MIGHTEE: multi-wavelength counterparts in the COSMOS field

(2023)

Authors:

IH Whittam, M Prescott, CL Hale, MJ Jarvis, I Heywood, Fangxia An, M Glowacki, N Maddox, L Marchetti, LK Morabito, NJ Adams, RAA Bowler, PW Hatfield, RG Varadaraj, J Collier, B Frank, AR Taylor, MG Santos, M Vaccari, J Afonso, Y Ao, J Delhaize, K Knowles, S Kolwa, SM Randriamampandry, Z Randriamanakoto, O Smirnov, DJB Smith, SV White

Cosmology from LOFAR Two-metre Sky Survey data release 2: angular clustering of radio sources

Monthly Notices of the Royal Astronomical Society Oxford University Press 527:3 (2023) 6540-6568

Authors:

Cl Hale, Dj Schwarz, Pn Best, Sj Nakoneczny, David Alonso, D Bacon, L Böhme, N Bhardwaj, M Bilicki, S Camera, Cs Heneka, M Pashapour-Ahmadabadi, P Tiwari, J Zheng, Kj Duncan, Mj Jarvis, R Kondapally, M Magliocchetti, Hja Rottgering, Tw Shimwell

Abstract:

Covering ∼ 5600 deg2 to rms sensitivities of ∼70−100 μJy beam−1, the LOFAR Two-metre Sky Survey Data Release 2 (LoTSS-DR2) provides the largest low-frequency (∼150 MHz) radio catalogue to date, making it an excellent tool for large-area radio cosmology studies. In this work, we use LoTSS-DR2 sources to investigate the angular two-point correlation function of galaxies within the survey. We discuss systematics in the data and an improved methodology for generating random catalogues, compared to that used for LoTSS-DR1, before presenting the angular clustering for ∼900 000 sources ≥1.5 mJy and a peak signal-to-noise ≥ 7.5 across ∼80 per cent of the observed area. Using the clustering, we infer the bias assuming two evolutionary models. When fitting angular scales of 0.5 ≤ θ < 5◦, using a linear bias model, we find LoTSS-DR2 sources are biased tracers of the underlying matter, with a bias of bC = 2.14+0.22 −0.20 (assuming constant bias) and bE(z = 0) = 1.79+0.15 −0.14 (for an evolving model, inversely proportional to the growth factor), corresponding to bE = 2.81+0.24 −0.22 at the median redshift of our sample, assuming the LoTSS Deep Fields redshift distribution is representative of our data. This reduces to bC = 2.02+0.17 −0.16 and bE(z = 0) = 1.67+0.12 −0.12 when allowing preferential redshift distributions from the Deep Fields to model our data. Whilst the clustering amplitude is slightly lower than LoTSS-DR1 (≥2 mJy), our study benefits from larger samples and improved redshift estimates.

The WISDOM of power spectra: how the galactic gravitational potential impacts a galaxy’s central gas reservoir in simulations and observations

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 526:4 (2023) 5590-5611

Authors:

Jindra Gensior, Timothy A Davis, Martin Bureau, JM Diederik Kruijssen, Michele Cappellari, Ilaria Ruffa, Thomas G Williams

Abstract:

<jats:title>ABSTRACT</jats:title> <jats:p>Observations indicate that the central gas discs are smoother in early-type galaxies than their late-type counterparts, while recent simulations predict that the dynamical suppression of star formation in spheroid-dominated galaxies is preceded by the suppression of fragmentation of their interstellar media. The mass surface density power spectrum is a powerful tool to constrain the degree of structure within a gas reservoir. Specifically here, we focus on the power spectrum slope and aim to constrain whether the shear induced by a dominant spheroidal potential can induce sufficient turbulence to suppress fragmentation, resulting in the smooth central gas discs observed. We compute surface density power spectra for the nuclear gas reservoirs of fourteen simulated isolated galaxies and twelve galaxies observed as part of the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM) project. Both simulated and observed galaxies range from disc-dominated galaxies to spheroids, with central stellar mass surface densities, a measure of bulge dominance, varying by more than an order of magnitude. For the simulations, the power spectra steepen with increasing central stellar mass surface density, thereby clearly linking the suppression of fragmentation to the shear-driven turbulence induced by the spheroid. The WISDOM observations show a different (but potentially consistent) picture: while there is no correlation between the power spectrum slopes and the central stellar mass surface densities, the slopes scatter around a value of 2.6. This is similar to the behaviour of the slopes of the simulated galaxies with high central stellar mass surface densities, and could indicate that high shear eventually drives incompressible turbulence.</jats:p>

Probing magnetic fields in the circumgalactic medium using polarization data from MIGHTEE

Astronomy & Astrophysics EDP Sciences 678 (2023) a56

Authors:

K Böckmann, M Brüggen, V Heesen, A Basu, Sp O’Sullivan, I Heywood, M Jarvis, A Scaife, J Stil, R Taylor, Nj Adams, Raa Bowler, Mn Tudorache

Abstract:

Context. The properties and evolution of magnetic fields surrounding galaxies are observationally largely unconstrained. The detection and study of these magnetic fields is important to understand galaxy evolution since magnetic fields are tracers for dynamical processes in the circumgalactic medium (CGM) and can have a significant impact on the evolution of the CGM. Aims. The Faraday rotation measure (RM) of the polarized light of background radio sources passing through the magnetized CGM of intervening galaxies can be used as a tracer for the strength and extent of magnetic fields around galaxies. Methods. We used rotation measures observed by the MIGHTEE-POL (MeerKAT International GHz Tiered Extragalactic Exploration polarization) survey by MeerKAT in the XMM-LSS and COSMOS fields to investigate the RM around foreground star-forming galaxies. We used spectroscopic catalogs of star-forming and blue cloud galaxies to measure the RM of MIGHTEE-POL sources as a function of the impact parameter from the intervening galaxy. In addition, we examined the dependence of the RM on redshift. We then repeated this procedure using a deeper galaxy catalog with photometric redshifts. Results. For the spectroscopic star-forming sample, we find a redshift-corrected |RM| excess of 5.6 ± 2.3 rad m-2 which corresponds to a 2.5I significance around galaxies with a median redshift of z., =., 0.46 for impact parameters below 130 kpc only selecting the intervenor with the smallest impact parameter. Making use of a photometric galaxy catalog and taking into account all intervenors with Mg < -13.6 mag, the signal disappears. We find no indication for a correlation between redshift and RM, nor do we find a connection between the total number of intervenors to the total |RM|. Conclusions. We have presented tentative evidence that the CGM of star-forming galaxies is permeated by coherent magnetic fields within the virial radius. We conclude that mostly bright, star-forming galaxies with impact parameters less than 130 kpc significantly contribute to the RM of the background radio source.

SN 2022jli: A Type Ic Supernova with Periodic Modulation of Its Light Curve and an Unusually Long Rise

The Astrophysical Journal Letters 956:1 (2023)

Authors:

T Moore, SJ Smartt, M Nicholl, S Srivastav, HF Stevance, DB Jess, SDT Grant, MD Fulton, L Rhodes, SA Sim, R Hirai, P Podsiadlowski, JP Anderson, C Ashall, W Bate, R Fender, CP Gutiérrez, DA Howell, ME Huber, C Inserra, G Leloudas, LAG Monard, TE Müller-Bravo, BJ Shappee, KW Smith, G Terreran, J Tonry, MA Tucker, DR Young, A Aamer, T-W Chen, F Ragosta, L Galbany, M Gromadzki, L Harvey, P Hoeflich, C McCully, M Newsome, EP Gonzalez, C Pellegrino, P Ramsden, M Pérez-Torres, EJ Ridley, X Sheng, J Weston