Asantha Cooray
A5072280155- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Cosmology and Gravitation Theories
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Dark Matter and Cosmic Phenomena
- Adaptive optics and wavefront sensing
- Geophysics and Gravity Measurements
- Superconducting and THz Device Technology
- History and Developments in Astronomy
- Scientific Research and Discoveries
- Calibration and Measurement Techniques
- Vehicle emissions and performance
- CCD and CMOS Imaging Sensors
- Astro and Planetary Science
- Pulsars and Gravitational Waves Research
- Spectroscopy and Laser Applications
- Solar and Space Plasma Dynamics
- Black Holes and Theoretical Physics
- Relativity and Gravitational Theory
University of California, Irvine
2016-2025
University College London
2024
University of Copenhagen
2024
Flatiron Health (United States)
2024
Flatiron Institute
2024
Royal Holloway University of London
2024
University of California, Davis
2022-2024
New York University
2024
Princeton University
2024
Marconi University
2024
(Abridged) We describe here the most ambitious survey currently planned in optical, Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST have unique capability faint time domain. The design is driven four main themes: probing dark energy matter, taking an inventory Solar System, exploring transient optical sky, mapping Milky Way. wide-field ground-based system sited at Cerro Pach\'{o}n northern Chile. telescope 8.4 m...
The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, over approximate redshift (z) range 8--1.5. It will image >250,000 distant galaxies using three separate cameras on Hubble Space Telescope, from mid-ultraviolet near-infrared, and find measure Type Ia supernovae at z>1.5 test their accuracy as standardizable candles for cosmology. Five premier multi-wavelength sky regions are selected, each with...
This paper describes the Hubble Space Telescope imaging data products and reduction procedures for Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). survey is designed to document evolution of galaxies black holes at $z\sim1.5-8$, study Type Ia SNe beyond $z>1.5$. Five premier multi-wavelength sky regions are selected, each with extensive multiwavelength observations. The primary CANDELS consist obtained in Wide Field Camera 3 / infrared channel (WFC3/IR) UVIS channel,...
A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of exciting science opportunities next decade. The Large Synoptic Survey Telescope (LSST) have an effective aperture 6.7 meters and imaging camera field view 9.6 deg^2, be devoted ten-year 20,000 deg^2 south +15 deg. Each pointing imaged 2000 times fifteen second exposures six broad from 0.35 1.1 microns, total point-source depth r~27.5. LSST Science Book describes basic...
The Herschel Multi-tiered Extragalactic Survey (HerMES) is a legacy programme designed to map set of nested fields totalling ∼380 deg2. Fields range in size from 0.01 ∼20 deg2, using the Herschel-Spectral and Photometric Imaging Receiver (SPIRE) (at 250, 350 500 μm) Herschel-Photodetector Array Camera Spectrometer (PACS) 100 160 μm), with an additional wider component 270 deg2 SPIRE alone. These bands cover peak redshifted thermal spectral energy distribution interstellar dust thus capture...
We present the science case, reference design, and project plan for Stage-4 ground-based cosmic microwave background experiment CMB-S4.
We present a UV-to-mid infrared multi-wavelength catalog in the CANDELS/GOODS-S field, combining newly obtained CANDELS HST/WFC3 F105W, F125W, and F160W data with existing public data. The is based on source detection WFC3 band. mosaic includes from deep wide observations as well previous ERS HUDF09 programs. reaches 5$\sigma$ limiting depth (within an aperture of radius 0.17 arcsec) 27.4, 28.2, 29.7 AB for wide, deep, HUDF regions, respectively. contains 34930 sources representative 50%...
We exploit the deep and extended far infrared data sets (at 70, 100 160 um) of Herschel GTO PACS Evolutionary Probe (PEP) Survey, in combination with HERschel Multi tiered Extragalactic Survey (HerMES) at 250, 350 500 um, to derive evolution restframe 35 60 90 total (IR) luminosity functions (LFs) up z~4. detect very strong for IR LF combined a density evolution. In agreement previous findings, increases steeply z~1, then flattens between z~1 z~3 decrease z greater than 3. Galaxies different...
Gravitational lensing is a powerful astrophysical and cosmological probe particularly valuable at submillimeter wavelengths for the study of statistical individual properties dusty starforming galaxies. However identification gravitational lenses often time-intensive, involving sifting large volumes imaging or spectroscopic data to find few candidates. We used early from Herschel Astrophysical Terahertz Large Area Survey demonstrate that wide-area surveys can simply easily detect strong...
Type Ia supernova data have recently become strong enough to enable, for the first time, constraints on time variation of dark energy density and its equation state. Most analyses, however, are using simple two or three-parameter descriptions evolution, since it is well known that allowing more degrees freedom introduces serious degeneracies. Here we present a method produce uncorrelated nearly model-independent band power estimates state as function redshift. We apply compiled data. Our...
A new time-dependent, scale-independent parameter, $\ensuremath{\varpi}$, is employed in a phenomenological model of the deviation from general relativity which Newtonian and longitudinal gravitational potentials slip apart on cosmological scales as dark energy, assumed to be arising theory gravitation, appears dominate Universe. comparison presented between $\ensuremath{\varpi}$ other parametrized post-Friedmannian models literature. The effect cosmic microwave background anisotropy...
We summarize the utility of precise cosmic microwave background (CMB) polarization measurements as probes physics inflation. focus on prospects for using CMB to differentiate various inflationary mechanisms. In particular, a detection primordial B‐mode would demonstrate that inflation occurred at very high energy scale, and inflaton traversed super‐Planckian distance in field space. explain how such or constraint illuminate aspects Planck scale. Moreover, can constrain scale‐dependence...
We present the multiwavelength - ultraviolet to mid-infrared catalog of UKIDSS Ultra-Deep Survey (UDS) field observed as part Cosmic Assembly Near-infrared Deep Extragalactic Legacy (CANDELS). Based on publicly available data, includes: CANDELS data from Hubble Space Telescope (near-infrared WFC3 F125W and F160W visible ACS F606W F814W data), u-band CFHT/Megacam, B, V, Rc, i' z' band Subaru/Suprime-Cam, Y Ks VLT/HAWK-I, J, H K bands (Data Release 8), Spitzer/IRAC (3.6, 4.5 SEDS, 5.8 8.0um...
We use deep Herschel PACS and SPIRE observations in GOODSS, GOODSN COSMOS to estimate the average dust mass (Mdust) of galaxies on a redshift-stellar (Mstar)-SFR grid. study scaling relations between Mdust, Mstar SFR at z<=2.5. No clear evolution Mdust is observed fixed Mstar. find tight correlation likely consequence Schmidt-Kennicutt (S-K) law. The Mstar-Mdust by previous works flattens or sometimes disappears when fixing SFR. Most it derives from combination Mdust-SFR Mstar-SFR...
We study a sample of 61 submillimetre galaxies (SMGs) selected from ground-based surveys, with known spectroscopic redshifts and observed Herschel as part the PACS Evolutionary Probe (PEP) Multi-tiered Extragalactic Survey (HerMES) key programmes. use broad far-infrared wavelength coverage (100-600um) provided by combination SPIRE observations. Using power-law temperature distribution model to derive infrared luminosities dust temperatures, we measure emissivity spectral index for SMGs...
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 CMB-S4—the next-generation ground-based cosmic microwave background (CMB) experiment—is set to significantly advance the sensitivity of CMB measurements and enhance our understanding origin evolution universe. Among science cases pursued with CMB-S4, quest for detecting primordial gravitational waves is a central driver experimental design. This work details development forecasting framework that includes power-spectrum-based semianalytic projection tool, targeted explicitly toward...
We report the identification of an extreme proto-cluster galaxies in early Universe whose core (nicknamed Distant Red Core, DRC) is formed by at least ten dusty star-forming (DSFGs), confirmed to lie $z_{\rm spec} = 4.002$ via detection [CI](1-0), $^{12}$CO(6-5), $^{12}$CO(4-3), $^{12}$CO(2-1) and ${\rm H_2O} (2_{11} - 2_{02})$ emission lines, detected using ALMA ATCA. The spectroscopically-confirmed components are distributed over a 260\, kpc \times 310\, kpc}$ region have collective...
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 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,...
The new capabilities that JWST offers in the near- and mid-infrared (IR) are used to investigate unprecedented detail nature of optical/near-IR faint, mid-IR bright sources, HST-dark galaxies among them. We gather data from CEERS survey EGS, jointly with HST data, analyze spatially resolved optical-to-mid-IR spectral energy distributions (SEDs) estimate both photometric redshifts 2 dimensions stellar populations properties a pixel-by-pixel basis. select 138 F150W-F356W>1.5 mag, F356W<27.5...