Debosmita Pathak
A5010949900- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Spectroscopy and Laser Applications
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Computational Physics and Python Applications
- Scientific Research and Discoveries
- Astronomical Observations and Instrumentation
- Biofield Effects and Biophysics
- Electromagnetic Fields and Biological Effects
- Cosmology and Gravitation Theories
- Phase Equilibria and Thermodynamics
- Magnetic and Electromagnetic Effects
The Ohio State University
2023-2024
Grinnell College
2021
Abstract The exquisite angular resolution and sensitivity of JWST are opening a new window for our understanding the Universe. In nearby galaxies, observations revolutionizing first phases star formation dusty interstellar medium. Nineteen local galaxies spanning range properties morphologies across star-forming main sequence have been observed as part PHANGS-JWST Cycle 1 Treasury program at spatial scales ∼5–50 pc. Here, we describe pjpipe , an image-processing pipeline developed that wraps...
The molecular-to-atomic gas ratio is crucial to our understanding of the evolution interstellar medium (ISM) in galaxies. We investigated balance between atomic (Σ HI ) and molecular H2 surface densities eight nearby star-forming galaxies using new high-quality observations from MeerKAT ALMA (for H I CO, respectively). defined as R mol = Σ /Σ measured how depends on local conditions galaxy disks multiwavelength observations. find that, depending galaxy, detected at > 3 σ out 20 − 120 kpc...
Abstract Polycyclic aromatic hydrocarbons (PAHs) are a ubiquitous component of the interstellar medium (ISM) in z ∼ 0 massive, star-forming galaxies and play key roles ISM energy balance, chemistry, shielding. Wide field-of-view, high-resolution mid-infrared (MIR) images from JWST provide ability to map fraction dust form PAHs properties these grains at 10–50 pc resolution outside Local Group. We use MIR photometric observations sample 19 nearby Physics High Angular Resolution Nearby...
Abstract The structure and chemistry of the dusty interstellar medium (ISM) are shaped by complex processes that depend on local radiation field, gas composition, dust grain properties. Of particular importance polycyclic aromatic hydrocarbons (PAHs), which emit strong vibrational bands in mid-infrared, play a key role ISM energy balance. We recently identified global correlations between PAH band optical line ratios across three nearby galaxies, suggesting connection heating ionization...
Abstract We present a comparison of observed polycyclic aromatic hydrocarbon (PAH) feature ratios in 19 nearby galaxies with grid theoretical expectations for near- and mid-infrared dust emission. The PAH are drawn from Cycle 1 JWST observations measured 7224 stellar clusters 29,176 associations which we have robust ages mass estimates Hubble Space Telescope five-band photometry. Though there galaxy-to-galaxy variations, the largely agree models, particularly those that skewed toward more...
Abstract Combining Atacama Large Millimeter/submillimeter Array CO(2–1) mapping and JWST near- mid-infrared imaging, we characterize the relationship between polycyclic aromatic hydrocarbon (PAH) emission at ≈100 pc resolution in 70 nearby star-forming galaxies. Leveraging a new Cycle 2 Treasury program targeting galaxies, expand sample size by more than an order of magnitude compared to previous CO–PAH comparisons. In regions galaxies where most gas is likely be molecular, find strong...
Abstract The PHANGS survey uses Atacama Large Millimeter/submillimeter Array, Hubble Space Telescope, Very and JWST to obtain an unprecedented high-resolution view of nearby galaxies, covering millions spatially independent regions. high dimensionality such a diverse multiwavelength data set makes it challenging identify new trends, particularly when they connect observables from different wavelengths. Here, we use unsupervised machine-learning algorithms mine this information-rich novel...
Abstract High-resolution JWST-MIRI images of nearby spiral galaxies reveal emission with complex substructures that trace dust heated both by massive young stars and the diffuse interstellar radiation field. We present high angular (0.″85) physical resolution (20–80 pc) measurements probability distribution function (PDF) mid-infrared (mid-IR) (7.7–21 μ m) from 19 star-forming PHANGS-JWST Cycle 1 Treasury. The PDFs mid-IR disks all consistently show two distinct components: an approximately...
We present a comparison of observed polycyclic aromatic hydrocarbon (PAH) feature ratios in 19 nearby galaxies with grid theoretical expectations for near- and mid-infrared dust emission. The PAH are drawn from Cycle 1 JWST observations measured 7224 stellar clusters 29176 associations which we have robust ages mass estimates HST five-band photometry. Though there galaxy-to-galaxy variations, the largely agree models, particularly those that skewed toward more ionized larger size...
Radiation pressure is a key mechanism by which stellar feedback disrupts molecular clouds and drives HII region expansion. This includes direct radiation exerted UV photons on dust grains, associated with photoionization, infrared (IR) grains due to dust-reprocessed IR photons. We present new method that combines high resolution mid-IR luminosities from JWST-MIRI, optical attenuation nebular line measurements VLT-MUSE, HST H$\alpha$-based sizes estimate the strength of in $\approx 18,000$...
Abstract Radiation pressure is a key mechanism by which stellar feedback disrupts molecular clouds and drives H ii region expansion. This includes direct radiation exerted UV photons on dust grains, associated with photoionization, infrared (IR) grains due to dust-reprocessed IR photons. We present new method that combines high-resolution mid-IR luminosities from JWST-MIRI, optical attenuation, nebular line measurements the Very Large Telecope Multi-Unit Spectroscopic Explorer (VLT-MUSE),...
Abstract Using the IllustrisTNG cosmological galaxy formation simulations, we analyze physical properties of young quiescent galaxies at z = 2 with stellar masses above 10 10.5 M ⊙ . This key population provides an unaltered probe into evolution from star-forming to quiescent, and has been recently targeted by several observational studies. Young in simulations do not appear unusually compact, tension observations, but they show unique age profiles that are qualitatively consistent observed...
Abstract We present a statistical analysis of the local, ≈50–100 pc scale, H α emission at locations recent (≤125 yr) supernovae (SNe) in nearby star-forming galaxies. Our sample consists 32 SNe 10 galaxies that are targets PHANGS-MUSE survey. find 41% (13/32) these occur coincident with previously identified ii region. For comparison, regions cover 32% area within ±1 kpc any SN. Contrasting this local covering fraction regions, we excess 7.6% ± 8.7% all to be associated regions. This...
The exquisite angular resolution and sensitivity of JWST is opening a new window for our understanding the Universe. In nearby galaxies, observations are revolutionizing first phases star formation dusty interstellar medium. Nineteen local galaxies spanning range properties morphologies across star-forming main sequence have been observed as part PHANGS-JWST Cycle 1 Treasury program at spatial scales $\sim$5-50pc. Here, we describe pjpipe, an image processing pipeline developed that wraps...
The PHANGS survey uses ALMA, HST, VLT, and JWST to obtain an unprecedented high-resolution view of nearby galaxies, covering millions spatially independent regions. high dimensionality such a diverse multi-wavelength dataset makes it challenging identify new trends, particularly when they connect observables from different wavelengths. Here we use unsupervised machine learning algorithms mine this information-rich novel patterns. We focus on three the PHANGS-JWST for which extract properties...
We present a statistical analysis of the local, approximately 50-100 pc scale, H-alpha emission at locations recent (less than 125 years) supernovae (SNe) in nearby star-forming galaxies. Our sample consists 32 SNe 10 galaxies that are targets PHANGS-MUSE survey. find 41% (13/32) these occur coincident with previously identified HII region. For comparison, regions cover 32% area within 1 kpc any SN. Contrasting this local covering fraction regions, we excess 7.6% +/- 8.7% all to be...
Polycyclic aromatic hydrocarbons (PAHs) are a ubiquitous component of the interstellar medium (ISM) in z~0 massive, star-forming galaxies and play key roles ISM energy balance, chemistry, shielding. Wide field view, high resolution mid-infrared (MIR) images from JWST provides ability to map fraction dust form PAHs properties these grains at 10-50 pc outside Local Group. We use MIR photometric observations sample 19 nearby "Physics High Angular Resolution Nearby GalaxieS" (PHANGS) survey...
The molecular-to-atomic gas ratio is crucial to the evolution of interstellar medium in galaxies. We investigate balance between atomic ($\Sigma_{\rm HI}$) and molecular H2}$) surface densities eight nearby star-forming galaxies using new high-quality observations from MeerKAT ALMA (for HI CO, respectively). define as $R_{\rm mol} = \Sigma_{\rm H2} / HI}$ measure how it depends on local conditions galaxy disks multi-wavelength observations. find that, depending galaxy, detected at $>3\sigma$...
Combining Atacama Large Millimeter/sub-millimeter Array CO(2-1) mapping and JWST near- mid-infrared imaging, we characterize the relationship between polycyclic aromatic hydrocarbon (PAH) emission at ~100 pc resolution in 66 nearby star-forming galaxies, expanding sample size from previous studies by more than an order of magnitude. Focusing on regions galaxies where most gas is likely to be molecular, find strong correlations 3.3 micron, 7.7 11.3 micron PAH emission, estimated JWST's F335M,...
The structure and chemistry of the dusty interstellar medium (ISM) are shaped by complex processes that depend on local radiation field, gas composition, dust grain properties. Of particular importance Polycyclic Aromatic Hydrocarbons (PAHs), which emit strong vibrational bands in mid-infrared, play a key role ISM energy balance. We recently identified global correlations between PAH band optical line ratios across three nearby galaxies, suggesting connection heating ionization throughout...
High-resolution JWST-MIRI images of nearby spiral galaxies reveal emission with complex substructures that trace dust heated both by massive young stars and the diffuse interstellar radiation field. We present high angular (0."85) physical resolution (20-80 pc) measurements probability distribution function (PDF) mid-infrared (mid-IR) (7.7-21 $\mu$m) from 19 star-forming PHANGS-JWST Cycle-1 Treasury. The PDFs mid-IR disks all consistently show two distinct components: an approximately...