matthias ehle the environments of galaxies crete, 9-13 august 2004 1 xmm-newton soc, esac hot...

Matthias EhleMatthias EhleThe Environments of GalaxiesCrete, 9-13 August 2004

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XMM-Newton SOC, ESAC

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

Matthias EhleEuropean Space Astronomy Centre (ESAC), Madrid, SpainXMM-Newton Science Operations Centre

European Space Agency (ESA),Research and Scientific Support Department,Science Operations and Data Systems Division

Michael DahlemCSIRO/ATNF - Paul Wild Observatory, Narrabri, Australia

Matthias EhleMatthias Ehle

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The Environments of GalaxiesCrete, 9-13 August 2004

Intro: Co-InvestigatorsIntro: Co-Investigators

List of (some) collaborators: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)


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Intro: MotivationIntro: Motivation

We want to know…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?


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Intro: Main GoalsIntro: 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


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Intro: Status 2004Intro: 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…


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Method: Multi-wavelength ObservationsMethod: 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-raysX-rays …


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Method: X-raysMethod: 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


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NGC 1511: The quest for hot gas in the haloNGC 1511: The quest for hot gas in the haloComparison with radio continuum data:

ATCA: 13 cm ATCA: 13 cm (Dahlem et al. 2001, 2004 (subm., improved))

EPIC 0.5-1.3 keVEPIC 0.5-1.3 keV

A&A 403, 547 (2003)


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NGC 1511: The quest for hot gas in the haloNGC 1511: The quest for hot gas in the haloX-ray spectroscopy with XMM-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) = 1.111040 erg s-1

log(LFIR/LX) = 3.62 typical for starburst galaxies LX,diffuse = 2.551039 erg s-1

log(LFIR/LX,diffuse) = 4.25 relatively low amount of diffuse emission (see Read & Ponman 2001)


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NGC 1511: The quest for hot gas in the haloNGC 1511: The quest for hot gas in the haloComparison with HI:

ATCA: ATCA: (Dahlem et al. 2004, subm.)


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NGC 1511: The quest for hot gas in the haloNGC 1511: The quest for hot gas in the halo

Summary: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 candidatenot an ideal candidate to test halo properties depending on star formation in underlying disk...


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NGC 4666: X-rays from a “Superwind” NGC 4666: X-rays from a “Superwind” ggalaxyalaxy

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. `97Dahlem 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

paper on X-ray results: Ehle et al. A&A (in prep.)


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X-ray imaging results: X-ray imaging results: ROSAT versus XMM-NewtonROSAT versus XMM-NewtonROSAT PSPC ROSAT PSPC (Dahlem et al. `98)

0.25 keV, 48” FWHMXMM-EPICXMM-EPIC0.2-0.5 keV, smoothed to 10” FWHM



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XMM-Newton energy bandsXMM-Newton energy bands


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Radio continuum & HRadio 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?

NGC 4666: X-rays from a “Superwind” galaxyNGC 4666: X-rays from a “Superwind” galaxy

Multi-wavelength (qualitative) comparison: Radio continuum, B-fields, HMulti-wavelength (qualitative) comparison: Radio continuum, B-fields, H

HI observationsHI observationsXMM-EPIC: 0.5-0.9 keVXMM-EPIC: 0.5-0.9 keV


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NGC 4666: Spectral analysis of EPIC-pn dataNGC 4666: Spectral analysis of EPIC-pn data

Disk: 0.18 & 0.54 keVDisk: 0.18 & 0.54 keV

fit model: phabsfg (mekal1 + phabs (mekal2 + powerl))

lower Halo: cf. Disklower Halo: cf. Diskupper Halo: no strong need for 2upper Halo: no strong need for 2ndnd mekal: mekal: single Temp. Fit: 0.23 keV single Temp. Fit: 0.23 keV

• 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)


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Summary: Characteristics of diffuse emission componentsSummary: Characteristics of diffuse emission components

NGC 4666: Spectral analysis of EPIC-pn dataNGC 4666: Spectral analysis of EPIC-pn data

LX = (T) ne nH dV (T) ne2 Vgeom

• In general: energy density of B-field predominant: channelling the outflow?In general: energy density of B-field predominant: channelling the outflow?

• Lower halo: higher thermal energy density Lower halo: higher thermal energy density outflow possible… outflow possible…


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NGC 4666: a “Superwind” galaxyNGC 4666: a “Superwind” galaxy

Summary: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


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NGC 3628: outflow & a veryNGC 3628: outflow & a very bright bright source source

• 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):XMM-Newton (~50 ksec): analysis started, some preliminary results...

Ehle, Read et al., A&A (in prep.)


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NGC 3628: outflow & halo emissionNGC 3628: outflow & halo emission

ROSAT PSPC ROSAT PSPC (Dahlem et al. `96)(Dahlem et al. `96)0.75 keV, 48” FWHM0.75 keV, 48” FWHM

XMM-EPIC XMM-EPIC (plus DSS contours)(plus DSS contours)0.3-0.5, 0.5-0.9, 0.9-2 keV, 10” FWHM0.3-0.5, 0.5-0.9, 0.9-2 keV, 10” FWHMXMM-EPIC XMM-EPIC (plus DSS contours)(plus DSS contours)0.3-0.5, 0.5-0.9, 0.9-2 keV, 10” FWHM0.3-0.5, 0.5-0.9, 0.9-2 keV, 10” FWHM

Overlay with VLT-FORS2:


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NGC 3628: central emissionNGC 3628: central emissionChandra Chandra ((Strickland et al. 2001))0.3-8 keV, 1” FWHM0.3-8 keV, 1” FWHM

XMM-EPICXMM-EPIC 0.3-8 keV slightly smoothed0.3-8 keV slightly smoothed

Preliminary spectral fit to IXO:


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Summary & OutlookSummary & 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…


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NGC 4666NGC 4666

NGC 4668 NGC 4668 (undet. ROSAT)(undet. ROSAT)

companioncompanion

companioncompanion

NGC 4666: a “Superwind” galaxyNGC 4666: a “Superwind” galaxyHI (VLA) map HI (VLA) map (Walter et al., ‘04) & 0.5-0.9 keV XMM-Newton EPIC & 0.5-0.9 keV XMM-Newton EPIC

• Prominent tidal arms

• Interacting with NGC 4668

• prev. unknown dwarf companions

Starburst activity Starburst activity probably caused by probably caused by interactioninteraction


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NGC 3628: ejection associated with Quasars?NGC 3628: ejection associated with Quasars?XMM-EPICXMM-EPIC 0.5-0.9 keV over VLT-FORS20.5-0.9 keV over VLT-FORS2

No connection between X-ray filament & QSOs Arp et al., 2002

XMM-EPICXMM-EPIC 0.5-0.9 keV over H0.5-0.9 keV over H (Rossa & Dettmar ’03)(Rossa & Dettmar ’03)

Correlation of X-ray filament & H plume?

matthias ehle the environments of galaxies crete, 9-13 august 2004 1 xmm-newton soc, esac hot...

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