The Square Kilometre Array (SKA): publications

MIGHTEE: deep 1.4 GHz source counts and the sky temperature contribution of star forming galaxies and active galactic nuclei

Monthly Notices of the Royal Astronomical Society Oxford University Press 520:2 (2022) 2668-2691

Authors:

Cl Hale, Ih Whittam, Mj Jarvis, Pn Best, Nl Thomas, I Heywood, M Prescott, N Adams, J Afonso, Fangxia An, Raa Bowler, Jd Collier, Rhw Cook, R Davé, Bs Frank, M Glowacki, Pw Hatfield, S Kolwa, Cc Lovell, N Maddox, L Marchetti, Lk Morabito, E Murphy, I Prandoni, Z Randriamanakoto, Ar Taylor

Abstract:

We present deep 1.4 GHz source counts from ∼5 deg2 of the continuum Early Science data release of the MeerKAT International Gigahertz Tiered Extragalactic Exploration (MIGHTEE) survey down to S1.4GHz ∼15 μJy. Using observations over two extragalactic fields (COSMOS and XMM-LSS), we provide a comprehensive investigation into correcting the incompleteness of the raw source counts within the survey to understand the true underlying source count population. We use a variety of simulations that account for: errors in source detection and characterisation, clustering, and variations in the assumed source model used to simulate sources within the field and characterise source count incompleteness. We present these deep source count distributions and use them to investigate the contribution of extragalactic sources to the sky background temperature at 1.4 GHz using a relatively large sky area. We then use the wealth of ancillary data covering a subset of the COSMOS field to investigate the specific contributions from both active galactic nuclei (AGN) and star forming galaxies (SFGs) to the source counts and sky background temperature. We find, similar to previous deep studies, that we are unable to reconcile the sky temperature observed by the ARCADE 2 experiment. We show that AGN provide the majority contribution to the sky temperature contribution from radio sources, but the relative contribution of SFGs rises sharply below 1 mJy, reaching an approximate 15-25 per cent contribution to the total sky background temperature (Tb ∼100 mK) at ∼15 μJy.

The Thousand-Pulsar-Array programme on MeerKAT -- X. Scintillation arcs of 107 pulsars

(2022)

Authors:

RA Main, A Parthasarathy, S Johnston, A Karastergiou, A Basu, AD Cameron, MJ Keith, LS Oswald, B Posselt, DJ Reardon, X Song, P Weltevrede

MIGHTEE: Deep 1.4 GHz Source Counts and the Sky Temperature Contribution of Star Forming Galaxies and Active Galactic Nuclei

(2022)

Authors:

CL Hale, IH Whittam, MJ Jarvis, PN Best, NL Thomas, I Heywood, M Prescott, N Adams, J Afonso, Fangxia An, RAA Bowler, JD Collier, RHW Cook, R Davé, BS Frank, M Glowacki, PW Hatfield, S Kolwa CC Lovell, N Maddox, L Marchetti, LK Morabito, E Murphy, I Prandoni, Z Randriamanakoto, AR Taylor

Optical Spectroscopy of Blazars for the Cherenkov Telescope Array -- II

(2022)

Authors:

E Kasai, P Goldoni, S Pita, DA Williams, W Max-Moerbeck, O Hervet, G Cotter, M Backes, C Boisson, J Becerra González, U Barres de Almeida, F D'Ammando, V Fallah Ramazani, E Lindfors

A Quarter Century of Guitar Nebula/Filament Evolution

The Astrophysical Journal American Astronomical Society 939:2 (2022) 70-70

Authors:

Martijn de Vries, Roger W Romani, Oleg Kargaltsev, George Pavlov, Bettina Posselt, Patrick Slane, Niccolo’ Bucciantini, C-Y Ng, Noel Klingler

Abstract:

We have collected a new deep Chandra X-Ray Observatory exposure of PSR B2224+65 and the "Guitar Nebula," mapping the complex X-ray structure. This is accompanied by a new Hubble Space Telescope (HST) Hα image of the head of the Guitar. Comparing the HST and Chandra structures in four epochs over 25 yr, we constrain the evolution of the TeV particles that light up the filament. Cross-field diffusion appears to be enhanced, likely by the injected particles, behind the filament's sharp leading edge, explaining the filament width and its evolving surface brightness profile...

51��