Search

Your search keyword '"E. Toloba"' showing total 21 results
Start Over Author "E. Toloba" Language english
21 results on '"E. Toloba"'

1. Hubble Space Telescope Imaging of Isolated Local Volume Dwarfs GALFA-Dw3 and Dw4

Author

P. Bennet, D. J. Sand, D. Crnojević, D. R. Weisz, N. Caldwell, P. Guhathakurta, J. R. Hargis, A. Karunakaran, B. Mutlu-Pakdil, E. Olszewski, J. J. Salzer, A. C. Seth, J. D. Simon, K. Spekkens, D. P. Stark, J. Strader, E. J. Tollerud, E. Toloba, and B. Willman

Subjects
010308 nuclear & particles physics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, FOS: Physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astronomy and Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 010303 astronomy & astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Astrophysics::Galaxy Astrophysics
Abstract

We present observations of the dwarf galaxies GALFA Dw3 and GALFA Dw4 with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST). These galaxies were initially discovered as optical counterparts to compact HI clouds in the GALFA survey. Both objects resolve into stellar populations which display an old red giant branch, younger helium burning, and massive main sequence stars. We use the tip of the red giant branch method to determine the distance to each galaxy, finding distances of 7.61$_{-0.29}^{+0.28}$ Mpc and 3.10$_{-0.17}^{+0.16}$ Mpc, respectively. With these distances we show that both galaxies are extremely isolated, with no other confirmed objects within ~1.5 Mpc of either dwarf. GALFA Dw4 is also found to be unusually compact for a galaxy of its luminosity. GALFA Dw3 and Dw4 contain HII regions with young star clusters and an overall irregular morphology; they show evidence of ongoing star formation through both ultraviolet and H$��$ observations and are therefore classified as dwarf irregulars (dIrrs). The star formation histories of these two dwarfs show distinct differences: Dw3 shows signs of a recently ceased episode of active star formation across the entire dwarf, while Dw4 shows some evidence for current star formation in spatially limited HII regions. Compact HI sources offer a promising method for identifying isolated field dwarfs in the Local Volume, including GALFA Dw3 & Dw4, with the potential to shed light on the driving mechanisms of dwarf galaxy formation and evolution., 18 pages, 7 figures, 1 table, submitted to ApJ

Published
2021

2. The Next Generation Virgo Cluster Survey (NGVS). XXXII. A Search for Globular Cluster Substructures in the Virgo Galaxy Cluster Core

Author

Joel Roediger, Simona Mei, Stephen Gwyn, Thomas H. Puzia, Eric W. Peng, Hong-Xin Zhang, A. Longobardi, P. Hudelot, Mathieu Powalka, Paul Eigenthaler, Rubén Sánchez-Janssen, Ariane Lançon, Chengze Liu, Patrick R. Durrell, John P. Blakeslee, Laura Ferrarese, Puragra Guhathakurta, Karla Alamo-Martínez, Roberto Munoz, Jean-Charles Cuillandre, Patrick Côté, E. Toloba, Pierre-Alain Duc, Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Pontificia Universidad Católica de Chile (UC), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), National Research Council of Canada (NRC), Youngstown State University (YSU), UCO/Lick Observatory, University of California [Santa Cruz] (UCSC), University of California-University of California, 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), Department of Physics and Astronomy [Shanghai], Shanghai Jiao Tong University [Shanghai], Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro de Investigacion y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Texas Tech University [Lubbock] (TTU), State Key Laboratory of CAD &CG [Zhejiang], Zhejiang University, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), University of California [Santa Cruz] (UC Santa Cruz), University of California (UC)-University of California (UC), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP)

Subjects
Physics, [PHYS]Physics [physics], 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Virgo Cluster, Core (optical fiber), Space and Planetary Science, Globular cluster, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Galaxy cluster, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS
Abstract

Substructure in globular cluster (GC) populations around large galaxies is expected in galaxy formation scenarios that involve accretion or merger events, and it has been searched for using direct associations between GCs and structure in the diffuse galaxy light, or with GC kinematics. Here, we present a search for candidate substructures in the GC population around the Virgo cD galaxy M87 through the analysis of the spatial distribution of the GC colors.~The study is based on a sample of $\sim\!1800$ bright GCs with high-quality $u,g,r,i,z,K_s$ photometry, selected to ensure a low contamination by foreground stars or background galaxies.~The spectral energy distributions of the GCs are associated with formal estimates of age and metallicity, which are representative of its position in a 4-D color-space relative to standard single stellar population models.~Dividing the sample into broad bins based on the relative formal ages, we observe inhomogeneities which reveal signatures of GC substructures.~The most significant of these is a spatial overdensity of GCs with relatively young age labels, of diameter $\sim\!0.1$\,deg ($\sim\!30\,$kpc), located to the south of M87.~The significance of this detection is larger than about 5$\sigma$ after accounting for estimates of random and systematic errors.~Surprisingly, no large Virgo galaxy is present in this area, that could potentially host these GCs.~But candidate substructures in the M87 halo with equally elusive hosts have been described based on kinematic studies in the past.~The number of GC spectra available around M87 is currently insufficient to clarify the nature of the new candidate substructure., Comment: 11 pages, 6 figures, Accepted for publication in ApJ

Published
2018
Full Text
View/download PDF

3. Abundance ratios in dwarf elliptical galaxies

Author

Agnieszka Sybilska, Jesús Falcón-Barroso, Thorsten Lisker, Heikki Salo, Joachim Janz, Reynier Peletier, Cahit Yeşilyaprak, E. Toloba, A. Vazdekis, Alessandro Boselli, M. den Brok, Gerhard Hensler, Eija Laurikainen, S. Sen, Sanjaya Paudel, G. van de Ven, J. J. Mentz, 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), Kapteyn Astronomical Institute, and Astronomy

Subjects
CAII TRIPLET ABSORPTION, Stellar population, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, ACS-VIRGO-CLUSTER, 01 natural sciences, Abundance (ecology), 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, SPECTRAL-SYNTHESIS, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, STAR-FORMATION HISTORIES, Physics, ta115, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Star formation, GALACTIC CHEMICAL EVOLUTION, INTERNAL DYNAMICS, Astronomy and Astrophysics, galaxies: dwarf, Virgo Cluster, Astrophysics - Astrophysics of Galaxies, Dwarf spheroidal galaxy, STELLAR POPULATION SYNTHESIS, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), Elliptical galaxy, galaxies: clusters: individual: Virgo, galaxies: stellar content, DIGITAL SKY SURVEY, galaxies: abundances, Astrophysics::Earth and Planetary Astrophysics, SPHEROIDAL GALAXIES, galaxies: evolution, GLOBULAR-CLUSTER GIANTS
Abstract

We determine abundance ratios of 37 dwarf ellipticals (dEs) in the nearby Virgo cluster. This sample is representative of the early-type population of galaxies in the absolute magnitude range -19.0 < Mr < -16.0. We analyze their absorption line-strength indices by means of index-index diagrams and scaling relations and use the stellar population models to interpret them. We present ages, metallicities and abundance ratios obtained from these dEs within an aperture size of Re/8. We calculate [Na/Fe] from NaD, [Ca/Fe] from Ca4227 and [Mg/Fe] from Mgb. We find that [Na/Fe] is under-abundant with respect to solar while [Mg/Fe] is around solar. This is exactly opposite to what is found for giant ellipticals, but follows the trend with metallicity found previously for the Fornax dwarf NGC 1396. We discuss possible formation scenarios that can result in such elemental abundance patterns and we speculate that dEs have disk-like SFH favouring them to originate from late-type dwarfs or small spirals. Na-yields appear to be very metal-dependent, in agreement with studies of giant ellipticals, probably due to the large dependence on the neutron-excess in stars. We conclude that dEs have undergone a considerable amount of chemical evolution, they are therefore not uniformly old, but have extended SFH, similar to many of the Local Group galaxies., 15 pages, 5 figures; accepted for publication in MNRAS

Published
2018
Full Text
View/download PDF

4. A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE)

Author

Stephen Gwyn, Annie Zavagno, Patrick R. Durrell, Médéric Boquien, Ming Sun, P. Côté, Baerbel Koribalski, Luca Cortese, E. Toloba, Matteo Fossati, Alessandro Boselli, Bernd Vollmer, Gerhard Hensler, Joel Roediger, Giuseppe Gavazzi, Stephanie Cote, V. Buat, Denis Burgarella, Jean-Charles Cuillandre, D. Russeil, Michele Fumagalli, G. Consolandi, Laura Ferrarese, Yannick Roehlly, Samuel Boissier, Boselli, A, Fossati, M, Cuillandre, J, Boissier, S, Boquien, M, Buat, V, Burgarella, D, Consolandi, G, Cortese, L, Cote, P, Cote, S, Durrell, P, Ferrarese, L, Fumagalli, M, Gavazzi, G, Gwyn, S, Hensler, G, Koribalski, B, Roediger, J, Roehlly, Y, Russeil, D, Sun, M, Toloba, E, Vollmer, B, Zavagno, A, 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), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Università degli Studi di Milano-Bicocca [Milano] (UNIMIB), Bordeaux population health (BPH), Université de Bordeaux (UB)-Institut de Santé Publique, d'Épidémiologie et de Développement (ISPED)-Institut National de la Santé et de la Recherche Médicale (INSERM), Shanghai Maritime University, Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universitätssternwarte der Ludwig-Maximiliansuniversität, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Unidad de Astronomia, Facultad de Ciencias Basicas, Universidad de Antofagasta, Milano, International Centre for Radio Astronomy Research, University of Western Australia (ICRAR), National Research Council of Canada (NRC), Department of Physics and Astronomy, Youngstown State University, Institute for Computational Cosmology, Department of Physics, Durham University, Durham (ICC), Department of Astrophysics, University of Vienna, Turkenschanzstrasse 17, 1180, Vienna, Austria, Australian Telescope National Facility (ATNF), Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Falmer, CSPAR and Physics Department, University of Alabama in Huntsville, Huntsville, Department of Physiscs, University of the Pacific, 3601 Pacific Avenue, Stockton, CA, 95211, USA, Observatoire astronomique de Strasbourg (OAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Milano-Bicocca = University of Milano-Bicocca (UNIMIB), CDS, Centre de Données astronomiques de Strasbourg, Observatoire astronomique de Strasbourg, France + ESO, European Southern Observatory, Garching bei Muenchen, Allemagne, Université de Strasbourg (UNISTRA)-Université Louis Pasteur - Strasbourg I, 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
[SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, [SCCO]Cognitive science, Intracluster medium, 0103 physical sciences, Galaxy formation and evolution, galaxies: interactions, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Galaxies: individual: NGC 4254, Astrophysics::Galaxy Astrophysics, Physics, Spiral galaxy, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Star formation, Galaxies: evolution, Astronomy and Astrophysics, Galaxies: clusters: individual: Virgo, Virgo Cluster, Astrophysics - Astrophysics of Galaxies, Galaxy, Ram pressure, Galaxies: ISM, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Galaxies: interaction, Astrophysics of Galaxies (astro-ph.GA), Spectral energy distribution, Astrophysics::Earth and Planetary Astrophysics, Galaxies: clusters: general, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

During pilot observations of the Virgo Environmental Survey Tracing Galaxy Evolution (VESTIGE), a blind narrow-band Halpha+[NII] imaging survey of the Virgo cluster carried out with MegaCam at the CFHT, we have observed the spiral galaxy NGC 4254 (M99). Deep Halpha+[NII] narrow-band and GALEX UV images revealed the presence of 60 compact (70-500 pc radius) star forming regions up to ~ 20 kpc outside the optical disc of the galaxy. These regions are located along a tail of HI gas stripped from the disc of the galaxy after a rapid gravitational encounter with another Virgo cluster member that simulations indicate occurred 280-750 Myr ago. We have combined the VESTIGE data with multifrequency data from the UV to the far-infrared to characterise the stellar populations of these regions and study the star formation process in an extreme environment such as the tails of stripped gas embedded in the hot intracluster medium. The colour, spectral energy distribution (SED), and linear size consistently indicate that these regions are coeval and have been formed after a single burst of star formation that occurred ~< 100 Myr ago. These regions might become free floating objects within the cluster potential well, and be the local analogues of compact sources produced after the interaction of gas-rich systems that occurred during the early formation of clusters., Accepted for publication on Astronomy & Astrophysics

Published
2018
Full Text
View/download PDF

5. Virgo Redux: The Masses and Stellar Content of Nuclei in Early-type Galaxies from Multiband Photometry and Spectroscopy

Author

Laura Ferrarese, Puragra Guhathakurta, Joel Roediger, Jean-Charles Cuillandre, Patrick Côté, Rubén Sánchez-Janssen, Roberto Munoz, Yiqing Liu, Simona Mei, Ariane Lançon, Mathieu Powalka, Andrew Zirm, Chelsea Spengler, E. Toloba, Stephen Gwyn, Thomas H. Puzia, Eric W. Peng, National Research Council of Canada (NRC), Texas Tech University [Lubbock] (TTU), UCO/Lick Observatory, University of California [Santa Cruz] (UC Santa Cruz), University of California (UC)-University of California (UC), 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), Centro de Investigacion y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Pontificia Universidad Católica de Chile (UC), Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Paris - Site de Paris (OP), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 California [Santa Cruz] (UCSC), University of California-University of California, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS), and École normale supérieure - Paris (ENS Paris)

Subjects
Physics, [PHYS]Physics [physics], 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Galaxy, Early type, Photometry (astronomy), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Content (measure theory), Spectroscopy, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS
Abstract

We present an analysis of 39 nuclei and their early-type hosts in the Virgo Cluster using ten broadband filters: F300W, F475W, F850LP, F160W, $u^*griz$, and $K_s$. We describe the Virgo Redux program, which provides high-resolution UV and NIR imaging. Combining this data with optical and NIR imaging from the ACS Virgo Cluster Survey and the Next Generation Virgo Cluster Survey, we estimate masses, metallicities and ages using simple stellar population (SSP) models. For 19 nuclei, we compare to SSP parameters derived from Keck and Gemini spectra and find reasonable agreement between the photometric and spectroscopic metallicity: the RMS scatter is 0.3 dex. We reproduce the nucleus-galaxy mass fraction of $0.33^{+0.09}_{-0.07}$ percent for galaxy stellar masses $10^{8.4}-10^{10.3} M_\odot$ with a typical precision of $\sim$35% for the nuclei masses. Based on available model predictions, there is no single preferred formation scenario for nuclei, suggesting that nuclei are formed stochastically through a mix of processes. Nuclei metallicities are statistically identical to those of their hosts, appearing $0.07 \pm 0.3$ dex more metal-rich on average -- although, omitting galaxies with unusual origins, nuclei are $0.20\pm0.28$ dex more metal-rich. Nuclei appear to be $0.56 \pm 0.12$ dex more metal rich than ultra-compact dwarf galaxies (UCDs) at fixed mass. We find no clear age difference between nuclei and their galaxies, with nuclei displaying a broad range of ages. Interestingly, we find that the most massive nuclei may be flatter and more closely aligned with the semi-major axes of their hosts, suggesting that they formed through predominantly dissipative processes., Comment: 46 pages, 25 figures, 9 tables. Accepted for publication in ApJ

Published
2017
Full Text
View/download PDF

6. The Next Generation Virgo Cluster Survey (NGVS). XXVI. The Issues of Photometric Age and Metallicity Estimates for Globular Clusters

Author

Hong-Xin Zhang, E. Toloba, Pierre-Alain Duc, Laura Ferrarese, Stephen Gwyn, Thomas H. Puzia, Joel Roediger, Jean-Charles Cuillandre, Patrick Côté, Rubén Sánchez-Janssen, Ariane Lançon, Eric W. Peng, Chengze Liu, Puragra Guhathakurta, Mathieu Powalka, P. Hudelot, Roberto Munoz, Patrick R. Durrell, Simona Mei, John P. Blakeslee, Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Pontificia Universidad Católica de Chile (UC), Kavli Institute for Astronomy and Astrophysics [Beijing] (KIAA-PKU), Peking University [Beijing], Department of Physics and Astronomy [Shanghai], Shanghai Jiao Tong University [Shanghai], Centro de Investigacion y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), National Research Council of Canada (NRC), Youngstown State University (YSU), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), UCO/Lick Observatory, University of California [Santa Cruz] (UC Santa Cruz), University of California (UC)-University of California (UC), NRC Herzberg Institute of Astrophysics, Services communs OMP (UMS 831), 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), Observatoire de Paris - Site de Paris (OP), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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), Texas Tech University [Lubbock] (TTU), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), University of California [Santa Cruz] (UCSC), University of California-University of California, Services communs OMP - UMS 831 (UMS 831), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), 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), École normale supérieure - Paris (ENS Paris), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
Physics, [PHYS]Physics [physics], Stellar population, 010308 nuclear & particles physics, Milky Way, Metallicity, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Virgo Cluster, Galaxy, Photometry (optics), Space and Planetary Science, Globular cluster, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS
Abstract

Large samples of globular clusters (GC) with precise multi-wavelength photometry are becoming increasingly available and can be used to constrain the formation history of galaxies. We present the results of an analysis of Milky Way (MW) and Virgo core GCs based on five optical-near-infrared colors and ten synthetic stellar population models. For the MW GCs, the models tend to agree on photometric ages and metallicities, with values similar to those obtained with previous studies. When used with Virgo core GCs, for which photometry is provided by the Next Generation Virgo cluster Survey (NGVS), the same models generically return younger ages. This is a consequence of the systematic differences observed between the locus occupied by Virgo core GCs and models in panchromatic color space. Only extreme fine-tuning of the adjustable parameters available to us can make the majority of the best-fit ages old. Although we cannot exclude that the formation history of the Virgo core may lead to more conspicuous populations of relatively young GCs than in other environments, we emphasize that the intrinsic properties of the Virgo GCs are likely to differ systematically from those assumed in the models. Thus, the large wavelength coverage and photometric quality of modern GC samples, such as used here, is not by itself sufficient to better constrain the GC formation histories. Models matching the environment-dependent characteristics of GCs in multi-dimensional color space are needed to improve the situation., Comment: 18 pages, 12 figures, Accepted for publication in ApJ

Published
2017
Full Text
View/download PDF

7. Abundance ratios in dwarf elliptical galaxies

Author

Seyda Sen, Jaco J. Mentz, Reynier Peletier, E. Toloba, Kapteyn Astronomical Institute, and Astronomy

Subjects
Physics, Stellar population, Star formation, stellar populations, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Virgo Cluster, abundance ratios, Space and Planetary Science, Abundance (ecology), individual (Virgo), galaxies: dwarf elliptical, Elliptical galaxy, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Scaling, Astrophysics::Galaxy Astrophysics
Abstract

The aim of this study is to determine abundance ratios and star formation histories (SFH) of dwarf ellipticals in the nearby Virgo cluster. We perform a stellar population analysis of 39 dEs and study them using index-index and scaling relations. We find an unusual behaviour where [Na/Fe] is under-abundant w.r.t. solar while [Ca/Fe] is over-abundant.

Published
2016

8. Stellar Kinematics and Structural Properties of Virgo Cluster Dwarf Early-type Galaxies from the SMAKCED Project. III. Angular Momentum and Constraints on Formation Scenarios

Author

Javier Gorgas, M. den Brok, E. Toloba, A. Rys, P. Guhathakurta, Sanjaya Paudel, Heikki Salo, Jesús Falcón-Barroso, Andrew J. Benson, J. Janz, T. Lisker, Reynier Peletier, S. Boissier, G. van de Ven, A. Boselli, Joshua J. Adams, Gerhard Hensler, Eija Laurikainen, E. Emsellem, J. D. Simon, Astronomy, UCO/Lick Observatory, University of California [Santa Cruz] (UCSC), University of California-University of California, Texas Tech University [Lubbock] (TTU), 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), University of Vienna [Vienna], University of California [Santa Cruz] (UC Santa Cruz), and University of California (UC)-University of California (UC)

Subjects
Astrofísica, Stellar kinematics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Rotation, 01 natural sciences, Luminosity, cD, symbols.namesake, 0103 physical sciences, Cluster (physics), Astrophysics::Solar and Stellar Astrophysics, galaxies: elliptical and lenticular, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, galaxies: kinematics and dynamics, Physics, 010308 nuclear & particles physics, Física atmosférica, Balmer series, Astronomy and Astrophysics, galaxies: dwarf, Virgo Cluster, Galaxy, Ram pressure, Astronomía, Space and Planetary Science, symbols, galaxies: clusters: individual: Virgo, galaxies: stellar content, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], galaxies: evolution
Abstract

International audience; We analyze the stellar kinematics of 39 dwarf early-type galaxies (dEs) in the Virgo Cluster. Based on the specific stellar angular momentum lambda(Re) and the ellipticity, we find 11 slow rotators and 28 fast rotators. The fast rotators in the outer parts of the Virgo Cluster rotate significantly faster than fast rotators in the inner parts of the cluster. Moreover, 10 out of the 11 slow rotators are located in the inner 3 degrees (D \textless 1 Mpc) of the cluster. The fast rotators contain subtle disk-like structures that are visible in high-pass filtered optical images, while the slow rotators do not exhibit these structures. In addition, two of the dEs have kinematically decoupled cores and four more have emission partially filling in the Balmer absorption lines. These properties suggest that Virgo Cluster dEs may have originated from late-type star-forming galaxies that were transformed by the environment after their infall into the cluster. The correlation between lambda(Re) and the clustercentric distance can be explained by a scenario where low luminosity star-forming galaxies fall into the cluster, their gas is rapidly removed by ram-pressure stripping, although some of it can be retained in their core, their star formation is quenched but their stellar kinematics are preserved. After a long time in the cluster and several passes through its center, the galaxies are heated up and transformed into slow rotating dEs.

Published
2015
Full Text
View/download PDF

9. Trends in dwarf early-type kinematics with cluster-centric radius driven by tidal stirring

Author

Joshua D. Simon, Lucio Mayer, Andrew J. Benson, Puragra Guhathakurta, E. Toloba, and University of Zurich

Subjects
Physics, 010308 nuclear & particles physics, 530 Physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Kinematics, Radius, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Virgo Cluster, Astrophysics - Astrophysics of Galaxies, Galaxy, Early type, 1912 Space and Planetary Science, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 10231 Institute for Computational Science, 0103 physical sciences, Cluster (physics), 3103 Astronomy and Astrophysics, Statistical analysis, 010303 astronomy & astrophysics, Galaxy cluster, Astrophysics::Galaxy Astrophysics
Abstract

We model the dynamics of dwarf early-type galaxies in the Virgo cluster when subject to a variety of environmental processes. We focus on how these processes imprint trends in dynamical state (rotational vs. pressure support as measured by the $\lambda^*_{\rm Re/2}$ statistic) with projected distance from the cluster center, and compare these results to observational estimates. We find a large scatter in the gradient of $\lambda^*_{\rm Re/2}$ with projected radius. A statistical analysis shows that models with no environmental effects produce gradients as steep as those observed in none of the 100 cluster realizations we consider, while in a model incorporating tidal stirring by the cluster potential 34% of realizations produce gradients as steep as that observed. Our results suggest that tidal stirring may be the cause of the observed radial dependence of dwarf early-type dynamics in galaxy clusters., Comment: 5 pages, accepted for publication in ApJ

Published
2015

10. The Next Generation Virgo Cluster Survey. XV. The photometric redshift estimation for background sources

Author

Nicholas M. Ball, Marc Huertas-Company, Jj Kavelaars, Stephen Gwyn, Thomas H. Puzia, Alessandro Boselli, Eric W. Peng, Anand Raichoor, Pierre-Alain Duc, Chengze Liu, Puragra Guhathakurta, T. Erben, Hong-Xin Zhang, Hendrik Hildebrandt, Jean-Charles Cuillandre, Patrick Côté, Ariane Lançon, Ying-Tung Chen, Simona Mei, Samuel Boissier, L. van Waerbeke, David C. Woods, R. Licitra, Olivier Ilbert, Marcin Sawicki, Laura Ferrarese, Patrick R. Durrell, E. Toloba, Lauren A. MacArthur, M. Muller, Roberto Munoz, Département de Physique des Particules (ex SPP) (DPP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), 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), NRC Herzberg Astronomy and Astrophysics, Conseil National de Recherches Canada (CNRC), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), National Research Council of Canada (NRC), Multi-disciplinary Materials Research Center, Xi'an Jiaotong University (Xjtu), Otto-von-Guericke University [Magdeburg] (OVGU), Departamento de Fisica y Astronomia [Valparaiso], Universidad de Valparaiso [Chile], Service de Marquage Moléculaire et de Chimie Bioorganique, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), UCO/Lick Observatory, University of California [Santa Cruz] (UCSC), University of California-University of California, Texas Tech University [Lubbock] (TTU), 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), Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), PSL Research University (PSL)-PSL Research University (PSL)-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), Département de Physique des Particules (ex SPP) (DPhP), 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), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Otto-von-Guericke-Universität Magdeburg = Otto-von-Guericke University [Magdeburg] (OVGU), University of California [Santa Cruz] (UC Santa Cruz), and University of California (UC)-University of California (UC)

Subjects
Physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], FOS: Physical sciences, Astronomy and Astrophysics, Phot, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Virgo Cluster, Astrophysics - Astrophysics of Galaxies, Galaxy, Redshift, Photometry (optics), Star cluster, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, Photometric redshift, Data reduction, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The Next Generation Virgo Cluster Survey is an optical imaging survey covering 104 deg^2 centered on the Virgo cluster. Currently, the complete survey area has been observed in the u*giz-bands and one third in the r-band. We present the photometric redshift estimation for the NGVS background sources. After a dedicated data reduction, we perform accurate photometry, with special attention to precise color measurements through point spread function-homogenization. We then estimate the photometric redshifts with the Le Phare and BPZ codes. We add a new prior which extends to iAB = 12.5 mag. When using the u*griz-bands, our photometric redshifts for 15.5 \le i \lesssim 23 mag or zphot \lesssim 1 galaxies have a bias |\Delta z| < 0.02, less than 5% outliers, and a scatter \sigma_{outl.rej.} and an individual error on zphot that increase with magnitude (from 0.02 to 0.05 and from 0.03 to 0.10, respectively). When using the u*giz-bands over the same magnitude and redshift range, the lack of the r-band increases the uncertainties in the 0.3 \lesssim zphot \lesssim 0.8 range (-0.05 < \Delta z < -0.02, \sigma_{outl.rej} ~ 0.06, 10-15% outliers, and zphot.err. ~ 0.15). We also present a joint analysis of the photometric redshift accuracy as a function of redshift and magnitude. We assess the quality of our photometric redshifts by comparison to spectroscopic samples and by verifying that the angular auto- and cross-correlation function w(\theta) of the entire NGVS photometric redshift sample across redshift bins is in agreement with the expectations., Comment: Accepted for publication in ApJS. 24 pages, 21 Figures (some with degraded quality to fit the arxiv size limit), 6 Tables

Published
2014
Full Text
View/download PDF

11. Discovery of a close pair of faint dwarf galaxies in the halo of Centaurus A

Author

Anil C. Seth, Jay Strader, Joshua D. Simon, E. Toloba, Nelson Caldwell, Brian McLeod, P. Guhathakurta, David J. Sand, and Denija Crnojević

Subjects
Physics, education.field_of_study, Centaurus A, Population, FOS: Physical sciences, Local Group, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Red-giant branch, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Elliptical galaxy, Asymptotic giant branch, 10. No inequality, education, Dwarf galaxy
Abstract

As part of the Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS) we report the discovery of a pair of faint dwarf galaxies (CenA-MM-Dw1 and CenA-MM-Dw2) at a projected distance of $\sim$90 kpc from the nearby elliptical galaxy NGC5128 (CenA). We measure a tip of the red giant branch distance to each dwarf, finding $D=3.63 \pm 0.41$ Mpc for CenA-MM-Dw1 and $D=3.60 \pm 0.41$ Mpc for CenA-MM-Dw2, both of which are consistent with the distance to NGC5128. A qualitative analysis of the color magnitude diagrams indicates stellar populations consisting of an old, metal-poor red giant branch ($\gtrsim 12$ Gyr, [Fe/H]$\sim-1.7$ to -1.9). In addition, CenA-MM-Dw1 seems to host an intermediate-age population as indicated by its candidate asymptotic giant branch stars. The derived luminosities ($M_V=-10.9\pm0.3$ for CenA-MM-Dw1 and $-8.4\pm0.6$ for CenA-MM-Dw2) and half-light radii ($r_{h}=1.4\pm0.04$ kpc for CenA-MM-Dw1 and $0.36\pm0.08$ kpc for CenA-MM-Dw2) are consistent with those of Local Group dwarfs. CenA-MM-Dw1's low central surface brightness ($\mu_{V,0}=27.3\pm0.1$ mag/arcsec$^2$) places it among the faintest and most extended M31 satellites. Most intriguingly, CenA-MM-Dw1 and CenA-MM-Dw2 have a projected separation of only 3 arcmin ($\sim3$ kpc): we are possibly observing the first, faint satellite of a satellite in an external group of galaxies., Comment: 7 pages, 4 figures; ApJL submitted

Published
2014

12. A Near-infrared Census of the Multicomponent Stellar Structure of Early-type Dwarf Galaxies in the Virgo Cluster

Author

Sanjaya Paudel, J. Janz, A. Boselli, S. Niemi, Jesús Falcón-Barroso, K. S. A. Hansson, Gerhard Hensler, Eija Laurikainen, Reynier Peletier, Hagen T. Meyer, M. den Brok, Heikki Salo, E. Toloba, A. Ryś, Thorsten Lisker, 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), and Kapteyn Astronomical Institute

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Luminosity, cD, Astrophysics::Solar and Stellar Astrophysics, Stellar structure, galaxies: elliptical and lenticular, Scaling, Galaxy cluster, Astrophysics::Galaxy Astrophysics, Dwarf galaxy, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, galaxies: clusters: individual: Virgo Cluster, galaxies: dwarf, Virgo Cluster, Galaxy, galaxies: photometry, Space and Planetary Science, Magnitude (astronomy), galaxies: structure, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The fraction of star-forming to quiescent dwarf galaxies varies from almost infinity in the field to zero in the centers of rich galaxy clusters. What is causing this pronounced morphology-density relation? What do quiescent dwarf galaxies look like when studied in detail, and what conclusions can be drawn about their formation mechanism? Here we study a nearly magnitude-complete sample (-19 < M_r < -16 mag) of 121 Virgo cluster early types with deep near-infrared images from the SMAKCED project. We fit two-dimensional models with optional inner and outer components, as well as bar and lens components (in ~15% of the galaxies), to the galaxy images. While a single S��rsic function may approximate the overall galaxy structure, it does not entirely capture the light distribution of two-thirds of our galaxies, for which multi-component models provide a better fit. This fraction of complex galaxies shows a strong dependence on luminosity, being larger for brighter objects. We analyze the global and component-specific photometric scaling relations of early-type dwarf galaxies and discuss similarities with bright early and late types. The dwarfs' global galaxy parameters show scaling relations that are similar to those of bright disk galaxies. The inner components are mostly fitted with S��rsic n values close to 1. At a given magnitude they are systematically larger than the bulges of spirals, suggesting that they are not ordinary bulges. We argue that the multi-component structures in early-type dwarfs are mostly a phenomenon inherent to the disks, and may indeed stem from environmental processing., Accepted for publication in ApJS, 34 pages, 30 figures. Online figures: http://www.smakced.net/data.html

Published
2014
Full Text
View/download PDF

13. The GALEX ultraviolet virgo cluster survey (GUViCS): IV. the role of the cluster environment on galaxy evolution

Author

Luca Cortese, E. Voyer, Olga Cucciati, G. Consolandi, Sebastien Heinis, Michele Fumagalli, Alessandro Boselli, Yannick Roehlly, E. Toloba, Giuseppe Gavazzi, Samuel Boissier, Boselli, A, Voyer, E, Boissier, S, Cucciati, O, Consolandi, G, Cortese, L, Fumagalli, M, Gavazzi, G, Heinis, S, Roehlly, Y, Toloba, E, 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), 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
Stellar mass, clusters: individual: Virgo [Galaxies], FOS: Physical sciences, Astrophysics, interactions [Galaxies], Astrophysics::Cosmology and Extragalactic Astrophysics, clusters: general [Galaxies], 01 natural sciences, 0103 physical sciences, ISM [Galaxies], Galaxy formation and evolution, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Galaxy rotation curve, Astrophysics::Galaxy Astrophysics, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Galaxies: star formation, 010308 nuclear & particles physics, Star formation, Galaxies: evolution, Astronomy and Astrophysics, Astronomy and Astrophysic, evolution [Galaxies], Galaxies: clusters: individual: Virgo, Virgo Cluster, Astrophysics - Astrophysics of Galaxies, Galaxy, Ram pressure, Interstellar medium, Galaxies: ISM, Galaxies: interaction, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Galaxies: clusters: general, star formation. [Galaxies]
Abstract

We study the role of the environment on galaxy evolution using a sample of 868 galaxies in the Virgo cluster and in its surrounding regions selected from the GUViCS Survey with the purpose of understanding the origin of the red sequence in dense environments. We collected multifrequency data covering the whole electromagnetic spectrum for most of the galaxies. We identify the different dynamical substructures composing the Virgo cluster and we calculate the local density of galaxies using different methods. We then study the distribution of galaxies belonging to the red sequence, the green valley, and the blue cloud within the different cluster substructures. Our analysis indicates that all the most massive galaxies are slow rotators and are the dominant galaxies of the different cluster substructures generally associated with a diffuse X-ray emission. They are probably the result of major merging events that occurred at early epochs. Slow rotators of lower stellar mass are also preferentially located within the different high-density substructures of the cluster. They are virialised within the cluster, thus Virgo members since its formation. They have been shaped by gravitational perturbations occurring within the infalling groups that later formed the cluster. On the contrary, low-mass star-forming systems are extremely rare in the inner regions of the Virgo cluster A, where the density of the intergalactic medium is at its maximum. Our ram pressure stripping models consistently indicate that these star-forming systems can be rapidly deprived of their interstellar medium during their interaction with the intergalactic medium. The lack of gas quenches their star formation activity transforming them into quiescent dwarf ellipticals. This mild transformation does not perturb the kinematic properties of these galaxies which still have rotation curves typical of star-forming systems., Comment: Submitted for publication on Astronomy & Astrophysics

Published
2014
Full Text
View/download PDF

14. DISSECTING EARLY-TYPE DWARF GALAXIES INTO THEIR MULTIPLE COMPONENTS

Author

E. Toloba, Alessandro Boselli, M. den Brok, Eija Laurikainen, Gerhard Hensler, Thorsten Lisker, Jesús Falcón-Barroso, Reynier Peletier, S. M. Niemi, Heikki Salo, Joachim Janz, UCO/Lick Observatory, University of California [Santa Cruz] (UCSC), University of California-University of California, Texas Tech University [Lubbock] (TTU), 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), University of Vienna [Vienna], University of California [Santa Cruz] (UC Santa Cruz), University of California (UC)-University of California (UC), and Astronomy

Subjects
Brightness, Cosmology and Nongalactic Astrophysics (astro-ph.CO), COMA CLUSTER, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, ACS-VIRGO-CLUSTER, 01 natural sciences, galaxies: clusters: individual (Virgo Cluster), cD, STRUCTURAL PARAMETERS, STELLAR POPULATIONS, ELLIPTIC GALAXIES, 0103 physical sciences, COLOR-MAGNITUDE RELATION, Astrophysics::Solar and Stellar Astrophysics, galaxies: elliptical and lenticular, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Dwarf galaxy, Physics, STAR, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Center (category theory), Astronomy and Astrophysics, galaxies: dwarf, Virgo Cluster, Galaxy, EVOLUTION, Early type, galaxies: photometry, Space and Planetary Science, Content (measure theory), galaxies: elliptical and lenticular, cD, galaxies: structure, DIGITAL SKY SURVEY, BARS, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Early-type dwarf galaxies, once believed to be simple systems, have recently been shown to exhibit an intriguing diversity in structure and stellar content. To analyze this further, we started the SMAKCED project, and obtained deep H-band images for 101 early-type dwarf galaxies in the Virgo cluster in a brightness range of -19 \leq M_r \leq -16 mag, typically reaching a signal-to-noise of 1 per pixel of \sim0.25" at surface brightnesses \sim22.5 mag/arcsec^2 in the H-band. Here we present the first results of decomposing their two-dimensional light distributions. This is the first study dedicated to early-type dwarf galaxies using the two-dimensional multi-component decomposition approach, which has been proven to be important for giant galaxies. Armed with this new technique, we find more structural components than previous studies: only a quarter of the galaxies fall into the simplest group, namely those represented by a single S\'ersic function, optionally with a nucleus. Furthermore, we find a bar fraction of 18%. We detect also a similar fraction of lenses which appear as shallow structures with sharp outer edges. Galaxies with bars and lenses are found to be more concentrated towards the Virgo galaxy center than the other sample galaxies., Comment: Accepted by ApJL, 6 pages, 4 figures, 1 table

Published
2012
Full Text
View/download PDF

15. Formation and evolution of dwarf early-type galaxies in the Virgo cluster. II. Kinematic scaling relations (Corrigendum)

Author

Alessandro Boselli, Javier Gorgas, E. Toloba, Jesús Falcón-Barroso, G. van de Ven, and Reynier Peletier

Subjects
Physics, Dwarf galaxy problem, Astronomy, Astronomy and Astrophysics, Astrophysics, galaxies: dwarf, Virgo Cluster, Dwarf spheroidal galaxy, cD, Space and Planetary Science, Elliptical galaxy, galaxies: clusters: individual: Virgo, Brightest cluster galaxy, galaxies: elliptical and lenticular, galaxies: evolution, Lenticular galaxy, addenda, Galaxy cluster, galaxies: kinematics and dynamics, errata, Dwarf galaxy
Abstract

Not Available

Published
2013
Full Text
View/download PDF

16. The Faint End of the Centaurus A Satellite Luminosity Function.

Author

D. Crnojević, D. J. Sand, P. Bennet, S. Pasetto, K. Spekkens, N. Caldwell, P. Guhathakurta, B. McLeod, A. Seth, J. D. Simon, J. Strader, and E. Toloba

Subjects
STELLAR luminosity function, STELLAR populations, GALACTIC halos, DWARF galaxies, ASTRONOMICAL photometry
Abstract

The Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS) is constructing a wide-field map of the resolved stellar populations in the extended halos of these two nearby, prominent galaxies. We present new Magellan/Megacam imaging of a ∼3 deg2 area around Centaurus A (Cen A), which filled in much of our coverage to its south, leaving a nearly complete halo map out to a projected radius of ∼150 kpc and allowing us to identify two new resolved dwarf galaxies. We have additionally obtained deep Hubble Space Telescope (HST) optical imaging of 11 out of the 13 candidate dwarf galaxies identified around Cen A and presented in Crnojević et al. 2016a: seven are confirmed to be satellites of Cen A, while four are found to be background galaxies. We derive accurate distances, structural parameters, luminosities, and photometric metallicities for the seven candidates confirmed by our HST/ACS imaging. We further study the stellar population along the ∼60 kpc long (in projection) stream associated with Dw3, which likely had an initial brightness of MV ∼ −15 and shows evidence for a metallicity gradient along its length. Using the total sample of 11 dwarf satellites discovered by the PISCeS survey, as well as 13 brighter previously known satellites of Cen A, we present a revised galaxy luminosity function for the Cen A group down to a limiting magnitude of MV ∼ −8, which has a slope of −1.14 ± 0.17, comparable to that seen in the Local Group and in other nearby groups of galaxies. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

17. Hubble Space Telescope Imaging of the Ultra-compact High Velocity Cloud AGC 226067: A Stripped Remnant in the Virgo Cluster.

Author

D. J. Sand, D. Crnojević, E. Toloba, B. Willman, A. C. Seth, K. Spekkens, J. Strader, E. A. K. Adams, N. Caldwell, S. Randall, P. Guhathakurta, J. Kenney, and J. D. Simon

Subjects
VIRGO Cluster, STELLAR populations, STELLAR luminosity function, STAR formation
Abstract

We analyze the optical counterpart to the ultra-compact high velocity cloud AGC 226067, utilizing imaging taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The color–magnitude diagram of the main body of AGC 226067 reveals an exclusively young stellar population, with an age of ∼7–50 Myr, and is consistent with a metallicity of [Fe/H] ∼ −0.3 as previous work has measured via H ii region spectroscopy. Additionally, the color–magnitude diagram is consistent with a distance of D ≈ 17 Mpc, suggesting an association with the Virgo cluster. A secondary stellar system located ∼1.′6 (∼8 kpc) away in projection has a similar stellar population. The lack of an old red giant branch (≳5 Gyr) is contrasted with a serendipitously discovered Virgo dwarf in the ACS field of view (Dw J122147+132853), and the total diffuse light from AGC 226067 is consistent with the luminosity function of the resolved ∼7–50 Myr stellar population. The main body of AGC 226067 has a MV = −11.3 ± 0.3, or Mstars = 5.4 ± 1.3 × 104M⊙ given the stellar population. We searched 20 deg2 of imaging data adjacent to AGC 226067 in the Virgo Cluster, and found two similar stellar systems dominated by a blue stellar population, far from any massive galaxy counterpart—if this population has star-formation properties that are similar to those of AGC 226067, it implies ∼0.1 M⊙ yr−1 in Virgo intracluster star formation. Given its unusual stellar population, AGC 226067 is likely a stripped remnant and is plausibly the result of compressed gas from the ram pressure stripped M86 subgroup (∼350 kpc away in projection) as it falls into the Virgo Cluster. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

18. THE EXTENDED HALO OF CENTAURUS A: UNCOVERING SATELLITES, STREAMS, AND SUBSTRUCTURES.

Author

D. Crnojević, D. J. Sand, K. Spekkens, N. Caldwell, P. Guhathakurta, B. McLeod, A. Seth, J. D. Simon, J. Strader, and E. Toloba

Subjects
CENTAURUS (Constellation), ELLIPTICAL galaxies, GALACTIC halos, ASTROPHYSICS, ACCRETION (Astrophysics)
Abstract

We present the widest-field resolved stellar map to date of the closest ( Mpc) massive elliptical galaxy NGC 5128 (Centaurus A; Cen A), extending out to a projected galactocentric radius of ∼150 kpc. The data set is part of our ongoing Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS) utilizing the Magellan/Megacam imager. We resolve a population of old red giant branch (RGB) stars down to ∼1.5 mag below the tip of the RGB, reaching surface brightness limits as low as mag arcsec−2. The resulting spatial stellar density map highlights a plethora of previously unknown streams, shells, and satellites, including the first tidally disrupting dwarf around Cen A (CenA-MM-Dw3), which underline its active accretion history. We report 13 previously unknown dwarf satellite candidates, of which 9 are confirmed to be at the distance of Cen A (the remaining 4 are not resolved into stars), with magnitudes in the range to −13.0, central surface brightness values of mag arcsec−2, and half-light radii of . These values are in line with Local Group dwarfs but also lie at the faint/diffuse end of their distribution; interestingly, CenA-MM-Dw3 has similar properties to the recently discovered ultradiffuse galaxies in Virgo and Coma. Most of the new dwarfs are fainter than the previously known Cen A satellites. The newly discovered dwarfs and halo substructures are discussed in light of their stellar populations, and they are compared to those discovered by the PAndAS survey of M31. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

19. A COMPREHENSIVE ARCHIVAL SEARCH FOR COUNTERPARTS TO ULTRA-COMPACT HIGH-VELOCITY CLOUDS: FIVE LOCAL VOLUME DWARF GALAXIES.

Author

D. J. Sand, D. Crnojević, P. Bennet, B. Willman, J. Hargis, J. Strader, E. Olszewski, E. J. Tollerud, J. D. Simon, N. Caldwell, P. Guhathakurta, B. L. James, S. Koposov, B. McLeod, N. Morrell, M. Peacock, R. Salinas, A. C. Seth, D. P. Stark, and E. Toloba

Subjects
DWARF galaxies, HIGH-velocity clouds (Astrophysics), LOW mass stars, GALACTIC magnetic fields, DIFFUSE sound fields
Abstract

We report five Local Volume dwarf galaxies (two of which are presented here for the first time) uncovered during a comprehensive archival search for optical counterparts to ultra-compact high-velocity clouds (UCHVCs). The UCHVC population of HI clouds are thought to be candidate gas-rich, low-mass halos at the edge of the Local Group and beyond, but no comprehensive search for stellar counterparts to these systems has been presented. Careful visual inspection of all publicly available optical and ultraviolet imaging at the position of the UCHVCs revealed six blue, diffuse counterparts with a morphology consistent with a faint dwarf galaxy beyond the Local Group. Optical spectroscopy of all six candidate dwarf counterparts show that five have an Hα-derived velocity consistent with the coincident HI cloud, confirming their association; the sixth diffuse counterpart is likely a background object. The size and luminosity of the UCHVC dwarfs is consistent with other known Local Volume dwarf irregular galaxies. The gas fraction () of the five dwarfs are generally consistent with that of dwarf irregular galaxies in the Local Volume, although ALFALFA-Dw1 (associated with ALFALFA UCHVC HVC274.68+74.70–123) has a very high ∼ 40. Despite the heterogenous nature of our search, we demonstrate that the current dwarf companions to UCHVCs are at the edge of detectability due to their low surface brightness, and that deeper searches are likely to find more stellar systems. If more sensitive searches do not reveal further stellar counterparts to UCHVCs, then the dearth of such systems around the Local Group may be in conflict with ΛCDM simulations. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

20. ERRATUM: “STELLAR KINEMATICS AND STRUCTURAL PROPERTIES OF VIRGO CLUSTER DWARF EARLY-TYPE GALAXIES FROM THE SMAKCED PROJECT. II. THE SURVEY AND A SYSTEMATIC ANALYSIS OF KINEMATIC ANOMALIES AND ASYMMETRIES” (2014, APJS, 215, 17).

Author

E. Toloba, P. Guhathakurta, R. F. Peletier, A. Boselli, T. Lisker, J. Falcón-Barroso, J. D. Simon, G. van de Ven, S. Paudel, E. Emsellem, J. Janz, M. den Brok, J. Gorgas, G. Hensler, E. Laurikainen, S.-M Niemi, A. Ryś, and H. Salo

Published
2015
Full Text
View/download PDF

21. An evolutionary continuum from nucleated dwarf galaxies to star clusters.

Author

Wang K, Peng EW, Liu C, Mihos JC, Côté P, Ferrarese L, Taylor MA, Blakeslee JP, Cuillandre JC, Duc PA, Guhathakurta P, Gwyn S, Ko Y, Lançon A, Lim S, MacArthur LA, Puzia T, Roediger J, Sales LV, Sánchez-Janssen R, Spengler C, Toloba E, Zhang H, and Zhu M

Subjects
Fossils, Heterochromatin, Galaxies, Biological Evolution
Abstract

Systematic studies 1-4 have revealed hundreds of ultra-compact dwarf galaxies (UCDs 5 ) in the nearby Universe. With half-light radii r h of approximately 10-100 parsecs and stellar masses M *  ≈ 10 6 -10 8  solar masses, UCDs are among the densest known stellar systems 6 . Although similar in appearance to massive globular clusters 7 , the detection of extended stellar envelopes 4,8,9 , complex star formation histories 10 , elevated mass-to-light ratio 11,12 and supermassive black holes 13-16 suggest that some UCDs are remnant nuclear star clusters 17 of tidally stripped dwarf galaxies 18,19 , or even ancient compact galaxies 20 . However, only a few objects have been found in the transient stage of tidal stripping 21,22 , and this assumed evolutionary path 19 has never been fully traced by observations. Here we show that 106 galaxies in the Virgo cluster have morphologies that are intermediate between normal, nucleated dwarf galaxies and single-component UCDs, revealing a continuum that fully maps this morphological transition and fills the 'size gap' between star clusters and galaxies. Their spatial distribution and redder colour are also consistent with stripped satellite galaxies on their first few pericentric passages around massive galaxies 23 . The 'ultra-diffuse' tidal features around several of these galaxies directly show how UCDs are forming through tidal stripping and that this evolutionary path can include an early phase as a nucleated ultra-diffuse galaxy 24,25 . These UCDs represent substantial visible fossil remnants of ancient dwarf galaxies in galaxy clusters, and more low-mass remnants probably remain to be found., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Published
2023
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results