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MIGHTEE: are giant radio galaxies more common than we thought?

Monthly Notices of the Royal Astronomical Society 91̽»¨ University Press 501:3 (2020) 3833-3845

Authors:

J Delhaize, Ian Heywood, M Prescott, Matthew Jarvis, I Delvecchio, Ih Whittam, Sv White, Mj Hardcastle, Cl Hale, J Afonso, Y Ao, M Brienza, M Brüggen, Jd Collier, E Daddi, M Glowacki, N Maddox, Lk Morabito, I Prandoni, Z Randriamanakoto, S Sekhar, F An, Nj Adams, S Blyth, Rebecca Bowler, L Leeuw, L Marchetti, Sm Randriamampandry, K Thorat, N Seymour, O Smirnov, Ar Taylor, C Tasse, M Vaccari

Abstract:

We report the discovery of two new giant radio galaxies (GRGs) using the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) survey. Both GRGs were found within a ∼1 deg2 region inside the COSMOS field. They have redshifts of z = 0.1656 and z = 0.3363 and physical sizes of 2.4 and 2.0 Mpc, respectively. Only the cores of these GRGs were clearly visible in previous high-resolution Very Large Array observations, since the diffuse emission of the lobes was resolved out. However, the excellent sensitivity and uv coverage of the new MeerKAT telescope allowed this diffuse emission to be detected. The GRGs occupy an unpopulated region of radio power – size parameter space. Based on a recent estimate of the GRG number density, the probability of finding two or more GRGs with such large sizes at z < 0.4 in a ∼1 deg2 field is only 2.7 × 10−6, assuming Poisson statistics. This 91̽»¨s the hypothesis that the prevalence of GRGs has been significantly underestimated in the past due to limited sensitivity to low surface brightness emission. The two GRGs presented here may be the first of a new population to be revealed through surveys like MIGHTEE that provide exquisite sensitivity to diffuse, extended emission.

Euclid mission status after mission critical design

Proceedings of SPIE--the International Society for Optical Engineering SPIE, the international society for optics and photonics 11443 (2020) 114430f-114430f-10

Authors:

R Laureijs, GD Racca, Y Mellier, P Musi, L Brouard, T Böenke, L Gaspar Venancio, E Maiorano, A Short, P Strada, B Altieri, G Buenadicha, X Dupac, P Gomez Alvarez, J Hoar, R Kohley, R Vavrek, A Rudolph, M Schmidt, J Amiaux, H Aussel, M Berthé, M Cropper, J-C Cuillandre, C Dabin, J Dinis, R Nakajima, T Maciaszek, R Scaramella, A da Silva, I Tereno, OR Williams, A Zacchei, R Azzollini, F Bernardeau, J Brinchmann, C Brockley-Blatt, F Castander, A Cimatti, C Conselice, A Ealet, P Fosalba, W Gillard, L Guzzo, H Hoekstra, P Hudelot, K Jahnke, T Kitching, L Miller, J Mohr, W Percival, V Pettorino, J Rhodes, A Sanchez, M Sauvage, S Serrano, R Teyssier, J Weller, J Zoubian

MIGHTEE: Are giant radio galaxies more common than we thought?

(2020)

Authors:

J Delhaize, I Heywood, M Prescott, MJ Jarvis, I Delvecchio, IH Whittam, SV White, MJ Hardcastle, CL Hale, J Afonso, Y Ao, M Brienza, M Brueggen, JD Collier, E Daddi, M Glowacki, N Maddox, LK Morabito, I Prandoni, Z Randriamanakoto, S Sekhar, Fangxia An, NJ Adams, S Blyth, RAA Bowler, L Leeuw, L Marchetti, SM Randriamampandry, K Thorat, N Seymour, O Smirnov, AR Taylor, C Tasse, M Vaccari

Towards simulating a realistic data analysis with an optimised angular power spectrum of spectroscopic galaxy surveys

Experimental Results , Volume 1 , 2020 , e54

Authors:

Guglielmo Faggioli, Konstantinos Tanidis, Stefano Camera

Abstract:

The angular power spectrum is a natural tool to analyse the observed galaxy number count fluctuations. In a standard analysis, the angular galaxy distribution is sliced into concentric redshift bins and all correlations of its harmonic coefficients between bin pairs are considered—a procedure referred to as ‘tomography’. However, the unparalleled quality of data from oncoming spectroscopic galaxy surveys for cosmology will render this method computationally unfeasible, given the increasing number of bins. Here, we put to test against synthetic data a novel method proposed in a previous study to save computational time. According to this method, the whole galaxy redshift distribution is subdivided into thick bins, neglecting the cross-bin correlations among them; each of the thick bin is, however, further subdivided into thinner bins, considering in this case all the cross-bin correlations. We create a simulated data set that we then analyse in a Bayesian framework. We confirm that the newly proposed method saves computational time and gives results that surpass those of the standard approach.

Towards simulating a realistic data analysis with an optimised angular power spectrum of spectroscopic galaxy surveys

Experimental Results 1 (2020)

Authors:

G Faggioli, K Tanidis, S Camera

Abstract:

The angular power spectrum is a natural tool to analyse the observed galaxy number count fluctuations. In a standard analysis, the angular galaxy distribution is sliced into concentric redshift bins and all correlations of its harmonic coefficients between bin pairs are considered - a procedure referred to as 'tomography'. However, the unparalleled quality of data from oncoming spectroscopic galaxy surveys for cosmology will render this method computationally unfeasible, given the increasing number of bins. Here, we put to test against synthetic data a novel method proposed in a previous study to save computational time. According to this method, the whole galaxy redshift distribution is subdivided into thick bins, neglecting the cross-bin correlations among them; each of the thick bin is, however, further subdivided into thinner bins, considering in this case all the cross-bin correlations. We create a simulated data set that we then analyse in a Bayesian framework. We confirm that the newly proposed method saves computational time and gives results that surpass those of the standard approach.