A5018395981- Galaxies: Formation, Evolution, Phenomena
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Cosmology and Gravitation Theories
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Superconducting and THz Device Technology
- Adaptive optics and wavefront sensing
- CCD and CMOS Imaging Sensors
- Calibration and Measurement Techniques
- Scientific Research and Discoveries
- Particle physics theoretical and experimental studies
- Advanced Vision and Imaging
- Spectroscopy and Laser Applications
- Energy, Environment, and Transportation Policies
- Laser-Matter Interactions and Applications
- Radio Wave Propagation Studies
- Infrastructure Maintenance and Monitoring
- Advanced Battery Technologies Research
- Electric Vehicles and Infrastructure
University of Oslo
2019-2022
University of Groningen
2015-2019
Astronomy and Space
2017
Instituto Politécnico de Lisboa
2010-2015
University of Lisbon
2011-2015
University of the Western Cape
2015
University of California, Irvine
2013-2015
Instituto Superior Técnico
2010-2011
ABSTRACT A new upper limit on the 21 cm signal power spectrum at a redshift of z ≈ 9.1 is presented, based 141 h data obtained with Low-Frequency Array (LOFAR). The analysis includes significant improvements in spectrally smooth gain-calibration, Gaussian Process Regression (GPR) foreground mitigation and optimally weighted inference. Previously seen ‘excess power’ due to spectral structure gain solutions has markedly reduced but some excess still remains correlation distinct from thermal...
The atomic C ii fine-structure line is one of the brightest lines in a typical star-forming galaxy spectrum with luminosity ∼0.1%–1% bolometric luminosity. It potentially reliable tracer dense gas distribution at high redshifts and could provide an additional probe to era reionization. By taking into account spontaneous, stimulated, collisional emission line, we calculate spin temperature mean intensity as function redshift. When averaged over cosmologically large volume, find that from...
While limited to low spatial resolution, the next generation low-frequency radio interferometers that target 21 cm observations during era of reionization and prior will have instantaneous fields-of-view are many tens square degrees on sky. Predictions related various statistical measurements brightness temperature must then be pursued with numerical simulations correspondingly large volume box sizes, order 1000 Mpc one side. We pursue a semi-numerical scheme simulate signal Reionization by...
We produce simulations of the atomic C ii line emission in large sky fields order to determine current and future prospects for mapping this during high-redshift epoch reionization. calculate intensity, redshift evolution, spatial fluctuations using observational relations between galaxy star formation rate over frequency range 200–300 GHz. estimate an averaged intensity . Observations will suffer contamination from lines at lower redshifts, particular CO rotational lines. Using simulations,...
ABSTRACT Observations of the redshifted 21-cm hyperfine line neutral hydrogen from early phases Universe such as Cosmic Dawn and Epoch Reionization promise to open a new window onto formation stars galaxies. We present first upper limits on power spectrum brightness temperature fluctuations in redshift range z = 19.8–25.2 (54–68 MHz frequency range) using 14 h data obtained with LOFAR-Low Band Antenna (LBA) array. also demonstrate application multiple pointing calibration technique calibrate...
ABSTRACT We derive constraints on the thermal and ionization states of intergalactic medium (IGM) at redshift ≈ 9.1 using new upper limits 21-cm power spectrum measured by LOFAR radio telescope a prior ionized fraction that estimated from recent cosmic microwave background (CMB) observations. have used results reionization simulation code grizzly Bayesian inference framework to constrain parameters which describe physical state IGM. find that, if gas heating remains negligible, an IGM with...
Abstract The CO Mapping Array Project (COMAP) aims to use line-intensity mapping of carbon monoxide (CO) trace the distribution and global properties galaxies over cosmic time, back Epoch Reionization (EoR). To validate technologies techniques needed for this goal, a Pathfinder instrument has been constructed fielded. Sensitive CO(1–0) emission from z = 2.4–3.4 fainter contribution CO(2–1) at 6–8, is surveying 12 deg 2 in 5 yr observing campaign detect signal ∼ 3. Using data first 13 months...
We calculate the absolute intensity and anisotropies of Lyα radiation field present during epoch reionization. consider emission from both galaxies intergalactic medium (IGM) take into account main contributions to production photons: recombinations, collisions, continuum galaxies, scattering Lyn photons in IGM. find that individual dominates over IGM with a total (times frequency) about (1.43–3.57) × 10−8 erg s−1 cm−2 sr−1 at redshift 7. This level is low, so it unlikely background...
We present a systematic study of the intensity mapping technique using updated models for different emission lines from galaxies and identify which ones are more promising cosmological studies post reionization epoch. consider ${\rm Ly\alpha}$, H\alpha}$, H$\beta$, optical infrared oxygen lines, nitrogen CII CO rotational lines. then that OII, lowest best candidates to be used as IM probes. These form complementary set probes spectra. use reasonable experimental setups current, planned or...
Abstract We present the current state of models for z ∼ 3 carbon monoxide (CO) line intensity signal targeted by CO Mapping Array Project (COMAP) Pathfinder in context its early science results. Our fiducial model, relating dark matter halo properties to luminosities, informs parameter priors with empirical galaxy–halo connection and previous (1–0) observations. The data spanning wavenumbers k = 0.051–0.62 Mpc −1 represent first direct 3D constraint on clustering component power spectrum....
We propose observations of the molecular gas distribution during era reionization. At $z \sim $ 6 to 8, $^{12}$CO$(J=1-0)$ line intensity results in a mean brightness temperature about 0.5 $\mu$K with rms fluctuations 0.1 at 1 10 Mpc spatial scales, corresponding 30 arcminute angular scales. This can be mapped an interferometer, similar existing and planned 21-cm background experiments, but operating $\sim$ 12 17 GHz. discuss feasibility detecting cross-correlation between HI CO since such...
Abstract Intensity mapping provides a unique means to probe the epoch of reionization (EoR), when neutral intergalactic medium was ionized by energetic photons emitted from first galaxies. The [C ii ] 158 μ m fine-structure line is typically one brightest emission lines star-forming galaxies and thus promising tracer global EoR star formation activity. However, intensity maps at 6 ≲ z 8 are contaminated interloping CO rotational (3 ≤ J upp 6) lower-redshift Here we present strategy remove...
Abstract This paper discusses the science case for a sensitive spectro-polarimetric survey of microwave sky. Such would provide tomographic and dynamic census three-dimensional distribution hot gas, velocity flows, early metals, dust, mass in entire Hubble volume, exploit CMB temperature polarisation anisotropies down to fundamental limits, track energy injection absorption into radiation background across cosmic times by measuring spectral distortions blackbody emission. In addition its...
We introduce COMAP-EoR, the next generation of Carbon Monoxide Mapping Array Project aimed at extending CO intensity mapping to Epoch Reionization. COMAP-EoR supplements existing 30 GHz COMAP Pathfinder with two additional instruments and a new 16 receiver. This combination frequencies will be able simultaneously map CO(1--0) CO(2--1) reionization redshifts ($z\sim5-8$) in addition providing significant boost $z\sim3$ sensitivity Pathfinder. examine set models EoR signal, find power spectra...
Abstract Intensity mapping is becoming a useful tool to study the large-scale structure of universe through spatial variations in integrated emission from galaxies and intergalactic medium. We intensity <?CDATA ${\rm{H}}\alpha \,6563\,\mathring{\rm A} $?> , [O iii ] 5007 Å, ii 3727 ${\rm{H}}\beta \,4861\,\mathring{\rm lines at $0.8\leqslant z\leqslant 5.2$?> . The mean intensities these four are estimated using observed luminosity functions (LFs), cosmological simulations, star formation...
Line-Intensity Mapping is an emerging technique which promises new insights into the evolution of Universe, from star formation at low redshifts to epoch reionization and cosmic dawn. It measures integrated emission atomic molecular spectral lines galaxies intergalactic medium over a broad range frequencies, using instruments with aperture requirements that are greatly relaxed relative surveys for single objects. A coordinated, comprehensive, multi-line intensity-mapping experimental effort...
Line-intensity mapping observations will find fluctuations of integrated line emission are attenuated by varying degrees at small scales due to the width profiles. This attenuation may significantly impact estimates astrophysical or cosmological quantities derived from measurements. We consider a theoretical treatment effect broadening on both clustering and shot-noise components power spectrum generic line-intensity using halo model. then possible simplifications allow easier application in...
This paper discusses the science case for a sensitive spectro-polarimetric survey of microwave sky. Such would provide tomographic and dynamic census three-dimensional distribution hot gas, velocity flows, early metals, dust, mass in entire Hubble volume, exploit CMB temperature polarisation anisotropies down to fundamental limits, track energy injection absorption into radiation background across cosmic times by measuring spectral distortions blackbody emission. In addition its exceptional...
The large-scale structure of the Universe can be mapped with unresolved intensity fluctuations 21 cm line. power spectrum has been proposed as a probe baryon acoustic oscillations at low to moderate redshifts interferometric experiments now under consideration. We discuss contamination low-redshift generated by 18 OH line since slightly higher redshift contribute observed in an experiment. assume megamaser luminosity is correlated star formation rate, and use simulation estimate signal...
Cosmic Dawn Intensity Mapper is a "Probe Class" mission concept for reionization studies of the universe. It will be capable spectroscopic imaging observations between 0.7 to 6-7 microns in near-Infrared. The primary observational objective pioneering spectral emission lines interest throughout cosmic history, but especially from first generation distant, faint galaxies when universe was less than 800 million years old. With spectro-imaging capabilities, using set linear variable filters...
The Cosmic Dawn Intensity Mapper (CDIM) will transform our understanding of the era reionization when Universe formed first stars and galaxies, UV photons ionized neutral medium. CDIM goes beyond capabilities upcoming facilities by carrying out wide area spectro-imaging surveys, providing redshifts galaxies quasars during as well spectral lines that carry crucial information on their physical properties. make use unprecedented sensitivity to surface brightness measure intensity fluctuations...
Observations of anisotropies in the brightness temperature 21 cm line neutral hydrogen from period before reionization would shed light on dawn first stars and galaxies. In this paper, we use large-scale semi-numerical simulations to analyse imprint signal spatial fluctuations Lyman-α flux arising clustering We show that an experiment such as Square Kilometer Array (SKA) can probe at onset reionization, giving us important information about UV emission spectra characterizing their host...
We produce simulations of emission the atomic CII line in large sky fields order to determine current prospects for mapping this during high redshift Epoch Reionization. estimate intensity, evolution and spatial fluctuations using observational relations between SFR a galaxy frequency range 200 GHz 300 GHz. obtained averaged intensity ${\rm I_{\rm CII}=(4 \pm 2)\times10^{2}\, Jy\, \rm sr^{-1}}$ $z\, \sim\, 5.3\, -\, 8.5$. Observations will suffer contamination from lines at lower redshifts,...
Abstract This paper outlines the science case for line-intensity mapping with a space-borne instrument targeting sub-millimeter (microwaves) to far-infrared (FIR) wavelength range. Our goal is observe and characterize large-scale structure in Universe from present times high redshift Epoch of Reionization. essential constrain cosmology our form better understanding various mechanisms that drive galaxy formation evolution. The proposed frequency range would make it possible probe important...