Constraining the distance to the North Polar Spur with Gaia DR2

Das, Kaustav K.; Zucker, Catherine Faron; Speagle, Joshua S.; Goodman, Alyssa A.; Green, Gregory

doi:10.1093/mnras/staa2702

Cited by 27 publications

(55 citation statements)

References 44 publications

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“…This is a strong indication that at high latitude Loop I, which dominates the polarized synchrotron emission in the area, is located within this range of distances. This conclusion is in agreement with several other determinations of the distance to Loop I (e.g., Salter 1983;Vidal et al 2015;Planck Collaboration et al 2016b;Das et al 2020).…”

Section: Loop Isupporting

confidence: 93%

“…Soon after its discovery, Bingham (1967) found that the electric vector position angles (polarization angles) of a small number (≈10) of stars were aligned with the B-field direction traced by synchrotron polarization, thus suggesting a distance of ∼100 pc to the high-latitude part of Loop I. Subsequent studies of the optical polarization have confirmed this conclusion (Spoelstra 1972;Ellis & Axon 1978;Leroy 1999;Santos et al 2011;Berdyugin et al 2014) and are in agreement with the distance to the neutral gas likely associated with the NPS (Puspitarini & Lallement 2012;Das et al 2020). In apparent contradiction with these determinations, an alternative model has been proposed for Loop I, in which the structure is located at the Galactic center and forms part of a bipolar hyperbubble extending out to the Galactic halo (Sofue 1977(Sofue , 2000.…”

Section: Introductionmentioning

confidence: 69%

“…However, combining these measurements results in much increased scatter per distance bin. This increased scatter may be related to the fact that there seems to be a distance gradient with latitude, as shown by the stellar extinction measurements of Das et al (2020). These authors find that the distance to the dust layer associated with Loop I varies gradually with latitude from 131 ± 7 pc (at b = 32°) to 70 ± 4 pc (at b = 55°).…”

Section: Calculating Upper and Lower Distance Limits For Loops I And Ivmentioning

confidence: 91%

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Revisiting the Distance to Radio Loops I and IV Using Gaia and Radio/Optical Polarization Data

Panopoulou

Dickinson

Readhead

et al. 2021

ApJ

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Galactic synchrotron emission exhibits large angular scale features known as radio spurs and loops. Determining the physical size of these structures is important for understanding the local interstellar structure and for modeling the Galactic magnetic field. However, the distance to these structures is either under debate or entirely unknown. We revisit a classical method of finding the location of radio spurs by comparing optical polarization angles with those of synchrotron emission as a function of distance. We consider three tracers of the magnetic field: stellar polarization, polarized synchrotron radio emission, and polarized thermal dust emission. We employ archival measurements of optical starlight polarization and Gaia distances and construct a new map of polarized synchrotron emission from WMAP and Planck data. We confirm that synchrotron, dust emission, and stellar polarization angles all show a statistically significant alignment at high Galactic latitude. We obtain distance limits to three regions toward Loop I of 112 ± 17 pc, 135 ± 20 pc, and <105 pc. Our results strongly suggest that the polarized synchrotron emission toward the North Polar Spur at b > 30° is local. This is consistent with the conclusions of earlier work based on stellar polarization and extinction, but in stark contrast with the Galactic center origin recently revisited on the basis of X-ray data. We also obtain a distance measurement toward part of Loop IV (180 ± 15 pc) and find evidence that its synchrotron emission arises from chance overlap of structures located at different distances. Future optical polarization surveys will allow the expansion of this analysis to other radio spurs.

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Section: Loop Isupporting

confidence: 93%

Section: Introductionmentioning

confidence: 69%

Section: Calculating Upper and Lower Distance Limits For Loops I And Ivmentioning

confidence: 91%

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Revisiting the Distance to Radio Loops I and IV Using Gaia and Radio/Optical Polarization Data

Panopoulou

Dickinson

Readhead

et al. 2021

ApJ

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“…The top panel of Fig. 12 shows the presence of high-latitude dust within the 500 pc sphere around the Sun, confirming that the so-called North Polar Spur (the dust filament reaching up to b ∼ 45 deg at l ∼ 0 deg) is a local structure and not related to the Fermi bubbles produced by the Galactic centre (see Das et al 2020 for a comprehensive discussion).…”

Section: Extinction Mapsmentioning

confidence: 58%

Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18

Anders

Khalatyan

Chiappini

et al. 2019

A&A

295

312

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Combining the precise parallaxes and optical photometry delivered by Gaia's second data release (Gaia DR2) with the photometric catalogues of Pan-STARRS1, 2MASS, and AllWISE, we derived Bayesian stellar parameters, distances, and extinctions for 265 million of the 285 million objects brighter than G = 18. Because of the wide wavelength range used, our results substantially improve the accuracy and precision of previous extinction and effective temperature estimates. After cleaning our results for both unreliable input and output data, we retain 137 million stars, for which we achieve a median precision of 5% in distance, 0.20 mag in Vband extinction, and 245 K in effective temperature for G ≤ 14, degrading towards fainter magnitudes (12%, 0.20 mag, and 245 K at G = 16; 16%, 0.23 mag, and 260 K at G = 17, respectively). We find a very good agreement with the asteroseismic surface gravities and distances of 7000 stars in the Kepler, K2-C3, and K2-C6 fields, with stellar parameters from the APOGEE survey, and with distances to star clusters. Our results are available through the ADQL query interface of the Gaia mirror at the Leibniz-Institut für Astrophysik Potsdam (gaia.aip.de) and as binary tables at data.aip.de. As a first application, we provide distanceand extinction-corrected colour-magnitude diagrams, extinction maps as a function of distance, and extensive density maps. These demonstrate the potential of our value-added dataset for mapping the three-dimensional structure of our Galaxy. In particular, we see a clear manifestation of the Galactic bar in the stellar density distributions, an observation that can almost be considered direct imaging of the Galactic bar.

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“…Rows two to five: ASS, LSA, BSS, and QSS models for the GMF, respectively. well localized in the sky towards regions of nearby known structures (spurs, arms, and clouds) mainly attributable to the nearby structures such as the Sco-Cen association (e.g., Das et al 2020). We used the gpempy software to investigate this further and we reached the conclusion that, in general, p lin is not boosted by the simple addition of a clump of dust towards such a maximum to solve the problem.…”

Section: Alternative Comparison Of Polarization Mapsmentioning

confidence: 99%

Galactic magnetic field reconstruction using the polarized diffuse Galactic emission: formalism and application to Planck data

Pelgrims

Macías-Pérez

Ruppin

2021

A&A

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The polarized Galactic synchrotron and thermal dust emission constitutes a major tool in the study of the Galactic magnetic field (GMF) and in constraining its strength and geometry for the regular and turbulent components. In this paper, we review the modeling of these two components of the polarized Galactic emission and present our strategy for optimally exploiting the currently existing data sets. We investigate a Markov chain Monte Carlo (MCMC) method to constrain the model parameter space through maximum-likelihood analysis, focusing mainly on dust polarized emission. Relying on simulations, we demonstrate that our methodology can be used to constrain the regular GMF geometry. Fitting for the reduced Stokes parameters, this reconstruction is only marginally dependent of the accuracy of the reconstruction of the Galactic dust grain density distribution. However, the reconstruction degrades, apart from the pitch angle, when including a turbulent component on the order of the regular one as suggested by current observational constraints. Finally, we applied this methodology to a set of Planck polarization maps at 353 GHz to obtain the first MCMC based constrains on the large-scale regular-component of the GMF from the polarized diffuse Galactic thermal dust emission. By testing various models of the dust density distribution and of the GMF geometry, we prove that it is possible to infer the large-scale geometrical properties of the GMF. We obtain coherent three-dimensional views of the GMF, from which we infer a mean pitch angle of 27 degrees with 14% scatter, which is in agreement with results obtained in the literature from synchrotron emission.

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Constraining the distance to the North Polar Spur with Gaia DR2

Cited by 27 publications

References 44 publications

Revisiting the Distance to Radio Loops I and IV Using Gaia and Radio/Optical Polarization Data

Revisiting the Distance to Radio Loops I and IV Using Gaia and Radio/Optical Polarization Data

Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18

Galactic magnetic field reconstruction using the polarized diffuse Galactic emission: formalism and application to Planck data

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