1 / 14

Multiwavelength Observations of the Circumnuclear Environment in NGC 2110

Multiwavelength Observations of the Circumnuclear Environment in NGC 2110. Dan Evans (CfA), Julia Lee (CfA), Maria Kamenetska (MIT), Sarah Gallagher (UCLA), Ralph Kraft (SAO), Martin Hardcastle (U. Herts), and Kim Weaver (GSFC). Contents. The circumnuclear environments of Seyferts

elpida
Download Presentation

Multiwavelength Observations of the Circumnuclear Environment in NGC 2110

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Multiwavelength Observations of the Circumnuclear Environment in NGC 2110 Dan Evans (CfA), Julia Lee (CfA), Maria Kamenetska (MIT), Sarah Gallagher (UCLA), Ralph Kraft (SAO), Martin Hardcastle (U. Herts), and Kim Weaver (GSFC)

  2. Contents • The circumnuclear environments of Seyferts • The nearby Seyfert 2 galaxy NGC 2110 • Small-scale X-ray emission: shock heated? Photoionized? • Constraints from HETGS data • Large-scale X-ray emission • Conclusions

  3. 2’’=360 pc Mrk 607 - HST [OIII] Circumnuclear Seyfert Environments • NLR (sub-kpc) and ENLR (up to ~10 kpc) are regions of warm (T~104 K), ionized gas • Seyferts with little radio activity have smooth, collimated [OIII] gas distributions • However, it’s long been known that some Seyferts may have small-scale radio jets

  4. ‘Disturbed’ Environments: A Rogues’ Gallery Mrk 573 - HST [OIII]/VLA ESO 428-G14 - HST [OIII]/VLA • See [OIII] survey by Schmitt et al. (2003) • Radio jet has strong influence on NLR, often resulting in a disturbed environment, with prominent series of arcs, strands, and knots • How is the emission produced? Shock heating? Photoionization? Important constraints from Chandra, HST spectroscopy IC 5063 - HST [OIII] Mrk 78 - HST [OIII]

  5. NGC 2110 - Overview • Nearby (z=0.0076, DL=33 Mpc, 1’’=160 pc) Seyfert 2 • Complex structure on a range of scales HST F606W / VLA (Mulchaey et al. 1994) HST [OIII] / VLA (Mulchaey et al. 1994)

  6. Chandra ACIS-S tri-color image Red=0.5-1 keV; Green=1-1.5 keV; Blue=4-5 keV Chandra Imaging/Spectroscopy • Extended soft X-ray emission North of the nucleus • Nuclear emission shows both soft and hard X-ray emission

  7. Chandra Imaging/Spectroscopy • Excellent spatial agreement between X-ray and [OIII] • Both clearly offset from radio, but extend along similar p.a. • X-ray & [OIII] emission influenced, but not directly associated with, radio jet? • X-ray spectrum modeled by two thermal plasma models (kT1~0.3 keV; kT2~5 keV) Chandra (0.5-1.5 keV) / VLA / HST [OIII] overlay Source, background spectral extraction regions 5’’=800 pc

  8. Emission Mechanisms & Energetics • Consider 3 different X-ray and [OIII] emission mechanisms • Shock heating: consideration of pressures • Minimum pressure of radio lobes, assuming min=2 up to max=105, and p=2.4, is ~10-10 Pa • HST [OIII] and [SII] constraints (Ferruit et al. 1999) give pressure ~few 10-10 Pa • Chandra spectrum, with plasma model, gives pressure ~few 10-10 Pa • A simple shock-heating model through multi-phase gas clouds provides an adequate explanation

  9. Emission Mechanisms & Energetics • Electron-scatted nuclear radiation • Assume nucleus emits isotropically and scattered into 45o cone • Ratio of scattered to ‘direct’ fluxes ~10-4 • Optical depth to Compton scattering gives Nscat~1022 cm-2 • For sensible volume, gives mass of scattering gas as 107M๏ • Unless nuclear radiation emitted anisotropically, scattering cannot account for extended emission • How does scattering explain the radio–X-ray/[OIII] offset?

  10. Emission Mechanisms & Energetics • Photoionization • Consider extended X-ray luminosity, and use sensible values of ionization parameter and emissivity • Nuclear luminosity required to photoionize gas 20x greater than that measured • This mechanism may be energetically viable, especially if nuclear emission emitted anisotropically • Radio–X-ray/[OIII] offset not easily explained • Would we observe photoionized line-emission in HETGS spectra?

  11. HETGS Data • 250 ks HETGS observation of NGC 2110 over 2 epochs separated by ~1 year • Detection of fluorescent Ka transitions of Fe, Si, S, Ca → consistent with reflection from cold, neutral material • Evidence of highly ionized iron at ~12 A (~1 keV)?

  12. Comparison with NGC 1068 • NGC 1068 (z=0.004, DL=16 Mpc) is the prototypical Seyfert 2 • Many strong X-ray emission lines, consistent with a photoionized plasma (Ogle et al. 2003) • X-ray, radio, [OIII] emission are spatially coincident (Young et al. 2001) • Do different physical processes produce different environments? NGC 1068: Chandra/VLA

  13. Large-scale X-ray Emission in NGC 2110 • Noticeable asymmetry in large-scale (~few kpc) X-ray gas • Does not trace optical continuum or [OIII] emission • Spectrum modeled with kT=0.9 keV plasma, internal energy=1055 ergs • Origin unclear, though prominence south of the nucleus is consistent with disk inclination • Two point sources, statistically consistent with background, though would have LX~1039 ergs/s at host

  14. Conclusions • Seyferts with strong radio emission show noticeably disturbed circumnuclear environments • The circumnuclear environment of NGC 2110 is consistent with shock-heating by the jet • Cannot rule out electron-scattering or photoionizaton • Comparison with NGC 1068: do different physical processes produce different circumnuclear environments in Seyferts?

More Related