A5048288979- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Molecular Spectroscopy and Structure
- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Adaptive optics and wavefront sensing
- Atmospheric Ozone and Climate
- Gamma-ray bursts and supernovae
- Spectroscopy and Laser Applications
- Calibration and Measurement Techniques
- Aerospace Engineering and Energy Systems
- Infrared Target Detection Methodologies
- Planetary Science and Exploration
- Solar and Space Plasma Dynamics
- Advanced Combustion Engine Technologies
- Spacecraft and Cryogenic Technologies
- History and Developments in Astronomy
- Atmospheric aerosols and clouds
- Advanced Chemical Physics Studies
- CCD and CMOS Imaging Sensors
- Ionosphere and magnetosphere dynamics
- Advanced Statistical Methods and Models
Tata Institute of Fundamental Research
2015-2024
Electronics Corporation of India
2014-2021
National Astronomical Observatory of Japan
2004-2005
Institut d'Astrophysique de Paris
1997-2003
Centre National de la Recherche Scientifique
2003
Observatoire des Sciences de l’Univers Terre Homme Environnement Temps Astronomie
1994-1995
Udaipur Solar Observatory
1989-1991
Abstract We present the discovery of a low-density planet orbiting high-metallicity early M-dwarf TOI-5688 A b. This was characterized as part search for transiting giant planets ( R ≳ 8 ⊕ ) through Searching Giant Exoplanets around Stars (GEMS) survey. The discovered with Transiting Exoplanet Survey Satellite, and ground-based transits from Red Buttes Observatory, Table Mountain Observatory Pomona College, radial velocity (RV) measurements Habitable-Zone Planet Finder on 10 m Hobby Eberly...
This paper presents a global analysis of the 2MASS (Two Micron All Sky Survey) data as observed in seven fields at different galactic latitudes our Galaxy. The allow preliminary determination scale parameters, which lead to strong constraints on radial and vertical structure thin thick disc. interpretation star counts colour distributions stars near-infrared with synthetic stellar population model gives evidence that disc density scalelength (hR) is rather short (2.8±0.3 kpc). revisited...
ABSTRACT Filamentary flows towards the centre of molecular clouds have been recognized as a crucial process in formation and evolution stellar clusters. In this paper, we present comprehensive observational study that investigates gas properties kinematics Giant Molecular Cloud G148.24+00.41 using observations CO (1-0) isotopologues. We find cloud is massive (105 M⊙) one most outer Galaxy. identified six likely velocity coherent filaments having length, width, mass range 14–38 pc, 2.5–4.2...
Introduction: Episiotomy is a frequent obstetric intervention during vaginal delivery, necessitating effective repair techniques to minimize complications and enhance recovery. Continuous interrupted suturing are widely used, but their comparative efficacy remains debated. This study evaluates the impact of these on wound healing, pain, complications, patient satisfaction. Method: A prospective was conducted over two years at Saraswathi Institute Medical Sciences, Hapur, involving 200 women...
The hierarchical interplay among gravity, magnetic fields, and turbulent gas flows in delivering the necessary material to form massive protostellar clusters remains enigmatic. We have performed high-resolution (beam size $\sim$14 arcsec $\simeq$ 0.05 pc at a distance 725 pc) 850 $\mu$m dust polarization C$^{18}$O molecular line observations of Cepheus A (Cep A), second closest star-forming region, using 15-meter James Clerk Maxwell Telescope (JCMT) along with SCUBA-2/POL-2 HARP instruments....
We present a comprehensive multiwavelength study of the star-forming region NGC 1893 to explore effects massive stars on low-mass star formation. Using near-infrared colours, slitless spectroscopy and narrow-band Hα photometry in cluster we have identified candidate young stellar objects (YSOs) distributed pattern from one nearby nebulae Sim 129. The V, (V−I) colour–magnitude diagram YSOs indicates that majority these ages between 1 5 Myr. spread may indicate non-coeval formation cluster....
(abridged) We develop a model which describes the coevolution of mass function dense cores and IMF in protocluster clump. In model, injected clump evolve under effect gas accretion. Accretion onto follows time-dependent accretion rate that turbulent medium. Once timescales exceed their contraction timescales, they are turned into stars. include feedback by newly formed massive stars through stellar winds. A fraction wind's energy is assumed to counter gravity disperse from as consequence,...
We investigate the star formation activity in molecular complex associated with Galactic HII region Sh2-90, using radio-continuum maps obtained at 1280 MHz and 610 MHz, Herschel Hi-GAL observations 70 -- 500 microns, deep near-infrared observation JHK bands, along Spitzer observations. Sh2-90 presents a bubble morphology mid-IR (size ~ 0.9 pc x 1.6 pc). Radio suggest it is an evolved electron density 144 cm^-3, emission measure 6.7 10^4 cm^-6 ionized mass 55 Msun. From found that part of...
We report the results of our observations S255IR area with SMA at 1.3 mm in very extended configuration and 0.8 compact as well IRAM-30m mm. The best achieved angular resolution is about 0.4 arcsec. dust continuum emission several tens molecular spectral lines are observed. majority detected only towards S255IR-SMA1 clump, which represents a rotating structure (probably disk) around young massive star. still insufficient for conclusions Keplerian or non-Keplerian character rotation....
The aim of this paper is to present the results photometric investigations central cluster W5 E region as well a follow-up study triggered star formation in and around bright-rimmed clouds (BRCs). We have carried out wide field $UBVI_c$ deep $VI_c$ photometry H{\sc ii} region. A distance $\sim$2.1 kpc mean age $\sim$1.3 Myr been obtained for cluster. young stellar objects (YSOs) associated with are identified on basis near-infrared mid-infrared observations. confirmed our earlier that...
We present a multiwavelength study of the W40 star-forming region using infrared (IR) observations in UKIRT JHK bands, Spitzer Infrared Array Camera and Herschel PACS 2.12 μm H2 narrowband imaging, radio continuum from GMRT (610 1280 MHz), field view (FoV) ∼34' × 40'. Archival conjunction with near-IR are used to identify 1162 Class II/III 40 I sources FoV. The nearest-neighbor stellar surface density analysis shows that majority these young objects (YSOs) constitute embedded cluster...
We present an analysis of multi-wavelength observations from various datasets and Galactic plane surveys to study the star formation process in W42 complex. A bipolar appearance complex is evident due ionizing feedback O5-O6 type a medium that highly inhomogeneous. The VLT/NACO adaptive-optics K L' images (resolutions ~0".2-0".1) resolved this source into multiple point-like sources below ~5000 AU scale. position angle ~15 deg molecular cloud consistent with H-band starlight mean...
ABSTRACT We present a detailed multiwavelength study of observations from X-ray, near-infrared, and centimeter wavelengths to probe the star formation processes in S237 region. Multiwavelength images trace an almost sphere-like shell morphology region, which is filled with 0.5–2 keV X-ray emission. The region contains two distinct environments—a bell-shaped cavity-like structure containing peak 1.4 GHz emission at center, elongated filamentary features without any radio detection edges...
The ISOGAL project is an infrared survey of specific regions sampling the Galactic Plane selected to provide information on structure, stellar populations, mass-loss and recent star formation history inner disk Bulge Galaxy. combines 7 15 μm ISOCAM observations – with a resolution 6″ at worst DENIS IJKs data determine nature sources interstellar extinction. We have observed about 16 square degrees sensitivity approaching 10–20 mJy, detecting ~105 sources, mostly AGB stars, red giants young...
We present a deep JHKs-band imaging survey of the W3 Main star-forming region, using near-infrared camera SIRIUS mounted on University Hawaii 2.2 m telescope. The covers an area ~24 arcmin2 with 10 σ limiting magnitudes ~19.0, 18.1, and 17.3 in J, H, Ks bands, respectively. construct JHK color-color J versus J-H K H-K color-magnitude diagrams to identify young stellar objects estimate their masses. Based these diagrams, rich population is identified that associated region. A large number...
We present subarcsecond (FWHM ~ 07), near-infrared (NIR) JHKs-band images and a high-sensitivity radio continuum image at 1280 MHz, using SIRIUS on the University of Hawaii 88 inch (2.2 m) telescope Giant Metrewave Radio Telescope (GMRT). The NIR survey covers an area ~24 arcmin2 with 10 σ limiting magnitudes ~19.5, 18.4, 17.3 in J, H, Ks bands, respectively. Our are deeper than any JHK surveys to date for larger NGC 7538 star-forming region. construct color-color J - H/J H K/K...
The aim of this paper is to quantitatively testify the "{\it small-scale sequential star formation}" hypothesis in and around bright-rimmed clouds (BRCs). As a continuation recent attempt by Ogura et al. (2007, Paper I), we have carried out $BVI_{c}$ photometry four more BRC aggregates along with deeper re-observations 2 previously observed BRCs. Again quantitative age gradients are found almost all BRCs studied present work. Archival Spitzer/IRAC data also support result. global...
We present results on the star-formation activity of an optically obscured region containing embedded cluster (S255-IR) and molecular gas between two evolved HII regions S255 S257. have studied complex using optical, near-infrared (NIR) imaging, optical spectroscopy radio continnum mapping at 15 GHz, along with Spitzer-IRAC results. It is found that main exciting sources S257 compact associated S255-IR are O9.5 - B3 V nature, consistent previous observations. Our NIR observations reveal 109...
An investigation of the IRAS 16148−5011 region – a cluster at distance 3.6 kpc is presented here, carried out using multiwavelength data in near-infrared (NIR) from 1.4 m Infrared Survey Facility telescope, mid-infrared (MIR) archival Spitzer GLIMPSE (Galactic Legacy Midplane Extraordinaire) survey, far-infrared (FIR) Herschel archive, and low-frequency radio continuum observations 1280 843 MHz Giant Metrewave Radio Telescope Molonglo respectively. A combination NIR MIR used to identify 7...
We have carried out an extensive multi-wavelength study to investigate the star formation process in S235 complex. The complex has a sphere-like shell appearance at wavelengths longer than 2 $\mu$m and harbors O9.5V type approximately its center. Near-infrared extinction map traces eight subregions (having A$_{V}$ $>$ 8 mag), five of them appear be distributed almost regularly spaced manner along surrounding ionized emission. This picture is also supported by integrated $^{12}$CO $^{13}$CO...
Abstract We present an analysis of multiwavelength observations area 0.°27 × around the Galactic H ii region G18.88−0.49, which is powered by O-type star (age ∼ 10 5 yr). The Herschel column density map reveals a shell-like feature extension ∼12 pc 7 and mass ∼2.9 4 M ⊙ region; its existence further confirmed distribution molecular ( 12 CO, 13 C 18 O, NH 3 ) gas at [60, 70] km s −1 . Four subregions are studied toward this show range ∼0.8–10.5 These associated with dense dominated nonthermal...
We study multiwavelength and multiscale data to investigate the kinematics of molecular gas associated with star-forming complexes G045.49+00.04 (G45E) G045.14+00.14 (G45W) in Aquila constellation. An analysis FUGIN $^{13}$CO(1-0) line unveils presence a giant filament (GMF G45.3+0.1; length $\sim$75 pc, mass $\sim$1.1$\times$10$^{6}$ M$_{\odot}$) having coherent velocity structure at [53, 63] km s$^{-1}$. The GMF G45.3+0.1 hosts G45E G45W its opposite ends. find large scale oscillations...
We present a multi-scale and multi-wavelength study to unveil massive star formation (MSF) processes around sites AFGL 5180, 6366S, both hosting Class II 6.7 GHz methanol maser emission. The radio continuum map at 8.46 reveals small cluster of sources toward 5180. Signatures the early stages MSF in our target are spatially seen opposite edges filamentary cloud (length $\sim$5 pc), which is observed sub-millimeter dust maps. Using near-infrared photometric data, spatial distribution young...
ABSTRACT The relative importance of magnetic fields, turbulence, and gravity in the early phases star formation is still not well understood. We report first high-resolution dust polarization observations at 850 $\mu$m around most massive clump, located hub Giant Molecular Cloud G148.24+00.41, using SCUBA-2/POL-2 James Clerk Maxwell Telescope. find that degree decreases steadily towards denser portion cloud. Comparing intensity gradients local with field orientations, we plays a dominant...