The science case for simultaneous mm-wavelength receivers in radio astronomy

Dodson, Richard; Rioja, María J.; Gómez, José L.; Bujarrabal, V.; Moscadelli, L.; Miller-Jones, J. C. A.; Tetarenko, Alexandra J.; Sivakoff, G. R.

doi:10.1016/j.newar.2017.09.003

Cited by 9 publications

(8 citation statements)

References 164 publications

(156 reference statements)

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“…This, combined with the (previously detected) SiO disk rotating perpendicular around the central star, and the existence of a binary system at the heart of the pPNe, provides compelling evidence that the evolutionary model for bipolar PNe is correct. It also underlines the power of simultaneous multi-frequency observations to provide registration between frequencies in mm-VLBI (Dodson et al 2017).…”

Section: Temporal Evolutionmentioning

confidence: 85%

Registration of H₂O and SiO masers in the Calabash Nebula, to confirm the Planetary Nebula paradigm

et al. 2017

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We report on the astrometric registration of VLBI images of the SiO and H 2 O masers in OH 231.8+4.2, the iconic Proto-Planetary Nebula also known as the Calabash nebula, using the KVN and Source/Frequency Phase Referencing. This, for the first time, robustly confirms the alignment of the SiO masers, close to the AGB star, driving the bi-lobe structure with the water masers in the out-flow. We are able to trace the bulk motions for the H 2 O masers over the last few decades to be 19 km s −1 and deduce that the age of this expansion stage is 38±2 years. The combination of this result with the distance allows a full 3D reconstruction, and confirms that the H 2 O masers lie on and expand along the known large-scale symmetry axis and that the outflow is only a few decades old, so mass loss is almost certainly on-going. Therefore we conclude that the SiO emission marks the stellar core of the nebular, the H 2 O emission traces the expansion, and that there must be multiple epochs of ejection to drive the macro-scale structure.

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Section: Temporal Evolutionmentioning

confidence: 85%

Registration of H₂O and SiO masers in the Calabash Nebula, to confirm the Planetary Nebula paradigm

et al. 2017

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“…The resulting decrease in sensitivity limits the overall number of detected data points and reduces the signal-to-noise ratio (S/N) of the data points that are detected, relative to observations at lower frequencies. We note that for the ngEHT, it may be possible to use frequency phase transfer (FPT) techniques (e.g., Rioja & Dodson 2011;Dodson et al 2017;Rioja & Dodson 2020) to bootstrap atmospheric phase solutions from lower-frequency observations up to 345 GHz, thereby substantially extending the coherent integration time and enabling additional detections (e.g., Issaoun et al 2023). However, in this paper we do not simulate observations that take advantage of FPT techniques.…”

Section: Generating Synthetic Ngeht Datamentioning

confidence: 99%

Multifrequency Black Hole Imaging for the Next-generation Event Horizon Telescope

Chael

Issaoun

Pesce

et al. 2023

ApJ

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The Event Horizon Telescope (EHT) has produced images of the plasma flow around the supermassive black holes in Sgr A* and M87* with a resolution comparable to the projected size of their event horizons. Observations with the next-generation Event Horizon Telescope (ngEHT) will have significantly improved Fourier plane coverage and will be conducted at multiple frequency bands (86, 230, and 345 GHz), each with a wide bandwidth. At these frequencies, both Sgr A* and M87* transition from optically thin to optically thick. Resolved spectral index maps in the near-horizon and jet-launching regions of these supermassive black hole sources can constrain properties of the emitting plasma that are degenerate in single-frequency images. In addition, combining information from data obtained at multiple frequencies is a powerful tool for interferometric image reconstruction, since gaps in spatial scales in single-frequency observations can be filled in with information from other frequencies. Here we present a new method of simultaneously reconstructing interferometric images at multiple frequencies along with their spectral index maps. The method is based on existing regularized maximum likelihood (RML) methods commonly used for EHT imaging and is implemented in the eht-imaging Python software library. We show results of this method on simulated ngEHT data sets as well as on real data from the Very Long Baseline Array and Atacama Large Millimeter/submillimeter Array. These examples demonstrate that simultaneous RML multifrequency image reconstruction produces higher-quality and more scientifically useful results than is possible from combining independent image reconstructions at each frequency.

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“…The impact of this multi-band system on spectral line VLBI is significant, as several different maser types in different frequency bands could be observed simultaneously, to obtain images of the emission with bona-fide astrometric registration for the first time; Dodson et al (2017a) provides a compilation of possible scientific applications and the performance impact is estimated in Sect. 7.1.3.…”

Section: Simultaneous Multiple Frequency Systemsmentioning

confidence: 99%

Precise radio astrometry and new developments for the next generation of instruments

Rioja,

Dodson

2020

Preprint

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We present a technique-led review of the progression of precise radio astrometry, from the first demonstrations, half a century ago, until to date and into the future. We cover the developments that have been fundamental to allow high accuracy and precision astrometry to be regularly achieved. We review the opportunities provided by the next-generation of instruments coming online, which are primarily: SKA, ngVLA and pathfinders, along with EHT and other (sub)mm-wavelength arrays, Space-VLBI, Geodetic arrays and optical astrometry from GAIA.From the historical development we predict the future potential astrometric performance, and therefore the instrumental requirements that must be provided to deliver these. The next-generation of methods will allow ultra-precise astrometry to be performed at a much wider range of frequencies (hundreds of MHz to hundreds of GHz). One of the key potentials is that astrometry will become generally applicable, and therefore unbiased large surveys can be performed. The next-generation methods are fundamental in allowing this. We review the small but growing number of major astrometric surveys in the radio, to highlight the scientific impact that such projects can provide.Based on these perspectives, the future of radio astrometry is bright. We foresee a revolution coming from: ultra-high precision radio astrometry, large surveys of many objects, improved sky coverage and at new frequency bands

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The science case for simultaneous mm-wavelength receivers in radio astronomy

Cited by 9 publications

References 164 publications

Registration of H₂O and SiO masers in the Calabash Nebula, to confirm the Planetary Nebula paradigm

Registration of H₂O and SiO masers in the Calabash Nebula, to confirm the Planetary Nebula paradigm

Multifrequency Black Hole Imaging for the Next-generation Event Horizon Telescope

Precise radio astrometry and new developments for the next generation of instruments

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The science case for simultaneous mm-wavelength receivers in radio astronomy

Cited by 9 publications

References 164 publications

Registration of H2O and SiO masers in the Calabash Nebula, to confirm the Planetary Nebula paradigm

Registration of H2O and SiO masers in the Calabash Nebula, to confirm the Planetary Nebula paradigm

Multifrequency Black Hole Imaging for the Next-generation Event Horizon Telescope

Precise radio astrometry and new developments for the next generation of instruments

Contact Info

Product

Resources

About

Registration of H₂O and SiO masers in the Calabash Nebula, to confirm the Planetary Nebula paradigm

Registration of H₂O and SiO masers in the Calabash Nebula, to confirm the Planetary Nebula paradigm