- ID:
- ivo://CDS.VizieR/J/A+A/656/A60
- Title:
- NGC1808 ALMA datacubes
- Short Name:
- J/A+A/656/A60
- Date:
- 21 Mar 2022 07:01:58
- Publisher:
- CDS
- Description:
- We report on Atacama Large Millimeter Array (ALMA) observations of CO(3-2) emission in the Seyfert2/starburst galaxy NGC 1808, at a spatial resolution of 4pc. Our aim is to investigate the morphology and dynamics of the gas inside the central 0.5kpc and to probe the nuclear feeding and feedback phenomena. We discovered a nuclear spiral of radius 1"=45pc. Within it, we found a decoupled circumnuclear disk or molecular torus of a radius of 0.13"=6pc. The HCN(4-3) and HCO^+^(4-3) and CS(7-6) dense gas line tracers were simultaneously mapped and detected in the nuclear spiral and they present the same misalignment in the molecular torus. At the nucleus, the HCN/HCO^+^ and HCN/CS ratios indicate the presence of an active galactic nucleus (AGN). The molecular gas shows regular rotation, within a radius of 400pc, except for the misaligned disk inside the nuclear spiral arms. The computations of the torques exerted on the gas by the barred stellar potential reveal that the gas within a radius of 100pc is feeding the nucleus on a timescale of five rotations or on an average timescale of ~60Myr. Some non-circular motions are observed towards the center, corresponding to the nuclear spiral arms. We cannot rule out that small extra kinematic perturbations could be interpreted as a weak outflow attributed to AGN feedback. The molecular outflow detected at >=250pc in the NE direction is likely due to supernovae feedback and it is connected to the kpc-scale superwind.
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- ID:
- ivo://CDS.VizieR/J/A+A/629/A54
- Title:
- NGC4388 and NGC2110 spectral files
- Short Name:
- J/A+A/629/A54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to measure the physical properties of the hot X-ray corona of two active galactic nuclei, NGC 4388 and NGC 2110. We analysed the hard X-ray (20-300keV) INTEGRAL spectrum in conjunction with archival XMM-Newton and NuSTAR data. The X-ray spectrum of both sources is phenomenologically well described by an absorbed cut-off power law. In agreement with previous results, we find no evidence of a Compton reflection component in these sources. We obtain a high-energy cut-off of 200_-40_^+75^keV for NGC 4388 and 320_-60_^+100^keV for NGC 2110. A fit with a thermal Comptonisation model yields a coronal temperature of 80_-20_^+40^keV and 75_-15_^+20^keV, respectively, and an optical depth of approximately two, assuming a spherical geometry. The coronal temperature and luminosity of both sources are consistent with pair production that acts as a thermostat for the thermal plasma. These results emphasise the importance of good signal-to-noise X-ray data above 100keV to probe the high-energy emission of AGNs.
- ID:
- ivo://CDS.VizieR/J/AJ/116/102
- Title:
- NGC 5548 BR photometry
- Short Name:
- J/AJ/116/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep Hubble Space Telescope Wide Field Camera (WFC-1) imaging of a region 3.7' east of the V=13mag Seyfert galaxy NGC 5548 in the F555W and F785LP bands, and deep ground-based V and I imaging, show a new extended, blue, low surface brightness structure, apparently a remnant of a tidal interaction associated with NGC 5548. If this straight, low surface brightness (V~27-28mag/arcsec^2^) tidal tail is associated with NGC 5548, it extends at least 80kpc from it and has an absolute magnitude of M_V~-16.4 (H_0_=65km/s/Mpc). Previous imaging surveys of Seyfert galaxies would have missed such low surface brightness tails. Morphologically similar to some brighter tails seen in other interacting systems and in simulations of merging galaxies, this faint tail is a useful diagnostic of an earlier interaction and of the progenitors' halo-to-disk mass ratios. Luminous ripples and a brighter tail wrapped around the galaxy are seen in the inner 1-10kpc region. Unresolved blue objects in the long tail have the colors and absolute magnitudes of young globular clusters. Taken together, the two tails and other features suggest that two spirals merged less than ~1Gyr ago. The inner luminosity profile of NGC 5548 is a good fit to a de Vaucouleurs profile with r_eff_=5.8kpc. Recent simulations of merged galaxies with high-mass halos fail to form lasting tidal tails, suggesting that the NGC 5548 progenitor spirals had modest halo masses.
- ID:
- ivo://CDS.VizieR/J/A+A/632/A61
- Title:
- NGC1068 CO and HCO images
- Short Name:
- J/A+A/632/A61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the fueling and the feedback of nuclear activity in the Seyfert 2 galaxy NGC1068, by studying the distribution and kinematics of molecular gas in the torus and its connections. We use ALMA to image the emission of a set of molecular gas tracers in the circumnuclear disk (CND) and the torus of the galaxy using the CO(2-1), CO(3-2) and HCO^+^(4-3) lines with spatial resolutions ~0.03"-0.09"(2-6pc). ALMA resolves the CND as an asymmetric ringed disk of D~400pc-size and mass of ~1.4x10^8^M_{sun}_. The inner edge of the ring is associated with edge-brightened arcs of NIR polarized emission identified with the working surface of the AGN ionized wind. ALMA proves the existence of a molecular torus of M_torus ~3x10^5^M_{sun}_, which extends over a large range of spatial scales D=10-30pc around the central engine. The new observations evidence the density radial stratification of the torus: the HCO^+^(4-3) torus, with a full size D=11pc, is a factor of 2-3 smaller than its CO(2-1) and CO(3-2) counterparts, which have full-sizes D=26pc and D=28pc, respectively. The torus is connected to the CND through a network of gas streamers. The kinematics of molecular gas show strong departures from circular motions in the torus, the gas streamers, and the CND. These velocity distortions are interconnected and are part of a 3D outflow that reflects the effects of AGN feedback on the kinematics of molecular gas across a wide range of spatial scales. We conclude that a wide-angle AGN wind launched from the accretion disk is impacting a sizeable fraction of the gas inside the torus (~0.4-0.6xM_torus_). However, a large gas reservoir (~1.2-1.8x10^5^M_{sun}_) close to the equatorial plane of the torus remains unaffected by the AGN wind and can continue fueling the AGN for ~1-4Myr. AGN fueling seems nevertheless thwarted on intermediate scales (15pc<r<50pc).
- ID:
- ivo://CDS.VizieR/J/A+A/634/A1
- Title:
- NGC 1068 GRAVITY reconstructed image
- Short Name:
- J/A+A/634/A1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared interferometric data on the Seyfert 2 galaxy NGC 1068, obtained with the GRAVITY instrument on the European Southern Observatory Very Large Telescope Interferometer. The extensive baseline coverage from 5 to 60M{lambda} allowed us to reconstruct a continuum image of the nucleus with an unrivaled 0.2pc resolution in the K-band.We find a thin ring-like structure of emission with a radius r=0.24+/-0.03pc, inclination i=70+/-5{deg}, position angle PA=-50+/-4{deg}, and h/r<0.14, which we associate with the dust sublimation region. The observed morphology is inconsistent with the expected signatures of a geometrically and optically thick torus. Instead, the infrared emission shows a striking resemblance to the 22GHz maser disc, which suggests they share a common region of origin. The near-infrared spectral energy distribution indicates a bolometric luminosity of (0.4-4.7)x10^45^erg/s, behind a large A_K_~=5.5 (A_V_~=90) screen of extinction that also appears to contribute significantly to obscuring the broad line region.
- ID:
- ivo://CDS.VizieR/J/A+A/551/A81
- Title:
- NGC 6951 intensity and velocity maps
- Short Name:
- J/A+A/551/A81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Gas inflowing along stellar bars is often stalled at the location of circumnuclear rings, which form an effective reservoir for massive star formation and thus shape the central regions of galaxies. However, how exactly star formation proceeds within these circumnuclear starburst rings is the subject of debate. Two main scenarios for this process have been put forward. In the first, the onset of star formation is regulated by the total amount of gas present in the ring with star forming starting, once a mass threshold has been reached, in "random" positions within the ring like "popcorn". In the second, star formation primarily takes place near the locations where the gas enters the ring. This scenario has been dubbed "pearls-on-a-string". Here we combine new optical IFU data covering the full stellar bar with existing multiwavelength data to study the 580pc radius circumnuclear starburst ring in detail in the nearby spiral galaxy NGC 6951. Using Hubble Space Telescope (HST) archival data together with SAURON and OASIS IFU data, we derive the ages and stellar masses of star clusters, as well as the total stellar content of the central region.
- ID:
- ivo://CDS.VizieR/J/A+A/550/A12
- Title:
- NGC253 near-infrared H_2_ emission
- Short Name:
- J/A+A/550/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Because of its large angular size and proximity to the Milky Way, NGC 253, an archetypal starburst galaxy, provides an excellent laboratory to study the intricacies of this intense episode of star formation. We aim to characterize the excitation mechanisms driving the emission in NGC 253. Specifically we aim to distinguish between shock excitation and ultraviolet (UV) excitation as the dominant driving mechanism, using Br{gamma}, H_2_ and [FeII] as diagnostic emission line tracers.
- ID:
- ivo://CDS.VizieR/J/A+A/566/A41
- Title:
- NGC 5427 WiFeS data cubes
- Short Name:
- J/A+A/566/A41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have observed the nearby, nearly face-on, Seyfert 2 galaxy, NGC 5427, using optical integral field spectroscopy of both the nuclear regions and the HII regions in the spiral arms. The observed spectra have been modelled using the MAPPINGS IV photoionisation code, both to derive the chemical abundances in the HII regions and the Seyfert nucleus, and to constrain the EUV spectral energy distribution of the AGN illuminating the extended narrow-line region.
- ID:
- ivo://CDS.VizieR/J/A+A/560/A99
- Title:
- NIR long-slit spectra of Seyfert galaxies
- Short Name:
- J/A+A/560/A99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The excitation of the gas phase of the interstellar medium can be driven by various mechanisms. In galaxies with an active nucleus, such as Seyfert galaxies, both radiative and mechanical energy from the central black hole, or the stars in the disk surrounding it may play a role. We investigate the relative importance and range of influence of the active galactic nucleus for the excitation of ionized and molecular gas in the central kiloparsec of its host galaxy. We present H- and K-band long-slit spectra for a sample of 21 nearby (D<70Mpc) Seyfert galaxies obtained with the NIRSPEC instrument on the Keck telescope. For each galaxy, we fit the nebular line emission, stellar continua, and warm molecular gas as a function of distance from the nucleus.
- ID:
- ivo://CDS.VizieR/J/MNRAS/468/L113
- Title:
- Nitrogen abundance of Seyfert 2 AGN
- Short Name:
- J/MNRAS/468/L113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtained new quantitative determinations of the nitrogen abundance and a consistent relation between the nitrogen and oxygen abundances for a sample of Seyfert 2 galaxies located at redshift z<0.1. We carried out this analysis using the CLOUDY code to build detailed photoionization models. We were able to reproduce observed optical narrow emission line intensities for 44 sources compiled from the literature. Our results show that Seyfert 2 nuclei have nitrogen abundances ranging from ~0.3 to ~7.5 times the solar value. We derived the relation log (N/H)=1.05(+/-0.09)x[log(O/H)]-0.35(+/-0.33). Results for N/O versus O/H abundance ratios derived for Seyfert 2 galaxies are in consonance with those recently derived for a sample of extragalactic disc HII regions with high metallicity.
