Jet-CO alignments in the environments high-z radio galaxies

AbstractIn the outskirts of massive high-redshift radio galaxies, powerful radio-jets often interact with ambient warm Lyα-emitting gas. We present the discovery of luminous reservoirs of cold molecular gas in these environments, based on CO(1-0) observations with the Australia Telescope Compact Array. The CO-emission is aligned with the radio jets, and found tens of kpc outside the host galaxy. These molecular gas reservoirs have CO luminosities in the range of those found in submm-galaxies (L'CO ~ 4-9 × 1010 K km/s pc2), but they lack any near-infrared counterpart in deep Spitzer imaging. These results suggest that jet-triggered feedback takes place in the circum-galactic environment of high-z radio galaxies. We prefer the interpretation that the CO-emitting gas is formed when the propagating jets enrich, shock and cool pre-existing dusty halo gas. We further argue that sensitive low-surface-brightness CO observations, using radio interferometers in very compact array-configurations, are essential to study the role of the cold molecular medium in the outskirts of massive high-z galaxies.

Download Full-text

SHARP – VI. Evidence for CO (1–0) molecular gas extended on kpc-scales in AGN star-forming galaxies at high redshift

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1342 ◽

2020 ◽

Vol 495 (2) ◽

pp. 2387-2407 ◽

Cited By ~ 3

Author(s):

C Spingola ◽

J P McKean ◽

S Vegetti ◽

D Powell ◽

M W Auger ◽

...

Keyword(s):

Galaxy Formation ◽

Surface Brightness ◽

High Redshift ◽

Host Galaxy ◽

Molecular Gas ◽

Host Galaxies ◽

Gas Reservoirs ◽

Star Forming ◽

Radio Jets ◽

First Time

ABSTRACT We present a study of the stellar host galaxy, CO (1–0) molecular gas distribution and AGN emission on 50–500 pc-scales of the gravitationally lensed dust-obscured AGN MG J0751+2716 and JVAS B1938+666 at redshifts 3.200 and 2.059, respectively. By correcting for the lensing distortion using a grid-based lens modelling technique, we spatially locate the different emitting regions in the source plane for the first time. Both AGN host galaxies have 300–500 pc-scale size and surface brightness consistent with a bulge/pseudo-bulge, and 2 kpc-scale AGN radio jets that are embedded in extended molecular gas reservoirs that are 5–20 kpc in size. The CO (1–0) velocity fields show structures possibly associated with discs (elongated velocity gradients) and interacting objects (off-axis velocity components). There is evidence for a decrement in the CO (1–0) surface brightness at the location of the host galaxy, which may indicate radiative feedback from the AGN, or offset star formation. We find CO–H2 conversion factors of around αCO = 1.5 ± 0.5 (K km s−1 pc2)−1, molecular gas masses of >3 × 1010 M⊙, dynamical masses of ∼1011 M⊙, and gas fractions of around 60 per cent. The intrinsic CO line luminosities are comparable to those of unobscured AGN and dusty star-forming galaxies at similar redshifts, but the infrared luminosities are lower, suggesting that the targets are less efficient at forming stars. Therefore, they may belong to the AGN feedback phase predicted by galaxy formation models, because they are not efficiently forming stars considering their large amount of molecular gas.

Download Full-text

Feeding and feedback in nuclei of galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320002239 ◽

2020 ◽

Vol 15 (S359) ◽

pp. 307-311

Author(s):

Anelise Audibert ◽

Françoise Combes ◽

Santiago García-Burillo ◽

Kalliopi Dasyra

Keyword(s):

High Resolution ◽

Active Galactic Nuclei ◽

Galaxy Evolution ◽

Galactic Nuclei ◽

Radio Galaxies ◽

Host Galaxy ◽

Molecular Gas ◽

Molecular Outflows ◽

Radio Jets ◽

The Impact

AbstractOur aim is to explore the close environment of Active Galactic Nuclei (AGN) and its connection to the host galaxy through the morphology and dynamics of the cold gas inside the central kpc in nearby AGN. We report Atacama Large Millimeter/submillimeter Array (ALMA) observations of AGN feeding and feedback caught in action in NGC613 and NGC1808 at high resolution (few pc), part of the NUclei of GAlaxies (NUGA) project. We detected trailing spirals inside the central 100 pc, efficiently driving the molecular gas into the SMBH, and molecular outflows driven by the AGN. We present preliminary results of the impact of massive winds induced by radio jets on galaxy evolution, based on observations of radio galaxies from the ALMA Radio-source Catalogue.

Download Full-text

The GLEAMing of the first supermassive black holes

Publications of the Astronomical Society of Australia ◽

10.1017/pasa.2020.6 ◽

2020 ◽

Vol 37 ◽

Author(s):

Guillaume Drouart ◽

Nick Seymour ◽

Tim J. Galvin ◽

Jose Afonso ◽

Joseph R. Callingham ◽

...

Keyword(s):

Near Infrared ◽

High Redshift ◽

Pilot Project ◽

Radio Galaxies ◽

Host Galaxy ◽

Wide Field ◽

Powerful Radio ◽

Massive Galaxies ◽

Luminous Objects

Abstract We present the results of a new selection technique to identify powerful ( $L_{\rm 500\,MHz} \gt 10^{27}\,\text{WHz}^{-1}$ ) radio galaxies towards the end of the Epoch of Reionisation. Our method is based on the selection of bright radio sources showing radio spectral curvature at the lowest frequency ( ${\sim}100\,\text{MHz}$ ) combined with the traditional faintness in K-band for high-redshift galaxies. This technique is only possible, thanks to the Galactic and Extra-galactic All-sky Murchison Wide-field Array survey which provides us with 20 flux measurements across the 70– $230\,\text{MHz}$ range. For this pilot project, we focus on the GAMA 09 field to demonstrate our technique. We present the results of our follow-up campaign with the Very Large Telescope, Australian Telescope Compact Array, and the Atacama Large Millimetre Array to locate the host galaxy and to determine its redshift. Of our four candidate high-redshift sources, we find two powerful radio galaxies in the $1<z<3$ range, confirm one at $z=5.55$ , and present a very tentative $z=10.15$ candidate. Their near-infrared and radio properties show that we are preferentially selecting some of the most radio luminous objects, hosted by massive galaxies very similar to powerful radio galaxies at $1<z<5$ . Our new selection and follow-up technique for finding powerful radio galaxies at $z>5.5$ has a high 25–50% success rate.

Download Full-text

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.

Download Full-text

The SINFONI survey of powerful radio galaxies at z ~ 2: Jet-driven AGN feedback during the Quasar Era

Astronomy and Astrophysics ◽

10.1051/0004-6361/201528040 ◽

2017 ◽

Vol 599 ◽

pp. A123 ◽

Cited By ~ 27

Author(s):

N. P. H. Nesvadba ◽

C. De Breuck ◽

M. D. Lehnert ◽

P. N. Best ◽

C. Collet

Keyword(s):

Kinetic Energy ◽

Interstellar Medium ◽

Large Scale ◽

High Redshift ◽

Radio Galaxies ◽

Energy Output ◽

Host Galaxy ◽

Powerful Radio ◽

Massive Galaxies ◽

Gas Kinematics

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.

Download Full-text

THE MOLECULAR GAS CONTENT OFz< 0.1 RADIO GALAXIES: LINKING THE ACTIVE GALACTIC NUCLEUS ACCRETION MODE TO HOST GALAXY PROPERTIES

The Astrophysical Journal ◽

10.1088/0004-637x/730/2/64 ◽

2011 ◽

Vol 730 (2) ◽

pp. 64 ◽

Cited By ~ 19

Author(s):

V. Smolčić ◽

D. A. Riechers

Keyword(s):

Active Galactic Nucleus ◽

Radio Galaxies ◽

Gas Content ◽

Host Galaxy ◽

Molecular Gas

Download Full-text

X-shooter and ALMA spectroscopy of GRB 161023A

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833094 ◽

2018 ◽

Vol 620 ◽

pp. A119 ◽

Cited By ~ 9

Author(s):

A. de Ugarte Postigo ◽

C. C. Thöne ◽

J. Bolmer ◽

S. Schulze ◽

S. Martín ◽

...

Keyword(s):

Near Infrared ◽

Gamma Ray ◽

High Redshift ◽

Nir Spectroscopy ◽

Host Galaxy ◽

Star Forming ◽

Star Forming Regions ◽

Molecular Features ◽

Short Period ◽

Luminous Objects

Context. Long gamma-ray bursts (GRBs) are produced during the dramatic deaths of massive stars with very short lifetimes, meaning that they explode close to the birth place of their progenitors. Over a short period they become the most luminous objects observable in the Universe, being perfect beacons to study high-redshift star-forming regions. Aims. We aim to use the afterglow of GRB 161023A at a redshift z = 2.710 as a background source to study the environment of the explosion and the intervening systems along its line of sight. Methods. For the first time, we complement ultraviolet (UV), optical and near-infrared (NIR) spectroscopy with millimetre spectroscopy using the Atacama Large Millimeter Array (ALMA), which allows us to probe the molecular content of the host galaxy. The X-shooter spectrum shows a plethora of absorption features including fine-structure and metastable transitions of Fe, Ni, Si, C, and O. We present photometry ranging from 43 s to over 500 days after the burst. Results. We infer a host-galaxy metallicity of [Zn/H] = −1.11 ± 0.07, which, corrected for dust depletion, results in [X/H] = −0.94 ± 0.08. We do not detect molecular features in the ALMA data, but we derive limits on the molecular content of log(NCO/cm−2) < 15.7 and log(NHCO+/cm−-12, which are consistent with those that we obtain from the optical spectra, log(NH2/cm−2)< 15.2 and log(NCO/cm−2) < 14.5. Within the host galaxy, we detect three velocity systems through UV, optical and NIR absorption spectroscopy, all with levels that were excited by the GRB afterglow. We determine the distance from these systems to the GRB to be in the range between 0.7 and 1.0 kpc. The sight line to GRB 161023A shows nine independent intervening systems, most of them with multiple components. Conclusions. Although no molecular absorption was detected for GRB 161023A, we show that GRB millimetre spectroscopy is now feasible and is opening a new window on the study of molecular gas within star-forming galaxies at all redshifts. The most favoured lines of sight for this purpose will be those with high metallicity and dust.

Download Full-text

The case for a high-redshift origin of GRB 100205A

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1811 ◽

2019 ◽

Vol 488 (1) ◽

pp. 902-909

Author(s):

A A Chrimes ◽

A J Levan ◽

E R Stanway ◽

E Berger ◽

J S Bloom ◽

...

Keyword(s):

Star Formation ◽

Galaxy Evolution ◽

Near Infrared ◽

Gamma Ray ◽

Hubble Space Telescope ◽

High Redshift ◽

Gamma Ray Bursts ◽

Host Galaxy ◽

Late Time ◽

Time Limits

Abstract The number of long gamma-ray bursts (GRBs) known to have occurred in the distant Universe (z > 5) is small (∼15); however, these events provide a powerful way of probing star formation at the onset of galaxy evolution. In this paper, we present the case for GRB 100205A being a largely overlooked high-redshift event. While initially noted as a high-z candidate, this event and its host galaxy have not been explored in detail. By combining optical and near-infrared Gemini afterglow imaging (at t < 1.3 d since burst) with deep late-time limits on host emission from the Hubble Space Telescope, we show that the most likely scenario is that GRB 100205A arose in the range 4 < z < 8. GRB 100205A is an example of a burst whose afterglow, even at ∼1 h post burst, could only be identified by 8-m class IR observations, and suggests that such observations of all optically dark bursts may be necessary to significantly enhance the number of high-redshift GRBs known.

Download Full-text

The nature of faint radio galaxies at high redshifts

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2516 ◽

2019 ◽

Vol 489 (4) ◽

pp. 5053-5075 ◽

Cited By ~ 1

Author(s):

A Saxena ◽

H J A Röttgering ◽

K J Duncan ◽

G J Hill ◽

P N Best ◽

...

Keyword(s):

Near Infrared ◽

High Redshift ◽

Radio Galaxies ◽

Star Forming ◽

Inverse Compton Scattering ◽

Inverse Compton ◽

Order Of Magnitude ◽

Stellar Masses ◽

Scattering Losses ◽

Rule Out

ABSTRACT We present spectra and near-infrared images of a sample of faint radio sources initially selected as promising high-redshift radio galaxy (HzRG) candidates. We have determined redshifts for a total of 13 radio galaxies with redshifts ranging from 0.52 ≤ $z$ ≤ 5.72. Our sample probes radio luminosities that are almost an order of magnitude fainter than previous large samples at the highest redshifts. We use near-infrared photometry for a subsample of these galaxies to calculate stellar masses using simple stellar population models, and find stellar masses to be in the range $10^{10.8} {--}10^{11.7} \, \mathrm{M}_\odot$. We then compare our faint radio galaxies with brighter radio galaxies at $z$ ≥ 2 from the literature. We find that fainter radio galaxies have lower Ly α luminosities and narrower line widths compared to the bright ones, implying photoionization by a weaker active galactic nucleus (AGN). We also rule out the presence of strong shocks in faint HzRGs. The stellar masses determined for faint HzRGs are lower than those observed for brighter ones. We find that faint HzRG population in the redshift range 2–4 forms a bridge between star-forming and narrow-line AGNs, whereas the ones at $z$ > 4 are likely to be dominated by star formation, and may be building up their stellar mass through cold accretion of gas. Finally, we show that the overall redshift evolution of radio sizes at $z$ > 2 is fully compatible with increased inverse Compton scattering losses at high redshifts.

Download Full-text