A5040359979- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Molecular Spectroscopy and Structure
- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Spectroscopy and Laser Applications
- Solar and Space Plasma Dynamics
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Advanced Combustion Engine Technologies
- Phase Equilibria and Thermodynamics
- Planetary Science and Exploration
- Ionosphere and magnetosphere dynamics
- Pulsars and Gravitational Waves Research
- Scientific Research and Discoveries
- Geophysics and Gravity Measurements
- Radio Astronomy Observations and Technology
- Geological and Geochemical Analysis
- Advanced Thermodynamic Systems and Engines
- Superconducting and THz Device Technology
- Space Exploration and Technology
Indian Institute of Space Science and Technology
2015-2024
Tata Institute of Fundamental Research
2006-2007
Observatoire astronomique de Strasbourg
2002-2003
Centre National de la Recherche Scientifique
2003
Physical Research Laboratory
1999-2002
Space Telescope Science Institute
2002
ABSTRACT We present ALMA Band-3/7 observations towards ‘the Heart’ of a massive hub-filament system (HFS) SDC335, to investigate its fragmentation and accretion. At resolution ∼0.03 pc, 3 mm continuum emission resolves two dense cores MM1 MM2, with $383(^{\scriptscriptstyle +234}_{\scriptscriptstyle -120})$ M⊙ (10–24 % mass Heart’) $74(^{\scriptscriptstyle +47}_{\scriptscriptstyle -24})$ M⊙, respectively. With down 0.01 0.87 shows further fragments into six condensations multi-transition...
ABSTRACT We present a statistical study of sample 17 hub-filament-system (HFS) clouds high-mass star formation using high-angular resolution (∼1–2 arcsec) ALMA 1.3 and 3 mm continuum data. The includes eight infrared (IR)-dark nine IR-bright types, which correspond to an evolutionary sequence from the IR-dark stage. central massive clumps their associated most cores are observed follow trend increasing mass (M) surface density (Σ) with evolution In addition, mass-segregated cluster young...
The "ATOMS," standing for {\it ALMA Three-millimeter Observations of Massive Star-forming regions}, survey has observed 146 active star forming regions with Band 3, aiming to systematically investigate the spatial distribution various dense gas tracers in a large sample Galactic massive clumps, study roles stellar feedback formation, and characterize filamentary structures inside clumps. In this work, observations, data analysis, example science "ATOMS" are presented, using case G9.62+0.19...
We present a comprehensive study of the gas kinematics associated with density structures at different spatial scales in filamentary infrared dark cloud, G034.43+00.24 (G34). This makes use H13CO+ (1-0) molecular line data from ALMA Three-millimeter Observations Massive Star-forming regions (ATOMS) survey, which has and velocity resolution 0.04 pc 0.2 km/s, respectively. Several tens dendrogram have been extracted position-position-velocity space H13CO+, include 21 small-scale leaves 20...
Abstract Leveraging the high resolution, sensitivity, and wide frequency coverage of Atacama Large Millimeter/submillimeter Array (ALMA), QUARKS survey, standing for “Querying Underlying mechanisms massive star formation with ALMA-Resolved gas Kinematics Structures”, is observing 139 star-forming clumps at ALMA Band 6 ( λ ∼ 1.3 mm). This paper introduces Compact (ACA) 7 m data describing ACA observations reduction. Combining multi-wavelength data, we provide first edition atlas, offering...
We have identified 453 compact dense cores in 3 mm continuum emission maps the ATOMS (ALMA Three-millimeter Observations of Massive Star-forming regions) survey, and compiled three catalogues high-mass star forming cores. One catalogue, referred to as H/UC-HII includes 89 that enshroud hyper/ultra (H/UC) HII regions characterized by associated H40alpha emission. A second pure s-cHMC, 32 candidate Hot Molecular Cores (HMCs) showing rich spectra (N>20lines) complex organic molecules (COMs) but...
Abstract There is growing evidence that high-mass star formation and hub-filament systems (HFS) are intricately linked. The gas kinematics along the filaments forming star(s) in central hub excellent agreement with new generation of global hierarchical models. In this paper, we present an observational investigation a typical HFS cloud, G310.142+0.758 (G310 hereafter), which reveals unambiguous mass inflow from cloud scale via onto protostar(s) at conforming model predictions. Continuum...
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...
Abstract Only a handful of massive starless core candidates have been discovered so far, but none them fully confirmed. Within the MM1 clump in filamentary infrared dark cloud G34.43+0.24 that was covered by Atacama Large Millimeter/submillimeter Array (ALMA) ATOMS survey at Band 3 (∼2″, 6000 au) and ALMA-QUARKS 6 (∼0.″3, 900 au), two prestellar MM1-C E1 with masses 71 20 M ⊙ radii 2100–4400 au were discovered. The cores show no obvious sign star formation activities. In particular, is very...
ABSTRACT Hot cores characterized by rich lines of complex organic molecules are considered as ideal sites for investigating the physical and chemical environments massive star formation. We present a search hot using typical nitrogen- oxygen-bearing (C2H5CN, CH3OCHO, CH3OH), based on ALMA Three-millimeter Observations Massive Star-forming regions (ATOMS). The angular resolutions line sensitivities observations better than 2 arcsec 10 mJy beam−1, respectively. A total 60 identified with 45...
ABSTRACT We present new continuum and molecular line data from the ALMA Three-millimeter Observations of Massive Star-forming regions (ATOMS) survey for two protoclusters, G12.42+0.50 G19.88−0.53. The 3 mm maps reveal seven cores in each globally contracting protoclusters. These satisfy radius–mass relation surface mass density criteria high-mass star formation. Similar to their natal clumps, virial analysis suggests that they are undergoing gravitational collapse ($\rm \alpha _{vir} \lt...
ABSTRACT We present new 3-mm continuum and molecular lines observations from the ATOMS survey towards massive protostellar clump, MM1, located in filamentary infrared dark cloud (IRDC), G034.43+00.24 (G34). The observed are tracers of either dense gas (e.g. HCO+/H13CO+ J= 1–0) or outflows CS 2–1). most complete picture to date seven cores MM1 is revealed by dust emission. These found be gravitationally bound, with virial parameter, αvir < 2. At least four identified a total outflowing...
Whether ionization feedback triggers the formation of massive stars is highly debated. Using ALMA 3 mm observations with a spatial resolution $\sim 0.05$ pc and mass sensitivity 1.1 $\rm M_\odot$ beam$^{-1}$ at 20 K, we investigate star gas flow structures within ionizing feedback-driven structure, clump-scale ($\gtrsim 1500$ M_\odot$) bright-rimmed cloud (BRC) associated IRAS 18290-0924. This BRC bound only if external compression from ionized considered. A small-scale ($\lesssim1$ pc) age...
ABSTRACT Hydrogen radio recombination lines (RRLs) are one of the major diagnostics physical properties H ii regions. We use RRL H40α, He40α, and 3 mm continuum emission to investigate a large sample resolved UC regions identified in ATOMS survey. In total, we identify 94 from H40α emission. The basic parameters for these regions, such as electron density, measure, temperature, ionic abundance ratio (n$_{\rm He^+}$/n$_{\rm H^+}$), line width derived. median density n$_{\rm H^+}$ derived RRLs...
Context. In about 2000, the south pole of Triton experienced an extreme summer solstice that occurs every ∼650 years, when subsolar latitude reached 50°S. Bracketing this epoch, a few occultations probed atmosphere in 1989, 1995, 1997, 2008, and 2017. A recent ground-based stellar occultation observed on 6 October 2022 provides new measurement atmospheric pressure Triton. This is presented here. Aims. The goal to constrain volatile transport models (VTMs) atmosphere. basically vapor...
We report studies of the relationships between total bolometric luminosity ($L_{\rm bol}$ or $L_{\rm TIR}$) and molecular line luminosities $J=1-0$ transitions H$^{13}$CN, H$^{13}$CO$^+$, HCN, HCO$^+$ with data obtained from ACA observations in "ATOMS" survey 146 active Galactic star forming regions. The correlations $L'_{\rm mol}$ four all appear to be approximately linear. Line emission isotopologues shows as large scatters bol}$-$L'_{\rm relations their main emission. log($L_{\rm...
We present a statistical study on the orientation of outflows with respect to large-scale filaments and magnetic fields. Although are widely observed toward Galactic star-forming regions, exact role in star formation is unclear. Studies low-mass regions revealed both preferred random respective filament long-axes, while massive mostly oriented perpendicular host filaments, parallel fields at similar physical scales. Here, we explore sample 11 protoclusters HII more evolved stage compared...
Abstract We present a detailed structural and gas kinematic study of the star-forming complex W5-NW. A cloud–cloud collision scenario unravels with evidence collision-induced star cluster formation. Various signatures such as “complementary distribution” “bridging features” are explored. At colliding region, two clouds have complementary morphologies, where W5-NWb has filamentary key-like shape that fits into U-shaped cavity in W5-NWa behaves like keyhole. The interaction region between is...
Galactic cosmic rays (GCRs) constitute a significant part of the energy budget our Galaxy, and study their accelerators is high importance in modern astrophysics. Their main sources are likely supernova remnants (SNRs). These objects capable to convert mechanical into accelerated charged particles. However, even though reservoir SNRs promising, conversion rate particle 10 20% necessary feed population GCRs. Such an efficiency however not guaranteed. Complementary deserve thus be...
IRAS 17256−3631 is a southern Galactic massive star-forming region located at distance of 2 kpc. In this paper, we present multiwavelength investigation the embedded cluster, H ii region, as well parent cloud. Radio images 325, 610 and 1372 MHz were obtained using Giant Metrewave Telescope, India while near-infrared imaging spectroscopy carried out United Kingdom Infrared Telescope Mt. Abu India. The K-band image reveals presence partially infrared cluster. spectral features brightest star...
Pulsation models are crucial for the interpretation of spectrophotometric and interferometric observations Mira variables. Comparing predicted observed spectra is one way establishing validity such models. In this paper, we focus on published between 1996 1998 by Bessell, Hofmann, Scholz Wood. A few new model added, to improve available phase coverage. We compare synthetic with low resolution optically selected oxygen-rich Miras, over a range optical near-IR wavelengths that encompasses most...
Low radio frequencies are favourable for the identification of emission from non-thermal processes such as synchrotron emission. The massive protostellar jet associated with IRAS 18162-2048 (also known HH80-81 system) has been imaged at low frequencies: 325, 610 and 1300 MHz, using Giant Metrewave Radio Telescope, India. This is first instance detection a frequencies. central region displays an elongated structure characteristic jet. In addition, Herbig-Haro objects HH80, HH81, HH80N, other...
Abstract The supersonic winds produced by massive stars carry a large amount of kinetic power. In numerous scenarios such have been proven to produce shocks in which relativistic particles are accelerated emitting nonthermal (NT) radiation. Here, we report the first detection NT emission from single stellar bubble, G2.4+1.4, associated with WO star. We observed this source upgraded Giant Meterwave Radio Telescope Band 4 (550–850 MHz) and 5 (1050–1450 MHz). present intensity spectral index...
With the aim of understanding role outflows in star formation, we performed a statistical study physical parameters eleven massive protoclusters associated with ultra-compact HII regions. A total 106 outflow lobes are identified these using ALMA CO (3-2), HCN (4-3) and HCO+ line observations. Although position angles do not differ three tracers, tend to detect lower terminal velocity compared CO. The majority our targets young typical dynamical time-scales 10^2-10^4 years, mostly composed...