scholarly journals The Galactic Center compared with nuclei of nearby galaxies

2016 ◽  
Vol 11 (S322) ◽  
pp. 245-252 ◽  
Author(s):  
Francoise Combes
Keyword(s):  
Star Formation ◽  
Galactic Center ◽  
Galactic Nuclei ◽  
Molecular Outflows ◽  
Star Formation Activity ◽  
Nearby Galaxies

AbstractUnderstanding our Galactic Center is easier with insights from nearby galactic nuclei. Both the star formation activity in nuclear gas disks, driven by bars and nuclear bars, and the fueling of low-luminosity AGN, followed by feedback of jets, driving molecular outflows, were certainly present in our Galactic Center, which appears now quenched. Comparisons and diagnostics are reviewed, in particular of m = 2 and m = 1 modes, lopsidedness, different disk orientations, and fossil evidences of activity and feedback.

scholarly journals Gas flows in galactic nuclei: observational constraints on BH-galaxy coevolution

2015 ◽  
Vol 11 (S315) ◽  
pp. 207-214 ◽  
Author(s):  
Santiago García-Burillo
Keyword(s):  
Star Formation ◽  
Scaling Laws ◽  
Galactic Nuclei ◽  
Active Galaxies ◽  
Gas Flows ◽  
Color Distribution ◽  
Close Relationship ◽  
Nearby Galaxies ◽  
Resolution Imaging ◽  
Different Populations

AbstractGalaxy nuclei are a unique laboratory to study gas flows. Their high-resolution imaging in galactic nuclei are instrumental in the study of the fueling and feedback of star formation and nuclear activity in nearby galaxies. Several fueling mechanisms can now be confronted in detail with observations done with state-of-the-art interferometers. Furthermore, the study of gas flows in galactic nuclei can probe the feedback of activity on the interstellar medium of galaxies. Feedback action from star formation and AGN activity is invoked to prevent galaxies from becoming overly massive, but also to explain scaling laws like black hole (BH)-bulge mass correlations and the bimodal color distribution of galaxies. This close relationship between galaxies and their central supermassive BH can be described as co-evolution. There is mounting observational evidence for the existence of gas outflows in different populations of starbursts and active galaxies, a manifestation of the feedback of activity. We summarize the main results recently obtained from the observation of galactic inflows and outflows in a variety of active galaxies with current millimeter interferometers such as ALMA or the IRAM array.

scholarly journals Molecular Gas and Star Formation in BIMA SONG Bars

2001 ◽  
Vol 205 ◽  
pp. 348-349
Author(s):  
Kartik Sheth ◽  
S.N. Vogel ◽  
A.I. Harris ◽  
M.W. Regan ◽  
M.D. Thornley ◽  
...  
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
Molecular Gas ◽  
Gas Flows ◽  
Gas Distribution ◽  
Hydrodynamic Models ◽  
Massive Star Formation ◽  
Downstream Side ◽  
Star Formation Activity ◽  
Nearby Galaxies

Using a sample of 7 barred spirals from the BIMA Survey of Nearby Galaxies (SONG), we compare the molecular gas distribution in the bar, to recent massive star formation activity. In all 7 galaxies, Hα is offset azimuthally from the CO on the downstream side. The maximum offset, at the bar ends, ranges from 170-570 pc, with an average of 320±120 pc. We discuss whether the observed offsets are consistent with the description of gas flows in bars provided by the two main classes of models: n-body models and hydrodynamic models.

scholarly journals A CENSUS OF BROAD-LINE ACTIVE GALACTIC NUCLEI IN NEARBY GALAXIES: COEVAL STAR FORMATION AND RAPID BLACK HOLE GROWTH

2013 ◽  
Vol 763 (2) ◽  
pp. 133 ◽  
Author(s):  
Jonathan R. Trump ◽  
Alexander D. Hsu ◽  
Jerome J. Fang ◽  
S. M. Faber ◽  
David C. Koo ◽  
...  
Keyword(s):  
Black Hole ◽  
Star Formation ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Broad Line ◽  
Black Hole Growth ◽  
Nearby Galaxies ◽  
Hole Growth

scholarly journals The starburst – active galactic nuclei connection on nuclear scales in near by Seyfert galaxies

2013 ◽  
Vol 9 (S304) ◽  
pp. 345-346
Author(s):  
Pilar Esquej
Keyword(s):  
Black Hole ◽  
Star Formation ◽  
Formation Rate ◽  
Galactic Nuclei ◽  
Seyfert Galaxies ◽  
High Angular Resolution ◽  
Physical Relation ◽  
Black Hole Accretion ◽  
Star Formation Activity ◽  
Hole Accretion

AbstractSeveral works have shown that there is an empirical correlation between the star formation rate and the luminosity of the active galactic nucleus (and thus the black hole accretion rate, ṀBH) of Seyfert galaxies. This suggests a physical relation between the gas forming stars on kpc scales and the gas on sub-pc scales that is feeding the black hole. Simulations predict this relation and also that the correlation should be more prominent on smaller physical scales. We have compiled high angular resolution (0.4–0.8″) mid-infrared spectroscopy obtained with T-ReCS, VISIR, and Michelle of 29 Seyferts. We use the 11.3 μm PAH feature to probe the star formation activity in the inner ~65 pc, and its relation with the ṀBH on these physical scales.

scholarly journals The Galactic center: not an active galactic nucleus

2013 ◽  
Vol 9 (S303) ◽  
pp. 54-58
Author(s):  
Deokkeun An ◽  
Solange V. Ramírez ◽  
Kris Sellgren
Keyword(s):  
Interstellar Medium ◽  
Emission Line ◽  
Active Galactic Nuclei ◽  
Active Galactic Nucleus ◽  
Galactic Center ◽  
Galactic Nuclei ◽  
Extensive Area ◽  
Star Forming ◽  
Nearby Galaxies

AbstractWe present 10 μm – 35μm Spitzer spectra of the interstellar medium in the central molecular zone (CMZ), the central 210 pc × 60 pc of the Galactic center (GC). We present maps of the CMZ in ionic and H2 emission, covering a more extensive area than earlier spectroscopic surveys in this region. We compare diagnostic line ratios measured in the Spitzer Infrared Nearby Galaxies Survey to our data. Previous work shows that forbidden line ratios can distinguish star-forming galaxies from low-ionization nuclear emission-line regions (LINERs) and active galactic nuclei (AGNs). Our GC line ratios agree with star-forming galaxies and not with LINERs or AGNs.

scholarly journals The AGN-Starburst Connection traced by the Nitrogen Abundance

2012 ◽  
Vol 8 (S290) ◽  
pp. 273-274
Author(s):  
Kenta Matsuoka ◽  
Tohru Nagao ◽  
Alessandro Marconi ◽  
Roberto Maiolino ◽  
Yoshiaki Taniguchi
Keyword(s):  
Black Holes ◽  
Star Formation ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Agb Stars ◽  
Line Flux ◽  
Quasar Spectra ◽  
Star Formation Activity ◽  
Nitrogen Abundance

AbstractThe connection between the active galactic nuclei (AGNs) and star formation activity is one of the most important issues in understanding the coevolution of supermassive black holes (SMBHs) and galaxies. In our recent study, by using SDSS quasar spectra we found that the emission-line flux rations involving a nitrogen line correlate with the Eddington ratio. This correlation suggests that the mass accretion in quasars is associated with a post-starburst phase, when AGB stars enrich the interstellar medium with the nitrogen. Moreover, we focused on nitrogen-loud quasars, that have prominent emission lines of the nitrogen, to investigate whether this argument is correct. In this symposium, we present our results regarding the relation between the star formation and feeding to SMBHs traced by the nitrogen abundance.

scholarly journals Influence of velocity dispersions on star-formation activities in galaxies

2020 ◽  
Vol 641 ◽  
pp. A24
Author(s):  
Tsan-Ming Wang ◽  
Chorng-Yuan Hwang
Keyword(s):  
Star Formation ◽  
High Velocity ◽  
Surface Density ◽  
Molecular Clouds ◽  
Velocity Dispersion ◽  
Power Index ◽  
Molecular Gas ◽  
Additional Parameter ◽  
Star Formation Activity ◽  
Nearby Galaxies

We investigated the influence of the random velocity of molecular gas on star-formation activities of six nearby galaxies. The physical properties of a molecular cloud, such as temperature and density, influence star-formation activities in the cloud. Additionally, local and turbulent motions of molecules in a cloud may exert substantial pressure on gravitational collapse and thus prevent or reduce star formation in the cloud. However, the influence of gas motion on star-formation activities remains poorly understood. We used data from the Atacama Large Millimeter/submillimeter Array to obtain 12CO(J = 1 − 0) flux and velocity dispersion. We then combined these data with 3.6 and 8 micron midinfrared data from the Spitzer Space Telescope to evaluate the effects of gas motion on star-formation activities in several nearby galaxies. We discovered that relatively high velocity dispersion in molecular clouds corresponds with relatively low star-formation activity. Considering the velocity dispersion as an additional parameter, we derived a modified Kennicutt-Schmidt law with a gas surface density power index of 0.84 and velocity dispersion power index of −0.61.

scholarly journals The link between star formation and gas in nearby galaxies

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Robert Feldmann
Keyword(s):  
Star Formation ◽  
Gas Content ◽  
Molecular Gas ◽  
Galaxy Mergers ◽  
Physical Processes ◽  
Star Forming ◽  
Star Formation Activity ◽  
Star Formation In Galaxies ◽  
Nearby Galaxies ◽  
Gas Accretion

AbstractObservations of the interstellar medium are key to deciphering the physical processes regulating star formation in galaxies. However, observational uncertainties and detection limits can bias the interpretation unless carefully modeled. Here I re-analyze star formation rates and gas masses of a representative sample of nearby galaxies with the help of multi-dimensional Bayesian modeling. Typical star forming galaxies are found to lie in a ‘star forming plane’ largely independent of their stellar mass. Their star formation activity is tightly correlated with the molecular and total gas content, while variations of the molecular-gas-to-star conversion efficiency are shown to be significantly smaller than previously reported. These data-driven findings suggest that physical processes that modify the overall galactic gas content, such as gas accretion and outflows, regulate the star formation activity in typical nearby galaxies, while a change in efficiency triggered by, e.g., galaxy mergers or gas instabilities, may boost the activity of starbursts.

scholarly journals Active galactic nuclei winds as the origin of the H2 emission excess in nearby galaxies

2019 ◽  
Vol 491 (1) ◽  
pp. 1518-1529 ◽  
Author(s):  
Rogemar A Riffel ◽  
Nadia L Zakamska ◽  
Rogério Riffel
Keyword(s):  
Star Formation ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Indirect Detection ◽  
Molecular Gas ◽  
Host Galaxies ◽  
Spatially Resolved ◽  
Tightly Coupled ◽  
Nearby Galaxies ◽  
A Minor

ABSTRACT In most galaxies, the fluxes of rotational H2 lines strongly correlate with star formation diagnostics [such as polycyclic aromatic hydrocarbons (PAHs)], suggesting that H2 emission from warm molecular gas is a minor by-product of star formation. We analyse the optical properties of a sample of 309 nearby galaxies derived from a parent sample of 2015 objects observed with the Spitzer Space Telescope. We find a correlation between the [O i]λ6300 emission-line flux and kinematics and the H2 S(3) 9.665 $\mu\mathrm{ m}$/PAH 11.3  $\mu\mathrm{ m}$. The [O i]λ6300 kinematics in active galactic nuclei (AGNs) cannot be explained only by gas motions due to the gravitational potential of their host galaxies, suggesting that AGN-driven outflows are important to the observed kinematics. While H2 excess also correlates with the fluxes and kinematics of ionized gas (probed by [O iii]), the correlation with [O i] is much stronger, suggesting that H2 and [O i] emissions probe the same phase or tightly coupled phases of the wind. We conclude that the excess of H2 emission seen in AGNs is produced by shocks due to AGN-driven outflows and in the same clouds that produce the [O i] emission. Our results provide an indirect detection of neutral and molecular winds and suggest a new way to select galaxies that likely host molecular outflows. Further ground- and space-based spatially resolved observations of different phases of the molecular gas (cold, warm, and hot) are necessary to test our new selection method.

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