Abstract
NenuFAR, the New Extension in Nancay Upgrading LOFAR, is currently in its early science phase. It is in this context that the Cosmic Filaments and Magnetism Pilot Survey is observing sources with the array as it is still under construction—with 57 (56 core, 1 distant) out of a total planned 102 (96 core, 6 distant) mini-arrays online at the time of observation—to get a first look at the low-frequency sky with NenuFAR. One of its targets is the Coma galaxy cluster: a well-known object, host of the prototype radio halo. It also hosts other features of scientific import, including a radio relic, along with a bridge of emission connecting it with the halo. It is thus a well-studied object.In this paper, we show the first confirmed NenuFAR detection of the radio halo and radio relic of the Coma cluster at 34.4 MHz, with associated intrinsic flux density estimates: we find an integrated flux value of 106.3 ± 3.5 Jy for the radio halo, and 102.0 ± 7.4 Jy for the radio relic. These are upper bound values, as they do not include point-source subtraction. We also give an explanation of the technical difficulties encountered in reducing the data, along with steps taken to resolve them. This will be helpful for other scientific projects which will aim to make use of standalone NenuFAR imaging observations in the future.
Highlights
As an object known to host several physical components of considerable scientific interest, it was chosen as the first galaxy cluster to be observed as part of the NenuFAR Cosmic Filaments & Magnetism Pilot Survey project
NenuFAR, the New Extension in Nançay Upgrading LoFAR [6], is a very powerful instrument optimised to offer unparalleled sensitivity in the Northern sky at the lowest astronomically-relevant frequencies (10–85 MHz) which can be probed from the Earth.In its imager mode, NenuFAR features a dense network of short baselines, making it exceptionally powerful for detecting diffuse emission on large scales
As for the flux measurements, we find that the Coma cluster core has an integrated flux density of 106.3 ± 3.5 Jy while the radio relic to its SouthWest has a total flux density of 102.0 ± 7.4 Jy
Summary
Its longest baselines are still quite short (3 km for the “distant” mini-arrays once complete); this means that it offers rather poor angular resolution (200 at the time our observation was taken, with 56 of a total planned 96 core mini-arrays online and only 1 of a planned 6 distant mini-arrays operational). This means that its sensitivity, in its standalone imager mode, is strongly limited by the confusion noise (i.e., the “noise” introduced by the presence of “clouds” of faint sources which cannot be resolved by the instrument).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
