* Astronomy

Title: Near-Infrared Polarimetric Adaptive Optics Observations of NGC 1068: A torus created by a hydromagnetic outflow wind
Author: E. Lopez-Rodriguez, C. Packham, T. J. Jones, R. Nikutta, L. McMaster, R. E. Mason, M. Elvis, D. Shenoy, A. Alonso-Herrero, E. Ramirez, O. Gonzalez Martin, S. F. Hoenig, N. A. Levenson, C. Ramos Almeida, E. Perlman

We present J' and K' imaging linear polarimetric adaptive optics observations of NGC 1068 using MMT-Pol on the 6.5-m MMT. These observations allow us to study the torus from a magnetohydrodynamical (MHD) framework. In a 0.5" (30 pc) aperture at K', we find that polarisation arising from the passage of radiation from the inner edge of the torus through magnetically aligned dust grains in the clumps is the dominant polarisation mechanism, with an intrinsic polarisation of 7.0%±2.2%. This result yields a torus magnetic field strength in the range of 4-82 mG through paramagnetic alignment, and 139^{+11}_{-20} mG through the Chandrasekhar-Fermi method. The measured position angle (P.A.) of polarisation at K' is found to be similar to the P.A. of the obscuring dusty component at few parsec scales using infrared interferometric techniques. We show that the constant component of the magnetic field is responsible for the alignment of the dust grains, and aligned with the torus axis onto the plane of the sky. Adopting this magnetic field configuration and the physical conditions of the clumps in the MHD outflow wind model, we estimate a mass outflow rate \le 0.17 solar masses yr^-1 at 0.4 pc from the central engine for those clumps showing near-infrared dichroism. The models used were able to create the torus in a timescale of \geq 10⁵ yr with a rotational velocity of \le 1228 km s^-1 at 0.4 pc. We conclude that the evolution, morphology and kinematics of the torus in NGC 1068 can be explained within a MHD framework.

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NGC 1068 (also M77, Cetus A, Arp 37, IRAS 02401-0013, UGC 2188 and PGC 10266) is a magnitude +9.6 barred spiral galaxy located 47 million light-years away in the constellation Cetus.

The galaxy was discovered by French astronomer Pierre François André Méchain using a 15.24 cm (6 inch) speculum Newtonian reflector on the 29th October 1780.

Charles Messier also observed the galaxy in December 1780.

Position (J2000): R.A. 02h 42m 40.7s  |  Dec. -00° 00' 48"

Title: Resolving the coronal line region of NGC1068 with near infrared integral field spectroscopy
Authors: X. Mazzalay (1), A. Rodríguez-Ardila (2), S. Komossa (3), Peter J. McGregor (4) ((1) Max-Planck-Institut für extraterrestrische Physik, Garching, Germany, (2) Laboratório Nacional de Astrofísica, Brazil, (3) Max-Planck-Institut für Radioastronomie, Bonn, Germany, (4) Research School of Astronomy & Astrophysics, Australian National University, Australia)

We present AO-assisted J- and K-band integral field spectroscopy of the inner 300 x 300 pc of the Seyfert 2 galaxy NGC1068. The data were obtained with the Gemini NIFS integral field unit spectrometer, which provided us with high-spatial and -spectral resolution sampling. The wavelength range covered by the observations allowed us to study the [CaVIII], [SiVI], [SiVII], [AlIX] and [SIX] coronal-line (CL) emission, covering ionisation potentials up to 328 eV. The observations reveal very rich and complex structures, both in terms of velocity fields and emission-line ratios. The CL emission is elongated along the NE-SW direction, with the stronger emission preferentially localized to the NE of the nucleus. CLs are emitted by gas covering a wide range of velocities, with maximum blueshifts/redshifts of ~ -1600/1000 km/s. There is a trend for the gas located on the NE side of the nucleus to be blueshifted while the gas located towards the SW is redshifted. The morphology and the kinematics of the near-infrared CLs are in very good agreement with the ones displayed by low-ionisation lines and optical CLs, suggesting a common origin. The line flux distributions, velocity maps, ionisation structure (traced by the [SiVII]/[SiVI] emission-line ratio) and low ionisation emission-line ratios (i.e., [FeII]/Pa\beta\ and [FeII]/[PII]) suggest that the radio jet plays an important role in the structure of the coronal line region of this object, and possibly in its kinematics.

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Title: Submillimetre line spectrum of the Seyfert galaxy NGC1068 from the Herschel-SPIRE Fourier Transform Spectrometer
Authors: Luigi Spinoglio, Miguel Pereira-Santaella, Gemma Busquet, Maximilien R. P. Schirm, Christine D. Wilson, Jason Glenn, Julia Kamenetzky, Naseem Rangwala, Philip R. Maloney, Tara J. Parkin, George J. Bendo, Suzanne C. Madden, Mark G. Wolfire, Alessandro Boselli, Asantha Cooray, Mathew J. Page

The first complete submillimetre spectrum (190-670um) of the Seyfert 2 galaxy NGC1068 has been observed with the SPIRE Fourier Transform Spectrometer onboard the Herschel Space Observatory. The sequence of CO lines (Jup=4-13), lines from water, the fundamental rotational transition of HF, two o-H_2O+ lines and one line each from CH+ and OH+ have been detected, together with the two [CI] lines and the [NII]205um line. The observations in both single pointing mode with sparse image sampling and in mapping mode with full image sampling allow us to disentangle two molecular emission components, one due to the compact circum-nuclear disk (CND) and one from the extended region encompassing the star forming ring (SF-ring). Radiative transfer models show that the two CO components are characterised by density of n(H_2)=10^4.5 and 10^2.9 cm^-3 and temperature of T=100K and 127K, respectively. The comparison of the CO line intensities with photodissociation region (PDR) and X-ray dominated region (XDR) models, together with other observational constraints, such as the observed CO surface brightness and the radiation field, indicate that the best explanation for the CO excitation of the CND is an XDR with density of n(H_2) 10^4 cm^-3 and X-ray flux of 9 erg s^-1 cm^-2, consistent with illumination by the active galactic nucleus, while the CO lines in the SF-ring are better modelled by a PDR. The detected water transitions, together with those observed with the \her \sim PACS Spectrometer, can be modelled by an LVG model with low temperature (T_kin \sim 40K) and high density (n(H_2) in the range 10^6.7-10^7.9 cm^-3).

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