P. Jablonka

Paris Diderot University, Lutetia Parisorum, Île-de-France, France

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Publications (166)457.87 Total impact

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    ABSTRACT: Chemo-dynamical N-body simulations are an essential tool for understanding the formation and evolution of galaxies. As the number of observationally determined stellar abundances continues to climb, these simulations are able to provide new constraints on the early star formaton history and chemical evolution inside both the Milky Way and Local Group dwarf galaxies. Here, we aim to reproduce the low α-element scatter observed in metal-poor stars. We first demonstrate that as stellar particles inside simulations drop below a mass threshold, increases in the resolution produce an unacceptably large scatter as one particle is no longer a good approximation of an entire stellar population. This threshold occurs at around 103M⊙, a mass limit easily reached in current (and future) simulations. By simulating the Sextans and Fornax dwarf spheroidal galaxies we show that this increase in scatter at high resolutions arises from stochastic supernovae explosions. In order to reduce this scatter down to the observed value, we show the necessity of introducing a metal mixing scheme into particle-based simulations. The impact of the method used to inject the metals into the surrounding gas is also discussed. We finally summarise the best approach for accurately reproducing the scatter in simulations of both Local Group dwarf galaxies and in the Milky Way.
    Full-text · Article · Feb 2016 · Astronomy and Astrophysics
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    ABSTRACT: We present a detailed study of the colours in late-type galaxy discs for ten of the EDisCS galaxy clusters with 0.5 < z < 0.8. Our cluster sample contains 172 spiral galaxies, and our control sample is composed of 96 field disc galaxies. We deconvolve their ground-based V and I images obtained with FORS2 at the VLT with initial spatial resolutions between 0.4 and 0.8 arcsec to achieve a final resolution of 0.1 arcsec with 0.05 arcsec pixels, which is close to the resolution of the ACS at the HST. After removing the central region of each galaxy to avoid pollution by the bulges, we measured the V-I colours of the discs. We find that 50% of cluster spiral galaxies have disc V-I colours redder by more than 1 sigma of the mean colours of their field counterparts. This is well above the 16% expected for a normal distribution centred on the field disc properties. The prominence of galaxies with red discs depends neither on the mass of their parent cluster nor on the distance of the galaxies to the cluster cores. Passive spiral galaxies constitute 20% of our sample. These systems are not abnormally dusty. They are are made of old stars and are located on the cluster red sequences. Another 24% of our sample is composed of galaxies that are still active and star forming, but less so than galaxies with similar morphologies in the field. These galaxies are naturally located in the blue sequence of their parent cluster colour-magnitude diagrams. The reddest of the discs in clusters must have stopped forming stars more than ~5 Gyr ago. Some of them are found among infalling galaxies, suggesting preprocessing. Our results confirm that galaxies are able to continue forming stars for some significant period of time after being accreted into clusters, and suggest that star formation can decline on seemingly long (1 to 5 Gyr) timescales.
    No preview · Article · Jan 2016 · Astronomy and Astrophysics
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    ABSTRACT: We present [C/Fe] and [N/Fe] abundance ratios and CH({\lambda}4300) and S({\lambda}3883) index measurements for 94 red giant branch (RGB) stars in the Sculptor dwarf spheroidal galaxy from VLT/VIMOS MOS observations at a resolving power R= 1150 at 4020 {\AA}. This is the first time that [N/Fe] abundances are derived for a large number of stars in a dwarf spheroidal. We found a trend for the [C/Fe] abundance to decrease with increasing luminosity on the RGB across the whole metallicity range, a phenomenon observed in both field and globular cluster giants, which can be interpreted in the framework of evolutionary mixing of partially processed CNO material. Both our measurements of [C/Fe] and [N/Fe] are in good agreement with the theoretical predictions for stars at similar luminosity and metallicity. We detected a dispersion in the carbon abundance at a given [Fe/H], which cannot be ascribed to measurement uncertainties alone. We interpret this observational evidence as the result of the contribution of different nucleosynthesis sources over time to a not well-mixed interstellar medium. We report the discovery of two new carbon-enhanced, metal-poor stars. These are likely the result of pollution from material enriched by asymptotic giant branch stars, as indicated by our estimates of [Ba/Fe]> +1. We also attempted a search for dissolved globular clusters in the field of the galaxy by looking for the distinctive C-N pattern of second population globular clusters stars in a previously detected, very metal-poor, chemodynamical substructure. We do not detect chemical anomalies among this group of stars. However, small number statistics and limited spatial coverage do not allow us to exclude the hypotheses that this substructure forms part of a tidally shredded globular cluster.
    Full-text · Article · Nov 2015 · Astronomy and Astrophysics
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    ABSTRACT: We present the high resolution spectroscopic study of five -3.9<=[Fe/H]<=-2.5 stars in the Local Group dwarf spheroidal, Sculptor, thereby doubling the number of stars with comparable observations in this metallicity range. We carry out a detailed analysis of the chemical abundances of alpha, iron peak, light and heavy elements, and draw comparisons with the Milky Way halo and the ultra faint dwarf stellar populations. We show that the bulk of the Sculptor metal-poor stars follows the same trends in abundance ratios versus metallicity as the Milky Way stars. This suggests similar early conditions of star formation and a high degree of homogeneity of the interstellar medium. We find an outlier to this main regime, which seems to miss the products of the most massive of the TypeII supernovae. In addition to its value to help refining galaxy formation models, this star provides clues to the production of cobalt and zinc. Two of our sample stars have low odd-to-even barium isotope abundance ratios, suggestive of a fair proportion of s-process; we discuss the implication for the nucleosynthetic origin of the neutron capture elements.
    Preview · Article · Jun 2015 · Astronomy and Astrophysics
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    ABSTRACT: We present results from a low-resolution spectroscopic survey for 21 galaxy clusters at 0.4<z<0.8 selected from the ESO Distant Cluster Survey (EDisCS). We measured spectra using the Low-Dispersion Prism (LDP) in IMACS on the Magellan Baade telescope and calculate redshifts with a precision of $\sigma_z=0.006$. We find 1,602 galaxies that are brighter than R=22.6 in the large-scale cluster environs. We identify the galaxies expected to be accreted by the clusters as they evolve to z=0 using spherical infall models, and find that ~30-70% of the z=0 cluster population lies outside the virial radius at z~0.6. For analogous clusters at z=0, we calculate that the ratio of galaxies that have fallen into the clusters since z~0.6 to that which were already in the core at that redshift is typically between ~0.3 and 1.5. This wide range of ratios is due to intrinsic scatter and is not a function of velocity dispersion, so a variety of infall histories is to be expected for clusters with current velocity dispersions of $300~<\sigma<~1200$ km/s. Within the infall regions of z~0.6 clusters, we find a larger red fraction of galaxies than in the field and greater clustering among red galaxies than blue. We interpret these findings as evidence of "preprocessing", where galaxies in denser local environments have their star formation rates affected prior to their aggregation into massive clusters, although the possibility of backsplash galaxies complicates the interpretation.
    Full-text · Article · Jun 2015
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    Matthew Nichols · Yves Revaz · Pascale Jablonka
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    ABSTRACT: As galaxy simulations increase in resolution more attention is being paid towards the evolution of dwarf galaxies and how the simulations compare to observations. Despite this increasing resolution we are however, far away from resolving the interactions of satellite dwarf galaxies and the hot coronae which surround host galaxies. We describe a new method which focuses only on the local region surrounding an infalling dwarf in an effort to understand how the hot baryonic halo will alter the chemodynamical evolution of dwarf galaxies. Using this method we examine how a dwarf, similar to Sextans dwarf spheroidal, evolves in the corona of a Milky Way like galaxy. We find that even at high perigalacticons the synergistic interaction between ram pressure and tidal forces transform a dwarf into a stream, suggesting that Sextans was much more massive in the past in order survive its perigalacticon passage. In addition the large confining pressure of the hot corona allows gas that was originally at the outskirts to begin forming stars, initially forming stars of low metallicity compared to the dwarf evolved in isolation. This increase in star formation eventually allows a dwarf galaxy to form more metal rich stars compared to one in isolation, but only if the dwarf retains gas for a sufficiently long period of time. In addition, dwarfs which formed substantial numbers of stars post-infall will have a slightly elevated [Mg/Fe] at high metallicity ([Fe/H] -1.5).
    Preview · Article · Mar 2015 · Astronomy and Astrophysics
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    ABSTRACT: Fornax is one of the most massive dwarf spheroidal galaxies in the Local Group. The Fornax field star population is dominated by intermediate age stars but star formation was going on over almost its entire history. It has been proposed that Fornax experienced a minor merger event. Despite recent progress, only the high metallicity end of Fornax field stars ([Fe/H]>-1.2 dex) has been sampled in larger number via high resolution spectroscopy. We want to better understand the full chemical evolution of this galaxy by better sampling the whole metallicity range, including more metal poor stars. We use the VLT-FLAMES multi-fibre spectrograph in high-resolution mode to determine the abundances of several alpha, iron-peak and neutron-capture elements in a sample of 47 individual Red Giant Branch stars in the Fornax dwarf spheroidal galaxy. We combine these abundances with accurate age estimates derived from the age probability distribution from the colour-magnitude diagram of Fornax. Similar to other dwarf spheroidal galaxies, the old, metal-poor stars of Fornax are typically alpha-rich while the young metal-rich stars are alpha-poor. In the classical scenario of the time delay between SNe II and SNe Ia, we confirm that SNe Ia started to contribute to the chemical enrichment at [Fe/H] between -2.0 and -1.8 dex. We find that the onset of SNe Ia took place between 12-10 Gyrs ago. The high values of [Ba/Fe], [La/Fe] reflect the influence of SNe Ia and AGB stars in the abundance pattern of the younger stellar population of Fornax. Our findings of low [alpha/Fe] and enhanced [Eu/Mg] are compatible with an initial mass function that lacks the most massive stars and with star formation that kept going on throughout the whole history of Fornax. We find that massive stars kept enriching the interstellar medium in alpha-elements, although they were not the main contributor to the iron enrichment.
    Full-text · Article · Sep 2014 · Astronomy and Astrophysics
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    Matthew Nichols · Yves Revaz · Pascale Jablonka
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    ABSTRACT: The effect of the local environment on the evolution of dwarf spheroidal galaxies is poorly understood. We have undertaken a suite of simulations to investigate the tidal impact of the Milky Way on the chemodynamical evolution of dwarf spheroidals that resemble present day classical dwarfs using the SPH code GEAR. After simulating the models through a large parameter space of potential orbits, the resulting properties are compared with observations from a dynamical point of view, and from the, often neglected, chemical point of view. In general, we find that tidal effects quench the star formation even inside gas-endowed dwarfs. This quenching may produce the radial distribution of dwarf spheroidals from the orbits seen within large cosmological simulations. We also find that the metallicity gradient within a dwarf is gradually erased through tidal interactions as stellar orbits move to higher radii. The model dwarfs also shift to higher ⟨[Fe/H]⟩/L ratios, but only when they lose ≳20% of stellar mass.Appendices are available in electronic form at http://www.aanda.org
    Preview · Article · Mar 2014 · Astronomy and Astrophysics
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    Matthew Nichols · Yves Revaz · Pascale Jablonka
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    ABSTRACT: The effect of the local environment on the evolution of dwarf spheroidal galaxies is poorly understood. We have undertaken a suite of simulations to investigate the tidal impact of the Milky Way on the chemodynamical evolution of dwarf spheroidals that resemble present day classical dwarfs using the SPH code GEAR. After simulating the models through a large parameter space of potential orbits the resulting properties are compared with observations from both a dynamical point of view, but also from the, often neglected, chemical point of view. In general, we find that tidal effects quench the star formation even inside gas-endowed dwarfs. Such quenching, may produce the radial distribution of dwarf spheroidals from the orbits seen within large cosmological simulations. We also find that the metallicity gradient within a dwarf is gradually erased through tidal interactions as stellar orbits move to higher radii. The model dwarfs also shift to higher $\langle$[Fe/H]$\rangle$/L ratios, but only when losing $>$$20\%$ of stellar mass.
    Preview · Article · Feb 2014
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    ABSTRACT: We present the first survey of resolved stellar populations in the remote outer halo of our nearest giant elliptical (gE), Centaurus A (D = 3.8 Mpc). Using the VIsible Multi Object Spectrograph (VIMOS)/Very Large Telescope (VLT) optical camera, we obtained deep photometry for four fields along the major and minor axes at projected elliptical radii of ˜30-85 kpc (corresponding to ˜5-14Reff). We use resolved star counts to map the spatial and colour distribution of red giant branch (RGB) stars down to ˜2 mag below the RGB tip. We detect an extended halo out to the furthermost elliptical radius probed (˜85 kpc or ˜14Reff), demonstrating the vast extent of this system. We detect a localized substructure in these parts, visible in both (old) RGB and (intermediate-age) luminous asymptotic giant branch stars, and there is some evidence that the outer halo becomes more elliptical and has a shallower surface brightness profile. We derive photometric metallicity distribution functions for halo RGB stars and find relatively high median metallicity values (<[Fe/H]>med ˜ -0.9 to -1.0 dex) that change very little with radius over the extent of our survey. Radial metallicity gradients are measured to be ≈ -0.002-0.004 dex kpc-1, and the fraction of metal-poor stars (defined as [Fe/H] < -1.0) is ≈40-50 per cent at all radii. We discuss these findings in the context of galaxy formation models for the buildup of gE haloes.
    Preview · Article · Jun 2013 · Monthly Notices of the Royal Astronomical Society
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    ABSTRACT: We use OSIRIS in its long-slit mode to look for mass transfer and induced star formation in the interacting galaxy pair KPG 468.
    No preview · Article · May 2013
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    P. Jablonka · F. Combes · K. Rines · R. Finn · T. Welch
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    ABSTRACT: Determining gas content and star formation rate has known remarkable progress in field galaxies, but has been much less investigated in galaxies inside clusters. We present the first CO observations of luminous infrared galaxies (LIRGs) inside the virial radii of two intermediate redshift clusters, CL1416+4446 (z=0.397) and CL0926+1242 (z=0.489). We detect three galaxies at high significance (5 to 10 sigma), and provide robust estimates of their CO luminosities, L'CO. In order to put our results into a general context, we revisit the relation between cold and hot gas and stellar mass in nearby field and cluster galaxies. We find evidence that at fixed LIR (or fixed stellar mass), the frequency of high L'CO galaxies is lower in clusters than in the field, suggesting environmental depletion of the reservoir of cold gas. The level of star formation activity in a galaxy is primarily linked to the amount of cold gas, rather than to the galaxy mass or the lookback time. In clusters, just as in the field, the conversion between gas and stars seems universal. The relation between LIR and L'CO for distant cluster galaxies extends the relation of nearby galaxies to higher IR luminosities. Nevertheless, the intermediate redshift galaxies fall well within the dispersion of the trend defined by local systems. Considering that L'CO is generally derived from the CO(1-0) line and sensitive to the vast majority of the molecular gas in the cold interstellar medium of galaxies, but less to the part which will actually be used to form stars, we suggest that molecular gas can be stripped before the star formation rate is affected. Combining the sample of Geach et al. (2009, 2011) and ours, we find evidence for a decrease in CO towards the cluster centers. This is the first hint of an environmental impact on cold gas at intermediate redshift.
    Full-text · Article · Mar 2013 · Astronomy and Astrophysics
  • Gregory Rudnick · P. Jablonka · J. Moustakas
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    ABSTRACT: Despite decades of work, it is still unclear whether a galaxy's properties are affected by environment or whether they are determined solely by the galaxy's mass. I will present new results that shed light on the key question of how the gas supplies of galaxies may be altered by dense environments. We use a stellar mass selected sample consisting of hundreds of cluster, group, and field galaxies at 0.4<z<0.8 with multi-wavelength imaging and deep spectroscopy. Using these data, we identify galaxies whose light is dominated by old stellar populations, as determined by the 4000 Angstrom Break and Balmer absorption line strengths. Contrary to expectations, we find that these "old" galaxies at intermediate redshift have a high likelihood of hosting weak [OII] emission. In contrast, analogously old galaxies in clusters and groups are significantly less likely to have activity. Based on the limited line ratio information that we have, the source of the emission in these galaxies is probably a weak AGN or gas heated by evolved stellar populations. Our results therefore imply that the cluster and group environments are effective at either stripping out gas from deep in the potential wells of galaxies or at cutting off their fuel supply of fresh new gas. Our work is possible because we probe a large number of clusters (not available in DEEP2 or COSMOS) as well as coeval group and field galaxies, and use deep Spitzer observations to search for dust-obscured star formation.
    No preview · Article · Jan 2013
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    ABSTRACT: We present abundances for seven stars in the (extremely) low-metallicity tail of the Sculptor dwarf spheroidal galaxy, from spectra taken with X-shooter on the ESO VLT. Targets were selected from the Ca II triplet (CaT) survey of the Dwarf Abundances and Radial Velocities Team (DART) using the latest calibration. Of the seven extremely metal-poor candidates, five stars are confirmed to be extremely metal-poor (i.e., [Fe/H]<-3 dex), with [Fe/H]=-3.47 +/- 0.07 for our most metal-poor star. All are around or below [Fe/H]=-2.5 dex from the measurement of individual Fe lines. These values are in agreement with the CaT predictions to within error bars. None of the seven stars is found to be carbon-rich. We estimate a 2-13% possibility of this being a pure chance effect, which could indicate a lower fraction of carbon-rich extremely metal-poor stars in Sculptor compared to the Milky Way halo. The [alpha/Fe] ratios show a range from +0.5 to -0.5, a larger variation than seen in Galactic samples although typically consistent within 1-2sigma. One star seems mildly iron-enhanced. Our program stars show no deviations from the Galactic abundance trends in chromium and the heavy elements barium and strontium. Sodium abundances are, however, below the Galactic values for several stars. Overall, we conclude that the CaT lines are a successful metallicity indicator down to the extremely metal-poor regime and that the extremely metal-poor stars in the Sculptor dwarf galaxy are chemically more similar to their Milky Way halo equivalents than the more metal-rich population of stars.
    Preview · Article · Nov 2012 · Astronomy and Astrophysics

  • No preview · Article · Oct 2012
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    ABSTRACT: We present a deep, wide-field optical study of the M81 group dwarf galaxy Holmberg II (HoII) based on Subaru/Suprime-Cam imaging. Individual stars are resolved down to I~25.2, i.e. about 1.5 mag below the tip of the red giant branch (RGB). We use resolved star counts in the outskirts of the galaxy to measure the radial surface brightness profile down to \mu_V~32 mag arcsec^-2, from which we determine a projected exponential scalelength of 0.70'+-0.01' (i.e. 0.69+-0.01 kpc). The composite profile, ranging from the cored centre out to R=7', is best fit by an EFF profile which gives a half-light radius of 1.41'+-0.04' (i.e. 1.39+-0.04 kpc), and an absolute magnitude M_V=-16.3. The low surface-brightness stellar component of HoII is regular and symmetric and has an extent much smaller than the vast HI cloud in which it is embedded. We compare the spatial distribution of the young, intermediate age, and old stellar populations, and find that the old RGB stars are significantly more centrally concentrated than the young stellar populations, contrary to what is observed in most dwarf galaxies of the Local Universe. We discuss these properties in the context of the comet-like distribution of HI gas around HoII, and argue for the presence of a hot intragroup medium in the vicinity of HoII to explain the contrasting morphologies of the gas and stars.
    Full-text · Article · Aug 2012 · Monthly Notices of the Royal Astronomical Society
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    ABSTRACT: We present new spectroscopic observations in a field containing the highest redshift cluster of the ESO Distant Cluster Survey (EDisCS). We measure galaxy redshifts and determine the velocity dispersions of the galaxy structures located in this field. Together with the main cluster Cl1103.7$-$1245 (z=0.9580; sigma_{clus} = 522 +/- 111 km/s) we find a secondary structure at z=0.9830, Cl1103.7-1245c. We then characterize the galaxy properties in both systems, and find that they contain very different galaxy populations. The cluster Cl1103.7-1245 hosts a mixture of passive elliptical galaxies and star-forming spirals and irregulars. In the secondary structure Cl1103.7-1245c all galaxies are lower-mass star-forming irregulars and peculiars. In addition, we compare the galaxy populations in the Cl1103.7-1245 z=0.9580 cluster with those in lower redshift EDisCS clusters with similar velocity dispersions. We find that the properties of the galaxies in Cl1103.7-1245 follow the evolutionary trends found at lower redshifts: the number of cluster members increases with time in line with the expected growth in cluster mass, and the fraction of passive early-type galaxies increases with time while star-forming late types become less dominant. Finally, we find that the mean stellar masses are similar in all clusters, suggesting that massive cluster galaxies were already present at z~1.
    Full-text · Article · Jul 2012 · Astronomy and Astrophysics
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    ABSTRACT: The target selection strategy, mask design procedure and observations are similar to those adopted for the EDisCS spectroscopy, described in detail in Halliday et al. (2004, Cat. J/A+A/427/397) and Milvang-Jensen et al. (2008, Cat. J/A+A/482/419). The target selection was based on the available VLT/FORS2 optical photometry (White et al., 2005, Cat. J/A+A/444/365) and the NTT/SOFI NIR photometry (Aragon-Salamanca et al., in preparation). The optical data cover 6.5'x6.5' and are well-matched to the FORS2 spectrograph field-of-view. The NIR data cover a somewhat smaller region of 4.2'x5.4'. Spectroscopic observations were completed using the FORS2 spectrograph (cf. Appenzeller et al., 1998Msngr..94....1A) on the VLT, during one observing run in March 2008, comprised of 3 half-nights. A high-efficiency grism was used (grism 600RI+19, λcentral=6780Å, resolution FWHM~6Å). The exposure time was 1800 seconds per frame, for a total of 8 frames per mask. A total of 3 masks were observed, for a total of 94 slits (33 slits in mask 1 and 2 and 28 slits in mask 3). The reduction was performed using an "improved sky subtraction", whose properties and advantages have been largely described and discussed in Milvang-Jensen et al. (2008, Cat. J/A+A/482/419). Galaxy redshifts were measured from the reduced 1D spectra, using emission lines where possible, as done in Poggianti et al. (2006ApJ...642..188P). In addition, when possible, we also measured the equivalent width of [OII] and Hδ. Note that for star-forming galaxies the Hδ absorption line may be affected by emission in-filling. We have not attempted to correct for this effect. (1 data file).
    No preview · Article · Jul 2012
  • Y. Revaz · P. Jablonka
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    ABSTRACT: GEAR is a new fully parallel chemodynamical Tree/SPH code designed to study the formation and evolution of galaxies. GEAR treats the complex physics of baryons, such as radiative cooling and feedback, star formation, and chemical evolution. It has been fully characterized by performing hundreds of simulations, including convergence tests with the spatial resolution varying from 100 pc down to 12 pc. We demonstrate here the performance of GEAR in the context of the evolution of the dwarf spheroidal galaxies. Our models, combined with the stellar chemical abundances derived from high resolution spectroscopy in a sample of dSphs (The ESO Large Programme DART), bring crucial clues on otherwise poorly constrained physical parameters, such as the supernova feedback, star formation efficiency or galaxy mass profiles. Moreover, these new simulations allow to predict the number of stars formed in a given dark matter halo mass, providing a crucial test for cosmology.
    No preview · Article · Jul 2012
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    ABSTRACT: The detailed abundances of 23 elements in nine bright RGB stars in the Carina dSph are presented based on high resolution spectra gathered at the VLT and Magellan telescopes. A spherical model atmospheres analysis is applied using standard methods to spectra ranging from 380 to 680 nm. The stars in this analysis range from -2.9 < [Fe/H] < -1.3, and adopting the ages determined by Lemasle et al. (2012), we are able to examine the chemical evolution of Carina's old and intermediate-aged populations. One of the main results from this work is the evidence for inhomogeneous mixing in Carina; a large dispersion in [Mg/Fe] indicates poor mixing in the old population, an offset in the [alpha/Fe] ratios between the old and intermediate-aged populations (when examined with previously published results) suggests that the second star formation event occurred in alpha-enriched gas, and one star, Car-612, seems to have formed in a pocket enhanced in SN Ia/II products. This latter star provides the first direct link between the formation of stars with enhanced SN Ia/II ratios in dwarf galaxies to those found in the outer Galactic halo (Ivans et al. 2003). Another important result is the potential evidence for SN II driven winds. We show that the very metal-poor stars in Carina have not been enhanced in AGB or SN Ia products, and therefore their very low ratios of [Sr/Ba] suggests the loss of contributions from the early SNe II. Low ratios of [Na/Fe], [Mn/Fe], and [Cr/Fe] in two of these stars support this scenario, with additional evidence from the low [Zn/Fe] upper limit for one star. It is interesting that the chemistry of the metal-poor stars in Carina is not similar to those in the Galaxy, most of the other dSphs, or the UFDs, and suggests that Carina may be at the critical mass where some chemical enrichment events are lost through SN II driven winds.
    Full-text · Article · May 2012 · The Astrophysical Journal

Publication Stats

3k Citations
457.87 Total Impact Points

Institutions

  • 2008-2015
    • Paris Diderot University
      Lutetia Parisorum, Île-de-France, France
  • 2006-2010
    • University of Geneva
      Genève, Geneva, Switzerland
  • 2005-2010
    • École Polytechnique Fédérale de Lausanne
      • Psychophysics Laboratory
      Lausanne, Vaud, Switzerland
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France
  • 2009
    • The Graduate University for Advanced Studies
      • Department of Astronomical Science
      Миура, Kanagawa, Japan
  • 1990-2007
    • Observatoire de Paris
      Lutetia Parisorum, Île-de-France, France
  • 2004
    • University of Nottingham
      • School of Physics and Astronomy
      Nottingham, ENG, United Kingdom
  • 2002-2003
    • University of Liège
      • Department of Astrophysics, Geophysics and Oceanography
      Luik, Walloon Region, Belgium
  • 1997
    • Columbia College
      Columbia, South Carolina, United States
  • 1996
    • The University of Tokyo
      白山, Tōkyō, Japan
    • European Southern Observatory
      Arching, Bavaria, Germany
  • 1991
    • Universidade Federal de Santa Maria
      Santa Maria da Boca do Monte, Rio Grande do Sul, Brazil
    • Durham University
      • Department of Physics
      Durham, England, United Kingdom