Snowballs in hell! X-ray galactic coronae in galaxy! clusters and the need for sub-arcsecond resolution! Simona Giacintucci (NRL)!

Transcription

1 Snowballs in hell X-ray galactic coronae in galaxy clusters and the need for sub-arcsecond resolution Simona Giacintucci (NRL) M. Markevitch (GSFC), T. Clarke (NRL), E. Richards (NRC-NRL) X-ray Skies with High-Res Eyes: Imaging the Cosmos with AXIS 6-7 August 2018, Washington DC

2 Compact X-ray Coronae in Cluster Galaxies Vikhlinin et al. 2001: X-ray coronae in two dominant galaxies in the Coma cluster Chandra, kev X-ray Optical 100 kpc NGC4889 kt = 2.0 kev NGC4874 kt = 1.1 kev 5 = 2 kpc Chandra 0.5 Ms kev Sanders et al S. Giacintucci (NRL)

3 Compact X-ray Coronae in Cluster Galaxies More of such X-ray corona remnants have been found in rich clusters (e.g., Yamasaki et al. 2002, Sun et al. 2005, 2007, Fujita et al. 2006, Jeltema et al. 2008, O Sullivan et al. 2010, Venturi et al. 2013) A 3627 kt ~ 1 kev r~ 3 kpc Chandra image from Sun et al S. Giacintucci (NRL)

4 Abell 2443: a violent cluster merger at z=0.1 (Clarke et al. 2013) Chandra kev cd galaxy 150 kpc S. Giacintucci (NRL)

5 Abell 2443: a violent cluster merger at z=0.1 (Clarke et al. 2013) Chandra kev Chandra kev Corona radius ~2 = 4 kpc cd galaxy 150 kpc Chandra PSF Giacintucci, Clarke et al. in prep. S. Giacintucci (NRL)

6 Abell 2443: a violent cluster merger at z=0.1 (Clarke et al. 2013) ~ 7 kev 1.7 kev Chandra kev Chandra kev Corona radius ~2 = 4 kpc cd galaxy 150 kpc Chandra PSF Giacintucci, Clarke et al. in prep. S. Giacintucci (NRL)

7 How can X-ray coronae survive in clusters? Evaporation and ram pressure stripping by the hot ICM should be efficient in removing gas from cluster galaxies Gas density Simulation of evaporation from thermal conduction with ram pressure of a massive galaxy in typical ICM conditions (Vijayaraghavan & Sarazin 2017, paper I) The frequency of X-ray coronae indicates that they must survive stripping and evaporation for several Gyr S. Giacintucci (NRL)

8 How can X-ray coronae survive in clusters? Heat conduction across ISM-ICM boundary must be suppressed by a factor ~ (e.g., Vikhlinin et al. 2001, Sun et al. 2007) Magnetic fields may be able to shield coronae from thermal evaporation Disjoint magnetic structure between ISM and ICM ICM ISM Magnetic field pressure See simulations in Vijayaraghavan & Sarazin 2017, paper II S. Giacintucci (NRL)

9 X-ray coronae in clusters as mini-versions of cool cores X-ray coronae have a short cooling time (~0.2 Gyr), thus they must contain a heat source that balances the energy loss due to X-ray radiation. Energy released from stellar mass losses is too small to balance cooling (e.g., Sun et al. 2007) AGN heating? Radio, X-ray cool core in Hydra A cluster S. Giacintucci (NRL)

10 Radio jets are anti-correlated with the corona X-ray emission NGC 4874 in Coma cluster Chandra kev VLA 5 GHz contours at 0.5 resoution Sanders et al S. Giacintucci (NRL)

11 Radio jets are anti-correlated with the corona X-ray emission A2443 Chandra kev 1 pixel = C449 VLA 8.5 GHz 0.3 resolution 2 kpc 2 kpc NGC 1265 (Perseus) VLA 8.5 GHz contours at 0.2 resolution Giacintucci, Clarke et al. in prep. VLA 8.5 GHz 0.8 resolution Other examples in Sun et al. 2005a,b, O Sullivan et al. 2010, Venturi et al S. Giacintucci (NRL)

12 Radio jets are anti-correlated with the corona X-ray emission 5 GHz 1 resolution, on Chandra kev 3C278 1 arcsec = 300 pc 10" = 3 kpc 1.4 GHz 5 resolution on Chandra kev (smoothed) 1.4 GHz (5 resolution) on optical S. Giacintucci (NRL)

13 Radio jets are anti-correlated with the corona X-ray emission Radio jets carry and deposit most of their energy outside the corona AGN jet heating may not be able to offset cooling in coronae S. Giacintucci (NRL)

14 Need for AXIS sub-arcsecond and high-sensitivity soft X-ray observations - match the high resolution of radio observations (SKA ~ 2030, ngvla?) - image X-ray substructures (channels, cavities, shock-related features..) within the corona region and at the corona boundary (where the radio jets appear to flare) NGC kev Central cavity with r~0.6 kpc? 1 pixel = Residual of a surface brightness fit Sanders et al S. Giacintucci (NRL)

15 An alternative to AGN heating Cooling may be balanced by reduced heat influx through the ICM/ ISM interface (first suggested by Vikhlinin et al for NGC 4874) Sanders et al Detailed temperature profiles of coronae are needed -> AXIS S. Giacintucci (NRL)

16 Thanks