core. Until now, molecular jets have been observed in early Class0 protostars. Using ALMA observation, for the first time, we detect a dense molecular jet in SiO emission from a source that has the characteristics of FHSCs as predicated by theory. We conclude that the source may be the earliest object discovered in the protostellar phase with a molecular jet. For details see Dutta et al. 2022.
Posted May 11, 2022

S228 SFR @ FCRAO,Herschel
In a recent work, using UKDISS, GMRT, and Herschel observations, we find evidences that the formation of a young cluster (and HII region) has occurred at the very end of a long filamentary cloud around 3 Myr ago, likely due to longitudinal collapse of the filament and second generation star formation is currently occuring in a clump at the junction of the HII region and filament. We propose that the star formation in the clump is either induced or being facilitated by the compression of the expanding HII region onto the inflowing filamentary material. For details see Yadav et al. 2021.
Posted November 17th, 2021

Cygnus OB2 CMD @ Subaru
In a recent work, we perform the deepest and widest optical photometry of Cygnus OB2 complex using Subaru 8.0-meter telescope. We detect sources down to ~28 mag and 27 mag in r2 and i2 bands,respectively, which allow us detect young sources down to 0.03 Msun @ 2kpc. For central cluster of the complex, we obtained an age ~5 Myr and a disk fraction ~9%. The disk fraction is on the lower side compared to young clusters of similar age. We propose that this could be due to the external photoevaporation of circumstellar disks by the UV photons of the massive OB stars. For deatails see Gupta et al. 2021.
Posted September 24th, 2021

IMF of young clusters at low-mass end
The shape of the mass distribution during the birth of stars and its potential dependence on the environment are not well known. In a recent work, we did analysis of nine young clusters that are under diverse environmental condition. We find that the log-normal fit can well explain the shape of the intial mass function (IMF) and also find no strong evidence of environment on the shape and the characteristic mass of these clusters. For details see Damian et al. 2021
Posted January 27th, 2021

Star Formation Scaling Laws
Star formation is an inefficient process and various laws have been formulated to understand what controls star formation.  In a recent article, we tested whether the Kennicutt-Schmidt relation can still be applicable to smaller scales or it is the local conditions that prevail and define the star-formation scaling laws. For details see Das et al. 2020.
Posted Septmber 16th, 2020
JCMT
We released CHIMPS2 survey's 12CO emission data of the Galactic Centre, obtained with the James Clerk Maxwell Telescope (JCMT) at an angular resolution of 15 arcsec and a velocity resolution of 1 km/s. We discuss several applications of these data. For details see Eden et al. 2020.
Posted Septmber 16th, 2020
We published a paper on structure and kinematics of PDRs around the compact HII regions S235 A and S235 C using SOFIA, where we discuss the expanding motion of the PDRs into the front molecular layer in both regions. Comparing the various observed line profiles with the spherical expanding models, we suggest that the [OI] line could be a reliable tracer of gas kinematics in PDRs. For details see Kirsanova et al. 2020.
Posted July 30th, 2020
We published a paper investigating the orientation, strength, and role of magnetic fields on the two clumps located at the waist of the bipolar H II region Sh2-201, based on JCMT SCUBA-2/POL-2 observations of 850 μm polarized dust emission. From virial analyses and critical mass ratio estimates, we discuss the stability of the clumps. We also discuss the role of the H II region on B-field morphologies around the clumps and the role of B-field in making bipolar HII region. For details see Eswaraiah et al. 2020.
Posted December 21st, 2019
In a recent work, we use SOFIA upGREAT observations of [C II] emission toward the H II region complex Sh2-235 to  understand the origin of [C II] emission. We found velocity-integrated [C II] intensity is strongly correlated with  WISE 12 μm intensity across the entire complex, indicating that both trace UV radiation fields. Alos found that the 22 μm and radio continuum intensities  are only correlated with [C II] intensity in the ionized hydrogen portion and the correlations between the [C II] and   molecular gas tracers are poor across the region. For details see Anderson et al. 2019.
Posted Septmber 10th, 2019
We present the first release of the data and compact-source catalogue for the JCMT Large Program SCUBA-2 Continuum Observations of Pre-protostellar Evolution (SCOPE). SCOPE consists of 850-um continuum observations of 1235 Planck Galactic Cold Clumps (PGCCs) made with the Submillimetre Common-User Bolometer Array 2 on the James Clerk Maxwell Telescope. These cores will be used to estimate various properties of clouds. For details see Eden et al. 2019.
Posted Feb 26th, 2019
We published a paper, where we tried to understand the origin of young, distributed, low-mass stars in cloud complexes. Using GLIMPSE, MIPS, and WISE survey images and point source catalogues, we proposed that star formation induced in the feedback generated structures such as elephant trunk-like structures (ETLSs) is one of the viable mechanisms for forming such stars. For details see Panwar et al. 2019
Posted Jan 3rd, 2019
Based on optical polarization measurements, we published a paper discussing the magnetic field's structure, strength and its role on star formation of a dark globule. We estimated B-field strength to be ∼56 micro gauss, the ratio of magnetic to turbulent pressure to be ∼3, and the ratio of mass to magnetic flux  to be less than 1, implying dominant role of B-fields in comparison to turbulence and gravity in rendering the cloud support.
Posted Dec 25th, 2018
We published a paper analyzing a Planck cold clump and filaments associated to it using JCMT, CFHT, and Spitzer Observations, and found that the clump is in the final assemble stage a moderately massive (∼ 240 Msun) cluster. Based our analysis, we attributed its formation is most likely due to the longitudinal collapse of the most massive filament of the complex.
Posted Agust 15th, 2018
We published catalog of classical bipolar HII regions of our Galaxy, and based on their morphologies, parental cloud structures, and star formation in their vicinities,  we  proposed that such regions formed in 2D or sheet-like clouds and also proposed a new view of induced star formation in such environments.
Posted Agust 3rd, 2018
We published a paper discovering 48 outflows from YSOs in one the massive star forming complex of our Galaxy using UWISH2 near-infrared survey observations. We found that 90% of the outflows are driven by intermediate-mass Class 0/I protostars thatare accreting from their protoplanetary disc.
Posted May 30th, 2018
We published a paper carrying investigation on 64 Plank cold clumps using CO lines and 850 micron dust continnum observations, and showed that in these clumps the core formation efficiency is around 3% and the mass-size relation of the core follows a power-law with exponent 1.67
Posted May 10th, 2018
We published a paper on the physical conditions and kinematics  of a filamentary cloud by analyzing CO, NH3, and CS line observations taken with ONSALA and IRAM observatories. In this work, we found that the filament is fragmented into several clumps, which we discuss in the context of observed the  gas dynamical coherence  and evidence of longitudinal collapse of the filament.
Posted Feb 20th, 2018
We published a paper analyzing JCMT, SMT, KVN, and NRO data of dust continnum and molecular line observations of a filamentary infrared dark cloud G26. From our analysis, we argued that fragmentation in the G26 filament from cloud scale to clump scale is in agreement with gravitational fragmentation of an isothermal, nonmagnetized, and turbulent supported cylinder.The G26 filament may be formed owing to large-scale compression flows evidenced by the temperature and velocity gradients across its natal cloud.
Posted Jan 10th, 2018
We published a paper on dust properties of Planck cold clumps using Herschel and JCMT observations, and showed that the most appropriate value of dust opacity spectral index for such clumps is ~1.7
Posted on Jan 2nd, 2018