ASP Online Seminars: Extremely Deep Milliarcsecond Radio Observation of the High Redshift Radio Source Population

by Ann Njeri (University of Manchester, UK)

Tuesday 13 Apr 2021, 13:30 → 15:00 GMT

Abstract:

Extremely Deep Milliarcsecond Radio Observation of the High Redshift Radio Source Population One of the enduring and most fundamental questions of modern astrophysics is understanding how galaxies form and evolve through cosmic time. Key to this question is understanding the interplay and feedback between star-formation (SF) and accretion onto supermassive blackholes SMBs in galaxies. Sensitivity and high angular resolution radio observations are crucial part of these investigations, uniquely providing spatially resolved tracer of SF and accretion (Active Galactic Nuclei, AGN) processes as they co-evolve in obscured galaxies. The e-MERLIN Galaxy Evolution survey (e-MERGE) Legacy project, is a large program of high-resolution 1.5 GHz and 5.5 GHz radio observations of the GOODS-N field. The main objective of this project is to resolve the SF processes and AGN activities in galaxies at high redshift. The eMERGE survey is split into Data Release One (DR1) and Data Release Two (DR2) due to the voluminous data sizes involved. In total ∼1,200 hours of e-MERLIN observations have been made at 1.2-1.7GHz, along with supplementary VLA data, amounting to over 15TB of raw data. DR1 comprises of∼140 hours of observation with eMERLIN and∼40 hours of observation with the Very Large Array(VLA).These first results have recently been published in Monthly Notices of the Royal Astronomical Society (Muxlow et al. (in Njeri), 2020). The long eMERLIN baselines provide high angular resolution while the short VLA baselines provide excellent surface brightness sensitivity, combined to produce a deep 1.5 GHz radio survey with∼2.81μJy beam−1sensitivity and angular resolutions of 0.2-0.7′′with a field-of-view (FoV)∼15′x 15′(the Lovell Half-Power Beam Width, HPBW). The DR1 has sampled > 800 star forming galaxies (SFGs)and AGNs at z≥1. These initial e-MERGE DR1 results are some of the most sensitive observations at these frequencies and angular resolutions that have ever been conducted. eMERGE DR2 on the other hand has∼1,200 hours observation with eMERLIN and 50 hours with VLA, increased sensitivity to∼0.5μJybeam−1and increased FoV to∼45′by 45′(the 25m telescope HPBW). DR2 is expected to sample≥2,500 SFGs and AGNs at high redshift. My project is working towards eMERGE DR2.

Ann Talk's Screen.png

ASP_20210413_AnnNjeri_Extremely Deep Milliarcsecond Radio Observation .mp4

Screen Shot 2021-04-13 at 10.54.42 AM.png

YouTube_AnnNjeri_20210413

zoom_0.mp4