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Register a new userGemini IFU, VLA and HST observations of the OH Megamaser galaxy IRASF23199+0123: the hidden monster and its outflow
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We present Gemini Multi-Object Spectrograph (GMOS) Integral field Unit (IFU), Very Large Array (VLA) and Hubble Space Telescope (HST) observations of the OH Megamaser (OHM) galaxy IRASF23199+0123. Our observations show that this system is an interacting pair, with two OHM sources associated to the eastern (IRAS23199E) member. The two members of the pair present somewhat extended radio emission at 3 and 20~cm, with flux peaks at each nucleus. The GMOS-IFU observations cover the inner $sim$6kpc of IRAS23199E at a spatial resolution of 2.3~kpc. The GMOS-IFU flux distributions in H$alpha$ and [NII]$lambda$6583 are similar to that of an HST [NII]+H$alpha$ narrow-band image, being more extended along the northeast-southwest direction, as also observed in the continuum HST F814W image. The GMOS-IFU H$alpha$ flux map of IRAS23199E shows three extranuclear knots attributed to star-forming complexes. We have discovered a Seyfert 1 nucleus in this galaxy, as its nuclear spectrum shows an unresolved broad (FWHM$approx$2170 kms$^{-1}$) double-peaked H$alpha$ component, from which we derive a black hole mass of M$_{BH}$= 3.8$^{+0.3}_{-0.2}times 10^{6}$M$_{odot}$. The gas kinematics shows low velocity dispersions ($sigma$) and low [NII]/H$alpha$ ratios for the star-forming complexes and higher $sigma$ and [NII]/H$alpha$ surrounding the radio emission region, supporting interaction between the radio-plasma and ambient gas. The two OH masers detected in IRASF23199E are observed in the vicinity of these enhanced $sigma$ regions, supporting their association with the active nucleus and its interaction with the surrounding gas. The gas velocity field can be partially reproduced by rotation in a disk, with residuals along the north-south direction being tentatively attributed to emission from the front walls of a bipolar outflow.
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We present a multiwavelength study of the OH megamaser galaxy (OHMG) IRAS17526+3253, based on new Gemini Multi-Object Spectrograph Integral Field Unit (GMOS/IFU) observations, Hubble Space Telescope F814W and H$alpha$+[N{sc ii}] images, and archival 2MASS and 1.49GHz VLA data. The HST images clearly reveal a mid-to-advanced stage major merger whose northwestern and southeastern nuclei have a projected separation of $sim$8.5kpc. Our HST/H$alpha$+[N{sc ii}] image shows regions of ongoing star-formation across the envelope on $sim$10kpc scales, which are aligned with radio features, supporting the interpretation that the radio emission originates from star-forming regions. The measured H$alpha$ luminosities imply that the unobscured star-formation rate is $sim$10-30,M$_{odot}$yr$^{-1}$. The GMOS/IFU data reveal two structures in northwestern separated by 850,pc and by a discontinuity in the velocity field of $sim$~200~km~s$^{-1}$. We associate the blue-shifted and red-shifted components with, respectively, the distorted disk of northwestern and tidal debris, possibly a tail originating in southeastern. Star-formation is the main ionization source in both components, which have SFRs of $sim$2.6-7.9,M$_{odot}$yr$^{-1}$ and $sim$1.5-4.5,M$_{odot}$yr$^{-1}$, respectively. Fainter line emission bordering these main components is consistent with shock ionization at a velocity $sim$200~km~s$^{-1}$ and may be the result of an interaction between the tidal tail and the northwestern galaxys disk. IRAS17526+3253 is one of only a few systems known to host both luminous OH and H$_{2}$O masers. The velocities of the OH and H$_{2}$O maser lines suggest that they are associated with the northwestern and southeastern galaxies, respectively.
We present two-dimensional stellar and gaseous kinematics of the inner 0.7 $times$ 1.2 kpc$^{2}$ of the Seyfert galaxy ESO 362-G18, derived from optical spectra obtained with the GMOS/IFU on the Gemini South telescope at a spatial resolution of $approx$170 pc and spectral resolution of 36 km s$^{-1}$. ESO 362-G18 is a strongly perturbed galaxy of morphological type Sa or S0/a, with a minor merger approaching along the NE direction. Previous studies have shown that the [OIII] emission shows a fan-shaped extension of $approx$ 10arcsec to the SE. We detect the [OIII] doublet, [NII] and H${alpha}$ emission lines throughout our field of view. The stellar kinematics is dominated by circular motions in the galaxy plane, with a kinematic position angle of $approx$137$^{circ}$. The gas kinematics is also dominated by rotation, with kinematic position angles ranging from 122$^{circ}$ to 139$^{circ}$. A double-Gaussian fit to the [OIII]$lambda$5007 and H${alpha}$ lines, which have the highest signal to noise ratios of the emission lines, reveal two kinematic components: (1) a component at lower radial velocities which we interpret as gas rotating in the galactic disk; and (2) a component with line of sight velocities 100-250 km s$^{-1}$ higher than the systemic velocity, interpreted as originating in the outflowing gas within the AGN ionization cone. We estimate a mass outflow rate of 7.4 $times$ 10$^{-2}$ M$_{odot}$ yr$^{-1}$ in the SE ionization cone (this rate doubles if we assume a biconical configuration), and a mass accretion rate on the supermassive black hole (SMBH) of 2.2 $times$ 10$^{-2}$ M$_{odot}$ yr$^{-1}$. The total ionized gas mass within $sim$84 pc of the nucleus is 3.3 $times$ 10$^{5}$ M$_{odot}$; infall velocities of $sim$34 km s$^{-1}$ in this gas would be required to feed both the outflow and SMBH accretion.
We present MERLIN observations of the continuum (both 1.6 and 5 GHz) and OH maser emission towards Arp220. the correct spatial configuration of the various componnents of the galaxy is revealed. In the eastern component the masers are shown to be generally coincident with the larger scale continuum emission; in the west, the masers and continuum do not generally arise from the same location. A velocity gradient (0.32+/-0.03km/s/pc) is found in the eastern nuclear region in MERLIN scales; this gradient is three times smaller than seen in OH and implies that the OH gas lies inside the HI. A re-analysis of previously presented global VLBI data (Lonsdale et al. 1998) reveals a very high velocity gradient (18.67+/-0.12km/s/pc) in one component, possibly the site of a heavily obscured AGN.
We present a multiwavelength study of the OH Megamaser galaxy (OHMG) IRAS16399-0937, based on new HST/ACS F814W and H$alpha$+[NII] images and archive data from HST, 2MASS, Spitzer, Herschel and the VLA. This system has a double nucleus, whose northern (IRAS16399N) and southern (IRAS16399S) components have a projected separation of $sim$ 6 (3.4 kpc) and have previously been identified based on optical spectra as a Low Ionization Nuclear Emission Line Region (LINER) and starburst nucleus, respectively. The nuclei are embedded in a tidally distorted common envelope, in which star formation is mostly heavily obscured. The infrared spectrum is dominated by strong polycyclic aromatic hydrocarbon (PAH), but deep silicate and molecular absorption features are also present, and are strongest in the IRAS16399N nucleus. The 0.435 - 500$mu$m SED was fitted with a model including stellar, ISM and AGN torus components using our new MCMC code, clumpyDREAM. The results indicate that the IRAS16399N contains an AGN (L$_{bol} sim 10^{44}$ ergs/s) deeply embedded in a quasi-spherical distribution of optically-thick clumps with a covering fraction $approx1$. We suggest that these clumps are the source of the OHM emission in IRAS16399-0937. The high torus covering fraction precludes AGN-photoionization as the origin of the LINER spectrum, however, the spectrum is consistent with shocks (v $sim100-200$ km s$^{-1}$). We infer that the $sim10^8$ M$_{odot}$ black-hole in IRAS16399N is accreting at a small fraction ($sim1$%) of its Eddington rate. The low accretion-rate and modest nuclear SFRs suggest that while the gas-rich major merger forming the IRAS16399-0937 system has triggered widespread star formation, the massive gas inflows expected from merger simulations have not yet fully developed.
Questions surround the connection of luminous extragalactic masers to galactic processes. The observation that water and hydroxyl megamasers rarely coexist in the same galaxy has given rise to a hypothesis that the two species appear in different phases of nuclear activity. The detection of simultaneous hydroxyl and water megamaser emission toward IC694 has called this hypothesis into question but, because many megamasers have not been surveyed for emission in the other molecule, it remains unclear whether IC694 occupies a narrow phase of galaxy evolution or whether the relationship between megamaser species and galactic processes is more complicated than previously believed. In this paper, we present results of a systematic search for 22 GHz water maser emission among OH megamaser hosts to identify additional objects hosting both megamaser. Our work roughly doubles the number of galaxies searched for emission in both molecules which host at least one confirmed maser. We confirm with high degree of confidence ($> 8 sigma$) the detection of water emission toward IIZw96, firmly establishing it as the second object to co-host both water and hydroxyl megamasers after IC694. We find high luminosity, narrow features in the water feature in IIZw96. All dual megamaser candidates appear in merging galaxy systems suggestive that megamaser coexistance may signal a brief phase along the merger sequence. A statistical analysis of the results of our observations provide possible evidence for an exclusion of H$_2$O kilomasers among OH megamaser hosts.
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