2020A&A...633A..42S


Query : 2020A&A...633A..42S

2020A&A...633A..42S - Astronomy and Astrophysics, volume 633A, 42-42 (2020/1-1)

Measuring bulk flows of the intracluster medium in the Perseus and Coma galaxy clusters using XMM-Newton.

SANDERS J.S., DENNERL K., RUSSELL H.R., ECKERT D., PINTO C., FABIAN A.C., WALKER S.A., TAMURA T., ZUHONE J. and HOFMANN F.

Abstract (from CDS):

We demonstrate a novel technique for calibrating the energy scale of the EPIC-pn detector on XMM-Newton, which allows us to measure bulk flows in the intracluster medium (ICM) of the Perseus and Coma galaxy clusters. The procedure uses the fluorescent instrumental background lines present in all observations, in particular, Cu-Kα. By studying their spatial and temporal variations, in addition to incorporating calibration observations, we refined the absolute energy scale of the detector to better than 150km/s at the Fe-K line, a large improvement over the nominal calibration accuracy of 550km/s. With our calibration, we mapped the bulk motions over much of the central 1200 and 800kpc of Perseus and Coma, respectively, in spatial regions down to 65 and 140kpc size. We cross-checked our procedure by comparing our measurements with those found in Perseus by Hitomi for an overlapping 65kpc square region, finding consistent results. For Perseus, there is a relative line-of-sight velocity increase of 480±210km/s (1σ) at a radius of 250kpc east of the nucleus. This region is associated with a cold front, providing direct evidence of the ICM sloshing in the cluster potential well. Assuming the intrinsic distribution of bulk motions is Gaussian, its width is 214±85km/s, excluding systematic uncertainties. Removing the sloshing region, this is reduced to 20-150km/s, which is similar in magnitude to the Hitomi line width measurements in undisturbed regions. In Coma, the line-of-sight velocity of the ICM varies between the velocities of the two central galaxies. Maps of the gas velocity and metallicity provide clues about the merger history of the Coma, with material to the north and east of the cluster core having a velocity similar to NGC 4874, while that to the south and west has velocities close to NGC 4889. Our results highlight the difference between a merging system, such as Coma, where we observe a ∼1000km/s range in velocity, and a relatively relaxed system, such as Perseus, with much weaker bulk motions.

Abstract Copyright: © J. S. Sanders et al. 2020

Journal keyword(s): galaxies: clusters: intracluster medium - X-rays: galaxies: clusters - galaxies: clusters: individual: Coma cluster - galaxies: clusters: individual: Perseus cluster - techniques: imaging spectroscopy

VizieR on-line data: <Available at CDS (J/A+A/633/A42): cal.dat data.dat>

Simbad objects: 8

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Number of rows : 8
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 ACO 426 ClG 03 19 47.2 +41 30 47           ~ 2254 1
2 3C 84 Sy2 03 19 48.1599902040 +41 30 42.108850836   13.10 12.48 11.09   ~ 4003 3
3 NGC 4839 rG 12 57 24.3563164776 +27 29 52.203087132 13.56 13.02 12.06     ~ 466 3
4 NGC 4874 LIN 12 59 35.7093764280 +27 57 33.293892204 13.01 13.7 11.40 12.122 11.386 ~ 780 3
5 ACO 1656 ClG 12 59 44.40 +27 54 44.9           ~ 4793 2
6 NGC 4889 EmG 13 00 08.097 +27 58 37.29 12.93 13.0 11.30 11.652 10.906 ~ 704 1
7 NGC 4911 LIN 13 00 56.0616749160 +27 47 27.152821212 14.58 13.7 13.33 12.601 12.068 ~ 209 0
8 NGC 4921 LIN 13 01 26.1222244152 +27 53 09.629006748   13.7       ~ 209 0

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