Detection of Iron emission line from the galaxy cluster including the distant radio galaxy 3C220.1

We present VLA Low-band Ionosphere and Transient Experiment (VLITE) 338 MHz observations of the galaxy cluster CL 0838+1948. We combine the VLITE data with Giant Metrewave Radio Telescope 610 MHz observations and survey data. The central galaxy hosts a 250 kpc source whose emission is dominated by two large lobes at low frequencies. At higher frequencies, a pair of smaller lobes (∼30 kpc) is detected within the galaxy optical envelope. The observed morphology is consistent with a restarted radio galaxy. The outer lobes have a spectral index αout=1.6, indicating that they are old, whereas the inner lobes have αinn=0.6, typical for an active source. Spectral modeling confirms that the outer emission is a dying source whose nuclear activity switched off not more than 110 Myr ago. Using archival Chandra X-ray data, we compare the radio and hot gas emission. We find that the active radio source is contained within the innermost and X-ray brightest region, possibly a galactic corona. Alternatively, it could be the remnant of a larger cool core whose outer layers have been heated by the former epoch of activity that has generated the outer lobes.

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Detection of Iron Emission Lines from the Galaxy Cluster Including the Radio Galaxy 3C 220.1 atz = 0.62

The Astrophysical Journal ◽

10.1086/308341 ◽

2000 ◽

Vol 530 (1) ◽

pp. 172-176 ◽

Cited By ~ 7

Author(s):

Naomi Ota ◽

Kazuhisa Mitsuda ◽

Makoto Hattori ◽

Tatehiro Mihara

Keyword(s):

Radio Galaxy ◽

Galaxy Cluster ◽

Emission Lines ◽

The Galaxy

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MeerKAT’s discovery of a radio relic in the bimodal merging cluster A2384

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2795 ◽

2020 ◽

Vol 499 (1) ◽

pp. 404-414

Author(s):

V Parekh ◽

K Thorat ◽

R Kale ◽

B Hugo ◽

N Oozeer ◽

...

Keyword(s):

Radio Galaxy ◽

Galaxy Cluster ◽

Physical Size ◽

X Ray ◽

New Class ◽

Extended Radio ◽

The Galaxy ◽

Low Mass ◽

Single Radio ◽

Radio Power

ABSTRACT We present the discovery of a single radio relic located at the edge of the galaxy cluster A2384, using the MeerKAT radio telescope. A2384 is a nearby (z = 0.092), low-mass, complex bimodal, merging galaxy cluster that displays a dense X-ray filament (∼700 kpc in length) between A2384(N; northern cluster) and A2384(S; southern cluster). The origin of the radio relic is puzzling. Using the MeerKAT observation of A2384, we estimate that the physical size of the radio relic is 824 × 264 kpc2 and that it is a steep spectrum source. The radio power of the relic is $P_{1.4\mathrm{GHz}}\, \sim$ (3.87 ± 0.40) × 1023 W Hz−1. This radio relic could be the result of shock wave propagation during the passage of the low-mass A2384(S) cluster through the massive A2384(N) cluster, creating a trail appearing as a hot X-ray filament. In the previous GMRT 325 MHz observation, we detected a peculiar FR I radio galaxy interacting with the hot X-ray filament of A2384, but the extended radio relic was not detected; it was confused with the southern lobe of the FR I galaxy. This newly detected radio relic is elongated and perpendicular to the merger axis, as seen in other relic clusters. In addition to the relic, we notice a candidate radio ridge in the hot X-ray filament. The physical size of the radio ridge source is ∼182 × 129 kpc2. Detection of the diffuse radio sources in the X-ray filament is a rare phenomenon, and could be a new class of radio source found between the two merging clusters of A2384(N) and A2384(S).

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Radio Galaxy Zoo: new giant radio galaxies in the RGZ DR1 catalogue

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2805 ◽

2020 ◽

Vol 499 (1) ◽

pp. 68-76

Author(s):

H Tang ◽

A M M Scaife ◽

O I Wong ◽

A D Kapińska ◽

L Rudnick ◽

...

Keyword(s):

Radio Galaxy ◽

Galaxy Cluster ◽

Radio Galaxies ◽

Selection Method ◽

Cluster Galaxy ◽

Science Project ◽

New Radio ◽

The Galaxy ◽

Using Data ◽

Citizen Science Project

ABSTRACT In this paper, we present the identification of five previously unknown giant radio galaxies (GRGs) using Data Release 1 of the Radio Galaxy Zoo citizen science project and a selection method appropriate to the training and validation of deep learning algorithms for new radio surveys. We associate one of these new GRGs with the brightest cluster galaxy (BCG) in the galaxy cluster GMBCG J251.67741+36.45295 and use literature data to identify a further 13 previously known GRGs as BCG candidates, increasing the number of known BCG GRGs by $\gt 60$ per cent. By examining local galaxy number densities for the number of all known BCG GRGs, we suggest that the existence of this growing number implies that GRGs are able to reside in the centres of rich (∼1014 M⊙) galaxy clusters and challenges the hypothesis that GRGs grow to such sizes only in locally underdense environments.

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Collimated synchrotron threads linking the radio lobes of ESO 137-006

Astronomy and Astrophysics ◽

10.1051/0004-6361/202037800 ◽

2020 ◽

Vol 636 ◽

pp. L1

Author(s):

M. Ramatsoku ◽

M. Murgia ◽

V. Vacca ◽

P. Serra ◽

S. Makhathini ◽

...

Keyword(s):

Southern Hemisphere ◽

Spectral Index ◽

Radio Galaxy ◽

Galaxy Cluster ◽

Unknown Origin ◽

Radio Spectrum ◽

The Galaxy

We present MeerKAT 1000 MHz and 1400 MHz observations of a bright radio galaxy in the southern hemisphere, ESO 137-006. The galaxy lies at the centre of the massive and merging Norma galaxy cluster. The MeerKAT continuum images (rms ∼0.02 mJy beam−1 at ∼10″ resolution) reveal new features that have never been seen in a radio galaxy before: collimated synchrotron threads of yet unknown origin, which link the extended and bent radio lobes of ESO 137-006. The most prominent of these threads stretches in projection for about 80 kpc and is about 1 kpc in width. The radio spectrum of the threads is steep, with a spectral index of up to α ≃ 2 between 1000 and 1400 MHz.

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The application of the adiabatic compression scenario to the radio relic in the galaxy cluster Abell 3411−3412

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2912 ◽

2020 ◽

Vol 499 (1) ◽

pp. 864-872

Author(s):

Charissa Button ◽

Paolo Marchegiani

Keyword(s):

Shock Front ◽

Radio Galaxy ◽

Galaxy Cluster ◽

Adiabatic Compression ◽

Shock Acceleration ◽

Acceleration Process ◽

Diffusive Shock Acceleration ◽

The Galaxy ◽

Post Shock ◽

Shock Mach Number

ABSTRACT Although radio relics are understood to originate in intracluster shock waves resulting from merger shocks, the most widely used model for describing this (re-)acceleration process at shock fronts, the diffusive shock acceleration (DSA) model, has several challenges, including the fact that it is inefficient at low shock Mach numbers. In light of these challenges, it is worthwhile to consider alternative mechanisms. One possibility is the adiabatic compression by a shock wave of a residual fossil electron population which has been left over from a radio galaxy jet. This paper applies this model to the relic hosted in the merging galaxy cluster Abell 3411−3412, where a radio bridge between the relic and a radio galaxy has been observed, with the aim to reproduce the spatial structure of the spectral index of the relic. Four scenarios are presented, in which different effects are investigated, such as effects behind the shock front and different shock strengths. The results show that the adiabatic compression model can reproduce the observed spectral indices across the relic for a shock Mach number that is lower than the value required by the DSA-type modelling of this relic and is in accordance with the values derived from X-ray observations, if other mechanisms, such as an expansion phase or post-shock turbulence, are effective behind the shock front.

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The role of AGN activity in the building up of the BCG at z ∼ 1.6

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320003105 ◽

2019 ◽

Vol 15 (S356) ◽

pp. 280-284

Author(s):

Angela Bongiorno ◽

Andrea Travascio

Keyword(s):

Galaxy Cluster ◽

Cluster Galaxy ◽

X Ray ◽

Groups Of Galaxies ◽

Star Forming ◽

The Core ◽

The Galaxy ◽

Multi Wavelength

AbstractXDCPJ0044.0-2033 is one of the most massive galaxy cluster at z ∼1.6, for which a wealth of multi-wavelength photometric and spectroscopic data have been collected during the last years. I have reported on the properties of the galaxy members in the very central region (∼ 70kpc × 70kpc) of the cluster, derived through deep HST photometry, SINFONI and KMOS IFU spectroscopy, together with Chandra X-ray, ALMA and JVLA radio data.In the core of the cluster, we have identified two groups of galaxies (Complex A and Complex B), seven of them confirmed to be cluster members, with signatures of ongoing merging. These galaxies show perturbed morphologies and, three of them show signs of AGN activity. In particular, two of them, located at the center of each complex, have been found to host luminous, obscured and highly accreting AGN (λ = 0.4−0.6) exhibiting broad Hα line. Moreover, a third optically obscured type-2 AGN, has been discovered through BPT diagram in Complex A. The AGN at the center of Complex B is detected in X-ray while the other two, and their companions, are spatially related to radio emission. The three AGN provide one of the closest AGN triple at z > 1 revealed so far with a minimum (maximum) projected distance of 10 kpc (40 kpc). The discovery of multiple AGN activity in a highly star-forming region associated to the crowded core of a galaxy cluster at z ∼ 1.6, suggests that these processes have a key role in shaping the nascent Brightest Cluster Galaxy, observed at the center of local clusters. According to our data, all galaxies in the core of XDCPJ0044.0-2033 could form a BCG of M* ∼ 1012Mȯ hosting a BH of 2 × 108−109Mȯ, in a time scale of the order of 2.5 Gyrs.

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Megamasers as probes of galaxy mass spectrum evolution

Symposium - International Astronomical Union ◽

10.1017/s0074180900239934 ◽

1991 ◽

Vol 147 ◽

pp. 440-440

Author(s):

V.K. Khersonskii ◽

N.V. Voshchinnikov

Keyword(s):

Mass Spectrum ◽

Spectral Line ◽

Emission Line ◽

Frequency Shift ◽

Empirical Relation ◽

Far Infrared ◽

Merging Galaxies ◽

Maser Emission ◽

The Galaxy ◽

Very High

OH megamasers having very high luminosities in the spectral line can be effectively used for the probing of the evolutionary properties of the galaxies in the earliest cosmological epochs. The frequency shift of the emission line uniqually determines the redshift z, which tells about the epoch of emission. One of the important cosmological problems is the investigation of the galaxy mass spectrum in the expanding Universe. There is the empirical relation between the OH and far-infrared luminosities of galaxies. Therefore, if in the earliest cosmological epochs, there were galaxies with sufficient powerful infrared excesses and containing molecular material, they can be detected using the observations of their OH maser emission. The interacting and merging galaxies can be considered as the best candidates for such objects.

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DeepChandraobservation of the galaxy cluster WARPJ1415.1+3612 atz=1

Astronomy and Astrophysics ◽

10.1051/0004-6361/201118162 ◽

2012 ◽

Vol 539 ◽

pp. A105 ◽

Cited By ~ 20

Author(s):

J. S. Santos ◽

P. Tozzi ◽

P. Rosati ◽

M. Nonino ◽

G. Giovannini

Keyword(s):

Galaxy Cluster ◽

The Galaxy

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