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

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.

scholarly journals Sunyaev-Zel’dovich detection of the galaxy cluster Cl J1449+0856 at z = 1.99: The pressure profile in uv space

2019 ◽  
Vol 629 ◽  
pp. A104 ◽  
Author(s):  
R. Gobat ◽  
E. Daddi ◽  
R. T. Coogan ◽  
A. M. C. Le Brun ◽  
F. Bournaud ◽  
...  
Keyword(s):  
Spatial Scales ◽  
High Redshift ◽  
Galaxy Cluster ◽  
Pressure Profile ◽  
Cluster Galaxy ◽  
X Ray ◽  
Amplitude Profile ◽  
The Galaxy ◽  
Sunyaev Zel'dovich Effect ◽  
Massive Clusters

We present Atacama Large Millimetre Array and Atacama Compact Array observations of the Sunyaev-Zel’dovich effect in the z = 2 galaxy cluster Cl J1449+0856, an X-ray-detected progenitor of typical massive clusters in the present day Universe. While in a cleaned but otherwise untouched 92 GHz map of this cluster little to no negative signal is visible, careful subtraction of known sub-millimetre emitters in the uv plane reveals a decrement at 5σ significance. The total signal is −190 ± 36 μJy, with a peak offset by 5″–9″ (∼50 kpc) from both the X-ray centroid and the still-forming brightest cluster galaxy. A comparison of the recovered uv-amplitude profile of the decrement with different pressure models allows us to derive total mass constraints consistent with the ∼6 × 1013M⊙ estimated from X-ray data. Moreover, we find no strong evidence for a deviation of the pressure profile with respect to local galaxy clusters, although a slight tension at small-to-intermediate spatial scales suggests a flattened central profile, opposite to that seen in a cool core and possibly an AGN-related effect. This analysis of the lowest mass single SZ detection so far illustrates the importance of interferometers when observing the SZ effect in high-redshift clusters, the cores of which cannot be considered quiescent, such that careful subtraction of galaxy emission is necessary.

scholarly journals A radio halo surrounding the Brightest Cluster Galaxy in RXCJ0232.2–4420: a mini-halo in transition?

2019 ◽  
Vol 486 (1) ◽  
pp. L80-L84 ◽  
Author(s):  
Ruta Kale ◽  
Krishna M Shende ◽  
Viral Parekh
Keyword(s):  
Radio Source ◽  
Surface Brightness ◽  
Galaxy Cluster ◽  
Cosmic Ray ◽  
Radio Sources ◽  
Cluster Galaxy ◽  
X Ray ◽  
Radio Halo ◽  
The Galaxy ◽  
Radio Power

ABSTRACT Diffuse radio sources associated with the intra-cluster medium are direct probes of the cosmic ray electrons and magnetic fields. We report the discovery of a diffuse radio source in the galaxy cluster RXCJ0232.2–4420 (SPT-CL J0232–4421, z = 0.2836) using 606 MHz observations with the Giant Metrewave Radio Telescope. The diffuse radio source surrounds the Brightest Cluster Galaxy in the cluster-like typical radio mini-haloes. However the total extent of it is 550 × 800 kpc2, which is larger than mini-haloes and similar to that of radio haloes. The BCG itself is also a radio source with a marginally resolved core at 7 arcsec (30 kpc) resolution. We measure the 606 MHz flux density of the RH to be 52 ± 5 mJy. Assuming a spectral index of 1.3, the 1.4 GHz radio power is 4.5 × 1024 W Hz−1. The dynamical state of the cluster has been inferred to be 'relaxed’ and also as 'complex’, depending on the classification methods based on the morphology of the X-ray surface brightness. This system thus seems to be in the transition phase from a mini-halo to a radio halo.

scholarly journals Multiple AGN activity during the BCG assembly of XDCPJ0044.0-2033 at z ∼ 1.6

2020 ◽  
Vol 498 (2) ◽  
pp. 2719-2733
Author(s):  
A Travascio ◽  
A Bongiorno ◽  
P Tozzi ◽  
R Fassbender ◽  
F De Gasperin ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Clusters ◽  
Elliptical Galaxy ◽  
Galactic Nuclei ◽  
Cluster Galaxy ◽  
X Ray ◽  
The Core ◽  
Galaxy Population

ABSTRACT Undisturbed galaxy clusters are characterized by a massive and large elliptical galaxy at their centre, i.e. the brightest cluster galaxy (BCG). How these central galaxies form is still debated. According to most models, a typical epoch for their assembly is $z$ ∼ 1–2. We have performed a detailed multiwavelength analysis of the core of XMM–Newton Distant Cluster Project (XDCP) J0044.0-2033 (XDCP0044), one of the most massive and densest galaxy clusters currently known at redshift $z$ ∼ 1.6, whose central galaxy population shows high star formation compared to lower z clusters and an X-ray active galactic nuclei (AGN) located close to its centre. SINFONI J-, H-, and KMOS YJ-, H-bands spectroscopic data have been analysed, together with deep archival HST photometric data in F105W, F140W, and F160W bands, Chandra X-ray, radio JVLA data at 1–2 GHz, and ALMA band-6 observations. In the very central region of the cluster (∼70 kpc × 70 kpc), two systems of interacting galaxies have been identified and studied (Complex A and B), with a total of seven confirmed cluster members. These galaxies show perturbed morphologies and three of them show signs of AGN activity. In particular, two type-1 AGN with typical broad lines have been found at the centre of each complex (both of them X-ray obscured and highly accreting with $\rm \lambda _{Edd}\sim 0.4-0.6$), while a type-2 AGN has been discovered in Complex A. The AGN at the centre of Complex B is also detected in X-ray, while the other two 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 (40) kpc. The observation of high star formation, merger signatures, and nuclear activity in the core of XDCP0044 suggests that all these processes are key ingredients in shaping the nascent BCG. According to our data, XDCP0044 could form a typical massive galaxy of $M_{\star }\sim 10^{12} \, \mathrm{M}_{\odot }$, hosting a black hole of $\rm 2 \times 10^8\!-\!10^9 \, \mathrm{M}_{\odot }$, in a time-scale of the order of ∼2.5 Gyr.

scholarly journals Thermal and non-thermal Sunyaev-Zel’dovich effect in the cavities of the galaxy cluster MS 0735.6+7421: the role of the thermal density in the cavity

2021 ◽  
Author(s):  
P Marchegiani
Keyword(s):  
Galaxy Cluster ◽  
Coulomb Interactions ◽  
Frequency Range ◽  
High Frequencies ◽  
X Ray ◽  
The Galaxy ◽  
Sunyaev Zel'dovich Effect ◽  
The One ◽  
Very High

Abstract The galaxy cluster MS 0735.6+7421 hosts two large X-ray cavities, filled with radio emission, where a decrease of the Sunyaev-Zel’dovich (SZ) effect has been detected, without establishing if its origin is thermal (from a gas with very high temperature) or non-thermal. In this paper we study how thermal and non-thermal contributions to the SZ effect in the cavities are related; in fact, Coulomb interactions with the thermal gas modify the spectrum of low energy non-thermal electrons, which dominate the non-thermal SZ effect; as a consequence, the intensity of the non-thermal SZ effect is stronger for lower density of the thermal gas inside the cavity. We calculate the non-thermal SZ effect in the cavities as a function of the thermal density, and compare the SZ effects produced by thermal and non-thermal components, and with the one from the external Intra Cluster Medium (ICM), searching for the best frequency range where it is possible to disentangle the different contributions. We find that for temperatures inside the cavities higher than ∼1500 keV the non-thermal SZ effect is expected to dominate on the thermal one, particularly at high frequencies (ν > 500 GHz), where it can also be a non-negligible fraction of the SZ effect from the external ICM. We also discuss the possible sources of astrophysical bias (as kinetic SZ effect and foreground emission from Galactic dust) and possible ways to address them, as well as necessary improvements in the modeling of the properties of cavities and the ICM.

scholarly journals The role of SN-driven turbulence on the formation of outflows, inflows and cooling flows: from Galaxies to Clusters of Galaxies

2009 ◽  
Vol 5 (H15) ◽  
pp. 452-453
Author(s):  
E. M. de Gouveia Dal Pino ◽  
D. Falceta-Gonçalves ◽  
J. S. Gallagher ◽  
C. Melioli ◽  
A. D'Ercole ◽  
...  
Keyword(s):  
High Speed ◽  
Galaxy Cluster ◽  
Maximum Height ◽  
Filamentary Structure ◽  
Star Forming ◽  
Cooling Flow ◽  
The Galaxy ◽  
Central Regions ◽  
Show Evidence

AbstractStar forming galaxies often exhibit hot halos with structures that resemble chimneys and fountains extending for several kpc above the galaxy. Observations indicate that they are probably produced by supernovae (SNe) which blow superbubbles that carve holes in the disk. Through these holes, high speed material is injected and expands buoyantly up to a maximum height and then returns to the disk pulled by the galaxy gravity. This circulating gas in a fountain tends to condense out forming high-velocity clouds and filaments. Starburst galaxies also show evidence that the spectacular winds that arise from their disk are fed by SNe explosions. Similarly, at galaxy cluster scales, most massive clusters exhibit rich filamentary structure of ionized gas which is distributed all around the central galaxy. We discuss here the role that SNe bubbles play in driving outflows and filamentary structures both at galaxy and galaxy-cluster scales. With the help of HD and MHD numerical simulations, we show in particular that SN-driven turbulence may play a key role at helping a central AGN halting and ”isotropize” the cooling flow in the central regions of a galaxy cluster.

scholarly journals A near-infrared study of the obscured 3C129 galaxy cluster

2020 ◽  
Vol 644 ◽  
pp. A107
Author(s):  
M. Ramatsoku ◽  
M. A. W. Verheijen ◽  
R. C. Kraan-Korteweg ◽  
T. H. Jarrett ◽  
K. Said ◽  
...  
Keyword(s):  
Near Infrared ◽  
Galactic Plane ◽  
Galaxy Cluster ◽  
Imaging Data ◽  
Infrared Study ◽  
X Ray ◽  
Cluster Galaxies ◽  
The Core ◽  
Main Cluster ◽  
The Galaxy

We present a catalogue of 261 new infrared selected members of the 3C 129 galaxy cluster. The cluster, located at z ≈ 0.02, forms part of the Perseus-Pisces filament and is obscured at optical wavelengths due to its location in the zone of avoidance. We identified these galaxies using the J- and K-band imaging data provided by the UKIDSS Galactic Plane Survey within an area with a radius of 1.1° centred on the X-ray emission of the cluster at ℓ, b ≈ 160.52° ,0.27°. A total of 26 of the identified galaxy members have known redshifts 24 of which are from our 2016 Westerbork H I survey and two are from optical spectroscopy. An analysis of the galaxy density at the core of the 3C 129 cluster shows it to be less dense than the Coma and Norma clusters, but comparable to the galaxy density in the core of the Perseus cluster. From an assessment of the spatial and velocity distributions of the 3C 129 cluster galaxies that have redshifts, we derived a velocity of cz = 5227 ± 171 km s−1 and σ = 1097 ± 252 km s−1 for the main cluster, with a substructure in the cluster outskirts at cz = 6923 ± 71 km s−1 with σ = 422 ± 100 km s−1. The presence of this substructure is consistent with previous claims based on the X-ray analysis that the cluster is not yet virialised and may have undergone a recent merger.

scholarly journals Exploring the multiphase medium in MKW 08: from the central active galaxy up to cluster scales

2019 ◽  
Vol 629 ◽  
pp. A82
Author(s):  
A. Tümer ◽  
F. Tombesi ◽  
H. Bourdin ◽  
E. N. Ercan ◽  
M. Gaspari ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Galactic Center ◽  
Galaxy Cluster ◽  
Pressure Profile ◽  
Nearby Galaxy ◽  
Cluster Galaxy ◽  
X Ray ◽  
The Galaxy ◽  
Central Regions ◽  
Photon Index

Context. The study of the brightest cluster galaxy (BCG) coronae embedded in noncool core (NCC) galaxy clusters is crucial to understand the BCG’s role in galaxy cluster evolution as well as the activation of the self-regulated cooling and heating mechanism in the central regions of galaxy clusters. Aims. We explore the X-ray properties of the intracluster medium (ICM) of the NCC galaxy cluster MKW 08 and the BCG corona, along with their interface region. With recent and deep archival Chandra observations, we study the BCG corona in detail, and with archival XMM-Newton observations, we investigate the implications of the central active galactic nuclei (AGN) on the BCG. Methods. We carry out imaging and spectral analyses of MKW 08 with archival XMM-Newton and Chandra X-ray observations. Results. Our spectral analysis suggests the presence of a central AGN by a power-law with a photon index of Γ ≃ 1.8 at the core of its BCG. Although the ICM does not exhibit a cluster scale cool core, the BCG manifests itself as a mini cool core characterized by a cooling time as short as 64 Myr at r = 3 kpc centered at the galaxy. The isothermality of the BCG corona seems to favor mechanical feedback from the central AGN as the major source of gas heating. The gas pressure profile of this mini cool core suggests that the BCG coronal gas reaches pressure equilibrium with the hotter and less dense ICM inside an interface of nearly constant pressure, delimited by radii 4 ≤ r ≤ 10 kpc at the galactic center. As revealed by the presence of a metal enriched tail (Z ≃ 0.5–0.9 Z⊙) extending up to 40 kpc, the BCG corona seems to be experiencing ram-pressure stripping by the surrounding ICM and/or interacting with a nearby galaxy, IC 1042.

scholarly journals Reconciling galaxy cluster shapes, measured by theorists versus observers

2020 ◽  
Vol 500 (2) ◽  
pp. 2627-2644
Author(s):  
David Harvey ◽  
Andrew Robertson ◽  
Sut-Ieng Tam ◽  
Mathilde Jauzac ◽  
Richard Massey ◽  
...  
Keyword(s):  
Hubble Space Telescope ◽  
Orientation Angle ◽  
Galaxy Cluster ◽  
Galactic Nuclei ◽  
Weak Lensing ◽  
Strongly Correlated ◽  
The Bahamas ◽  
Cluster Galaxy ◽  
Moments Of Inertia ◽  
X Ray

ABSTRACT If properly calibrated, the shapes of galaxy clusters can be used to investigate many physical processes: from feedback and quenching of star formation, to the nature of dark matter. Theorists frequently measure shapes using moments of inertia of simulated particles’. We instead create mock (optical, X-ray, strong-, and weak-lensing) observations of the 22 most massive ($\sim 10^{14.7}\, \mathrm{ M}_\odot$) relaxed clusters in the BAHAMAS simulations. We find that observable measures of shape are rounder. Even when moments of inertia are projected into 2D and evaluated at matched radius, they overestimate ellipticity by 56 per cent (compared to observable strong lensing) and 430 per cent (compared to observable weak lensing). Therefore, we propose matchable quantities and test them using observations of eight relaxed clusters from the Hubble Space Telescope (HST) and Chandra X-Ray Observatory. We also release our HST data reduction and lensing analysis software to the community. In real clusters, the ellipticity and orientation angle at all radii are strongly correlated. In simulated clusters, the ellipticity of inner (<rvir/20) regions becomes decoupled: for example, with greater misalignment of the central cluster galaxy. This may indicate overly efficient implementation of feedback from active galactic nuclei. Future exploitation of cluster shapes as a function of radii will require better understanding of core baryonic processes. Exploitation of shapes on any scale will require calibration on simulations extended all the way to mock observations.

scholarly journals X-ray properties of He ii λ 1640 emitting galaxies in VANDELS

2020 ◽  
Vol 496 (3) ◽  
pp. 3796-3807
Author(s):  
A Saxena ◽  
L Pentericci ◽  
D Schaerer ◽  
R Schneider ◽  
R Amorin ◽  
...  
Keyword(s):  
Formation Rate ◽  
Galactic Nuclei ◽  
X Ray ◽  
Star Forming ◽  
Set Constraints ◽  
Significant Difference ◽  
Low Metallicity ◽  
Matched Samples ◽  
X Ray Binaries

ABSTRACT We explore X-ray emission from a sample of 18 He ii λ1640 emitting star-forming galaxies at z ∼ 2.3–3.6 from the VANDELS survey in the Chandra Deep Field South, to set constraints on the role of X-ray sources in powering the He ii emission. We find that 4 He ii emitters have tentative detections with S/N ∼ 2 and have X-ray luminosities, LX = 1.5−4.9 × 1041 erg s−1. The stacked luminosity of all 18 He ii emitters is 2.6 × 1041 erg s−1, and that of a subset of 13 narrow He ii emitters (FHWM(He ii) < 1000 km s−1) is 3.1 × 1041 erg s−1. We also measure stacked LX for non-He ii emitters through bootstrapping of matched samples, and find LX = 2.5 × 1041 erg s−1, which is not significantly different from LX measured for He ii emitters. The LX per star formation rate for He ii emitters (log (LX/SFR) ∼ 40.0) and non-emitters (log (LX/SFR) ∼ 39.9) are also comparable and in line with the redshift evolution and metallicity dependence predicted by models. Due to the non-significant difference between the X-ray emission from galaxies with and without He ii, we conclude that X-ray binaries or weak or obscured active galactic nuclei are unlikely to be the dominant producers of He ii ionizing photons in VANDELS star-forming galaxies at z ∼ 3. Given the comparable physical properties of both He ii emitters and non-emitters reported previously, alternative He ii ionizing mechanisms such as localized low-metallicity stellar populations, Pop-III stars, etc. may need to be explored.

scholarly journals Anisotropy of the galaxy cluster X-ray luminosity–temperature relation

2018 ◽  
Vol 611 ◽  
pp. A50 ◽  
Author(s):  
Konstantinos Migkas ◽  
Thomas H. Reiprich
Keyword(s):  
Galaxy Clusters ◽  
Statistical Significance ◽  
Cosmological Parameters ◽  
Galaxy Cluster ◽  
Luminosity Distance ◽  
Temperature Relation ◽  
X Ray ◽  
Two Samples ◽  
The Galaxy ◽  
Group A

We introduce a new test to study the cosmological principle with galaxy clusters. Galaxy clusters exhibit a tight correlation between the luminosity and temperature of the X-ray-emitting intracluster medium. While the luminosity measurement depends on cosmological parameters through the luminosity distance, the temperature determination is cosmology-independent. We exploit this property to test the isotropy of the luminosity distance over the full extragalactic sky, through the normalization a of the LX–T scaling relation and the cosmological parameters Ωm and H0. To this end, we use two almost independent galaxy cluster samples: the ASCA Cluster Catalog (ACC) and the XMM Cluster Survey (XCS-DR1). Interestingly enough, these two samples appear to have the same pattern for a with respect to the Galactic longitude. More specifically, we identify one sky region within l ~ (−15°, 90°) (Group A) that shares very different best-fit values for the normalization of the LX–T relation for both ACC and XCS-DR1 samples. We use the Bootstrap and Jackknife methods to assess the statistical significance of these results. We find the deviation of Group A, compared to the rest of the sky in terms of a, to be ~2.7σ for ACC and ~3.1σ for XCS-DR1. This tension is not significantly relieved after excluding possible outliers and is not attributed to different redshift (z), temperature (T), or distributions of observable uncertainties. Moreover, a redshift conversion to the cosmic microwave background (CMB) frame does not have an important impact on our results. Using also the HIFLUGCS sample, we show that a possible excess of cool-core clusters in this region, is not able to explain the obtained deviations. Furthermore, we tested for a dependence of the results on supercluster environment, where the fraction of disturbed clusters might be enhanced, possibly affecting the LX–T relation. We indeed find a trend in the XCS-DR1 sample for supercluster members to be underluminous compared to field clusters. However, the fraction of supercluster members is similar in the different sky regions, so this cannot explain the observed differences, either. Constraining Ωm and H0 via the redshift evolution of LX–T and the luminosity distance via the flux–luminosity conversion, we obtain approximately the same deviation amplitudes as for a. It is interesting that the general observed behavior of Ωm for the sky regions that coincide with the CMB dipole is similar to what was found with other cosmological probes such as supernovae Ia. The reason for this behavior remains to be identified.

Sign in / Sign up

Export Citation Format

Share Document