Holographic beam mapping of the CHIME pathfinder array

Berger, Philippe; Newburgh, Laura; Amiri, M.; Bandura, Kevin; Cliche, J. F.; Connor, Liam; Deng, Meiling; Denman, Nolan; Dobbs, M.; Fandino, Mateus; Gilbert, A.; Good, Deborah C.; Halpern, M.; Hanna, D.; Hincks, Adam D.; Hinshaw, G.; Höfer, Carolin; Johnson, Andre M.; Landecker, T. L.; Masui, Kiyoshi; Parra, John de la; Oppermann, N.; Pen, Ue-Li; Peterson, Jeffrey B.; Recnik, Andre; Robishaw, Timothy; Shaw, J. Richard; Siegel, Seth R.; Sigurdson, Kris; Smith, Kendrick M.; Storer, Émilie; Tretyakov, Ian; Gassen, Kwinten Van; Vanderlinde, K.; Wiebe, Donald

doi:10.1117/12.2233782

Cited by 27 publications

(10 citation statements)

References 26 publications

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“…Further improvements to the beam model are under active development. In particular, holography observations of both steady sources and pulsars are being used to refine the model of the primary beam (Berger et al 2016).…”

Section: Source Localizationmentioning

confidence: 99%

CHIME/FRB Discovery of Eight New Repeating Fast Radio Burst Sources

Andersen¹,

Bandura²,

Bhardwaj³

et al. 2019

ApJL

365

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We report on the discovery of eight repeating fast radio burst (FRB) sources found using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope. These sources span a dispersion measure (DM) range of 103.5-1281 pc cm −3 . They display varying degrees of activity: six sources were detected twice, another three times, and one 10 times. These eight repeating FRBs likely represent the bright and/or high-rate end of a distribution of infrequently repeating sources. For all sources, we determine sky coordinates with uncertainties of ∼10′. FRB 180916.J0158+65 has a burst-averaged DM=349.2±0.3 pc cm −3 and a low DM excess over the modeled Galactic maximum (as low as ∼20 pc cm −3 ); this source also has a Faraday rotation measure (RM) of −114.6±0.6 rad m −2 , which is much lower than the RM measured for FRB 121102. FRB 181030.J1054+73 has the lowest DM for a repeater, 103.5±0.3 pc cm −3 , with a DM excess of ∼70 pc cm −3 . Both sources are interesting targets for multi-wavelength follow-up due to their apparent proximity. The DM distribution of our repeater sample is statistically indistinguishable from that of the first 12 CHIME/FRB sources that have not yet repeated. We find, with 4σ significance, that repeater bursts are generally wider than those of CHIME/FRB bursts that have not repeated, suggesting different emission mechanisms. Many of our repeater events show complex morphologies that are reminiscent of the first two discovered repeating FRBs. The repetitive behavior of these sources will enable interferometric localizations and subsequent host galaxy identifications.

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Section: Source Localizationmentioning

confidence: 99%

CHIME/FRB Discovery of Eight New Repeating Fast Radio Burst Sources

Andersen¹,

Bandura²,

Bhardwaj³

et al. 2019

ApJL

365

View full text Add to dashboard Cite

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“…For example, Neben et al (2016) and Line et al (2018) use the ORBCOMM satellite to map the antenna response. Holography, a well-known technique in radio astronomy, is also used to study the instrument response (Berger et al 2016). Recently, Virone et al (2014), Pupillo et al (2015), Jacobs et al (2017), and de Lera Acedo et al (2018) have demonstrated that we can make direct measurements of the primary beam using unmanned aerial vehicles; however, they are accompanied by challenges that require further investigation.…”

Section: Introductionmentioning

confidence: 99%

Measuring HERA's Primary Beam in Situ: Methodology and First Results

Nunhokee

Parsons

Kern

et al. 2020

ApJ

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The central challenge in 21 cm cosmology is isolating the cosmological signal from bright foregrounds. Many separation techniques rely on the accurate knowledge of the sky and the instrumental response, including the antenna primary beam. For drift-scan telescopes, such as the Hydrogen Epoch of Reionization Array (HERA), that do not move, primary beam characterization is particularly challenging because standard beam-calibration routines do not apply (Cornwell et al.) and current techniques require accurate source catalogs at the telescope resolution. We present an extension of the method from Pober et al. where they use beam symmetries to create a network of overlapping source tracks that break the degeneracy between source flux density and beam response and allow their simultaneous estimation. We fit the beam response of our instrument using early HERA observations and find that our results agree well with electromagnetic simulations down to a −20 dB level in power relative to peak gain for sources with high signal-to-noise ratio. In addition, we construct a source catalog with 90 sources down to a flux density of 1.4 Jy at 151 MHz.

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“…However, extensive radio surveys of the Milky Way galactic center have not found enough pulsars to conclusively strengthen or invalidate the hypothesis that dark matter implodes neutron stars in that region. Fortuitously, the unprecedented sensitivity of laser interferometer gravitational wave detectors at LIGO/Virgo [8], the broad optical purview of DES [9,10], BlackGEM [11], and other optical telescopes, as well as kilo-channel radio reception at CHIME [12] and HIRAX [13], are better scrutinizing the dynamics of neutron stars and black holes. Indeed, recently a neutron star merger was found both in gravitational waves [14] and follow-on telescope observations [15].…”

Section: Introductionmentioning

confidence: 99%

Searching for dark matter with neutron star mergers and quiet kilonovae

2018

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We identify new astrophysical signatures of dark matter that implodes neutron stars (NSs), which could decisively test whether NS-imploding dark matter is responsible for missing pulsars in the Milky Way galactic center, the source of some r-process elements, and the origin of fast-radio bursts. First, NSimploding dark matter forms ∼10 −10 solar mass or smaller black holes inside neutron stars, which proceed to convert neutron stars into ∼1.5 solar mass black holes (BHs). This decreases the number of neutron star mergers seen by LIGO/Virgo (LV) and associated merger kilonovae seen by telescopes like DES, BlackGEM, and ZTF, instead producing a population of "black mergers" containing ∼1.5 solar mass black holes. Second, dark matter-induced neutron star implosions may create a new kind of kilonovae that lacks a detectable, accompanying gravitational signal, which we call "quiet kilonovae." Using DES data and the Milky Way's r-process abundance, we constrain quiet kilonovae. Third, the spatial distribution of neutron star merger kilonovae and quiet kilonovae in galaxies can be used to detect dark matter. NS-imploding dark matter destroys most neutron stars at the centers of disc galaxies, so that neutron star merger kilonovae would appear mostly in a donut at large radii. We find that as few as ten neutron star merger kilonova events, located to ∼1 kpc precision could validate or exclude dark matter-induced neutron star implosions at 2σ confidence, exploring dark matter-nucleon cross-sections 4-10 orders of magnitude below current direct detection experimental limits. Similarly, NS-imploding dark matter as the source of fast radio bursts can be tested at 2σ confidence once 20 bursts are located in host galaxies by radio arrays like CHIME and HIRAX.

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Holographic beam mapping of the CHIME pathfinder array

Cited by 27 publications

References 26 publications

CHIME/FRB Discovery of Eight New Repeating Fast Radio Burst Sources

CHIME/FRB Discovery of Eight New Repeating Fast Radio Burst Sources

Measuring HERA's Primary Beam in Situ: Methodology and First Results

Searching for dark matter with neutron star mergers and quiet kilonovae

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