MIGHTEE-HI: deep spectral line observations of the COSMOS field

I. Heywood*, A. A. Ponomareva, N. Maddox, M. J. Jarvis, B. S. Frank, E. A.K. Adams, M. Baes, A. Bianchetti, J. D. Collier, R. P. Deane, M. Glowacki, S. L. Jung, H. Pan, S. H.A. Rajohnson, G. Rodighiero, I. Ruffa, M. G. Santos, F. Sinigaglia, M. Vaccari

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

Abstract

The MIGHTEE survey utilizes 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 HI line to a redshift of z ≃ 0.58, and OH megamasers to z ≃ 0.9. We present the MIGHTEE-HI 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 5σHI 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 HI at z = 0 of 12 arcsec. We describe the spectral line processing workflow that will be the basis for future MIGHTEE-HI 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 HI 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.

Original languageEnglish
Pages (from-to)76-96
Number of pages21
JournalMonthly Notices of the Royal Astronomical Society
Volume534
Issue number1
Early online date5 Sept 2024
DOIs
Publication statusPublished - 1 Oct 2024

Bibliographical note

Publisher Copyright:
© 2024 The Author(s).

Keywords

  • methods: data analysis
  • radio lines: galaxies
  • techniques: interferometric

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