Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published May 2021 | Submitted + Published
Journal Article Open

Detection of spectral variations of Anomalous Microwave Emission with QUIJOTE and C-BASS

Abstract

Anomalous Microwave Emission (AME) is a significant component of Galactic diffuse emission in the frequency range 10–60GHz and a new window into the properties of sub-nanometre-sized grains in the interstellar medium. We investigate the morphology of AME in the ≈10° diameter λ Orionis ring by combining intensity data from the QUIJOTE experiment at 11, 13, 17, and 19GHz19GHz and the C-Band All Sky Survey (C-BASS) at 4.76GHz⁠, together with 19 ancillary data sets between 1.42 and 3000GHz⁠. Maps of physical parameters at 1° resolution are produced through Markov chain Monte Carlo (MCMC) fits of spectral energy distributions (SEDs), approximating the AME component with a lognormal distribution. AME is detected in excess of 20σ at degree-scales around the entirety of the ring along photodissociation regions (PDRs), with three primary bright regions containing dark clouds. A radial decrease is observed in the AME peak frequency from ≈35GHz near the free–free region to ≈21GHz in the outer regions of the ring, which is the first detection of AME spectral variations across a single region. A strong correlation between AME peak frequency, emission measure and dust temperature is an indication for the dependence of the AME peak frequency on the local radiation field. The AME amplitude normalized by the optical depth is also strongly correlated with the radiation field, giving an overall picture consistent with spinning dust where the local radiation field plays a key role.

Additional Information

© 2021 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2021 February 21. Received 2021 January 26; in original form 2020 January 14. Published: 27 February 2021. The QUIJOTE experiment is being developed by the Instituto de Astrofísica de Canarias (IAC), the Instituto de Física de Cantabria (IFCA), and the Universities of Cantabria, Manchester and Cambridge. The C-BASS project is a collaboration between Oxford and Manchester Universities in the UK, the California Institute of Technology in the U.S.A., Rhodes University, UKZN and the South African Radio Observatory in South Africa, and the King Abdulaziz City for Science and Technology (KACST) in Saudi Arabia. Partial financial support for QUIJOTE is provided by the Spanish Ministry of Economy and Competitiveness (MINECO) under the projects AYA2007-68058-C03-01, AYA2010-21766-C03-02, AYA2014-60438-P, AYA2017-84185-P, IACA13-3E-2336, IACA15-BE-3707, and EQC2018-004918-P; Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER, UE), under projects ESP2017-83921-C2-1-R and AYA2017-90675-REDC; the European Union's Horizon 2020 research and innovation programme under grant agreement number 687312 (RADIOFOREGROUNDS) and number 658499 (PolAME); Unidad de Excelencia María de Maeztu (MDM-2017-0765), and the Consolider-Ingenio project CSD2010-00064 (EPI: Exploring the Physics of Inflation). C-BASS has been supported by the NSF awards AST-0607857, AST-1010024, AST-1212217, and AST-1616227, and NASA award NNX15AF06G, the University of Oxford, the Royal Society, STFC, and the other participating institutions. C-BASS is also supported by the South African Radio Astronomy Observatory, which is a facility of the National Research Foundation, an agency of the Department of Science and Technology. RCA would like to thank Aaron Bell, Takashi Onaka, and the AKARI collaboration for providing access to the AKARI 9μm data in the region. We make use of the healpix package (Górski et al. 2005) and Python astropy (Astropy Collaboration 2013, 2018), corner, emcee (Foreman-Mackey et al. 2013), healpy (Zonca et al. 2019), matplotlib (Hunter 2007), numpy (Harris et al. 2020), and scipy (Virtanen et al. 2020) packages. RCA acknowledges support from an STFC postgraduate studentship and a President's Doctoral Scholar Award from the University of Manchester. FP acknowledges support from the Spanish Ministerio de Ciencia, Innovación y Universidades (MICINN) under grant numbers ESP2015-65597-C4-4-R, ESP2017-86852-C4-2-R,ESP2015-65597-C4-4-R, and ESP2017-86852-C4-2-R. The authors thank the referee for useful feedback and recommendations. Data Availability: The data presented in this article can be made available on request to the author or the C-BASS or QUIJOTE collaborations. In the near future, both C-BASS and QUIJOTE data will be publicly released.

Attached Files

Published - stab583.pdf

Submitted - 2001.07159.pdf

Files

stab583.pdf
Files (18.9 MB)
Name Size Download all
md5:1b14c353900a01722543da149f4e0235
11.6 MB Preview Download
md5:66870aa7bced9b4942c2727f611901f1
7.3 MB Preview Download

Additional details

Created:
August 20, 2023
Modified:
October 23, 2023