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Hot gaseous Halos & their Dependence on Activity in the underlying galactic Disks

Hot gaseous Halos & their Dependence on Activity in the underlying galactic Disks. Matthias Ehle European Space Astronomy Centre (ESAC), Madrid, Spain XMM-Newton Science Operations Centre European Space Agency (ESA), Research and Scientific Support Department,

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Hot gaseous Halos & their Dependence on Activity in the underlying galactic Disks

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  1. Hot gaseous Halos & their Dependence on Activity in the underlying galactic Disks Matthias Ehle European Space Astronomy Centre (ESAC), Madrid, Spain XMM-Newton Science Operations Centre European Space Agency (ESA), Research and Scientific Support Department, Science Operations and Data Systems Division Michael Dahlem CSIRO/ATNF - Paul Wild Observatory, Narrabri, Australia XMM-Newton SOC, ESAC

  2. Intro: Co-Investigators List of (some) collaborators: • A. M. Read (Uni. Leicester), T. J. Ponman (Uni. Birmingham) • D. Breitschwerdt (Inst. f. Astron., Uni. of Vienna) • S. Ryder (AAO) • U. Lisenfeld (Inst. Astrof. Andalucia) • T. Heckman, D. K. Strickland (Johns Hopkins Uni.) • K. Weaver (NASA/GSFC) • F. Walter (NRAO) XMM-Newton SOC, ESAC

  3. Intro: Motivation We want to know… • How is the IGM fed with metals? • Do star formation-driven galactic outflows play a significant role? • How do SF-driven outflows work? • How are gaseous halos energised? • Is there a direct link between galactic disk activity and halo (existence and properties)? • How much energy is required to initiate disk-halo interactions? XMM-Newton SOC, ESAC

  4. Intro: Main Goals • Build galaxy sample of sufficient size to study dependence of halo properties on… • total SFR • SFR per unit surface area (or take into account volume filling factor of HII regions); energy input rate: ĖAtotĖ / ASF proportional to LFIR / ASF • Study interdependence of different components of halo ISM: • spatial correlation? • energy budget / equilibrium? • Caveats: • interaction partners • galaxy’s size, i.e. shape of its gravitational potential • nuclear activity XMM-Newton SOC, ESAC

  5. Intro: Status 2004 • Halos break off further inwards than underlying disks. • Ėatot can quantify Norman & Ikeuchi’s “breakout condition” for the creation of chimneys. • Same rules apply for archetypical starburst galaxies and systems with widespread SF. • Many more gaseous halos detected over past decade: • In H, radio continuum and/or X-ray emission (Rossa, Dettmar, Rand, Irwin, Strickland + others) • Progress on X-ray imaging (XMM-Newton, Chandra; Strickland, Read, Bregman, Pietsch, Vogler + others) • First detections of HI in galaxy halos (Swaters, Irwin, Fraternali + others) • New results presented at this (and Dwingeloo June ’04) conference… XMM-Newton SOC, ESAC

  6. Method: Multi-wavelength Observations • multi-wavelength study: • Tracers of SF in galactic disk: • FIR continuum (selection criteria) • H  warm ionized gas, SF regions • thermal radio continuum (< a few cm) • Tracers of galactic halos: • H: spurs & filaments • non-thermal radio continuum (: cm – dm)  cosmic rays & B-fields • radio lines: HI, CO cold, neutral gas: dynamics, inclination, outflow? • last (but not least) X-rays … XMM-Newton SOC, ESAC

  7. Method: X-rays • X-rays: • Imaging disc & halo emission, existence & distribution of extra-planar hot gas • Timing  variability of emission (source identification) • Spectroscopy origin of emission: individual sources and/or hot gas nuclear or extended starburst, AGN? temperature, metallicity of hot gas • (chemical) evolution of a galaxy • potential impact on enrichment of IGM • Strengths of XMM-Newton • a lot of photons • High resolution soft X-ray spectroscopy: not-so-bright objects • Will show three beasts from the (X-ray) zoo... • NGC 1511 (news from the radio), NGC 4666, NGC 3628 • NGC 1511 (X-ray halo detected) Dahlem, Ehle et al., A&A 403, 547 (2003) • NGC 1808 (nuclear starburst/AGN) Jimenez Bailon et al., astro-ph/0301109, A&A in prep. • NGC 7090 observed May 2004 XMM-Newton SOC, ESAC

  8. NGC 1511: The quest for hot gas in the halo A&A 403, 547 (2003) Comparison with radio continuumdata: ATCA: 13 cm (Dahlem et al. 2001, 2004 (subm., improved)) EPIC 0.5-1.3 keV XMM-Newton SOC, ESAC

  9. NGC 1511: The quest for hot gas in the halo X-ray spectroscopywithXMM-Newton: (bright source excluded) • simple models do not fit: •  complex emission composition • best fit: (others are possible) • phabsfg(mekal1 + phabs (mekal2 + powerl)) •  0.19 keV (12 % of total flux) • 0.59 keV (11 %) • photon index 1.4 (77 %) •  LX(0.2-12 keV) = 1.111040 erg s-1 • log(LFIR/LX) = 3.62 • typical for starburst galaxies •  LX,diffuse = 2.551039 erg s-1 • log(LFIR/LX,diffuse) = 4.25 • relatively low amount of diffuse • emission(see Read & Ponman 2001) XMM-Newton SOC, ESAC

  10. NGC 1511: The quest for hot gas in the halo Comparison with HI: ATCA: (Dahlem et al. 2004, subm.) XMM-Newton SOC, ESAC

  11. NGC 1511: The quest for hot gas in the halo Summary: • XMM-Newton revealed previously unknown extended hot gas, partly extending out of disk plane, extra-planar emission also in radio continuum • spectral analysis: complex emission composition • X-ray properties characterise NGC 1511 as starburst galaxy • UV, H, NIR, esp. HI suggest: NGC 1511 heavily disturbed (by two small companions)  not an ideal candidate to test halo properties depending on star formation in underlying disk... XMM-Newton SOC, ESAC

  12. NGC 4666: X-rays from a “Superwind” galaxy paper on X-ray results: Ehle et al. A&A (in prep.) State of knowledge before XMM-Newton: • FIR luminosity higher than for actively star-forming galaxies NGC 253 and NGC 4631  high global SFR in NGC 4666 • log (LFIR/LB) = 0.48 & FIR colour f60/f100 = 0.45  NGC 4666 is a typical FIR-selected galaxy(Lehnert & Heckman `95)good candidate for multi wavelength search for halo emission • First evidence for existence of starburst driven galactic superwind in NGC 4666 reported in Dahlem et al. `97: • optical emission line imagery: filaments • optical line diagnostics: shocks as main heating source • radio continuum maps: halo detected • radio polarization data: B-fields follow flow or allow it (?) • X-rays: ROSAT PSPC: soft extended extra-planar emission XMM-Newton SOC, ESAC

  13. ROSAT PSPC (Dahlem et al. `98) 0.25 keV, 48” FWHM XMM-EPIC 0.2-0.5 keV, smoothed to 10” FWHM NGC 4666: X-rays from a “Superwind” galaxy X-ray imaging results: ROSAT versus XMM-Newton XMM-Newton SOC, ESAC

  14. NGC 4666: X-rays from a “Superwind” galaxy XMM-Newton energy bands XMM-Newton SOC, ESAC

  15. XMM-EPIC: 0.5-0.9 keV NGC 4666: X-rays from a “Superwind” galaxy Multi-wavelength (qualitative) comparison: Radio continuum, B-fields, H • Radio continuum & H(Dahlem et al. `97): • clear detection of radio halo (6, 20 cm) • spectral steepening away from disk • outflow cone from central starburst (radial diameter 6.5 kpc), traced by optical filaments up to 7.5 kpc above disk • polarized radio spurs: outer wall of outflow cone? • vertical B-fields: pushed out by superwind, or poloidal dynamo field? HI observations XMM-Newton SOC, ESAC

  16. lower Halo: cf. Disk Disk: 0.18 & 0.54 keV upper Halo: no strong need for 2nd mekal: single Temp. Fit: 0.23 keV NGC 4666: Spectral analysis of EPIC-pn data fit model: phabsfg (mekal1 + phabs (mekal2 + powerl)) • halo fit improves with free Z...(~ 0.1-0.3 Zsolar), seems unphysical (starburst enriches out-flowing material) • wrong CIE assumption (Breitschwerdt 2003), TBC • bulk of soft emission due to hot gas: mekal contribution • 0.3-0.9 keV flux: 72% (disk), 69% (lower), 92% (upper halo) • mekal2 (high T2) contribution decreases in upper halo: • fluxT1/fluxT2: 1.12 (disk), 0.72 (lower), 6.07 (upper halo) • in disk & lower halo higher contribution due to powerl: • unresolved point-like sources, XRBs • 0.3-12 keV flux: 81% (disk), 80% (lower), 56% (upper halo) XMM-Newton SOC, ESAC

  17. Lower halo: higher thermal energy density  outflow possible… NGC 4666: Spectral analysis of EPIC-pn data Summary: Characteristics of diffuse emission components LX = (T)  ne nH dV  (T) ne2  Vgeom • In general: energy density of B-field predominant: channelling the outflow? XMM-Newton SOC, ESAC

  18. NGC 4666: a “Superwind” galaxy Summary: • XMM-Newton observations reveal huge, structured hot gas halo, on both sides of disk; southern soft emission absorbed due to inclined disk • X-ray properties confirm: superwind exists in NGC 4666 • HI shows: starburst probably triggered due to tidal interactions • interesting correlation of X-ray, H, polarization filaments: outflow cone & walls? • comparison of energy densities: B-fields important plasma  < 1; only in lower halo possibly > 1 • spectral analysis shows complex emission composition: fit with mekal (CIE) model NOT unambiguous: NIE-model currently under testing XMM-Newton SOC, ESAC

  19. NGC 3628: outflow & a very bright source Ehle, Read et al., A&A (in prep.) • NGC 3628 is interacting member of Leo Triplet • collimated outflow from starburst nucleus detected by Einstein (Fabbiano et al `90) and X-ray ‘halo’ confirmed by ROSAT (Dahlem et al. `96) • strange central X-ray source (unresolved with ROSAT): strong variability (faded by factor >27 between 1991 - 1994) variable obscuration of AGN or HXRB (>75 Msun black hole)? Chandra (52 ksec,Strickland et al. 2001):luminous source visible again, but 20” offset from nucleus • XMM-Newton (~50 ksec):analysis started, some preliminary results... XMM-Newton SOC, ESAC

  20. XMM-EPIC (plus DSS contours) 0.3-0.5, 0.5-0.9, 0.9-2 keV, 10” FWHM XMM-EPIC (plus DSS contours) 0.3-0.5, 0.5-0.9, 0.9-2 keV, 10” FWHM NGC 3628: outflow & halo emission ROSAT PSPC (Dahlem et al. `96) 0.75 keV, 48” FWHM Overlay with VLT-FORS2: XMM-Newton SOC, ESAC

  21. NGC 3628: central emission Chandra (Strickland et al. 2001) 0.3-8 keV, 1” FWHM XMM-EPIC 0.3-8 keV slightly smoothed Preliminary spectral fit to IXO: XMM-Newton SOC, ESAC

  22. Summary & Outlook • high f60/f100 FIR colour (> 0.4): successful criterion for halo candidates (shown for radio halos, X-ray sample still small, but promising…), main targets: M82, NGC 3175, NGC 4666, NGC 4700, NGC 7090, NGC 7462 • galaxies with highest ĖAtot Ė / ASF show ‘most prominent’ radio halos; X-ray halos, too (details still to be quantified) • High spatial resolution & sensitivity of XMM-Newton is important: • disentangle starburst/AGN/point-like sources/diffuse/disk/halo emission • detailed spatial comparison with optical/radio/B-field filaments (originating in strongest SF regions) • spectral sensitivity allows detailed study of hot gas (CIE vs. NIE, T, Z, ne,…)  energy budget of different ISM components • Search for other extra-planar phases of the ISM, e.g. HI(Dahlem, Ehle et al., A&A, subm.) • Investigate influence of more parameters, such as galaxy mass, on halo properties. Many thanks for your attention… XMM-Newton SOC, ESAC

  23. NGC 4666 companion companion NGC 4668 (undet. ROSAT) NGC 4666: a “Superwind” galaxy HI (VLA) map (Walter et al., ‘04) & 0.5-0.9 keV XMM-Newton EPIC • Prominent tidal arms • Interacting with NGC 4668 • prev. unknown dwarf companions  Starburst activity probably caused by interaction XMM-Newton SOC, ESAC

  24. XMM-EPIC 0.5-0.9 keV over VLT-FORS2 XMM-EPIC 0.5-0.9 keV over H (Rossa & Dettmar ’03) No connection between X-ray filament & QSOs  Arp et al., 2002 Correlation of X-ray filament & H plume? NGC 3628: ejection associated with Quasars? XMM-Newton SOC, ESAC

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