HUBBLE SPACE TELESCOPEWEAK-LENSING STUDY OF THE GALAXY CLUSTER XMMU J2235.3 – 2557 ATz∼ 1.4: A SURPRISINGLY MASSIVE GALAXY CLUSTER WHEN THE UNIVERSE IS ONE-THIRD OF ITS CURRENT AGE

AbstractThe SDSS galaxy catalog is one of the best databases for galaxy distribution studies. The SDSS DR8 data is used to construct the galaxy cluster catalog. We construct the clusters from the calculated luminosity density field and identify denser regions. Around these peak regions we construct galaxy clusters. Another interesting question in cosmology is how observable galaxy structures are connected to underlying dark matter distribution. To study this we compare the SDSS DR7 galaxy group catalog with galaxy groups obtained from the semi-analytical Millennium N-Body simulation. Specifically, we compare the group richness, virial radius, maximum separation and velocity dispersion distributions and find a relatively good agreement between the mock catalog and observations. This strongly supports the idea that the dark matter distribution and galaxies in the semi-analytical models and observations are very closely linked.

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Ultra-steep spectrum emission in the merging galaxy cluster Abell 1914

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833992 ◽

2019 ◽

Vol 622 ◽

pp. A22 ◽

Cited By ~ 6

Author(s):

S. Mandal ◽

H. T. Intema ◽

T. W. Shimwell ◽

R. J. van Weeren ◽

A. Botteon ◽

...

Keyword(s):

Low Frequency ◽

Galaxy Cluster ◽

Diffuse Emission ◽

Radio Observations ◽

Very Large Array ◽

Radio Halo ◽

The Galaxy ◽

Distinct Source ◽

Relativistic Particles ◽

Massive Galaxy

A number of radio observations have revealed the presence of large synchrotron-emitting sources associated with the intra-cluster medium. There is strong observational evidence that the emitting particles have been (re-)accelerated by shocks and turbulence generated during merger events. The particles that are accelerated are thought to have higher initial energies than those in the thermal pool but the origin of such mildly relativistic particles remains uncertain and needs to be further investigated. The galaxy cluster Abell 1914 is a massive galaxy cluster in which X-ray observations show clear evidence of merging activity. We carried out radio observations of this cluster with the LOw Frequency ARay (LOFAR) at 150 MHz and the Giant Metrewave Radio Telescope (GMRT) at 610 MHz. We also analysed Very Large Array (VLA) 1.4 GHz data, archival GMRT 325 MHz data, CFHT weak lensing data and Chandra observations. Our analysis shows that the ultra-steep spectrum source (4C38.39; α ≲ −2), previously thought to be part of a radio halo, is a distinct source with properties that are consistent with revived fossil plasma sources. Finally, we detect some diffuse emission to the west of the source 4C38.39 that could belong to a radio halo.

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Early-type galaxies in low-density environments: NGC 6876 explored through its globular cluster system

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1660 ◽

2019 ◽

Vol 488 (1) ◽

pp. 770-781 ◽

Cited By ~ 1

Author(s):

Ana I Ennis ◽

Lilia P Bassino ◽

Juan P Caso ◽

Bruno J De Bórtoli

Keyword(s):

Globular Cluster ◽

Galaxy Cluster ◽

Host Galaxy ◽

Distance Modulus ◽

Early Type ◽

The Galaxy ◽

Colour Distribution ◽

Poor Group ◽

Early Type Galaxy ◽

Massive Galaxy

ABSTRACT We present the results of a photometric study of the early-type galaxy NGC 6876 and the surrounding globular cluster (GC) system. The host galaxy is a massive elliptical, the brightest of this type in the Pavo Group. According to its intrinsic brightness (Mv ∼ −22.7), it is expected to belong to a galaxy cluster instead of a poor group. Observational material consists of g′, r′, i′ images obtained with the Gemini/GMOS camera. The selected GC candidates present a clear bimodal colour distribution at different galactocentric radii, with mean colours and dispersions for the metal-poor (‘blue’) and metal-rich (‘red’) typical of old GCs. The red subpopulation dominates close to the galaxy centre, in addition to the radial projected distribution showing that they are more concentrated towards the galaxy centre. The azimuthal projected distribution shows an overdensity in the red subpopulation in the direction of a trail observed in X-ray that could be evidence of interactions with its spiral neighbour NGC 6872. The turnover of the luminosity function gives an estimated distance modulus (m − M) ≈ 33.5 and the total population amounts to 9400 GCs, i.e. a quite populous system. The halo mass obtained using the number ratio (i.e. the number of GCs with respect to the baryonic and dark mass) gives a total of ∼1013, meaning it is a very massive galaxy, given the environment.

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The Multiply Imaged Strongly Lensed Supernova Refsdal

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316006955 ◽

2015 ◽

Vol 11 (A29B) ◽

pp. 822-824

Author(s):

Patrick Kelly

Keyword(s):

Rest Frame ◽

Hubble Space Telescope ◽

Galaxy Cluster ◽

Supernova Explosion ◽

Gravitational Lens ◽

Cluster Center ◽

Arrival Times ◽

The Galaxy ◽

Multiple Paths ◽

Massive Galaxy

AbstractIn 1964, Sjur Refsdal first considered the possibility that the light from a background supernova could traverse multiple paths around a strong gravitational lens towards us. He showed that the arrival times of the supernova's light would depend on the cosmic expansion rate, as well as the distribution of matter in the lens. I discussed the discovery of the first such multiply imaged supernova, which exploded behind the MACS J1149.6+2223 galaxy cluster. We have obtained Hubble Space Telescope grism and ground-based spectra of the four images of the supernova, which form an Einstein Cross configuration around an elliptical cluster member. These spectra as well as rest-frame optical light curves have allowed us to learn about the properties of the peculiar core-collapse supernova explosion, which occurred 4.3 Gyr after the Bang Bang, and contain information about the lenses matter distribution as well as their stellar populations. A delayed image of the supernova is expected close to the galaxy cluster center as early as this Fall, and will serve as an unprecedented probe of the potential of a massive galaxy cluster.

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Probing Saraswati’s heart: evaluating the dynamical state of the massive galaxy cluster A2631 through a comprehensive weak-lensing and dynamical analysis

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3575 ◽

2020 ◽

Vol 501 (1) ◽

pp. 756-768

Author(s):

R Monteiro-Oliveira ◽

A C Soja ◽

A L B Ribeiro ◽

J Bagchi ◽

S Sankhyayan ◽

...

Keyword(s):

Galaxy Cluster ◽

Dynamical Analysis ◽

Weak Lensing ◽

Data Sets ◽

Dynamical State ◽

Massive Structure ◽

The Galaxy ◽

Dynamics Of Galaxies ◽

Massive Galaxy

ABSTRACT In this work, we investigate the dynamical state of the galaxy cluster Abell 2631, a massive structure located at the core of the Saraswati supercluster. To do this, we first solve a tension found in the literature regarding the weak-lensing mass determination of the cluster. We do this through a comprehensive weak-lensing analysis, exploring the power of the combination of shear and magnification data sets. We find $M_{200}^{\rm wl} = 8.7_{-2.9}^{+2.5} \times 10^{14}$ M⊙. We also determined the mass based on the dynamics of spectroscopic members, corresponding to $M_{200}^{\rm dy} = 12.2\pm 3.0 \times 10^{14}$ M⊙, consistent within a 68 per cent CL with the weak-lensing estimate. The scenarios provided by the mass distribution and dynamics of galaxies are reconciled with those provided by X-ray observations in a scenario where A2631 is observed at a late stage of merging.

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SPT-CL J2032–5627: A new Southern double relic cluster observed with ASKAP

Publications of the Astronomical Society of Australia ◽

10.1017/pasa.2020.51 ◽

2021 ◽

Vol 38 ◽

Author(s):

S. W. Duchesne ◽

M. Johnston-Hollitt ◽

I. Bartalucci ◽

T. Hodgson ◽

G. W. Pratt

Keyword(s):

Surface Brightness ◽

Galaxy Cluster ◽

Large Area ◽

X Ray ◽

Mass Scaling ◽

Public Data ◽

Low Surface Brightness ◽

The Galaxy ◽

The Universe ◽

Compact Array

Abstract We present a radio and X-ray analysis of the galaxy cluster SPT-CL J2032–5627. Investigation of public data from the Australian Square Kilometre Array Pathfinder (ASKAP) at 943 MHz shows two previously undetected radio relics at either side of the cluster. For both relic sources, we utilise archival Australia Telescope Compact Array (ATCA) data at 5.5 GHz in conjunction with the new ASKAP data to determine that both have steep integrated radio spectra ( $\ensuremath{{\alpha_\mathrm{SE} = -1.52 \pm 0.10}}$ and $\ensuremath{{\alpha_\mathrm{NW,full} = -1.18 \pm 0.10}}$ for the southeast and northwest relic sources, respectively). No shock is seen in XMM-Newton observations; however, the southeast relic is preceded by a cold front in the X-ray–emitting intra-cluster medium. We suggest the lack of a detectable shock may be due to instrumental limitations, comparing the situation to the southeast relic in Abell 3667. We compare the relics to the population of double relic sources and find that they are located below the current power–mass scaling relation. We present an analysis of the low-surface brightness sensitivity of ASKAP and the ATCA, the excellent sensitivity of both allow the ability to find heretofore undetected diffuse sources, suggesting these low-power radio relics will become more prevalent in upcoming large-area radio surveys such as the Evolutionary Map of the Universe.

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The Long View of Planetary Systems

10.1093/oso/9780198799894.003.0011 ◽

2018 ◽

Author(s):

Karel Schrijver

Keyword(s):

Solar System ◽

Milky Way ◽

Planetary Systems ◽

Giant Planets ◽

Milky Way Galaxy ◽

Population Statistics ◽

The Past ◽

General Terms ◽

The Galaxy ◽

The Universe

How many planetary systems formed before our’s did, and how many will form after? How old is the average exoplanet in the Galaxy? When did the earliest planets start forming? How different are the ages of terrestrial and giant planets? And, ultimately, what will the fate be of our Solar System, of the Milky Way Galaxy, and of the Universe around us? We cannot know the fate of individual exoplanets with great certainty, but based on population statistics this chapter sketches the past, present, and future of exoworlds and of our Earth in general terms.

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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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Investigating the properties of a galaxy group at z = 0.6

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320001945 ◽

2020 ◽

Vol 15 (S359) ◽

pp. 188-189

Author(s):

Daniela Hiromi Okido ◽

Cristina Furlanetto ◽

Marina Trevisan ◽

Mônica Tergolina

Keyword(s):

Large Scale ◽

The Other ◽

Numerical Density ◽

Spectroscopy Data ◽

Stellar Kinematics ◽

Galaxy Groups ◽

The Galaxy ◽

The Difference ◽

The Impact ◽

The Universe

AbstractGalaxy groups offer an important perspective on how the large-scale structure of the Universe has formed and evolved, being great laboratories to study the impact of the environment on the evolution of galaxies. We aim to investigate the properties of a galaxy group that is gravitationally lensing HELMS18, a submillimeter galaxy at z = 2.39. We obtained multi-object spectroscopy data using Gemini-GMOS to investigate the stellar kinematics of the central galaxies, determine its members and obtain the mass, radius and the numerical density profile of this group. Our final goal is to build a complete description of this galaxy group. In this work we present an analysis of its two central galaxies: one is an active galaxy with z = 0.59852 ± 0.00007, while the other is a passive galaxy with z = 0.6027 ± 0.0002. Furthermore, the difference between the redshifts obtained using emission and absorption lines indicates an outflow of gas with velocity v = 278.0 ± 34.3 km/s relative to the galaxy.

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MACS: A Quest for the Most Massive Galaxy Clusters in the Universe

The Astrophysical Journal ◽

10.1086/320958 ◽

2001 ◽

Vol 553 (2) ◽

pp. 668-676 ◽

Cited By ~ 326

Author(s):

H. Ebeling ◽

A. C. Edge ◽

J. P. Henry

Keyword(s):

Galaxy Clusters ◽

The Universe ◽

Massive Galaxy

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