scholarly journals Massive Molecular Gas as a Fuel Tank for Active Galactic Nuclei Feedback In Central Cluster Galaxies

2022 ◽  
Vol 924 (1) ◽  
pp. 24
Author(s):  
Yutaka Fujita ◽  
Nozomu Kawakatu ◽  
Hiroshi Nagai
Keyword(s):  
Gravitational Instability ◽  
Simple Relation ◽  
Fuel Tank ◽  
Cooling Time ◽  
Molecular Gas ◽  
Cluster Galaxies ◽  
Hot Gas ◽  
The Galaxy ◽  
Circumnuclear Disk ◽  
Cold Gas

Abstract Massive molecular gas has been discovered in giant elliptical galaxies at the centers of galaxy clusters. To reveal its role in active galactic nucleus (AGN) feedback in those galaxies, we construct a semianalytical model of gas circulation. This model especially focuses on the massive molecular gas (interstellar cold gas on a scale of ∼10 kpc) and the circumnuclear disk (≲0.5 kpc). We consider the destruction of the interstellar cold gas by star formation and the gravitational instability for the circumnuclear disk. Our model can reproduce the basic properties of the interstellar cold gas and the circumnuclear disk, such as their masses. We also find that the circumnuclear disk tends to stay at the boundary between stable and unstable states. This works as an “adjusting valve” that regulates mass accretion toward the supermassive black hole. On the other hand, the interstellar cold gas serves as a “fuel tank” in the AGN feedback. Even if the cooling of the galactic hot gas is prevented, the interstellar cold gas can sustain the AGN activity for ≳0.5 Gyr. We also confirm that the small entropy of hot gas (≲30 keV cm2) or the short cooling time (≲1 Gyr) is a critical condition for the existence of massive amounts of molecular gas in the galaxy. The dissipation time of the interstellar cold gas may be related to the critical cooling time. The galaxy behavior is described by a simple relation among the disk stability, the cloud dissipation time, and the gas cooling rate.

scholarly journals Study of the molecular gas in the central parsec of the Galaxy through regularized 3D spectroscopy

2013 ◽  
Vol 9 (S303) ◽  
pp. 83-85
Author(s):  
A. Ciurlo ◽  
T. Paumard ◽  
D. Rouan ◽  
Y. Clénet
Keyword(s):  
Molecular Gas ◽  
Imaging Data ◽  
Ionized Gas ◽  
Central Cavity ◽  
Neutral Gas ◽  
The Galaxy ◽  
Circumnuclear Disk ◽  
Cool Gas ◽  
Central Parsec ◽  
Spectro Imaging

AbstractThe cool gas in the central parsec of the Galaxy is organized in the surrounding circumnuclear disk, made of neutral gas, and the internal minispiral, composed of dust and ionized gas. In order to study the transition between them we have investigated the presence of H2 neutral gas in this area, through NIR spectro-imaging data observed with SPIFFI. To preserve the spatial resolution we implemented a new method consisting of a regularized 3D fit. We concentrated on the supposedly fully ionized central cavity and the very inner edge of the CND. H2 is detected everywhere: at the boundary of the CND and in the central cavity, where it seems to split in two components, one in the background of the minispiral and one inside the Northern arm.

scholarly journals Fossil Galaxy Groups; Scaling Relations, Galaxy Properties and Formation of BCGs

2006 ◽  
Vol 2 (S235) ◽  
pp. 214-214
Author(s):  
Habib G. Khosroshahi ◽  
T. J. Ponman
Keyword(s):  
Scaling Relations ◽  
X Ray ◽  
Cluster Galaxies ◽  
Galaxy Groups ◽  
Hot Gas ◽  
Early Formation ◽  
Central Galaxy ◽  
Brightest Cluster Galaxies ◽  
The Galaxy

AbstractWe study fossil galaxy groups, their hot gas and the galaxy properties. Fossils are more X-ray luminous than non-fossil groups, however, they fall comfortably on the conventional L-T relation of galaxy groups and clusters indicating that their X-ray luminosity and temperature are both boosted, arguably, as a result of their early formation. The central dominant galaxy in fossils have optical luminosity comparable to the brightest cluster galaxies (BCGs), however, the isophotal shapes of the central galaxy in fossils are non-boxy in contrast to the isophotes of majority of the BCGs.

scholarly journals Driving massive molecular gas flows in central cluster galaxies with AGN feedback

2019 ◽  
Vol 490 (3) ◽  
pp. 3025-3045 ◽  
Author(s):  
H R Russell ◽  
B R McNamara ◽  
A C Fabian ◽  
P E J Nulsen ◽  
F Combes ◽  
...  
Keyword(s):  
Free Fall ◽  
Molecular Structures ◽  
Molecular Gas ◽  
Gas Flows ◽  
Cluster Galaxies ◽  
Central Cluster ◽  
Emerging Trends ◽  
The Galaxy ◽  
Stellar Velocity ◽  
Low Entropy

Abstract We present an analysis of new and archival ALMA observations of molecular gas in 12 central cluster galaxies. We examine emerging trends in molecular filament morphology and gas velocities to understand their origins. Molecular gas masses in these systems span $10^9 {--}10^{11} {\rm \, M_{\odot }}$, far more than most gas-rich galaxies. ALMA images reveal a distribution of morphologies from filamentary to disc-dominated structures. Circumnuclear discs on kiloparsec scales appear rare. In most systems, half to nearly all of the molecular gas lies in filamentary structures with masses of a few $\times 10^{8{\text{--}}10}{\rm \, M_{\odot }}$ that extend radially several to several tens of kpc. In nearly all cases the molecular gas velocities lie far below stellar velocity dispersions, indicating youth, transience, or both. Filament bulk velocities lie far below the galaxy’s escape and free-fall speeds indicating they are bound and being decelerated. Most extended molecular filaments surround or lie beneath radio bubbles inflated by the central active galactic nuclei (AGNs). Smooth velocity gradients found along the filaments are consistent with gas flowing along streamlines surrounding these bubbles. Evidence suggests most of the molecular clouds formed from low entropy X-ray gas that became thermally unstable and cooled when lifted by the buoyant bubbles. Uplifted gas will stall and fall back to the galaxy in a circulating flow. The distribution in morphologies from filament to disc-dominated sources therefore implies slowly evolving molecular structures driven by the episodic activity of the AGNs.

scholarly journals FIR Spectroscopy of the Galactic Center: Hot and Warm Molecular Gas

2016 ◽  
Vol 11 (S322) ◽  
pp. 168-169
Author(s):  
Javier R. Goicoechea ◽  
Mireya Etxaluze ◽  
José Cernicharo ◽  
Maryvonne Gerin ◽  
Jerome Pety ◽  
...  
Keyword(s):  
Angular Resolution ◽  
Galactic Center ◽  
Rotational Line ◽  
Molecular Gas ◽  
Central Cavity ◽  
Stellar Cluster ◽  
Line Intensities ◽  
The Galaxy ◽  
Circumnuclear Disk ◽  
Sgr A

AbstractThe angular resolution (~10″) achieved by the Herschel Space Observatory ~3.5 m telescope at FIR wavelengths allowed us to roughly separate the emission toward the inner parsec of the galaxy (the central cavity) from that of the surrounding circumnuclear disk (the CND). The FIR spectrum toward Sgr A* is dominated by intense [O iii], [O i], [C ii], [N iii], [N ii], and [C i] fine-structure lines (in decreasing order of luminosity) arising in gas irradiated by the strong UV field from the central stellar cluster. The high-J CO rotational line intensities observed at the interface between the inner CND and the central cavity are consistent with a hot isothermal component at Tk ≈ 103.1 K and n(H2)≈ 104 cm−3. They are also consistent with a distribution of lower temperatures at higher gas density, with most CO at Tk≈300 K. The hot CO component (either the bulk of the CO column density or just a small fraction depending on the above scenario) likely results from a combination of UV and shock-driven heating. If UV-irradiated and heated dense clumps do not exist, shocks likely dominate the heating of the hot molecular gas component. Although this component is beam diluted in our FIR observations, it may be resolved at much higher angular resolution. An ALMA project using different molecular tracers to characterize UV-irradiated shocks in the innermost layers of the CND is ongoing.

scholarly journals Constraining cold accretion on to supermassive black holes: molecular gas in the cores of eight brightest cluster galaxies revealed by joint CO and CN absorption

2019 ◽  
Vol 489 (1) ◽  
pp. 349-365 ◽  
Author(s):  
Tom Rose ◽  
A C Edge ◽  
F Combes ◽  
M Gaspari ◽  
S Hamer ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Silicon Monoxide ◽  
Absorption Lines ◽  
Molecular Gas ◽  
Cluster Galaxies ◽  
Supermassive Black Hole ◽  
Systemic Velocity ◽  
Brightest Cluster Galaxies ◽  
The Galaxy

Abstract To advance our understanding of the fuelling and feedback processes which power the Universe’s most massive black holes, we require a significant increase in our knowledge of the molecular gas which exists in their immediate surroundings. However, the behaviour of this gas is poorly understood due to the difficulties associated with observing it directly. We report on a survey of 18 brightest cluster galaxies lying in cool cores, from which we detect molecular gas in the core regions of eight via carbon monoxide (CO), cyanide (CN) and silicon monoxide (SiO) absorption lines. These absorption lines are produced by cold molecular gas clouds which lie along the line of sight to the bright continuum sources at the galaxy centres. As such, they can be used to determine many properties of the molecular gas which may go on to fuel supermassive black hole accretion and AGN feedback mechanisms. The absorption regions detected have velocities ranging from −45 to 283 km s−1 relative to the systemic velocity of the galaxy, and have a bias for motion towards the host supermassive black hole. We find that the CN N = 0 − 1 absorption lines are typically 10 times stronger than those of CO J  = 0 − 1. This is due to the higher electric dipole moment of the CN molecule, which enhances its absorption strength. In terms of molecular number density CO remains the more prevalent molecule with a ratio of CO/CN ∼10, similar to that of nearby galaxies. Comparison of CO, CN, and H i observations for these systems shows many different combinations of these absorption lines being detected.

scholarly journals Survival of molecular gas in a stellar feedback-driven outflow witnessed with the MUSE TIMER project and ALMA

2019 ◽  
Vol 488 (3) ◽  
pp. 3904-3928 ◽  
Author(s):  
Ryan Leaman ◽  
Francesca Fragkoudi ◽  
Miguel Querejeta ◽  
Gigi Y C Leung ◽  
Dimitri A Gadotti ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Star Formation ◽  
Mechanical Energy ◽  
Molecular Gas ◽  
Ionized Gas ◽  
Star Forming ◽  
Stellar Feedback ◽  
Dominant Component ◽  
The Galaxy ◽  
Field Lines

ABSTRACT Stellar feedback plays a significant role in modulating star formation, redistributing metals, and shaping the baryonic and dark structure of galaxies – however, the efficiency of its energy deposition to the interstellar medium is challenging to constrain observationally. Here we leverage HST and ALMA imaging of a molecular gas and dust shell ($M_{\mathrm{ H}_2} \sim 2\times 10^{5}\, {\rm M}_{\odot }$) in an outflow from the nuclear star-forming ring of the galaxy NGC 3351, to serve as a boundary condition for a dynamical and energetic analysis of the outflowing ionized gas seen in our MUSE TIMER survey. We use starburst99 models and prescriptions for feedback from simulations to demonstrate that the observed star formation energetics can reproduce the ionized and molecular gas dynamics – provided a dominant component of the momentum injection comes from direct photon pressure from young stars, on top of supernovae, photoionization heating, and stellar winds. The mechanical energy budget from these sources is comparable to low luminosity active galactic neuclei, suggesting that stellar feedback can be a relevant driver of bulk gas motions in galaxy centres – although here ≲10−3 of the ionized gas mass is escaping the galaxy. We test several scenarios for the survival/formation of the cold gas in the outflow, including in situ condensation and cooling. Interestingly, the geometry of the molecular gas shell, observed magnetic field strengths and emission line diagnostics are consistent with a scenario where magnetic field lines aided survival of the dusty ISM as it was initially launched (with mass-loading factor ≲1) from the ring by stellar feedback. This system’s unique feedback-driven morphology can hopefully serve as a useful litmus test for feedback prescriptions in magnetohydrodynamical galaxy simulations.

scholarly journals Poor Groups Around Strong Gravitational Lenses

2006 ◽  
Vol 2 (S235) ◽  
pp. 230-230
Author(s):  
Ivelina Momcheva ◽  
Kurtis Williams ◽  
Ann Zabludoff ◽  
Charles Keeton
Keyword(s):  
Galaxy Evolution ◽  
Velocity Dispersion ◽  
Gravitational Lenses ◽  
Local Universe ◽  
Groups Of Galaxies ◽  
Hot Gas ◽  
Gas Kinematics ◽  
The Galaxy ◽  
Group Centroid ◽  
Group Galaxy

AbstractPoor groups are common and interactive environments for galaxies, and thus are important laboratories for studying galaxy evolution. Unfortunately, little is known about groups at z ≥ 0.1, because of the difficulty in identifying them in the first place. Here we present results from our ongoing survey of the environments of strong gravitational lenses, in which we have so far discovered six distant (z ≥ 0.5) groups of galaxies. As in the local Universe, the highest velocity dispersion groups contain a brightest member spatially coincident with the group centroid, whereas lower-dispersion groups tend to have an offset brightest group galaxy. This suggests that higher-dispersion groups are more dynamically relaxed than lower-dispersion groups and that at least some evolved groups exist by z ~ 0.5. We also compare the galaxy and hot gas kinematics with those of similarly distant clusters and of nearby groups.

scholarly journals Probing the cool ISM in galaxies via 21 cm H i absorption

2012 ◽  
Vol 8 (S292) ◽  
pp. 188-188
Author(s):  
J. R. Allison ◽  
E. M. Sadler ◽  
S. J. Curran ◽  
S. N. Reeves
Keyword(s):  
Spectral Line ◽  
Active Galactic Nuclei ◽  
Large Scale ◽  
Galactic Nuclei ◽  
Host Galaxies ◽  
The Galaxy ◽  
Early Type Galaxy ◽  
Finding Method ◽  
Compact Array ◽  
Cold Gas

AbstractRecent targeted studies of associated H i absorption in radio galaxies are starting to map out the location, and potential cosmological evolution, of the cold gas in the host galaxies of Active Galactic Nuclei (AGN). The observed 21 cm absorption profiles often show two distinct spectral-line components: narrow, deep lines arising from cold gas in the extended disc of the galaxy, and broad, shallow lines from cold gas close to the AGN (e.g. Morganti et al. 2011). Here, we present results from a targeted search for associated H i absorption in the youngest and most recently-triggered radio AGN in the local universe (Allison et al. 2012b). So far, by using the recently commissioned Australia Telescope Compact Array Broadband Backend (CABB; Wilson et al. 2011), we have detected two new absorbers and one previously-known system. While two of these show both a broad, shallow component and a narrow, deep component (see Fig. 1), one of the new detections has only a single broad, shallow component. Interestingly, the host galaxies of the first two detections are classified as gas-rich spirals, while the latter is an early-type galaxy. These detections were obtained using a spectral-line finding method, based on Bayesian inference, developed for future large-scale absorption surveys (Allison et al. 2012a).

scholarly journals Searching for Mg ii absorbers in and around galaxy clusters

2021 ◽  
Vol 503 (3) ◽  
pp. 4309-4319
Author(s):  
Jong Chul Lee ◽  
Ho Seong Hwang ◽  
Hyunmi Song
Keyword(s):  
Galaxy Clusters ◽  
Detection Rate ◽  
Massive Star ◽  
Sloan Digital Sky Survey ◽  
Number Density ◽  
Cluster Galaxies ◽  
Star Forming ◽  
Quasar Spectra ◽  
Sky Survey ◽  
The Galaxy

ABSTRACT To study environmental effects on the circumgalactic medium (CGM), we use the samples of redMaPPer galaxy clusters, background quasars, and cluster galaxies from the Sloan Digital Sky Survey (SDSS). With ∼82 000 quasar spectra, we detect 197 Mg ii absorbers in and around the clusters. The detection rate per quasar is 2.7 ± 0.7 times higher inside the clusters than outside the clusters, indicating that Mg ii absorbers are relatively abundant in clusters. However, when considering the galaxy number density, the absorber-to-galaxy ratio is rather low inside the clusters. If we assume that Mg ii absorbers are mainly contributed by the CGM of massive star-forming galaxies, a typical halo size of cluster galaxies is smaller than that of field galaxies by 30 ± 10 per cent. This finding supports that galaxy haloes can be truncated by interaction with the host cluster.

scholarly journals The global star formation law: from dense cores to extreme starbursts

2006 ◽  
Vol 2 (S237) ◽  
pp. 331-335
Author(s):  
Yu Gao
Keyword(s):  
Star Formation ◽  
Linear Correlation ◽  
Molecular Clouds ◽  
High Redshift ◽  
Gas Content ◽  
Molecular Gas ◽  
Giant Molecular Clouds ◽  
Active Star ◽  
Dense Cores ◽  
The Galaxy

AbstractActive star formation (SF) is tightly related to the dense molecular gas in the giant molecular clouds' dense cores. Our HCN (measure of the dense molecular gas) survey in 65 galaxies (including 10 ultraluminous galaxies) reveals a tight linear correlation between HCN and IR (SF rate) luminosities, whereas the correlation between IR and CO (measure of the total molecular gas) luminosities is nonlinear. This suggests that the global SF rate depends more intimately upon the amount of dense molecular gas than the total molecular gas content. This linear relationship extends to both the dense cores in the Galaxy and the hyperluminous extreme starbursts at high-redshift. Therefore, the global SF law in dense gas appears to be linear all the way from dense cores to extreme starbursts, spanning over nine orders of magnitude in IR luminosity.

Sign in / Sign up

Export Citation Format

Share Document