Thomson, Alec J. M.Alec J. M.ThomsonMcConnell, DavidDavidMcConnellLenc, EmilEmilLencGalvin, Timothy J.Timothy J.GalvinRudnick, LawrenceLawrenceRudnickHeald, GeorgeGeorgeHealdHale, Catherine L.Catherine L.HaleDuchesne, Stefan W.Stefan W.DuchesneAnderson, Craig S.Craig S.AndersonCARRETTI, ETTOREETTORECARRETTIFederrath, ChristophChristophFederrathGaensler, B. M.B. M.GaenslerHarvey-Smith, LisaLisaHarvey-SmithHaverkorn, MarijkeMarijkeHaverkornHotan, Aidan W.Aidan W.HotanKi Ma, YikYikKi MaMurphy, TaraTaraMurphyMcClure-Griffiths, N. M.N. M.McClure-GriffithsMoss, Vanessa A.Vanessa A.MossO’Sullivan, Shane P.Shane P.O’SullivanRaja, WasimWasimRajaSeta, AmitAmitSetaVan Eck, Cameron L.Cameron L.Van EckWest, Jennifer L.Jennifer L.WestWhiting, Matthew T.Matthew T.WhitingWieringa, Mark H.Mark H.Wieringa2023-09-112023-09-1120231448-6083http://hdl.handle.net/20.500.12386/34371The Australian SKA Pathfinder (ASKAP) radio telescope has carried out a survey of the entire Southern Sky at 887.5 MHz. The wide area, high angular resolution, and broad bandwidth provided by the low-band Rapid ASKAP Continuum Survey (RACS-low) allow the production of a next-generation rotation measure (RM) grid across the entire Southern Sky. Here we introduce this project as Spectral and Polarisation in Cutouts of Extragalactic sources from RACS (SPICE-RACS). In our first data release, we image 30 RACS-low fields in Stokes I, Q, U at 25" angular resolution, across 744-1032 MHz with 1 MHz spectral resolution. Using a bespoke, highly parallelised, software pipeline we are able to rapidly process wide-area spectro-polarimetric ASKAP observations. Notably, we use `postage stamp' cutouts to assess the polarisation properties of 105912 radio components detected in total intensity. We find that our Stokes Q and U images have an rms noise of ∼ 80 μJy PSF-1, and our correction for instrumental polarisation leakage allows us to characterise components with ≳ 1% polarisation fraction over most of the field of view. We produce a broadband polarised radio component catalogue that contains 5818 RM measurements over an area of ∼ 1300 deg2 with an average error in RM of 1.6+1.1-1.0 rad m-2, and an average linear polarisation fraction 3.4+3.0-1.6%. We determine this subset of components using the conditions that the polarised signal-to-noise ratio is > 8, the polarisation fraction is above our estimated polarised leakage, and the Stokes I spectrum has a reliable model. Our catalogue provides an areal density of 4±2 RMs deg-2; an increase of ∼ 4 times over the previous state-of-the-art (Taylor, Stil, Sunstrum <xref rid="ref94" ref-type="bibr">2009</xref>, ApJ, 702, 1230). Meaning that, having used just 3% of the RACS-low sky area, we have produced the 3rd largest RM catalogue to date. This catalogue has broad applications for studying astrophysical magnetic fields; notably revealing remarkable structure in the Galactic RM sky. We will explore this Galactic structure in a follow-up paper. We will also apply the techniques described here to produce an all-Southern-sky RM catalogue from RACS observations. Finally, we make our catalogue, spectra, images, and processing pipeline publicly available.STAMPAenArticle10.1017/pasa.2023.38https://arxiv.org/abs/2307.07207https://www.cambridge.org/core/journals/publications-of-the-astronomical-society-of-australia/article/rapid-askap-continuum-survey-iii-spectra-and-polarisation-in-cutouts-of-extragalactic-sources-spiceracs-first-data-release/7355C6B8459B29E3F838B6DEF4CFAE3B2023PASA...40...40TFIS/05 - ASTRONOMIA E ASTROFISICA