Daniel Jacobs
A5040510580- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Antenna Design and Optimization
- Radio Wave Propagation Studies
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Spacecraft Design and Technology
- Astronomical Observations and Instrumentation
- Superconducting and THz Device Technology
- Particle Accelerators and Free-Electron Lasers
- Electromagnetic Compatibility and Measurements
- Stellar, planetary, and galactic studies
- Spacecraft and Cryogenic Technologies
- Millimeter-Wave Propagation and Modeling
- Scientific Research and Discoveries
- Soil Moisture and Remote Sensing
- History and Developments in Astronomy
- Satellite Communication Systems
- Computational Physics and Python Applications
- Microwave Engineering and Waveguides
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Advanced Wireless Communication Techniques
- Adaptive optics and wavefront sensing
- Photocathodes and Microchannel Plates
Arizona State University
2016-2025
California NanoSystems Institute
2024
University of California, Los Angeles
2024
University of Pennsylvania
2010-2024
Jet Propulsion Laboratory
2022-2024
Swiss Center for Electronics and Microtechnology (Switzerland)
2022-2023
University of California, Berkeley
2023
Albert Einstein College of Medicine
2023
New England Institute of Art
2023
École Polytechnique Fédérale de Lausanne
2022
Astronomical wide-field imaging of interferometric radio data is computationally expensive, especially for the large volumes created by modern non-coplanar many-element arrays. We present a new imager that uses w-stacking algorithm and can make use w-snapshot algorithm. The performance dependences casa's w-projection our are analysed analytical functions derived describe required computing cost both imagers. On from Murchison Widefield Array, we find method to be an order magnitude faster...
The Hydrogen Epoch of Reionization Array (HERA) is a staged experiment to measure 21 cm emission from the primordial intergalactic medium (IGM) throughout cosmic reionization ($z=6-12$), and explore earlier epochs our Cosmic Dawn ($z\sim30$). During these epochs, early stars black holes heated ionized IGM, introducing fluctuations in emission. HERA designed characterize evolution power spectrum constrain timing morphology reionization, properties first galaxies, large-scale structure,...
We are developing the Precision Array for Probing Epoch of Re-ionization (PAPER) to detect 21 cm emission from early universe, when first stars and galaxies were forming. describe overall experiment strategy architecture summarize two PAPER deployments: a four-antenna array in low radio frequency interference (RFI) environment Western Australia an eight-antenna at prototyping site NRAO facilities near Green Bank, WV. From these activities we report on system performance, including primary...
A critical challenge in measuring the power spectrum of 21 cm emission from cosmic reionization is compensating for frequency dependence an interferometer's sampling pattern, which can cause smooth-spectrum foregrounds to appear unsmooth and degrade separation between target signal. In this paper, we present approach foreground removal that explicitly accounts dependence. We apply delay transformation introduced Parsons & Backer each baseline interferometer concentrate within bounds maximum...
In this paper, we report new limits on 21cm emission from cosmic reionization based a 135-day observing campaign with 64-element deployment of the Donald C. Backer Precision Array for Probing Epoch Reionization (PAPER) in South Africa. This work extends presented Parsons et al. (2014) more collecting area, longer period, improved redundancy-based calibration, optimal fringe-rate filtering, and power-spectral analysis using quadratic estimators. The result is $2\sigma$ upper limit...
We present new constraints on the 21cm Epoch of Reionization (EoR) power spectrum derived from 3 months observing with a 32-antenna, dual-polarization deployment Donald C. Backer Precision Array for Probing (PAPER) in South Africa. In this paper, we demonstrate efficacy delay-spectrum approach to avoiding foregrounds, achieving over 8 orders magnitude foreground suppression (in $\textrm{mK}^2$). Combining procedure removing off-diagonal covariances arising instrumental systematics, achieve...
A number of experiments are currently working toward a measurement the 21 cm signal from epoch reionization (EoR). Whether or not these deliver detection cosmological emission, their limited sensitivity will prevent them providing detailed information about astrophysics reionization. In this work, we consider what types measurements be enabled by next generation larger EoR telescopes. To calculate type constraints that possible with such arrays, use simple models for instrument, foreground...
Following the first two annual intensity mapping workshops at Stanford in March 2016 and Johns Hopkins June 2017, we report on recent advances theory, instrumentation observation that were presented these meetings some of opportunities challenges identified looking forward. With preliminary detections CO, [CII], Lya low-redshift 21cm, a host experiments set to go online next few years, field is rapidly progressing all fronts, with great anticipation for flood new exciting results. This...
The Murchison Widefield Array (MWA) has collected hundreds of hours Epoch Reionization (EoR) data and now faces the challenge overcoming foreground systematic contamination to reduce a cosmological measurement. We introduce several novel analysis techniques such as cable reflection calibration, hyper-resolution gridding kernels, diffuse model subtraction, quality control methods. Each change pipeline is tested against two dimensional power spectrum figure merit demonstrate improvement....
We compute the spherically-averaged power spectrum from four seasons of data obtained for Epoch Reionisation (EoR) project observed with Murchison Widefield Array (MWA). measure EoR over $k= 0.07-3.0~h$Mpc$^{-1}$ at redshifts $z=6.5-8.7$. The largest aggregation 110 hours on EoR0 high-band (3,340 observations), yields a lowest measurement (43~mK)$^2$ = 1.8$\times$10$^3$ mK$^2$ $k$=0.14~$h$Mpc$^{-1}$ and $z=6.5$ (2$\sigma$ thermal noise plus sample variance). Using Real-Time System to...
Abstract We report upper limits on the Epoch of Reionization 21 cm power spectrum at redshifts 7.9 and 10.4 with 18 nights data (∼36 hr integration) from Phase I Hydrogen Array (HERA). The show evidence for systematics that can be largely suppressed systematic models down to a dynamic range ∼10 9 respect peak foreground power. This yields 95% confidence limit <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi...
Abstract Recently, the Hydrogen Epoch of Reionization Array (HERA) has produced experiment’s first upper limits on power spectrum 21 cm fluctuations at z ∼ 8 and 10. Here, we use several independent theoretical models to infer constraints intergalactic medium (IGM) galaxies during epoch reionization from these limits. We find that IGM must have been heated above adiabatic-cooling threshold by 8, uncertainties about ionization radio background. Combining HERA with complementary observations...
Abstract We report the most sensitive upper limits to date on 21 cm epoch of reionization power spectrum using 94 nights observing with Phase I Hydrogen Epoch Reionization Array (HERA). Using similar analysis techniques as in previously reported limits, we find at 95% confidence that Δ 2 ( k = 0.34 h Mpc −1 ) ≤ 457 mK z 7.9 and 0.36 3496 10.4, an improvement by a factor 2.1 2.6, respectively. These are mostly consistent thermal noise over wide range after our data quality cuts, despite...
We present new observations with the Precision Array for Probing Epoch of Reionization aim measuring properties foreground emission 21 cm epoch reionization (EoR) experiments at 150 MHz. focus on footprint foregrounds in cosmological Fourier space to understand which modes power spectrum will most likely be compromised by emission. These confirm predictions that can isolated a "wedge"-like region two-dimensional (k⊥, k∥)-space, creating window studies higher k∥ values. also find extends past...
Telescopes aiming to measure 21cm emission from the Epoch of Reionization must toe a careful line, balancing need for raw sensitivity against stringent calibration requirements removing bright foregrounds. It is unclear what optimal design achieving both these goals. Via pedagogical derivation an interferometer's response power spectrum reionization fluctuations, we show that even under optimistic scenarios, first-generation arrays will yield low-SNR detections, and different compact array...
The Murchison Widefield Array (MWA) is a new low-frequency interferometric radio telescope built in Western Australia at one of the locations future Square Kilometre (SKA). We describe automated radio-frequency interference (RFI) detection strategy implemented for MWA, which based on AOFlagger platform, and present 72-231-MHz RFI statistics from 10 observing nights. removes 1.1% data. digital TV (DTV) observed 3% time due to occasional ionospheric or atmospheric propagation. After excision,...
Measurements of 21 cm Epoch Reionization (EoR) structure are subject to systematics originating from both the analysis and observation conditions. Using 2013 data Murchison Widefield Array (MWA), we show importance mitigating sources contamination. A direct comparison between results Beardsley et al. 2016 our updated demonstrates new precision techniques, lowering by a factor 2.8 in power. We then further lower excising observations contaminated ultra-faint RFI, reducing an additional 3.8...
The separation of the faint cosmological background signal from bright astrophysical foregrounds remains one most daunting challenges mapping high-redshift intergalactic medium with redshifted 21 cm line neutral hydrogen. Advances in and modeling diffuse point source have improved subtraction accuracy, but no scheme is perfect. Precisely quantifying errors error correlations due to missubtracted allows for both rigorous analysis power spectrum maximal isolation "EoR window" foreground...
Detection of the cosmological neutral hydrogen signal from Epoch Reionization, and estimation its basic physical parameters, is principal scientific aim many current low-frequency radio telescopes. Here we describe Cosmological HI Power Spectrum Estimator (CHIPS), an algorithm developed implemented with data Murchison Widefield Array (MWA), to compute two-dimensional spherically-averaged power spectrum brightness temperature fluctuations. The motivations for CHIPS are application realistic...
Detection of 21~cm emission HI from the epoch reionization, at redshifts z>6, is limited primarily by foreground emission. We investigate signatures wide-field measurements and an all-sky model using delay spectrum technique that maps to object locations through signal delays between antenna pairs. demonstrate interferometric are inherently sensitive all scales, including largest angular owing nature measurements. These effects generic observations but shapes impact their amplitudes...
We present first results from radio observations with the Murchison Widefield Array seeking to constrain power spectrum of 21 cm brightness temperature fluctuations between redshifts 11.6 and 17.9 (113 75 MHz). 3 h were conducted over two nights significantly different levels ionospheric activity. use these data assess impact systematic errors at low frequency, including ionosphere radio-frequency interference, on a measurement. find that after 1–3 integration presented here, our...
Abstract The compact configuration of Phase II the Murchison Widefield Array (MWA) consists both a redundant subarray and pseudo-random baselines, offering unique opportunities to perform sky-model interferometric calibration. highly hexagonal cores give improved power spectrum sensitivity. In this paper, we present analysis nearly 40 hr data targeting one MWA’s epoch reionization (EoR) fields observed in 2016. We use techniques presented Barry et al. several additional developed for work,...
Abstract This paper presents the design and deployment of Hydrogen Epoch Reionization Array (HERA) phase II system. HERA is designed as a staged experiment targeting 21 cm emission measurements Reionization. First results from I array are published early 2022, system nearing completion. We describe discuss progress on commissioning future upgrades. As designated Square Kilometre pathfinder instrument, we also show number “case studies” that investigate systematics seen while system, which...
We confirm our recent prediction of the "pitchfork" foreground signature in power spectra high-redshift 21 cm measurements where interferometer is sensitive to large-scale structure on all baselines. This due inherent response a wide-field instrument and characterized by enhanced from emission Fourier modes adjacent those considered be most cosmological H i signal. In paper, many signatures simulation that predicted this feature were validated against Murchison Widefield Array (MWA) data,...