المؤلفون: García-Burillo, S., Hicks, E. K. S., Alonso-Herrero, A., Pereira-Santaella, M., Usero, A., Querejeta, M., González-Martin, O., Delaney, D., Almeida, C. Ramos, Combes, F., Anglés-Alcázar, D., Audibert, A., Bellocchi, E., Davies, R. I., Davis, T. A., Elford, J. S., García-Bernete, I., Hönig, S., Labiano, A., Leist, M. T., Levenson, N. A., López-Rodríguez, E., Mercedes-Feliz, J., Packham, C., Ricci, C., Rosario, D. J., Shimizu, T., Stalevski, M., Zhang, L.

مصطلحات موضوعية: Astrophysics - Astrophysics of Galaxies

الوصف: We use a sample of 64 nearby (D=7-45 Mpc) disk galaxies including 45 AGN and 19 non-AGN, that have high spatial resolution multiline CO observations obtained with the ALMA and/or PdBI arrays to study the distribution of cold molecular gas in their circumunuclear disks (CND). We analyze whether the concentration of cold molecular gas changes as a function of the X-ray luminosity in the 2-10 keV range ($L_{\rm X}$). We also study the concentration of the hot molecular gas using NIR data obtained for the H2 1-0S(1) line. We find a turnover in the distribution of the cold molecular gas concentration as a function of $L_{\rm X}$ with a breakpoint which divides the sample into two branches: the AGN build-up branch ($L_{\rm X}\leq10^{41.5\pm0.3}$erg/s) and the AGN feedback branch ($L_{\rm X}\geq10^{41.5\pm0.3}$erg/s) . Lower luminosity AGN and non-AGN of the AGN build-up branch show high cold molecular gas concentrations and centrally peaked radial profiles on nuclear ($r\leq50$~pc) scales. Higher luminosity AGN of the AGN feedback branch, show a sharp decrease in the concentration of molecular gas and flat or inverted radial profiles. The cold molecular gas concentration index ($CCI$), defined as the ratio of surface densities at $r\leq50$~pc and $r\leq200$~pc , namely $CCI \equiv$~log$_{\rm 10}(\Sigma^{\rm gas}_{\rm 50}/\Sigma^{\rm gas}_{\rm 200}$), spans a factor ~4-5 between the galaxies lying at the high end of the AGN build-up branch and the galaxies of the AGN feedback branch. The concentration and radial distributions of the hot molecular gas in our sample follow less extreme trends as a function of the X-ray luminosity. These observations confirm, on a three times larger sample, previous evidence found by the GATOS survey that the imprint of AGN feedback on the CND-scale distribution of molecular gas is more extreme in higher luminosity Seyfert galaxies of the local universe.
Comment: Accepted by Astronomy & Astrophysics (A&A) (14/06/2024), 26 pages, 16 figures

URL الوصول: http://arxiv.org/abs/2406.11398

المؤلفون: Lu, Anan, Haggard, Daryl, Bureau, Martin, Gensior, Jindra, Jeffreson, Sarah, Robert, Carmelle, Williams, Thomas G., Liang, Fu-Heng, Choi, Woorak, Davis, Timothy A., Babic, Sara, Boyce, Hope, Cheung, Benjamin, Drissen, Laurent, Elford, Jacob S., Liu, Lijie, Martin, Thomas, Rhea, Carter, Rousseau-Nepton, Laurie, Ruffa, Ilaria

مصطلحات موضوعية: Astrophysics - Astrophysics of Galaxies

الوصف: Early-type galaxies (ETGs) are known to harbour dense spheroids of stars but scarce star formation (SF). Approximately a quarter of these galaxies have rich molecular gas reservoirs yet do not form stars efficiently. We study here the ETG NGC~524, with strong shear suspected to result in a smooth molecular gas disc and low star-formation efficiency (SFE). We present new spatially-resolved observations of the \textsuperscript{12}CO(2-1)-emitting cold molecular gas from the Atacama Large Millimeter/sub-millimeter Array (ALMA) and of the warm ionised-gas emission lines from SITELLE at the Canada-France-Hawaii Telescope. Although constrained by the resolution of the ALMA observations ($\approx37$~pc), we identify only $52$ GMCs with radii ranging from $30$ to $140$~pc, a low mean molecular gas mass surface density $\langle\Sigma_{\rm gas}\rangle\approx125$~M$_\odot$~pc$^{-2}$ and a high mean virial parameter $\langle\alpha_{\rm obs,vir}\rangle\approx5.3$. We measure spatially-resolved molecular gas depletion times ($\tau_{\rm dep}\equiv1/{\rm SFE}$) with a spatial resolution of $\approx100$~pc within a galactocentric distance of $1.5$~kpc. The global depletion time is $\approx2.0$~Gyr but $\tau_{\rm dep}$ increases toward the galaxy centre, with a maximum $\tau_{\rm dep,max}\approx5.2$~Gyr. However, no pure \ion{H}{II} region is identified in NGC~524 using ionised-gas emission-line ratio diagnostics, so the $\tau_{\rm dep}$ inferred are in fact lower limits. Measuring the GMC properties and dynamical states, we conclude that shear is the dominant mechanism shaping the molecular gas properties and regulating SF in NGC~524. This is supported by analogous analyses of the GMCs in a simulated ETG similar to NGC~524.
Comment: 17 pages, 10 figures. To be published in MNRAS, accepted on May 27

URL الوصول: http://arxiv.org/abs/2406.01291

المؤلفون: Zhang, Hengyue, Bureau, Martin, Smith, Mark D., Cappellari, Michele, Davis, Timothy A., Dominiak, Pandora, Elford, Jacob S., Liang, Fu-Heng, Ruffa, Ilaria, Williams, Thomas G.

مصطلحات موضوعية: Astrophysics - Astrophysics of Galaxies

الوصف: The mass ($M_\mathrm{BH}$) of a supermassive black hole (SMBH) can be measured using spatially-resolved kinematics of the region where the SMBH dominates gravitationally. The most reliable measurements are those that resolve the smallest physical scales around the SMBHs. We consider here three metrics to compare the physical scales probed by kinematic tracers dominated by rotation: the radius of the innermost detected kinematic tracer $R_\mathrm{min}$ normalised by respectively the SMBH's Schwarzschild radius ($R_\mathrm{Schw}\equiv 2GM_\mathrm{BH}/c^2$, where $G$ is the gravitational constant and $c$ the speed of light), sphere-of-influence (SOI) radius ($R_\mathrm{SOI}\equiv GM_\mathrm{BH}/\sigma_\mathrm{e}^2$, where $\sigma_\mathrm{e}$ is the stellar velocity dispersion within the galaxy's effective radius) and equality radius [the radius $R_\mathrm{eq}$ at which the SMBH mass equals the enclosed stellar mass, $M_\mathrm{BH}=M_*(R_\mathrm{eq})$, where $M_*(R)$ is the stellar mass enclosed within the radius $R$]. All metrics lead to analogous simple relations between $R_\mathrm{min}$ and the highest circular velocity probed $V_\mathrm{c}$. Adopting these metrics to compare the SMBH mass measurements using molecular gas kinematics to those using megamaser kinematics, we demonstrate that the best molecular gas measurements resolve material that is physically closer to the SMBHs in terms of $R_\mathrm{Schw}$ but is slightly farther in terms of $R_\mathrm{SOI}$ and $R_\mathrm{eq}$. However, molecular gas observations of nearby galaxies using the most extended configurations of the Atacama Large Millimeter/sub-millimeter Array can resolve the SOI comparably well and thus enable SMBH mass measurements as precise as the best megamaser measurements.
Comment: 13 pages, 9 figures. Accepted by MNRAS

URL الوصول: http://arxiv.org/abs/2404.16345

المؤلفون: Elford, Jacob S., Davis, Timothy A., Ruffa, Ilaria, Bureau, Martin, Cappellari, Michele, Gensior, Jindra, Iguchi, Satoru, Liang, Fu-Heng, Liu, Lijie, Lu, Anan, Williams, Thomas G.

مصطلحات موضوعية: Astrophysics - Astrophysics of Galaxies

الوصف: We use high-resolution data from the millimetre-Wave Interferometric Survey of Dark Object Masses (WISDOM) project to investigate the connection between circumnuclear gas reservoirs and nuclear activity in a sample of nearby galaxies. Our sample spans a wide range of nuclear activity types including radio galaxies, Seyfert galaxies, low-luminosity active galactic nuclei (AGN) and inactive galaxies. We use measurements of nuclear millimetre continuum emission along with other archival tracers of AGN accretion/activity to investigate previous claims that at, circumnuclear scales (<100 pc), these should correlate with the mass of the cold molecular gas. We find that the molecular gas mass does not correlate with any tracer of nuclear activity. This suggests the level of nuclear activity cannot solely be regulated by the amount of cold gas around the supermassive black hole (SMBH). This indicates that AGN fuelling, that drives gas from the large scale galaxy to the nuclear regions, is not a ubiquitous process and may vary between AGN type, with timescale variations likely to be very important. By studying the structure of the central molecular gas reservoirs, we find our galaxies have a range of nuclear molecular gas concentrations. This could indicate that some of our galaxies may have had their circumnuclear regions impacted by AGN feedback, even though they currently have low nuclear activity. On the other hand, the nuclear molecular gas concentrations in our galaxies could instead be set by secular processes.
Comment: 15 pages plus 3 in the appendix, 8 figures plus 1 in the appendix, 3 tables plus 4 in the appendix

URL الوصول: http://arxiv.org/abs/2311.17848

المؤلفون: Liang, Fu-Heng, Smith, Mark D., Bureau, Martin, Gao, Feng, Davis, Timothy A., Cappellari, Michele, Elford, Jacob S., Greene, Jenny E., Iguchi, Satoru, Lelli, Federico, Lu, Anan, Ruffa, Ilaria, Williams, Thomas G., Zhang, Hengyue

مصطلحات موضوعية: Astrophysics - Astrophysics of Galaxies

الوصف: The co-evolution of galaxies and supermassive black holes (SMBHs) underpins our understanding of galaxy evolution, but different methods to measure SMBH masses have only infrequently been cross-checked. We attempt to identify targets to cross-check two of the most accurate methods, megamaser and cold molecular gas dynamics. Three promising galaxies are selected from all those with existing megamaser SMBH mass measurements. We present Atacama Large Millimeter/sub-millimeter Array (ALMA) 12CO(2-1) and 230-GHz continuum observations with angular resolutions of about 0.5". Every galaxy has an extended rotating molecular gas disc and 230-GHz continuum source(s), but all also have irregularities and/or non-axisymmetric features: NGC1194 is highly inclined and has disturbed and lopsided central 12CO(2-1) emission; NGC3393 has a nuclear disc with fairly regular but patchy 12CO(2-1) emission with little gas near the kinematic major axis, faint emission in the very centre and two brighter structures reminiscent of a nuclear ring and/or spiral; NGC5765B has a strong bar and very bright 12CO(2-1) emission concentrated along two bisymmetric offset dust lanes and two bisymmetric nuclear spiral arms. 12CO(2-1) and 12CO(3-2) observations with the James Clerk Maxwell Telescope are compared with the ALMA observations. Because of the disturbed gas kinematics and the impractically long integration times required for higher angular resolution observations, none of the three galaxies is suitable for a future SMBH mass measurement. Nonetheless, increasing the number of molecular gas observations of megamaser galaxies is valuable, and the ubiquitous disturbances suggest a link between large-scale gas properties and the existence of megamasers.
Comment: 17 pages, 5 figures, accepted by MNRAS

URL الوصول: http://arxiv.org/abs/2311.15447

المؤلفون: Marcelo C. Andrade, Hernán López-Fernández, Elford A. Liverpool

المصدر: Neotropical Ichthyology, Vol 17, Iss 4 (2019)

مصطلحات موضوعية: Endemic, Myletes, Sexually dichromatism, Species inquirenda, Taxonomy, Zoology, QL1-991

الوصف: ABSTRACT A new species in the serrasalmid genus Myloplus is described from the middle Mazaruni River, Essequibo River basin, Guyana. The new species is similar to Myleus pacu and Myloplus planquettei in its silver to purplish black coloration and its overall morphology, and has a putative syntopic distribution with those species. The new species is, however, readily distinguishable from the other two by meristic counts of the unpaired fins and by differences in color pattern, primarily in males. Additionally, we provide comments on Myleus pacu and other species that have been confounded under that name.

وصف الملف: electronic resource

Relation: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252019000500202&tlng=en; http://www.scielo.br/pdf/ni/v17n4/1982-0224-ni-17-04-e1900261.pdf; https://doaj.org/toc/1982-0224

URL الوصول: https://doaj.org/article/192aac7eb8454cdca996d94908d833fe

المؤلفون: Williams, Thomas G., Bureau, Martin, Davis, Timothy A., Cappellari, Michele, Choi, Woorak, Elford, Jacob S., Iguchi, Satoru, Gensior, Jindra, Liang, Fu-Heng, Lu, Anan, Ruffa, Ilaria, Zhang, Hengyue

مصطلحات موضوعية: Astrophysics - Astrophysics of Galaxies

الوصف: We present a study of the molecular gas of seven early-type galaxies with high angular resolution data obtained as part of the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM) project with the Atacama Large Millimeter/submillimeter Array. Using a fixed spatial scale approach, we study the mass surface density ($\Sigma$) and velocity dispersion ($\sigma$) of the molecular gas on spatial scales ranging from $60$ to $120$pc. Given the spatial resolution of our data ($20$ - $70$pc), we characterise these properties across many thousands of individual sight lines ($\approx50,000$ at our highest physical resolution). The molecular gas along these sight lines has a large range ($\approx2$dex) of mass surface densities and velocity dispersions $\approx40\%$ higher than those of star-forming spiral galaxies. It has virial parameters $\alpha_\mathrm{vir}$ that depend weakly on the physical scale observed, likely due to beam smearing of the bulk galactic rotation, and is generally super-virial. Comparing the internal turbulent pressure ($P_\mathrm{turb}$) to the pressure required for dynamic equilibrium ($P_\mathrm{DE}$), the ratio $P_\mathrm{turb}$/$P_\mathrm{DE}$ is significantly less than unity in all galaxies, indicating that the gas is not in dynamic equilibrium and is strongly compressed, in apparent contradiction to the virial parameters. This may be due to our neglect of shear and tidal forces, and/or the combination of three-dimensional and vertical diagnostics. Both $\alpha_\mathrm{vir}$ and $P_\mathrm{turb}$ anti-correlate with the global star-formation rate of our galaxies. We therefore conclude that the molecular gas in early-type galaxies is likely unbound, and that large-scale dynamics likely plays a critical role in its regulation. This contrasts to the giant molecular clouds in the discs of late-type galaxies, that are much closer to dynamical equilibrium.
Comment: 32 pages (16 of Appendices), 39 Figures (27 in Appendices). Accepted for publication in MNRAS

URL الوصول: http://arxiv.org/abs/2308.05146

المؤلفون: Shafiul Azam, A B M, Schmidt, William Hal, Elford, Kellie, Vicklund, Kevin, Dymond, Matt

المصدر: 2022 IEEE PES Generation, Transmission and Distribution Conference and Exposition – Latin America (IEEE PES GTD Latin America) Generation, Transmission and Distribution Conference and Exposition – Latin America (IEEE PES GTD Latin America), 2022 IEEE PES. :1-6 Oct, 2022

Relation: 2022 IEEE PES Generation, Transmission and Distribution Conference and Exposition – Latin America (IEEE PES GTD Latin America)

المؤلفون: Elford, Alexander T.^{Aff1, Aff2, Aff3, IDs12664023015088_cor1}, Ardalan, Zaid^{Aff1, Aff2, Aff4, Aff5}, Simkin, Paul, Christensen, Britt^{Aff1, Aff2}

المصدر: Indian Journal of Gastroenterology. 43(1):64-77

المؤلفون: Ruffa, Ilaria, Davis, Timothy A., Elford, Jacob S., Bureau, Martin, Cappellari, Michele, Gensior, Jindra, Haggard, Daryl, Iguchi, Satoru, Lelli, Federico, Liang, Fu-Heng, Liu, Lijie, Sarzi, Marc, Williams, Thomas G., Zhang, Hengyue

مصطلحات موضوعية: Astrophysics - Astrophysics of Galaxies

الوصف: We report the discovery of the ``mm fundamental plane of black-hole accretion'', which is a tight correlation between the nuclear 1 mm luminosity ($L_{\rm \nu, mm}$), the intrinsic $2$ -- $10$~keV X-ray luminosity ($L_{\rm X,2-10}$) and the supermassive black hole (SMBH) mass ($M_{\rm BH}$) with an intrinsic scatter ($\sigma_{\rm int}$) of $0.40$ dex. The plane is found for a sample of 48 nearby galaxies, most of which are low-luminosity active galactic nuclei (LLAGN). Combining these sources with a sample of high-luminosity (quasar-like) nearby AGN, we find that the plane still holds. We also find that $M_{\rm BH}$ correlates with $L_{\rm \nu, mm}$ at a highly significant level, although such correlation is less tight than the mm fundamental plane ($\sigma_{\rm int}=0.51$ dex). Crucially, we show that spectral energy distribution (SED) models for both advection-dominated accretion flows (ADAFs) and compact jets can explain the existence of these relations, which are not reproduced by the standard torus-thin accretion disc models usually associated to quasar-like AGN. The ADAF models reproduces the observed relations somewhat better than those for compact jets, although neither provides a perfect prediction. Our findings thus suggest that radiatively-inefficient accretion processes such as those in ADAFs or compact (and thus possibly young) jets may play a key role in both low- and high-luminosity AGN. This mm fundamental plane also offers a new, rapid method to (indirectly) estimate SMBH masses.
Comment: 9 pages, 5 figures

URL الوصول: http://arxiv.org/abs/2307.13872