Gas kinematics in powerful radio galaxies atz~ 2: Energy supply from star formation, AGN, and radio jets

We present VLT/SINFONI imaging spectroscopy of the rest-frame optical emission lines of warm ionized gas in 33 powerful radio galaxies at redshifts z ≳ 2, which are excellent sites to study the interplay of rapidly accreting active galactic nuclei and the interstellar medium of the host galaxy in the very late formation stages of massive galaxies. Our targets span two orders of magnitude in radio size (2−400 kpc) and kinetic jet energy (a few 1046– almost 1048 erg s-1). All sources have complex gas kinematics with broad line widths up to ~1300 km s-1. About half have bipolar velocity fields with offsets up to 1500 km s-1 and are consistent with global back-to-back outflows. The others have complex velocity distributions, often with multiple abrupt velocity jumps far from the nucleus of the galaxy, and are not associated with a major merger in any obvious way. We present several empirical constraints that show why gas kinematics and radio jets seem to be physically related in all galaxies of the sample. The kinetic energy in the gas from large scale bulk and local outflow or turbulent motion corresponds to a few 10-3 to 10-2 of the kinetic energy output of the radio jet. In galaxies with radio jet power ≳ 1047 erg s-1, the kinetic energy in global back-to-back outflows dominates the total energy budget of the gas, suggesting that bulk motion of outflowing gas encompasses the global interstellar medium. This might be facilitated by the strong gas turbulence, as suggested by recent analytical work. We compare our findings with recent hydrodynamic simulations, and discuss the potential consequences for the subsequent evolution of massive galaxies at high redshift. Compared with recent models of metal enrichment in high-z AGN hosts, we find that the gas-phase metallicities in our galaxies are lower than in most low-z AGN, but nonetheless solar or even super-solar, suggesting that the ISM we see in these galaxies is very similar to the gas from which massive low-redshift galaxies formed most of their stars. This further highlights that we are seeing these galaxies near the end of their active formation phase.

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Through the kaleidoscope: star formation the host galaxies of radio-AGN

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314004177 ◽

2013 ◽

Vol 9 (S304) ◽

pp. 323-326

Author(s):

Marios Karouzos ◽

Myungshin Im ◽

Markos Trichas ◽

Tomo Goto ◽

Matt Malkan ◽

...

Keyword(s):

Star Formation ◽

Feedback Mechanism ◽

Host Galaxy ◽

Radio Sources ◽

Radio Luminosity ◽

Powerful Radio ◽

Host Galaxies ◽

Radio Jets ◽

The North ◽

Multi Wavelength

AbstractThere exist strong evidence supporting the co-evolution of central supermassive black holes and their host galaxies; however it is still under debate how such a relation comes about and whether it is relevant for all or only a subset of galaxies. A rich multi-wavelength dataset is available for the North Ecliptic Pole field, most notably surveyed by the AKARI infrared space telescope. We investigate the star-formation properties of the host galaxies of radio-AGN together with the radio feedback mechanism, potentially responsible for the eventual quenching of star formation. Using broadband SED modelling, the nuclear and host galaxy components of these sources are studied as a function of their radio luminosity. Here we present results concerning the AGN content of the radio sources in this field, while offering evidence supporting a “maintenance” type of feedback from powerful radio-jets.

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HI absorption in Radio Galaxies

Symposium - International Astronomical Union ◽

10.1017/s0074180900168688 ◽

2002 ◽

Vol 199 ◽

pp. 118-121 ◽

Cited By ~ 1

Author(s):

R. Morganti ◽

T.A. Oosterloo ◽

G. van Moorsel ◽

C.N. Tadhunter ◽

N. Killeen

Keyword(s):

Star Formation ◽

Interstellar Medium ◽

Radio Galaxies ◽

Narrow Line ◽

Powerful Radio ◽

Systemic Velocity

Twenty-two powerful radio galaxies have been searched for HI absorption. We find the highest probability of detecting HI in absorption among narrow-line compact (or small) galaxies or galaxies with indication of richer interstellar medium (i.e. with ongoing or recent star-formation). We discuss the difficulty in the interpretation of the origin of the HI absorption due to the uncertainty in the systemic velocity of the galaxies.

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The AGN fuelling/feedback cycle in nearby radio galaxies – II. Kinematics of the molecular gas

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2368 ◽

2019 ◽

Vol 489 (3) ◽

pp. 3739-3757 ◽

Cited By ~ 2

Author(s):

Ilaria Ruffa ◽

Timothy A Davis ◽

Isabella Prandoni ◽

Robert A Laing ◽

Rosita Paladino ◽

...

Keyword(s):

Position Angle ◽

Radio Galaxies ◽

Host Galaxy ◽

Molecular Gas ◽

Gas Kinematics ◽

Radio Jets ◽

Feedback Cycle ◽

Rotation Pattern ◽

Special Cases ◽

Cold Gas

ABSTRACT This is the second paper of a series exploring the multicomponent (stars, warm and cold gas, and radio jets) properties of a sample of 11 nearby low-excitation radio galaxies, with the aim of better understanding the active galactic nuclei (AGN) fuelling/feedback cycle in these objects. Here, we present a study of the molecular gas kinematics of six sample galaxies detected in 12CO(2-1) with the Atacama Large Millimeter/submillimeter Array (ALMA). In all cases, our modelling suggests that the bulk of the gas in the observed (sub-)kpc CO discs is in ordered rotation. Nevertheless, low-level distortions are ubiquitous, indicating that the molecular gas is not fully relaxed into the host galaxy potential. The majority of the discs, however, are only marginally resolved, preventing us from drawing strong conclusions. NGC 3557 and NGC 3100 are special cases. The features observed in the CO velocity curve of NGC 3557 allow us to estimate a supermassive black hole (SMBH) mass of (7.10 ± 0.02) × 108 M⊙, in agreement with expectations from the MSMBH–σ* relation. The rotation pattern of NGC 3100 shows distortions that appear to be consistent with the presence of both a position angle and an inclination warp. Non-negligible radial motions are also found in the plane of the CO disc, likely consistent with streaming motions associated with the spiral pattern found in the inner regions of the disc. The dominant radial motions are likely to be inflows, supporting a scenario in which the cold gas is contributing to the fuelling of the AGN.

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Massive galaxies on the road to quenching: ALMA observations of powerful high redshift radio galaxies

Astronomy and Astrophysics ◽

10.1051/0004-6361/201732485 ◽

2019 ◽

Vol 621 ◽

pp. A27 ◽

Cited By ~ 12

Author(s):

Theresa Falkendal ◽

Carlos De Breuck ◽

Matthew D. Lehnert ◽

Guillaume Drouart ◽

Joël Vernet ◽

...

Keyword(s):

Star Formation ◽

Dust Emission ◽

Radio Galaxies ◽

Band 3 ◽

Continuum Emission ◽

Synchrotron Emission ◽

Host Galaxies ◽

Massive Galaxies ◽

Radio Jets ◽

Order Of Magnitude

We present 0.″3 (band 6) and 1.″5 (band 3) ALMA observations of the (sub)millimeter dust continuum emission for 25 radio galaxies at 1 < z < 5.2. Our survey reaches a rms flux density of ∼50 μJy in band 6 (200–250 GHz) and ∼20 μJy in band 3 (100–130 GHz). This is an order of magnitude deeper than single-dish 850 μm observations, and reaches fluxes where synchrotron and thermal dust emission are expected to be of the same order of magnitude. Combining our sensitive ALMA observations with low-resolution radio data from ATCA, higher resolution VLA data, and infrared photometry from Herschel and Spitzer, we have disentangled the synchrotron and thermal dust emission. We determine the star-formation rates and AGN infrared luminosities using our newly developed Multi-resolution and multi-object/origin spectral energy distribution fitting code (MR-MOOSE). We find that synchrotron emission contributes substantially at λ ∼ 1 mm. Through our sensitive flux limits and accounting for a contribution from synchrotron emission in the mm, we revise downward the median star-formation rate by a factor of seven compared to previous estimates based solely on Herschel and Spitzer data. The hosts of these radio-loud AGN appear predominantly below the main sequence of star-forming galaxies, indicating that the star formation in many of the host galaxies has been quenched. Future growth of the host galaxies without substantial black hole mass growth will be needed to bring these objects on the local relation between the supermassive black holes and their host galaxies. Given the mismatch in the timescales of any star formation that took place in the host galaxies and lifetime of the AGN, we hypothesize that a key role is played by star formation in depleting the gas before the action of the powerful radio jets quickly drives out the remaining gas. This positive feedback loop of efficient star formation rapidly consuming the gas coupled to the action of the radio jets in removing the residual gas is how massive galaxies are rapidly quenched.

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The role of AGN jets and intracluster magnetic fields in the formation and acceleration of cosmic rays

Proceedings of the International Astronomical Union ◽

10.1017/s1743921311014815 ◽

2010 ◽

Vol 6 (S275) ◽

Author(s):

Nectaria A. B. Gizani

Keyword(s):

Cosmic Rays ◽

Magnetic Fields ◽

Radio Emission ◽

Radio Galaxies ◽

Powerful Radio ◽

X Ray ◽

Cooling Flow ◽

The Core ◽

Radio Jets

AbstractUsing radio and X-ray data of two powerful radio galaxies, we attempt to find out the role that radio jets (in terms of composition and power), as well as intracluster magnetic fields, play in the formation, propagation, and acceleration of cosmic rays. For this study we have selected the powerful radio galaxies Hercules A and 3C 310 because of the presence of ring-like features in their kpc-scale radio emission instead of the usual hotspots. These two FR1.5 lie at the center of galaxy cooling flow clusters in a dense environment. We observed the unique jets of Hercules both in kpc-scales (multifrequency VLA data) and pc-scales (EVN observations at 18 cm). We have also observed the core and inner jets of 3C310 at 18 cm using global VLBI. We report on the work in progress.

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A Powerful Jet/Cloud Interaction in the Radio Galaxy PKS 2250-41

Symposium - International Astronomical Union ◽

10.1017/s007418090008058x ◽

1996 ◽

Vol 175 ◽

pp. 227-229

Author(s):

R. Morganti ◽

C.N. Tadhunter ◽

N. Clark ◽

N. Killeen

Keyword(s):

Emission Line ◽

Strong Evidence ◽

Radio Galaxy ◽

High Redshift ◽

Radio Galaxies ◽

Radio Sources ◽

Excitation Mechanism ◽

Powerful Radio ◽

Radio Jets ◽

Extended Emission

Extended emission line regions aligned with the radio axis are a common feature of powerful radio galaxies and there is much interest in the origin of the extended gas and excitation mechanism. One model that can produce this alignment is photoionization by anisotropic nuclear continuum radiation. However, strong evidence exists, especially in high redshift radio galaxies, for powerful interactions between the relativistic radio jets and the ISM/IGM. Here we present the results of our study of the southern radio galaxy PKS 2250–41 (z = 0.308). This object is the most spectacular found in a sample of southern radio sources studied by Tadhunter et al. (1993) and it displays particularly clear evidence for such an interaction (Tadhunter et al. 1994; Dickson et al. 1995).

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Lyα excess in high-redshift radio galaxies: a signature of star formation★

Monthly Notices of the Royal Astronomical Society ◽

10.1111/j.1365-2966.2006.11371.x ◽

2007 ◽

Vol 375 (4) ◽

pp. 1299-1310 ◽

Cited By ~ 46

Author(s):

M. Villar-Martín ◽

A. Humphrey ◽

C. De Breuck ◽

R. Fosbury ◽

L. Binette ◽

...

Keyword(s):

Star Formation ◽

High Redshift ◽

Radio Galaxies

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The supergiant shell with triggered star formation in the dwarf irregular galaxy IC 2574: neutral and ionized gas kinematics

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stu1369 ◽

2014 ◽

Vol 444 (1) ◽

pp. 376-391 ◽

Cited By ~ 13

Author(s):

O. V. Egorov ◽

T. A. Lozinskaya ◽

A. V. Moiseev ◽

G. V. Smirnov-Pinchukov

Keyword(s):

Star Formation ◽

Irregular Galaxy ◽

Ionized Gas ◽

Gas Kinematics

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Resolved Gas Kinematics in a Sample of Low-Redshift High Star-Formation Rate Galaxies

Publications of the Astronomical Society of Australia ◽

10.1017/pasa.2016.3 ◽

2016 ◽

Vol 33 ◽

Cited By ~ 10

Author(s):

Mathew Varidel ◽

Michael Pracy ◽

Scott Croom ◽

Matt S. Owers ◽

Elaine Sadler

Keyword(s):

Star Formation ◽

Velocity Gradient ◽

Velocity Dispersion ◽

Star Formation Rate ◽

Formation Rate ◽

Local Effect ◽

Line Of Sight ◽

Mean Velocity ◽

Gas Kinematics ◽

Integral Field Spectroscopy

AbstractWe have used integral field spectroscopy of a sample of six nearby (z ~ 0.01–0.04) high star-formation rate ($\text{SFR} \sim 10\hbox{--}40$$\text{M}_\odot \text{ yr$^{-1}$}$) galaxies to investigate the relationship between local velocity dispersion and star-formation rate on sub-galactic scales. The low-redshift mitigates, to some extent, the effect of beam smearing which artificially inflates the measured dispersion as it combines regions with different line-of-sight velocities into a single spatial pixel. We compare the parametric maps of the velocity dispersion with the Hα flux (a proxy for local star-formation rate), and the velocity gradient (a proxy for the local effect of beam smearing). We find, even for these very nearby galaxies, the Hα velocity dispersion correlates more strongly with velocity gradient than with Hα flux—implying that beam smearing is still having a significant effect on the velocity dispersion measurements. We obtain a first-order non parametric correction for the unweighted and flux weighted mean velocity dispersion by fitting a 2D linear regression model to the spaxel-by-spaxel data where the velocity gradient and the Hα flux are the independent variables and the velocity dispersion is the dependent variable; and then extrapolating to zero velocity gradient. The corrected velocity dispersions are a factor of ~ 1.3–4.5 and ~ 1.3–2.7 lower than the uncorrected flux-weighted and unweighted mean line-of-sight velocity dispersion values, respectively. These corrections are larger than has been previously cited using disc models of the velocity and velocity dispersion field to correct for beam smearing. The corrected flux-weighted velocity dispersion values are σm ~ 20–50 km s−1.

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