The Square Kilometre Array (SKA)

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MIGHTEE-H i: Deep spectral line observations of the COSMOS field

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) (2024)

Authors:

I Heywood, AA Ponomareva, N Maddox, MJ Jarvis, BS Frank, EAK Adams, M Baes, A Bianchetti, JD Collier, RP Deane, M Glowacki, SL Jung, H Pan, SHA Rajohnson, G Rodighiero, I Ruffa, MG Santos, F Sinigaglia, M Vaccari

Abstract:

Abstract The MIGHTEE survey utilises the South African MeerKAT radio telescope to observe four extragalactic deep fields, with the aim of advancing our understanding of the formation and evolution of galaxies across cosmic time. MIGHTEE’s frequency coverage encompasses the $\textrm {H}\scriptstyle \mathrm{I}$ line to a redshift of z ≃ 0.58, and OH megamasers to z ≃ 0.9.. We present the MIGHTEE-$\textrm {H}\scriptstyle \mathrm{I}$ imaging products for the COSMOS field, using a total of 94.2 h on-target and a close-packed mosaic of 15 individual pointings. The spectral imaging covers two broad, relatively interference-free regions (960–1150 and 1290–1520 MHz) within MeerKAT’s L-band, with up to 26 kHz spectral resolution (5.5 km s−1 at z = 0). The median noise in the highest spectral resolution data is 74 μJy beam−1, corresponding to a 5σ $\textrm {H}\scriptstyle \mathrm{I}$ mass limit of 108.5 M⊙ for a 300 km s−1 line at z = 0.07. The mosaics cover >4 deg2, provided at multiple angular resolution / sensitivity pairings, with an angular resolution for $\textrm {H}\scriptstyle \mathrm{I}$ at z = 0 of 12″. We describe the spectral line processing workflow that will be the basis for future MIGHTEE-$\textrm {H}\scriptstyle \mathrm{I}$ products, and validation of, and some early results from, the spectral imaging of the COSMOS field. We find no evidence for line emission at the position of the z = 0.376 $\textrm {H}\scriptstyle \mathrm{I}$ line reported from the CHILES survey at a >94 per cent confidence level, placing a 3σ upper limit of 8.1 × 109 M⊙ on MHI for this galaxy. A public data release accompanies this article.
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Deep extragalactic H i survey of the COSMOS field with FAST

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) (2024) stae2054

Authors:

Hengxing Pan, Matt J Jarvis, Ming Zhu, Yin-Zhe Ma, Mario G Santos, Anastasia A Ponomareva, Ian Heywood, Yingjie Jing, Chen Xu, Ziming Liu, Yogesh Chandola, Yipeng Jing
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The sizes of bright Lyman-break galaxies at z ≃ 3–5 with JWST PRIMER

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) (2024)

Authors:

RG Varadaraj, RAA Bowler, MJ Jarvis, NJ Adams, N Choustikov, AM Koekemoer, AC Carnall, DJ McLeod, JS Dunlop, CT Donnan, NA Grogin

Abstract:

Abstract We use data from the JWST Public Release IMaging for Extragalactic Research (PRIMER) survey to measure the size scaling relations of 1668 rest-frame UV-bright Lyman-break galaxies (LBGs) at z = 3–5 with stellar masses log10(M⋆/M⊙) > 9. The sample was selected from seeing-dominated ground-based data, presenting an unbiased sampling of the morphology and size distributions of luminous sources. We fit Sérsic profiles to eight NIRCam bands and also measure a non-parametric half-light radius. We find that the size distributions with both measurements are well-fit by a log-normal distribution at all redshifts, consistent with disk formation models where size is governed by host dark-matter halo angular momentum. We find a size-redshift evolution of Re = 3.51(1 + z)−0.60 ± 0.22 kpc, in agreement with JWST studies. When considering the typical (modal) size over z = 3–5, we find little evolution with bright LBGs remaining compact at Re ≃ 0.7 − 0.9 kpc. Simultaneously, we find evidence for a build-up of large (Re > 2 kpc) galaxies by z = 3. We find some evidence for a negatively sloped size-mass relation at z = 5 when Sérsic profiles are used to fit the data in F200W. The intrinsic scatter in our size-mass relations increases at higher redshifts. Additionally, measurements probing the rest-UV (F200W) show larger intrinsic scatter than those probing the rest-optical (F356W). Finally, we leverage rest-UV and rest-optical photometry to show that disky galaxies are well established by z = 5, but are beginning to undergo dissipative processes, such as mergers, by z = 3. The agreement of our size-mass and size-luminosity relations with simulations provides tentative evidence for centrally concentrated star formation at high-redshift.
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Correction to: A new pulsar candidate in 47 Tucanae discovered with MeerKAT imaging

Monthly Notices of the Royal Astronomical Society: Letters Oxford University Press (OUP) 534:1 (2024) l21-l21
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Radio observations of the 2022 outburst of the transitional Z-Atoll source XTE J1701-462

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) (2024) stae1875

Authors:

KVS Gasealahwe, IM Monageng, RP Fender, PA Woudt, AK Hughes, SE Motta, J van den Eijnden, P Saikia, E Tremou
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