J/A+A/665/A48       RXC J2014.8-2430 fits images            (Mroczkowski+, 2022)

The strongest cool core in REXCESS: Missing X-ray cavities in RXC J2014.8-2430. Mroczkowski T., Donahue M., van Marrewijk J., Clarke T.E., Hoffer A., Intema H., Di Mascolo L., Popping G., Pratt G.W., Sun M., Voit M. <Astron. Astrophys. 665, A48 (2022)> =2022A&A...665A..48M 2022A&A...665A..48M (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; X-ray sources ; Radio sources Keywords: galaxies: clusters: intracluster medium - galaxies: clusters: individual: RXC J2014.8-2430 - X-rays: galaxies: clusters - submillimeter: galaxies - radio continuum: galaxies - galaxies: clusters: general Abstract: We present a broad, multi-wavelength study of RXC J2014.8-2430, the most extreme cool-core cluster in the Representative XMM-Newton Cluster Structure Survey (REXCESS), using Chandra X-ray, Southern Astrophysical Research (SOAR) Telescope spectroscopic and narrow-band imaging, Atacama Large Millimeter/submillimeter Array (ALMA), Very Large Array, and Giant Metrewave Radio Telescope observations. While feedback from an active galactic nucleus (AGN) is thought to be the dominant mechanism by which a cooling flow is suppressed, the Chandra imaging observations surprisingly do not reveal the bi-lateral X-ray cavities one might expect to see in the intracluster medium (ICM) of an extreme cool core hosting a powerful radio source, though cavities commonly appear in many similar sources. We discuss the limits on the properties of putative radio bubbles associated with any undetected X-ray cavities. We place upper limits on any significant X-ray AGN in the brightest cluster galaxy (BCG), and show that the X-ray peak is offset from the central radio source, which exhibits a steep low-frequency radio spectrum indicative of electron ageing. The imaging and spectroscopy provided by SOAR reveal an extended, luminous optical emission-line source. From our narrow-band Hα imaging of the BCG, the central Hα peak is coincident with the radio observations, yet offset from the X-ray peak, consistent with sloshing found previously in this cluster. ALMA observations of the CO(1-0) emission reveal a large reservoir of molecular gas that traces the extended Hα emission in the direction of the cool core. We conclude either that the radio source and its cavities in the X-ray gas are nearly aligned along the line of sight, or that ram pressure induced by sloshing has significantly displaced the cool molecular gas feeding it, perhaps preempting the AGN feedback cycle. We argue that the sloshing near the core is likely subsonic, as expected, given the co-location of the Hα, CO(1-0), radio continuum, and stellar emission peaks and their proximity to the X-ray peak. Further, the X-ray emission from the core is strongly concentrated, as is the distribution of metals, indicating the cool core remains largely intact. Deeper Chandra observations will be crucial for definitively establishing the presence or lack of X-ray cavities, while X-ray micro-calorimetric observations from Athena could establish if the motion of the cold and warm gas is dominated by large-scale motions of the surrounding ICM. Description: A 20 ks Chandra observation of RXC J2014.8-2430 was taken on August 25, 2009 (ObsID 11757) as part of the Chandra Guest Observers programme. Narrow-band optical imaging was taken on the SOAR Telescope with the SOAR Optical Imager on September 6, 2010. We use millimetre-wave observations performed by ALMA on December 24, 2018, to probe the location and dynamics of the molecular gas traced by the lowest transition of the dominant form of carbon monoxide, CO(1-0), which has a rest frequency of 115.271GHz. The VLA performed L-band (1-2GHz) observations on May 29, 2014, of the continuum radio emission from RXC J2014.8-2430 as part of Project code 14A-280. As part of a larger observing programme (project code 14JHC01), RXC J2014.8-2430 was observed at 610MHz by the GMRT for 3.1h in 6 equal blocks during the night of June 21, 2008. The VLITE is a commensal 338MHz system that operates on the NRAO VLA in parallel with standard observing programmes that use the 1-50GHz feeds. RXC J2014.8-2430 was detected in six separate VLITE observations at distances between 0.5° and 1.4° from the phase centre between December 10, 2017, and November 22, 2020. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file lines.dat 65 74 Lines for the SOAR spectroscopy list.dat 188 12 List of fits images and datacubes fits/* . 12 Individual fits images and datacubes -------------------------------------------------------------------------------- Byte-by-byte Description of file: lines.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 9 A9 --- Line Spectral line 11- 13 I3 pix RegCent ? Region centre 15- 21 F7.2 0.1nm LineCent Line centre 23- 27 F5.2 0.1nm e_LineCent Line centre error 29- 34 F6.1 0.1nm EW Equivalent width 36- 39 F4.1 0.1nm e_EW Equivalent width error 41- 47 F7.4 10-19W/m2 Flux Flux 49- 52 F4.2 10-19W/m2 e_Flux Flux error 54- 59 F6.3 0.1nm FWHM FWHM 61- 65 F5.2 0.1nm e_FWHM FWHM error -------------------------------------------------------------------------------- Byte-by-byte Description of file: list.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 9 F9.5 deg RAdeg Right Ascension of center (J2000) 10- 18 F9.5 deg DEdeg Declination of center (J2000) 20- 23 I4 --- Nx Number of pixels along X-axis 25- 28 I4 --- Ny Number of pixels along Y-axis 30- 32 I3 --- Nz ? Number of slices for the datacubes 34- 55 A22 "datime" Obs.date Observation date 57- 62 I6 Kibyte size Size of FITS file 64-128 A65 --- FileName Name of FITS file, in subdirectory fits 130-188 A59 --- Title Title of the FITS file -------------------------------------------------------------------------------- Acknowledgements: Tony Mroczkowski, tony.mroczkowski(at)eso.org
(End) Patricia Vannier [CDS] 22-Jul-2022
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