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1. Translational Tomography with the Wide-field Imager for Parker Solar Probe (WISPR). I. Theoretical Basis and Initial Modeling

Author

M. N. Kenny, C. E. DeForest, M. J. West, and P. C. Liewer

Subjects
Solar corona, Solar wind, Astrophysics, QB460-466
Abstract

In the first of a planned sequence of articles, we present a simple method for reconstructing radial density structures of the solar corona in the vicinity of the Parker Solar Probe (PSP) near and during perihelion passes. We describe how we model the apparent kinematics of stationary K-corona striae from the PSP Wide-field Imager for Parker Solar Probe (WISPR) viewpoint using a simple two-parameter model, form a partial basis of the data space that is a WISPR image sequence, and change the basis from image coordinates to “tomographic coordinates” in order to determine the parameters of such features. We apply the method to a simple three-dimensional model of a WISPR coronal flythrough, demonstrate the ways that it succeeds and fails, and discuss possible improvements to the sensitivity and applicability of the method for real WISPR data.

Published
2023
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2. Space Weather Monitor at the L5 Point: A Case Study of a CME Observed with STEREO B

Author

L. Rodriguez, C. Scolini, M. Mierla, A. N. Zhukov, and M. J. West

Subjects
Space weather, Coronal Mass Ejections, Lagrange points, Instrumentation, Space Weather Forecasts, Sun‐Earth Connection, Meteorology. Climatology, QC851-999, Astrophysics, QB460-466
Abstract

Abstract An important location for future space weather monitoring is the Lagrange point 5 (L5) of the Sun‐Earth system. We test the performance of L5 for space weather monitoring using STEREO B observations of an Earth‐directed coronal mass ejection (CME), seen as a partial halo by SOHO at L1. STEREO B (located close to L5) continuously tracked the CME. By using these data in combination with methods to calculate the CME arrival time at the Earth (extrapolation, drag‐based model, and a magnetohydrodynamic model), we demonstrate that the estimation of the CME arrival time can be drastically improved by adding L5 data. Based on the L1 data alone, one could predict that the CME would arrive at the Earth. Using only the L5 data, one would not expect an arrival, as the estimations of the CME 3‐D configuration is uncertain. The combination of L1 and L5 data leads to an ambiguous prediction of the CME arrival due to low CME brightness in L1 data. To obtain an unambiguous prediction, one needs its 3‐D configuration, from observing the CME material close to the plane of the sky from at least two viewpoints (in this case L5 and, coincidentally, L4). This event demonstrates that L1 observations may be better to determine CME arrival, but L5 observations are superior for constraining arrival time. In this work, the advantages and caveats of using data from a space weather monitor at L5 for predicting interplanetary propagation of CMEs are discussed and demonstrated in a direct case study.

Published
2020
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3. A deep wide survey of faint low surface brightness galaxies in the direction of the Coma cluster of galaxies

Author

Melville P. Ulmer, S. Kasun, Roser Pello, Christopher J. Conselice, Michael D. Gregg, J. P. Picat, C. Adami, Florence Durret, R. Scheidegger, A. Mazure, M. J. West, arXiv, Import, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Services communs OMP (UMS 831), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy, Northwestern University, Evanston, Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Department of Physics and Astronomy, University of Hawaii, California Institute of Technology, Department of Astronomy (CALTECH), Department of Physics, Le Conte Hall, University of California, Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, 010308 nuclear & particles physics, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Coma (optics), Astrophysics, 01 natural sciences, Galaxy, Redshift, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [SDU]Sciences of the Universe [physics], [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Space and Planetary Science, 0103 physical sciences, Magnitude (astronomy), Coma Cluster, Surface brightness, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics
Abstract

We report on a search for faint (R total magnitude fainter than 21) and low surface brightness galaxies (R central surface brightness fainter than ~24) (fLSBs) in a 0.72x0.82 deg2 area centered on the Coma cluster. We analyzed deep B and R band CCD imaging obtained using the CFH12K camera at CFHT and found 735 fLSBs. The total B magnitudes, at the Coma cluster redshift, range from -13 to -9 with B central surface brightness as faint as 27 mag/arcsec2. Using empty field comparisons, we show that most of these fLSBs are probably inside the Coma cluster. We present the results of comparing the projected fLSB distributions with the distributions of normal galaxies and with known X-ray over densities. We also investigate their projected distribution relative to their location in the color magnitude relation. Colors of fLSBs vary between B-R~0.8 and ~1.4 for 2/3 of the sample and this part is consistent with the known CMR red-sequence for bright (R, To be published in A&A, 3 jpeg figures, data and full resolution article can be retrieved from http://cencosw.oamp.fr/. Updated CFHT ackowledgements

Published
2006
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4. On the 3-D reconstruction of Coronal Mass Ejections using coronagraph data

Author

M. Mierla, B. Inhester, A. Antunes, Y. Boursier, J. P. Byrne, R. Colaninno, J. Davila, C. A. de Koning, P. T. Gallagher, S. Gissot, R. A. Howard, T. A. Howard, M. Kramar, P. Lamy, P. C. Liewer, S. Maloney, C. Marqué, R. T. J. McAteer, T. Moran, L. Rodriguez, N. Srivastava, O. C. St. Cyr, G. Stenborg, M. Temmer, A. Thernisien, A. Vourlidas, M. J. West, B. E. Wood, A. N. Zhukov, Royal Observatory of Belgium [Brussels] (ROB), Institute of Geodynamics Sabba S. Stefanescu, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Naval Research Laboratory (NRL), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Trinity College Dublin, George Mason University [Fairfax], NASA Goddard Space Flight Center (GSFC), Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado [Boulder]-National Oceanic and Atmospheric Administration (NOAA), Southwest Research Institute [Boulder] (SwRI), Catholic University of America, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Udaipur Solar Observatory, Physical Research Laboratory [Ahmedabad] (PRL), Indian Space Research Organisation (ISRO)-Indian Space Research Organisation (ISRO), Karl-Franzens-Universität Graz, D.V. Skobeltsyn Institute of Nuclear Physics (SINP), Lomonosov Moscow State University (MSU), Max-Planck-Institut für Sonnensystemforschung (MPS), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Perturbation (astronomy), Interplanetary medium, Magnetosphere, Field of view, Astrophysics, 01 natural sciences, law.invention, law, 0103 physical sciences, Flares and mass ejections, Earth and Planetary Sciences (miscellaneous), Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, lcsh:Science, 010303 astronomy & astrophysics, Coronagraph, 0105 earth and related environmental sciences, Physics, Solar physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], lcsh:QC801-809, Astronomy, Geology, Astronomy and Astrophysics, Plasma, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, Space and Planetary Science, Physics::Space Physics, lcsh:Q, Astrophysics::Earth and Planetary Astrophysics, lcsh:Physics
Abstract

Coronal Mass ejections (CMEs) are enormous eruptions of magnetized plasma expelled from the Sun into the interplanetary space, over the course of hours to days. They can create major disturbances in the interplanetary medium and trigger severe magnetic storms when they collide with the Earth's magnetosphere. It is important to know their real speed, propagation direction and 3-D configuration in order to accurately predict their arrival time at the Earth. Using data from the SECCHI coronagraphs onboard the STEREO mission, which was launched in October 2006, we can infer the propagation direction and the 3-D structure of such events. In this review, we first describe different techniques that were used to model the 3-D configuration of CMEs in the coronagraph field of view (up to 15 R⊙). Then, we apply these techniques to different CMEs observed by various coronagraphs. A comparison of results obtained from the application of different reconstruction algorithms is presented and discussed.

Published
2010
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5. Coma cluster object populations down to M_R~-9.5

Author

Florence Durret, M. J. West, J. P. Picat, C. Adami, R. Pello, A. Mazure, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy, University of Hawaii, Services communs OMP (UMS 831), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Météo-France -Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)

Subjects
Absolute magnitude, Astrophysics::High Energy Astrophysical Phenomena, Population, FOS: Physical sciences, Coma (optics), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Luminosity, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, Coma Cluster, Astrophysics::Solar and Stellar Astrophysics, education, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Luminosity function (astronomy), Physics, education.field_of_study, 010308 nuclear & particles physics, Astrophysics (astro-ph), Astronomy and Astrophysics, Galaxy, Space and Planetary Science, Globular cluster, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

This study follows a recent analysis of the galaxy luminosity functions and colour-magnitude red sequences in the Coma cluster (Adami et al. 2007). We analyze here the distribution of very faint galaxies and globular clusters in an east-west strip of $\sim 42 \times 7$ arcmin$^2$ crossing the Coma cluster center (hereafter the CS strip) down to the unprecedented faint absolute magnitude of M$_R \sim -9.5$. This work is based on deep images obtained at the CFHT with the CFH12K camera in the B, R, and I bands. The analysis shows that the observed properties strongly depend on the environment, and thus on the cluster history. When the CS is divided into four regions, the westernmost region appears poorly populated, while the regions around the brightest galaxies NGC 4874 and NGC 4889 (NGC 4874 and NGC 4889 being masked) are dominated by faint blue galaxies. They show a faint luminosity function slope of -2, very significantly different from the field estimates. Results are discussed in the framework of galaxy destruction (which can explain part of the very faint galaxy population) and of structures infalling on to Coma., To be published in A&A

Published
2007
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6. Deep and wide field imaging of the Coma cluster: the data

Author

C. Adami, J. P. Picat, C. Savine, A. Mazure, M. J. West, J. C. Cuillandre, R. Pelló, A. Biviano, C. J. Conselice, F. Durret, J. S. Gallagher, M. Gregg, C. Moreau, M. Ulmer, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy, University of Hawaii, Canada-France-Hawaii Telescope Corporation (CFHT), National Research Council of Canada (NRC)-Centre National de la Recherche Scientifique (CNRS)-University of Hawai'i [Honolulu] (UH), INAF-Osservatorio Astronomico di Trieste (INAF-OATs), California Institute of Technology, Department of Astronomy (CALTECH), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), University of Wisconsin-Madison, Department of Physics, Le Conte Hall, University of California, Northwestern University, Evanston, and Beaussier, Catherine

Subjects
Physics, education.field_of_study, Astrophysics (astro-ph), Population, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrometry, Galaxy, Redshift, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Cover (topology), [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Space and Planetary Science, Magnitude (astronomy), Coma Cluster, education, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Data reduction
Abstract

We have obtained deep and wide field imaging of the Coma cluster of galaxies with the CFH12K camera at CFHT in the B, V, R and I filters. In this paper, we present the observations, data reduction, catalogs and first scientific results. We investigated the quality of our data by internal and external literature comparisons. We also checked the realisation of the observational requirements we set. Our observations cover two partially overlapping areas of $42 \times 28$ arcmin$^2$, leading to a total area of 0.72 $\times$ 0.82 deg$^2$. We have produced catalogs of objects that cover a range of more than 10 magnitudes and are complete at the 90% level at B$\sim$25, V$\sim$24, R$\sim$24 and I$\sim$23.5 for stellar-like objects, and at B$\sim$22, V$\sim$21, R$\sim$20.75 and I$\sim$20.5 for faint low-surface-brightness galaxy-like objects. Magnitudes are in good agreement with published values from R$\sim$16 to R$\sim$25. The photometric uncertainties are of the order of 0.1 magnitude at R$\sim$20 and of 0.3 magnitude at R$\sim$25. Astrometry is accurate to 0.5~arcsec and also in good agreement with published data. Our catalog provides a rich dataset that can be mined for years to come to gain new insights into the formation and evolution of the Coma cluster and its galaxy population. As an illustration of the data quality, we examine the bright part of the Colour Magnitude Relation (B-R versus R) derived from the catalog and find that it is in excellent agreement with that derived for galaxies with redshifts in the Coma cluster, and with previous CMRs estimated in the literature., A&A, 2006, 451, 1159. Catalog available at http://cencosw.oamp.fr/ with no restriction. High resolution figures can be found at A&A, 2006, 451, 1159

Published
2006
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7. Spatial variations of the optical galaxy luminosity functions and red sequences in the Coma cluster: clues to its assembly history

Author

R. Pello, C. Adami, J. P. Picat, B. Meneux, Florence Durret, M. J. West, A. Mazure, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France, Department of Physics and Astronomy, University of Hawaii, Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Milano), and Beaussier, Catherine

Subjects
Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Coma (optics), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Luminosity, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, Coma Cluster, Cluster (physics), Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, 010308 nuclear & particles physics, Late type, Astrophysics (astro-ph), Astronomy and Astrophysics, Galaxy, Early type, Space and Planetary Science, [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Magnitude (astronomy), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Clusters of galaxies are believed to be at the intersections of cosmological filaments and to grow by accreting matter from these filaments. Such continuous infall has major consequences not only on clusters but also on the physics of cluster galaxies. Faint galaxies are particularly interesting as they are very sensitive to environmental effects, and may have a different behaviour from that of bright galaxies. The aim of this paper is to sample the Coma cluster building history, based on the analysis of galaxy luminosity functions and red sequences in the Color Magnitude Relation down to faint magnitudes, which are privileged tools for this purpose. The present analysis is based on deep (R~24), wide (~0.5 deg2) multiband (BVRI Vega system) images of the Coma cluster obtained with the CFH12K camera at the CFHT. We have derived LFs and CMRs in twenty 10x10 arcmin2 regions and in larger regions. In all photometric bands, we found steeply rising LFs in the north-northeast half of the cluster (due to early type galaxies at bright magnitudes and due to late type galaxies at the faint end), and much flatter LFs in the south-southwest region. Although the fine behaviour of the CMR RS is different in these two regions, a good agreement is found in general between the RS computed for faint and for bright galaxies. All these results can be interpreted consistently in the framework of the building up process previously proposed. The Northern Coma area is a relatively quiescent region while the southern area experiences several infalls., Comment: To be published in A&A, several figures in jpg format, full resolution figures and paper available at http://cencosw.oamp.fr/ under the Coma page. The lacking figures are available at the same adress. Updated CFHT acknowledgements and aa format

Published
2006
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8. The Relative Ages of the Globular Cluster Subpopulations in M87

Author

Patrick Côté, Andrés Jordán, M. J. West, and R. O. Marzke

Subjects
Physics, 010504 meteorology & atmospheric sciences, Age differences, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Galaxy, Redshift, On board, Photometry (optics), Space and Planetary Science, Globular cluster, 0103 physical sciences, Elliptical galaxy, Population synthesis, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences
Abstract

Relative ages for the globular cluster (GC) subpopulations in the Virgo giant elliptical galaxy M87 (NGC 4486) have been determined from Stroemgren photometry obtained with WFPC2 on board HST. Using a variety of population synthesis models, and assuming the GC mass at the turnover of the luminosity function is the same for both subpopulations, differential ages have been determined from the observed magnitudes at the turnover of the globular cluster luminosity function and from the mean color of each subpopulation. We measure an age difference between the two subpopulations of 0.2 +/- 1.5 (systematic) +/- 2 (random) Gyr, in the sense that the blue GCs are formally older. Thus, to within our measurement errors, the two subpopulations are found to be coeval. Combined with previous spectroscopic age determinations for M87 GCs, our results favor a picture in which the GCs associated with this galaxy are formed at high redshift, and within a period of a few Gyr., Comment: 5 pages, 2 postscript figures. Accepted for publication in ApJ Letters

Published
2002
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9. Globular cluster systems in fossil groups: NGC 6482, NGC 1132, and ESO 306-017

Author

P. Cote, Andrés Jordán, Michael D. Gregg, Rosa A. González-Lópezlira, M. J. West, Michael J. Drinkwater, K. A. Alamo-Martinez, S. van den Bergh, and John P. Blakeslee

Subjects
Physics, education.field_of_study, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrophysics::High Energy Astrophysical Phenomena, Metallicity, Population, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Advanced Camera for Surveys, Galaxy, Luminosity, Space and Planetary Science, Globular cluster, Elliptical galaxy, Astrophysics::Solar and Stellar Astrophysics, Surface brightness, education, Astrophysics::Galaxy Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We study the globular cluster (GC) systems in three representative fossil group galaxies: the nearest (NGC6482), the prototype (NGC1132) and the most massive known to date (ESO306-017). This is the first systematic study of GC systems in fossil groups. Using data obtained with the Hubble Space Telescope Advanced Camera for Surveys in the F475W and F850LP filters, we determine the GC color and magnitude distributions, surface number density profiles, and specific frequencies. In all three systems, the GC color distribution is bimodal, the GCs are spatially more extended than the starlight, and the red population is more concentrated than the blue. The specific frequencies seem to scale with the optical luminosities of the central galaxy and span a range similar to that of the normal bright elliptical galaxies in rich environments. We also analyze the galaxy surface brightness distributions to look for deviations from the best-fit S\'ersic profiles; we find evidence of recent dynamical interaction in all three fossil group galaxies. Using X-ray data from the literature, we find that luminosity and metallicity appear to correlate with the number of GCs and their mean color, respectively. Interestingly, although NGC6482 has the lowest mass and luminosity in our sample, its GC system has the reddest mean color, and the surrounding X-ray gas has the highest metallicity., Comment: 16 pages, 13 figures. Accepted for publication in A&A

Published
2012
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10. Alignments of clusters of galaxies as a probe for superclusters

Author

S. J. Aarseth, M. J. West, and A. Dekel

Subjects
Physics, media_common.quotation_subject, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Universe, Galaxy, Cosmology, Hierarchical clustering, Many-body problem, Galaxy groups and clusters, Space and Planetary Science, Galaxy cluster, media_common, Principal axis theorem
Abstract

We use N-body simulations of competing cosmological scenarios to study the relative orientations of the principal axes of clusters of galaxies and the lines connecting them to neighboring clusters and find that they provide a sensitive test for the formation of the large-scale structure in the universe. The observed tendency of clusters to point toward each other reflects the existence of 20-50 Mpc h/sup -1/ elongated superclusters that construct a large-scale cell structure. Tidal interactions between clusters are found not to produce similar alignments, presumably because the clusters are surrounded by underdense regions. Hence the scenario in which superclusters have collapsed from excessive fluctuations on large scales in favored over hierarchical clustering from fluctuations on smaller scales. Rich clusters (but not necessarily galaxies) had to be formed after, or during, the aspherical collapse of superclusters, i.e., not long before zapprox.1.

Published
1984
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