silikonaction.blogg.se

#COMA X RAY VERIFICATION#
#COMA X RAY LICENSE#

1995) via the Sunyaev-Zeldovich (SZ) effect ( Sunyaev & Zeldovich 1972). In microwaves, it became the first nearby cluster detected ( Herbig et al. 1959 Willson 1970) and a radio relic (e.g., Jaffe & Rudnick 1979 Ballarati et al. In radio band, it became the first cluster where a radio halo (e.g., Seeger et al. The Coma cluster was one of the very first clusters detected in X-rays (e.g., Boldt et al. For instance, the presence of dark matter in the Coma cluster was suggested by Fritz Zwicky in 1933 based on velocity measurements of member galaxies ( Zwicky 1933). X 2013) and proximity ( z = 0.0231) makes it an attractive target – bright and well resolved – for many case studies. The combination of its mass ( M 500 ~ 6 10 14 M ⊙ Planck Collaboration Int. The Coma cluster (Abell 1656) is one of the best-studied clusters in all energy bands. Open Access funding provided by Max Planck Society.

#COMA X RAY LICENSE#

Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License ( ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Such a two-stage process might explain the formation of the radio halo in the Coma cluster. Unlike “runway” merger shocks, the mini-accretion shock does not feature a rarefaction region downstream and, therefore, the radio emission can survive longer. After passing through the primary shock, the gas should spend much of the time in a rarefaction region, where radiative losses of electrons are small, until the gas is compressed again by the mini-accretion shock. The gas in the Coma core went through two shocks, first through the shock driven by NGC 4839 during its first passage through the cluster some gigayear ago and, more recently, through the “mini-accretion shock” associated with the gas settling back to quasi-hydrostatic equilibrium in the core. In particular, we identify a faint X-ray bridge connecting the group with the cluster, which is convincing proof that NGC 4839 has already crossed the main cluster.

In this study, we discuss the rich morphology revealed by the X-ray observations (also in combination with the SZ data) and argue that the most salient features can be naturally explained by a recent (ongoing) merger with the NGC 4839 group. The stability of the instrumental background and operation of the SRG observatory in the scanning mode provided us with an excellent data set for studies of the diffuse emission up to a distance of ~1.5 R 200 from the Coma center. The data cover a ~3° × 3° area around the cluster with a typical exposure time of more than 20 ks.

#COMA X RAY VERIFICATION#

This is the first paper in a series of studies of the Coma cluster using the SRG/eROSITA X-ray data obtained in the course of the calibration and performance verification observations. Astronomical objects: linking to databasesĮ.Including author names using non-Roman alphabets.Suggested resources for more tips on language editing in the sciences Punctuation and style concerns regarding equations, figures, tables, and footnotes