A. Ramírez

University of La Serena

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J. A. de Diego

Universidad Nacional Autónoma de México

E. R. Carrasco

Gemini South Observatory

E. Benítez

Universidad Nacional Autónoma de México

J. L. Nilo Castellón

University of La Serena

H. Cuevas

University of La Serena

D. G. Lambas

Universidad Nacional de Córdoba

M. V. Alonso

Universidad Nacional de Córdoba

Haydee M. Cuevas

Universidad Independiente

D. Dultzin‐Hacyan

Universidad Nacional Autónoma de México

E. S. Cypriano

Universidade de São Paulo

Cooperative Institutions

National Institute for Astrophysics

Center for Astrophysics Harvard & Smithsonian

University of Turku

Osservatorio Astrofisico di Torino

University of La Serena

Universidade de São Paulo

Museu de Astronomia e Ciências Afins

Pontificia Universidad Católica de Chile

Boston University

Universidad Nacional Autónoma de México

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VizieR Online Data Catalog: Low X-ray luminosity galaxy clusters (Nilo Castellon+, 2014)

VizieR Online Data Catalog (2015)

J. L. Nilo Castellón M. V. Alonso D. G. Lambas Ana Laura O’Mill C. Valotto

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Clash of Titans: A MUSE dynamical study of the extreme cluster merger SPT-CL J0307-6225

Monthly Notices of the Royal Astronomical Society (2022)

D. Hernández-Lang A. Zenteno A. Diaz-Ocampo H. Cuevas John Clancy

ABSTRACT We present MUSE spectroscopy, Megacam imaging, and Chandra X-ray emission for SPT-CL J0307-6225, a $z = 0.58$ major merging galaxy cluster with a large BCG-SZ centroid separation and a highly disturbed X-ray morphology. The galaxy density distribution shows two main overdensities with separations of 0.144 and 0.017 arcmin to their respective BCGs. We characterize the central regions of the two colliding structures, namely 0307-6225N and 0307-6225S, finding velocity derived masses of M200, N = 2.44 ± 1.41 × 1014M⊙ and M200, S = 3.16 ± 1.88 × 1014M⊙, with a line-of-sight velocity difference of |Δv| = 342 km s−1. The total dynamically derived mass is consistent with the SZ derived mass of 7.63 h$_{70}^{-1}$ ± 1.36 × 1014M⊙. We model the merger using the Monte Carlo Merger Analysis Code, estimating a merging angle of 36$^{+14}_{-12}$ ° with respect to the plane of the sky. Comparing with simulations of a merging system with a mass ratio of 1:3, we find that the best scenario is that of an ongoing merger that began 0.96$^{+0.31}_{-0.18}$ Gyr ago. We also characterize the galaxy population using Hδ and [O ii] λ3727 Å lines. We find that most of the emission-line galaxies belong to 0307-6225S, close to the X-ray peak position with a third of them corresponding to red-cluster sequence galaxies, and the rest to blue galaxies with velocities consistent with recent periods of accretion. Moreover, we suggest that 0307-6225S suffered a previous merger, evidenced through the two equally bright BCGs at the centre with a velocity difference of ∼674 km s−1.

Line (geometry)

10.1093/mnras/stac2480

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Shape of the Galactic Orbits in the CNOC1 Clusters

The Astrophysical Journal (2000)

A. Ramírez R. de Souza D. Schade

We present an analysis of the orbital properties of nine intermediate-redshift clusters of the Canadian Network for Observational Cosmology (CNOC1) survey and compare them to a control sample of 12 nearby clusters. Similar to the nearby elliptical galaxies, the bulge-dominated galaxies in clusters at redshifts ~0.1-0.4 present orbits that are more eccentric than those of disk-dominated galaxies. However, the orbital segregation is less significant than that found for elliptical and spiral galaxies in nearby clusters. The strongest orbital segregation is found when galaxies are separated by colors [red galaxies with colors in the rest frame (U-V)0 > 1.4, blue galaxies with (U-V)0 ≤ 1.4]. Therefore, the segregation we find seems to modify the star formation activity more efficiently than the internal shape of the galaxies. When we compare the orbits of early-type galaxies at intermediate redshift with those for z = 0, they seem to develop significant changes, becoming much more eccentric. A different behavior is observed in the late-type galaxies, which present no significant evolution in their orbit shapes.

Peculiar galaxy

10.1086/308633

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LOW X-RAY LUMINOSITY GALAXY CLUSTERS: MAIN GOALS, SAMPLE SELECTION, PHOTOMETRIC AND SPECTROSCOPIC OBSERVATIONS

The Astronomical Journal (2016)

J. L. Nilo Castellón M. V. Alonso D. G. Lambas C. Valotto Ana Laura O’ Mill

ABSTRACT We present our study of 19 low X-ray luminosity galaxy clusters ( L X ∼ 0.5–45 × 10 43 erg s −1 ), selected from the ROSAT Position Sensitive Proportional Counters Pointed Observations and the revised version of Mullis et al. in the redshift range of 0.16–0.7. This is the introductory paper of a series presenting the sample selection, photometric and spectroscopic observations, and data reduction. Photometric data in different passbands were taken for eight galaxy clusters at Las Campanas Observatory; three clusters at Cerro Tololo Interamerican Observatory; and eight clusters at the Gemini Observatory. Spectroscopic data were collected for only four galaxy clusters using Gemini telescopes. Using the photometry, the galaxies were defined based on the star-galaxy separation taking into account photometric parameters. For each galaxy cluster, the catalogs contain the point-spread function and aperture magnitudes of galaxies within the 90% completeness limit. They are used together with structural parameters to study the galaxy morphology and to estimate photometric redshifts. With the spectroscopy, the derived galaxy velocity dispersion of our clusters ranged from 507 km s −1 for [VMF98]022 to 775 km s −1 for [VMF98]097 with signs of substructure. Cluster membership has been extensively discussed taking into account spectroscopic and photometric redshift estimates. In this sense, members are the galaxies within a projected radius of 0.75 Mpc from the X-ray emission peak and with clustercentric velocities smaller than the cluster velocity dispersion or 6000 km s −1 , respectively. These results will be used in forthcoming papers to study, among the main topics, the red cluster sequence, blue cloud and green populations, the galaxy luminosity function, and cluster dynamics.

ROSAT

Velocity dispersion

Photometric redshift

10.3847/0004-6256/151/6/151

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Witnessing the Formation of Galaxy Clusters: Photometric and Spectroscopic Evidence of Sub-Structures in RX J1124,3-1700 ([VMF98]102) at z~0.41

BAAA (2010)

J. L. Nilo Castellón M. V. Alonso Haydee M. Cuevas E. R. Carrasco D. G. Lambas

We present a photometric and spectroscopic study of the poor cluster RX J1124,0-1700 ([VMF98]102) based on GMOS/Gemini South observations. The cluster shows a complex morphology, with a mean redshift of 0,409 and a velocity dispertion of 674,94 km/s. Using deep photometry in the r band, we find evidence of overdensities in the projected galaxy distribution, showing at least three sub-structures in the cluster neighborhoods. We obtained spectral data of two of them (North and South sub-structure), showing a separation of about 2000 km/s in the cluster rest of frame. These evidences suggest that the cluster [VMF98]102 is an example of a poor cluster in process of accreting substructures to become a rich cluster. Resumen. Presentamos un estudio fotometrico y espectroscopico del cumulo pobre RX J1124,0-1700 ([VMF98]102) basados en observaciones realizadas en GMOS/Gemini South. El cumulos muestra una morfoloǵia compleja, con un corrimiento al rojo promedio de 0,409 y una dispersion de velocidades de 674,94 km/s. Usando fotometŕia profunda en la banda r, encontramos evidencias de sobredendidades en la distribucion proyectada de galaxias, mostrando al menos 3 subestructuras en las vecindades del cumulo. Obtuvimos informacion espectroscopica de 2 de ellos (subestructuras Norte y Sur) mostrando una separacion de 2.000 km/s aproximadamente. Estas evidencias sugieren que el cumulo [VMF98]102 seŕia un ejemplo de cumulo pobre en proceso de acrecion de subestructuras para convertirse en un cumulo rico.

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Low mass galaxy clusters and galaxy morphology evolution

BAAA (2011)

J. L. Nilo Castellón Yasna Órdenes-Briceño F. Ramos M. V. Alonso Haydee M. Cuevas

Unbarred spiral galaxy

Supercluster (genetic)

Morphology

Irregular galaxy

Protogalaxy

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Re-assessing the Ordinary Chondrites Paradox

AAS/Division for Planetary Sciences Meeting Abstracts #41 (2009)

T. Mothé-Diniz F. L. Jasmin J. M. Carvano D. Lazzaro David Nesvorný

Ordinary chondrite

Chondrule

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Spectral microvariability in Quasars

Revista Mexicana de Astronomía y Astrofísica (2008)

A. Ramírez D. Dultzin J. A. de Diego

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High relative velocity central dumbbells in poor clusters

Astronomische Nachrichten (2009)

H. Quintana D. Proust G. Hertling A. Ramírez I. Toledo

Abstract We propose that some high relative velocity dumbbell galaxies are the centers of poor clusters or groups that are coming into a merging process. The components of these galaxies closely follow the incoming velocity of the merging groups, as revealed by the bimodality of the velocity histograms. Only mergers in a direction with a small angle to the line of sight can show the large velocity difference of the components and the velocity separation of incoming subgroups in the histograms. In this case the simple interpretation would be that the dumbbells components are also in an early phase of their merger, as they still keep the information of the incoming orbits, but analysis of a numerous sample is needed to prove this suggestion (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Bimodality

Dumbbell

Relative velocity

Peculiar velocity

Group velocity

10.1002/asna.200911264

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Citations (1)

Redshifts of 165 Abell and southern rich clusters of galaxies

The Astrophysical Journal Supplement Series (1995)

H. Quintana A. Ramírez

view Abstract Citations (36) References (52) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Redshifts of 165 Abell and Southern Rich Clusters of Galaxies Quintana, H. ; Ramirez, A. Abstract We present spectroscopic observations and accurate positions for 286 galaxies in clusters taken over several observing sessions, mostly with the DuPont telescope at Las Campanas Observatory. We derive 165 redshifts of rich clusters of which 130 are apparently new values. Redshifts encompass a wide range out to z = 0.27. Publication: The Astrophysical Journal Supplement Series Pub Date: February 1995 DOI: 10.1086/192122 Bibcode: 1995ApJS...96..343Q Keywords: Galactic Clusters; Position (Location); Red Shift; Southern Sky; Astronomical Spectroscopy; Telescopes; Astronomy; GALAXIES: CLUSTERS: GENERAL; GALAXIES: DISTANCES AND REDSHIFTS full text sources ADS | data products NED (441) SIMBAD (422) CDS (2) Related Materials (1) Catalog: 1997yCat..20960343Q

Extragalactic astronomy

10.1086/192122

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Citations (46)