The Simons Observatory: Galactic Science Goals and Forecasts

Hensley, Brandon; Clark, Susan; Fanfani, Valentina; Krachmalnicoff, N.; Fabbian, Giulio; Poletti, D.; Puglisi, Giuseppe; Coppi, Gabriele; Nibauer, Jacob; Gerasimov, Roman; Galitzki, Nicholas; Choi, Steve K.; Ashton, Peter; Baccigalupi, C.; Baxter, Eric J.; Burkhart, Blakesley; Calabrese, E.; Chluba, Jens; Errard, Josquin; Frolov, A.; Hervías-Caimapo, Carlos; Huffenberger, K. M.; Johnson, Bradley R.; Jost, Baptiste; Keating, Brian; McCarrick, Heather; Nati, F.; Rao, Mayuri Sathyanarayana; Engelen, Alexander van; Walker, Samantha; Wolz, Kevin J.; Xu, Zhilei; Zhu, Ningfeng; Zonca, A.

doi:10.3847/1538-4357/ac5e36

Cited by 17 publications

(10 citation statements)

References 233 publications

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“…We note that these forecasts are different with respect to the ones presented in Hensley et al (2022), as the two forecasts are drawn from two different catalogues employing different kind of sources, molecular clouds with size larger than 1 pc from Miville-Deschênes et al (2017). Reassuringly however, both methods lead to a similar expected number of detections in intensity at 280 GHz: 12,000 cold clump detections in this work and 8500 in Hensley et al (2022).…”

Section: Forecasts For Somentioning

confidence: 65%

“…The lower noise levels and finer angular resolution of the SO survey will also better resolve any substructure in the cold clumps, in both intensity and polarization. Hensley et al (2022) previously presented forecasts for the number of similar molecular clouds that SO will resolve in polarization, highlighting this fact. These resolved studies will allow us to expand our understanding of the magnetic field structure of cold clumps and relationship to their surrounding filaments and molecular clouds.…”

Section: Conclusion/summarymentioning

confidence: 89%

See 1 more Smart Citation

Polarization fraction of $Planck$ Galactic cold clumps and forecasts for the Simons Observatory

Clancy¹,

Puglisi²,

E.³

et al. 2023

Preprint

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We measure the polarization fraction of a sample of 6282 Galactic cold clumps at 353 GHz, consisting of Planck Galactic cold clump (PGCC) catalogue category 1 objects (flux densities measured with signal-to-noise ratio (S/N) > 4). We find the mean-squared polarization fraction at 353 GHz to be Π 2 = [4.79 ± 0.44] × 10 −4 equating to an 11 𝜎 detection of polarization. We test if the polarization fraction depends on the clumps' physical properties, including flux density, luminosity, Galactic latitude and physical distance. We see a trend towards increasing polarization fraction with increasing Galactic latitude, but find no evidence that polarization depends on the other tested properties. The Simons Observatory, with angular resolution of order 1 and noise levels between 22 and 54 𝜇K−arcmin at high frequencies, will substantially enhance our ability to determine the magnetic field structure in Galactic cold clumps. At ≥ 5 𝜎 significance, we predict the Simons Observatory will detect at least ∼12,000 cold clumps in intensity and ∼430 cold clumps in polarization. This number of polarization detections would represent a two orders of magnitude increase over the current Planck results.

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Section: Forecasts For Somentioning

confidence: 65%

Section: Conclusion/summarymentioning

confidence: 89%

Polarization fraction of $Planck$ Galactic cold clumps and forecasts for the Simons Observatory

Clancy¹,

Puglisi²,

E.³

et al. 2023

Preprint

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show abstract

“…Furthermore, our analysis is restricted to only the section of the Stream that intersects the BICEP/Keck region. Extending the sky area to include the entire Stream, running the RHT on forthcoming H I emission data from the Galactic Australian Square Kilometre Array Pathfinder Survey (Dickey et al 2013) with 30″ angular resolution, and using higher angular resolution dust polarization data (Hensley et al 2022;CMB-S4 collaboration et al 2022;CCAT-Prime collaboration et al 2023) are all possible extensions of this work that can improve the sensitivity of this method for detecting or setting limits on dust polarization from the Stream.…”

Section: Polarized Dust In Magellanic Stream Imentioning

confidence: 99%

“…We also measure the SED of the dust correlated with H I filaments. Knowledge of the dust SED is essential for CMB studies (Chluba et al 2017;Hensley & Bull 2018) and for providing constraints for physical models of dust composition (e.g., Hensley et al 2022).…”

Section: Introductionmentioning

confidence: 99%

BICEP/Keck. XVI. Characterizing Dust Polarization through Correlations with Neutral Hydrogen

Ade

Ahmed

Amiri

et al. 2023

ApJ

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We characterize Galactic dust filaments by correlating BICEP/Keck and Planck data with polarization templates based on neutral hydrogen (H i) observations. Dust polarization is important for both our understanding of astrophysical processes in the interstellar medium (ISM) and the search for primordial gravitational waves in the cosmic microwave background (CMB). In the diffuse ISM, H i is strongly correlated with the dust and partly organized into filaments that are aligned with the local magnetic field. We analyze the deep BICEP/Keck data at 95, 150, and 220 GHz, over the low-column-density region of sky where BICEP/Keck has set the best limits on primordial gravitational waves. We separate the H i emission into distinct velocity components and detect dust polarization correlated with the local Galactic H i but not with the H i associated with Magellanic Stream i. We present a robust, multifrequency detection of polarized dust emission correlated with the filamentary H i morphology template down to 95 GHz. For assessing its utility for foreground cleaning, we report that the Hi morphology template correlates in B modes at a ∼10%–65% level over the multipole range 20 < ℓ < 200 with the BICEP/Keck maps, which contain contributions from dust, CMB, and noise components. We measure the spectral index of the filamentary dust component spectral energy distribution to be β = 1.54 ± 0.13. We find no evidence for decorrelation in this region between the filaments and the rest of the dust field or from the inclusion of dust associated with the intermediate velocity H i. Finally, we explore the morphological parameter space in the H i-based filamentary model.

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“…New, high spatial resolution observations of the polarised dust emission that probes the entire line of sight through the SMC, using forthcoming instruments such as the Prime-cam (CCAT-Prime Collaboration et al 2023) and the Simons Observatory (Hensley et al 2022), similar to the few other nearby galaxies observed with the Stratospheric Observatory for Infrared Astronomy (SOFIA) Highresolution Airborne Wideband Camera Plus (HAWC+ Jones et al 2020;Lopez-Rodriguez et al 2022), can be compared with our H filament orientation map (Figure 6). This will test whether the magnetic alignment of H filaments persists through the full SMC volume.…”

Section: Polarised Starlight and Dust Emission Of The Smcmentioning

confidence: 99%

HI filaments as potential compass needles? Comparing the magnetic field structure of the Small Magellanic Cloud to the orientation of GASKAP-HI filaments

Ma¹,

McClure‐Griffiths²,

Clark³

et al. 2023

Preprint

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High-spatial-resolution H observations have led to the realisation that the nearby (within few hundreds of parsecs) Galactic atomic filamentary structures are aligned with the ambient magnetic field. Enabled by the high quality data from the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope for the Galactic ASKAP H (GASKAP-H ) survey, we investigate the potential magnetic alignment of the 10 pc-scale H filaments in the Small Magellanic Cloud (SMC). Using the Rolling Hough Transform (RHT) technique that automatically identifies filamentary structures, combined with our newly devised raytracing algorithm that compares the H and starlight polarisation data, we find that the H filaments in the northeastern end of the SMC main body ("Bar" region) and the transition area between the main body and the tidal feature ("Wing" region) appear preferentially aligned with the magnetic field traced by starlight polarisation. Meanwhile, the remaining SMC volume lacks starlight polarisation data of sufficient quality to draw any conclusions. This suggests for the first time that filamentary H structures can be magnetically aligned across a large spatial volume ( kpc) outside of the Milky Way. In addition, we generate maps of the preferred orientation of H filaments throughout the entire SMC, revealing the highly complex gaseous structures of the galaxy likely shaped by a combination of the intrinsic internal gas dynamics, tidal interactions, and star formation feedback processes. These maps can further be compared with future measurements of the magnetic structures in other regions of the SMC.

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The Simons Observatory: Galactic Science Goals and Forecasts

Cited by 17 publications

References 233 publications

Polarization fraction of $Planck$ Galactic cold clumps and forecasts for the Simons Observatory

Polarization fraction of $Planck$ Galactic cold clumps and forecasts for the Simons Observatory

BICEP/Keck. XVI. Characterizing Dust Polarization through Correlations with Neutral Hydrogen

HI filaments as potential compass needles? Comparing the magnetic field structure of the Small Magellanic Cloud to the orientation of GASKAP-HI filaments

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