Rachana Bhatawdekar
A5044244886- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Adaptive optics and wavefront sensing
- Cosmology and Gravitation Theories
- Astronomical Observations and Instrumentation
- Radio Astronomy Observations and Technology
- CCD and CMOS Imaging Sensors
- Spectroscopy and Laser Applications
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Scientific Research and Discoveries
- Particle physics theoretical and experimental studies
- Geophysics and Gravity Measurements
- Superconducting and THz Device Technology
- Photocathodes and Microchannel Plates
- Particle Accelerators and Free-Electron Lasers
- Electron and X-Ray Spectroscopy Techniques
- Calibration and Measurement Techniques
- Atmospheric and Environmental Gas Dynamics
- Radiation Therapy and Dosimetry
- Photoreceptor and optogenetics research
European Space Astronomy Centre
2023-2025
European Space Research and Technology Centre
2020-2024
European Space Agency
2022-2024
The University of Melbourne
2022
ARC Centre of Excellence for All-sky Astrophysics
2022
University of Nottingham
2018-2021
Abstract We present an investigation into the first 500 Myr of galaxy evolution from Cosmic Evolution Early Release Science (CEERS) survey. CEERS, one 13 JWST ERS programs, targets formation z ∼ 0.5 to >10 using several imaging and spectroscopic modes. make use epoch CEERS NIRCam imaging, spanning 35.5 arcmin 2 , search for candidate galaxies at > 9. Following a detailed data reduction process implementing custom steps produce high-quality reduced images, we perform multiband...
We report the discovery of a candidate galaxy with photo-z z~12 in first epoch JWST Cosmic Evolution Early Release Science (CEERS) Survey. Following conservative selection criteria we identify source robust z_phot = 11.8^+0.3_-0.2 (1-sigma uncertainty) m_F200W=27.3, and >7-sigma detections five filters. The is not detected at lambda < 1.4um deep imaging from both HST JWST, has faint ~3-sigma F150W F160W, which signal Ly-alpha break near red edge filters, implying z~12. This object (Maisie's...
Abstract This paper characterizes the actual science performance of James Webb Space Telescope (JWST), as determined from six month commissioning period. We summarize spacecraft, telescope, instruments, and ground system, with an emphasis on differences pre-launch expectations. Commissioning has made clear that JWST is fully capable achieving discoveries for which it was built. Moreover, almost across board, better than expected; in most cases, will go deeper faster expected. The telescope...
We present JADES JWST/NIRSpec spectroscopy of GN-z11, the most luminous candidate z > 10 Lyman break galaxy in GOODS-North field with M UV = −21.5. derive a redshift 10.603 (lower than previous determinations) based on multiple emission lines our low and medium resolution spectra over 0.7 − 5.3 μm. significantly detect continuum measure blue rest-UV spectral slope β −2.4. Remarkably, we see spatially extended Lyman- α (despite highly neutral intergalactic expected at this early epoch),...
Abstract The Near-Infrared Spectrograph (NIRSpec) is one of the four focal plane instruments on James Webb Space Telescope. In this paper, we summarize in-orbit performance NIRSpec, as derived from data collected during its commissioning campaign and first few months nominal science operations. More specifically, discuss some critical hardware components such two NIRSpec Hawaii-2RG detectors, wheel mechanisms, microshutter array. We also accuracy target acquisition procedures used to...
We give an overview and describe the rationale, methods, first results from NIRCam images of JWST "Prime Extragalactic Areas for Reionization Lensing Science" ("PEARLS") project. PEARLS uses up to eight filters survey several prime extragalactic areas: two fields at North Ecliptic Pole (NEP); seven gravitationally lensing clusters; high redshift proto-clusters; iconic backlit VV 191 galaxy system map its dust attenuation. also includes NIRISS spectra one NEP NIRSpec high-redshift quasars....
Lyman Break Galaxy (LBG) candidates at z>10 are rapidly being identified in JWST/NIRCam observations. Due to the (redshifted) break produced by neutral hydrogen absorption of rest-frame UV photons, these sources expected drop out bluer filters while well detected redder filters. However, here we show that dust-enshrouded star-forming galaxies lower redshifts (z<7) may also mimic near-infrared (near-IR) colors LBGs, representing potential contaminants LBG candidate samples. First, analyze...
We present JWST NIRCam 9-band near-infrared imaging of the luminous $z=10.6$ galaxy GN-z11 from Advanced Deep Extragalactic Survey (JADES) GOODS-N field. find a spectral energy distribution (SED) entirely consistent with expected form high-redshift galaxy: clear blue continuum 1.5 to 4 microns complete dropout in F115W. The core is extremely compact imaging. analyze image two-component model, using point source and S\'{e}rsic profile that fits half-light radius 200 pc an index $n=0.9$....
Abstract JWST has revolutionized the field of extragalactic astronomy with its sensitive and high-resolution infrared view distant Universe. Adding to new legacy observations, we present first NIRCam imaging data release from Advanced Deep Extragalactic Survey (JADES), providing nine filters ∼25 arcmin 2 covering Hubble Ultra Field portions Great Observatories Origins South. Utilizing 87 on-sky dual-filter hours exposure time, these images reveal deepest ever near-infrared this iconic field....
We present rest-frame optical emission-line flux ratio measurements for five $z>5$ galaxies observed by the JWST Near-Infared Spectrograph (NIRSpec) in SMACS 0723 Early Release Observations. add several quality-control and post-processing steps to NIRSpec pipeline reduction products order ensure reliable relative calibration of emission lines that are closely separated wavelength, despite uncertain \textit{absolute} spectrophotometry current version reductions. Compared $z\sim3$ literature,...
ABSTRACT We present an interstellar medium and stellar population analysis of three spectroscopically confirmed z &gt; 7 galaxies in the Early Release Observations JWST/NIRCam JWST/NIRSpec data SMACS J0723.3−7327 cluster. use Bayesian spectral energy distribution-fitting code prospector with a flexible star formation history (SFH), variable dust attenuation law, self-consistent model nebular emission (continuum lines). Importantly, we self-consistently fit both line fluxes from...
We present emission-line ratios from a sample of 27 Lyman-break galaxies z ∼ 5.5 − 9.5 with −17.0 < M 1500 −20.4, measured ultra-deep JWST/NIRSpec multi-object spectroscopy the JWST Advanced Deep Extragalactic Survey (JADES). used combination 28 h deep PRISM/CLEAR and 7 G 395 / F 290 LP observations to measure, or place strong constraints on, widely studied rest-frame optical emission lines including H α , β [O II ] λλ 3726, 3729, [Ne III λ 3869, 4959, 5007, I 6300, [N 6583, [S 6716, 6731...
Abstract We present JWST Extragalactic Medium-band Survey, the first public medium-band imaging survey carried out using JWST/NIRCam and NIRISS. These observations use ∼2 ∼4 μ m filters (NIRCam F182M, F210M, F430M, F460M, F480M; NIRISS F430M F480M in parallel) over 15.6 arcmin 2 Hubble Ultra Deep Field (UDF), thereby building on deepest multiwavelength data sets available anywhere sky. describe our science goals, design, NIRCam image reduction methods, release of science-ready mosaics, which...
We analysed the gas-phase metallicity properties of a sample low-stellar-mass (log M ⋆ / ⊙ ≲ 9) galaxies at 3 < z 10 observed with JWST/NIRSpec as part JADES programme in its deep GOODS-S tier. By combining this more massive similar redshifts from other programmes, we study scaling relations between stellar mass ( ), oxygen abundance (O/H), and star-formation rate (SFR) for 146 spanning three orders magnitude out to epoch early galaxy assembly. find evidence shallower slope low-mass end...
Abstract We present a catalog of 717 candidate galaxies at z > 8 selected from 125 square arcmin NIRCam imaging as part the JWST Advanced Deep Extragalactic Survey (JADES). combine full JADES data set with Medium and First Reionization Epoch Spectroscopic COmplete (FRESCO) along extremely deep existing observations Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) final filter that includes 15 JWST/NIRCam filters five HST/ACS filters. The high-redshift galaxy candidates were...
We present JADES JWST/NIRSpec spectroscopy of GN-z11, the most luminous candidate $z>10$ Lyman break galaxy in GOODS-North field with $M_{UV}=-21.5$. derive a redshift $z=10.603$ (lower than previous determinations) based on multiple emission lines our low and medium resolution spectra over $0.8-5.3 μ$m. significantly detect continuum measure blue rest-UV spectral slope $β=-2.4$. Remarkably, we see spatially-extended Lyman-$α$ (despite highly-neutral IGM expected at this early epoch),...
We present an overview of the James Webb Space Telescope (JWST) Advanced Deep Extragalactic Survey (JADES), ambitious program infrared imaging and spectroscopy in GOODS-S GOODS-N deep fields, designed to study galaxy evolution from high redshift cosmic noon. JADES uses about 770 hours Cycle 1 guaranteed time largely Near-Infrared Camera (NIRCam) Spectrograph (NIRSpec) instrument teams. In GOODS-S, around Hubble Ultra Field Chandra South, produces a region ~45 arcmin$^2$ with average 130 hrs...
Abstract We present an analysis of the ultraviolet luminosity function (UV LF) and star formation rate density distant galaxies (7.5 < z 13.5) in “blank” fields Prime Extragalactic Areas for Reionization Lensing Science (PEARLS) survey combined with Early Release data from CEERS, GLASS, NGDEEP surveys/fields first release JADES. use strict quality cuts on EAZY photometric redshifts to obtain a reliable selection characterization high-redshift ( > 6.5) consistently processed set deep,...
Abstract Using deep JWST imaging from JADES, JEMS, and SMILES, we characterize optically faint extremely red galaxies at z > 3 that were previously missing galaxy census estimates. The data indicate the existence of abundant, dusty, poststarburst-like down to 10 8 M ⊙ , below sensitivity limit Spitzer Atacama Large Millimeter/submillimeter Array (ALMA). Modeling NIRCam Hubble Space Telescope (HST) photometry these sources can result in high values for both stellar mass star formation rate...
We describe the NIRSpec component of JWST Deep Extragalactic Survey (JADES), and provide deep spectroscopy 253 sources targeted with micro-shutter assembly in Hubble Ultra Field surrounding GOODS-South. The multi-object spectra presented here are deepest so far obtained JWST, amounting to up 28 hours low-dispersion ($R 30-300$) prism, 7 each three medium-resolution $R 1000$ gratings one high-dispersion grating, G395H Our medium-dispersion cover wavelength range $0.6-5.3\ selection...
We present the properties of 17 faint Lyman- α emitting galaxies (LAEs) at z > 5.8 from JWST Advanced Deep Extragalactic Survey (JADES) spectroscopic data in Hubble Ultra Field/GOODS-S. These LAEs span a redshift range ≈ − 8.0 and UV magnitude M −17 to −20.6, with Ly equivalent width (EW) ≈25 350 Å. The detection other rest-optical emission lines spectra these enables determination accurate systemic redshifts velocity offsets, as well physical chemical composition their stars interstellar...
ABSTRACT Reionization is thought to be driven by faint star-forming galaxies, but characterizing this population has long remained very challenging. Here, we utilize deep nine-band JADES (JWST Advanced Deep Extragalactic Survey)/NIRCam (Near-Infrared Camera) imaging study the and ionizing properties of 756 $z\sim 6-9$ including hundreds ultraviolet (UV)-faint objects ($M_\mathrm{UV}\gt -18$). The faintest ($m\sim 30$) galaxies in our sample typically have stellar masses $M_\ast \sim...