Готові списки джерел за темами / Dwarf Satellites

Добірка наукової літератури з теми "Dwarf Satellites"

Автор: Grafiati
Опубліковано: 6 вересня 2023

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Статті в журналах з теми "Dwarf Satellites"

1

Carlsten, Scott G., Jenny E. Greene, Johnny P. Greco, Rachael L. Beaton, and Erin Kado-Fong. "Structures of Dwarf Satellites of Milky Way-like Galaxies: Morphology, Scaling Relations, and Intrinsic Shapes." Astrophysical Journal 922, no. 2 (December 1, 2021): 267. http://dx.doi.org/10.3847/1538-4357/ac2581.

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Анотація:
Abstract The structure of a dwarf galaxy is an important probe of the effects of stellar feedback and environment. Using an unprecedented sample of 223 low-mass satellites from the ongoing Exploration of Local Volume Satellites survey, we explore the structures of dwarf satellites in the mass range 105.5 < M ⋆ < 108.5 M ⊙. We survey satellites around 80% of the massive, M K < − 22.4 mag, hosts in the Local Volume (LV). Our sample of dwarf satellites is complete to luminosities of M V <−9 mag and surface brightness μ 0,V < 26.5 mag arcsec−2 within at least ∼200 projected kpc of the hosts. For this sample, we find a median satellite luminosity of M V = −12.4 mag, median size of r e = 560 pc, median ellipticity of ϵ = 0.30, and median Sérsic index of n = 0.72. We separate the satellites into late- and early-type (29.6% and 70.4%, respectively). The mass–size relations are very similar between them within ∼5%, which indicates that the quenching and transformation of a late-type dwarf into an early-type one involves only very mild size evolution. Considering the distribution of apparent ellipticities, we infer the intrinsic shapes of the early- and late-type samples. Combining with literature samples, we find that both types of dwarfs are described roughly as oblate spheroids that get more spherical at fainter luminosities, but early-types are always rounder at fixed luminosity. Finally, we compare the LV satellites with dwarf samples from the cores of the Virgo and Fornax clusters. We find that the cluster satellites show similar scaling relations to the LV early-type dwarfs but are roughly 10% larger at fixed mass, which we interpret as being due to tidal heating in the cluster environments. The dwarf structure results presented here are a useful reference for simulations of dwarf galaxy formation and the transformation of dwarf irregulars into spheroidals.
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Garrison-Kimmel, Shea, Andrew Wetzel, Philip F. Hopkins, Robyn Sanderson, Kareem El-Badry, Andrew Graus, T. K. Chan, et al. "Star formation histories of dwarf galaxies in the FIRE simulations: dependence on mass and Local Group environment." Monthly Notices of the Royal Astronomical Society 489, no. 4 (September 10, 2019): 4574–88. http://dx.doi.org/10.1093/mnras/stz2507.

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ABSTRACT We study star formation histories (SFHs) of 500 dwarf galaxies (stellar mass $M_\ast =10^5\!-\!10^9\, \rm {M}_\odot$) from FIRE-2 cosmological zoom-in simulations. We compare dwarfs around individual Milky Way (MW)-mass galaxies, dwarfs in Local Group (LG)-like environments, and true field (i.e. isolated) dwarf galaxies. We reproduce observed trends wherein higher mass dwarfs quench later (if at all), regardless of environment. We also identify differences between the environments, both in terms of ‘satellite versus central’ and ‘LG versus individual MW versus isolated dwarf central.’ Around the individual MW-mass hosts, we recover the result expected from environmental quenching: central galaxies in the ‘near field’ have more extended SFHs than their satellite counterparts, with the former more closely resemble isolated (true field) dwarfs (though near-field centrals are still somewhat earlier forming). However, this difference is muted in the LG-like environments, where both near-field centrals and satellites have similar SFHs, which resemble satellites of single MW-mass hosts. This distinction is strongest for M* = 106–$10^7\, \rm {M}_\odot$ but exists at other masses. Our results suggest that the paired halo nature of the LG may regulate star formation in dwarf galaxies even beyond the virial radii of the MW and Andromeda. Caution is needed when comparing zoom-in simulations targeting isolated dwarf galaxies against observed dwarf galaxies in the LG.
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Garling, Christopher T., Annika H. G. Peter, Christopher S. Kochanek, David J. Sand, and Denija Crnojević. "A search for satellite galaxies of nearby star-forming galaxies with resolved stars in LBT-SONG." Monthly Notices of the Royal Astronomical Society 507, no. 4 (August 31, 2021): 4764–78. http://dx.doi.org/10.1093/mnras/stab2447.

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ABSTRACT We present results from a resolved stellar population search for dwarf satellite galaxies of six nearby (D &lt; 5 Mpc), sub-Milky Way mass hosts using deep (m ∼ 27 mag) optical imaging from the Large Binocular Telescope. We perform image simulations to quantify our detection efficiency for dwarfs over a large range in luminosity and size, and develop a fast catalogue-based emulator that includes a treatment of unresolved photometric blending. We discover no new dwarf satellites, but we recover two previously known dwarfs (DDO 113 and LV J1228+4358) with MV &lt; −12 that lie in our survey volume. We preview a new theoretical framework to predict satellite luminosity functions using analytical probability distribution functions and apply it to our sample, finding that we predict one fewer classical dwarf and one more faint dwarf (MV ∼ −7.5) than we find in our observational sample (i.e. the observational sample is slightly top-heavy). However, the overall number of dwarfs in the observational sample (2) is in good agreement with the theoretical expectations. Interestingly, DDO 113 shows signs of environmental quenching and LV J1228+4358 is tidally disrupting, suggesting that low-mass hosts may affect their satellites more severely than previously believed.
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Korol, V., S. Toonen, A. Klein, V. Belokurov, F. Vincenzo, R. Buscicchio, D. Gerosa, et al. "Populations of double white dwarfs in Milky Way satellites and their detectability with LISA." Astronomy & Astrophysics 638 (June 2020): A153. http://dx.doi.org/10.1051/0004-6361/202037764.

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Context. Milky Way dwarf satellites are unique objects that encode the early structure formation and therefore represent a window into the high redshift Universe. So far, their study has been conducted using electromagnetic waves only. The future Laser Interferometer Space Antenna (LISA) has the potential to reveal Milky Way satellites through gravitational waves emitted by double white dwarf (DWD) binaries. Aims. We investigate gravitational wave signals that will be detectable by LISA as a possible tool for the identification and characterisation of the Milky Way satellites. Methods. We used the binary population synthesis technique to model the population of DWDs in dwarf satellites and we assessed the impact on the number of LISA detections when making changes to the total stellar mass, distance, star formation history, and metallicity of satellites. We calibrated predictions for the known Milky Way satellites on their observed properties. Results. We find that DWDs emitting at frequencies ≳3 mHz can be detected in Milky Way satellites at large galactocentric distances. The number of these high frequency DWDs per satellite primarily depends on its mass, distance, age, and star formation history, and only mildly depends on the other assumptions regarding their evolution such as metallicity. We find that dwarf galaxies with M⋆ > 106 M⊙ can host detectable LISA sources; the number of detections scales linearly with the satellite’s mass. We forecast that out of the known satellites, Sagittarius, Fornax, Sculptor, and the Magellanic Clouds can be detected with LISA. Conclusions. As an all-sky survey that does not suffer from contamination and dust extinction, LISA will provide observations of the Milky Way and dwarf satellites galaxies, which will be valuable for Galactic archaeology and near-field cosmology.
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Bell, Eric F., Adam Smercina, Paul A. Price, Richard D’Souza, Jeremy Bailin, Roelof S. de Jong, Katya Gozman, et al. "Ultrafaint Dwarf Galaxy Candidates in the M81 Group: Signatures of Group Accretion." Astrophysical Journal Letters 937, no. 1 (September 1, 2022): L3. http://dx.doi.org/10.3847/2041-8213/ac8e5e.

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Abstract The faint and ultrafaint dwarf galaxies in the Local Group form the observational bedrock upon which our understanding of small-scale cosmology rests. In order to understand whether this insight generalizes, it is imperative to use resolved-star techniques to discover similarly faint satellites in nearby galaxy groups. We describe our search for ultrafaint galaxies in the M81 group using deep ground-based resolved-star data sets from Subaru’s Hyper Suprime-Cam. We present one new ultrafaint dwarf galaxy in the M81 group and identify five additional extremely low surface brightness candidate ultrafaint dwarfs that reach deep into the ultrafaint regime to M V ∼ − 6 (similar to current limits for Andromeda satellites). These candidates’ luminosities and sizes are similar to known Local Group dwarf galaxies Tucana B, Canes Venatici I, Hercules, and Boötes I. Most of these candidates are likely to be real, based on tests of our techniques on blank fields. Intriguingly, all of these candidates are spatially clustered around NGC 3077, which is itself an M81 group satellite in an advanced state of tidal disruption. This is somewhat surprising, as M81 itself and its largest satellite M82 are both substantially more massive than NGC 3077 and, by virtue of their greater masses, would have been expected to host as many or more ultrafaint candidates. These results lend considerable support to the idea that satellites of satellites are an important contribution to the growth of satellite populations around Milky Way–mass galaxies.
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6

Forbes, Duncan A. "A Tale of Giants Stealing from Dwarfs." Highlights of Astronomy 13 (2005): 177–78. http://dx.doi.org/10.1017/s1539299600015525.

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Анотація:
Cold Dark Matter simulations predict 10-100 x more dwarf satellite galaxies than are observed. Some of these ‘missing satellites’ may have been accreted, along with their globular clusters (GCs), by giant galaxies (Cote et al. 1998). But examples of dwarfs in the early stages of disruption have remained elusive.
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Sales, Laura V. "The Future of Dwarf Galaxy Research: What Simulations will Predict?" Proceedings of the International Astronomical Union 14, S344 (August 2018): 17–26. http://dx.doi.org/10.1017/s1743921318007391.

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AbstractWe present a summary of the predictions from numerical simulations to our understanding of dwarf galaxies. It centers the discussion around the Λ Cold Dark Matter scenario (ΛCDM) but discusses also implications for alternative dark matter models. Four key predictions are identified: the abundance of dwarf galaxies, their dark matter content, their relation with environment and the existence of dwarf satellites orbiting dwarf field galaxies. We discuss tensions with observations and identify the most exciting predictions expected from simulations in the future, including i) the existence of “dark galaxies” (dark matter halos without stars), ii) the ability to resolve the structure (size, morphology, dark matter distribution) in dwarfs and iii) the number of ultra-faint satellites around dwarf galaxies. All of these predictions shall inform future observations, not only the faintest galaxies to be discovered within the Local Volume but also distant dwarfs driving galaxy formation in the early universe.
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Fattahi, Azadeh, Julio F. Navarro, and Carlos S. Frenk. "The missing dwarf galaxies of the Local Group." Monthly Notices of the Royal Astronomical Society 493, no. 2 (February 10, 2020): 2596–605. http://dx.doi.org/10.1093/mnras/staa375.

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Анотація:
ABSTRACT We study the Local Group (LG) dwarf galaxy population predicted by the APOSTLE ΛCDM cosmological hydrodynamics simulations. These indicate that: (i) the total mass within 3 Mpc of the Milky Way–Andromeda mid-point (M3Mpc) typically exceeds ∼3 times the sum of the virial masses (M200crit) of the two primaries and (ii) the dwarf galaxy formation efficiency per unit mass is uniform throughout the volume. This suggests that the satellite population within the virial radii of the Milky Way and Andromeda should make up fewer than one third of all LG dwarfs within 3 Mpc. This is consistent with the fraction of observed LG galaxies with stellar mass $M_*\gt 10^7\, {\rm M}_\odot$ that are satellites (12 out of 42; i.e. 28 per cent). For the APOSTLE galaxy mass–halo mass relation, the total number of such galaxies further suggests an LG mass of $M_{\rm 3 Mpc}\sim 10^{13}\, {\rm M}_\odot$. At lower galaxy masses, however, the observed satellite fraction is substantially higher (42 per cent for $M_*\gt 10^5\, { \mathrm{ M}}_\odot$). If this is due to incompleteness in the field sample, then ∼50 dwarf galaxies at least as massive as the Draco dwarf spheroidal must be missing from the current LG field dwarf inventory. The incompleteness interpretation is supported by the pronounced flattening of the LG luminosity function below $M_*\sim 10^7\, {\rm M}_\odot$, and by the scarcity of low surface brightness LG field galaxies compared to satellites. The simulations indicate that most missing dwarfs should lie near the virial boundaries of the two LG primaries, and predict a trove of nearby dwarfs that await discovery by upcoming wide-field imaging surveys.
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Müller, Oliver, Marina Rejkuba, Marcel S. Pawlowski, Rodrigo Ibata, Federico Lelli, Michael Hilker, and Helmut Jerjen. "The dwarf galaxy satellite system of Centaurus A." Astronomy & Astrophysics 629 (August 26, 2019): A18. http://dx.doi.org/10.1051/0004-6361/201935807.

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Анотація:
Dwarf galaxy satellite systems are essential probes to test models of structure formation, making it necessary to establish a census of dwarf galaxies outside of our own Local Group. We present deep FORS2 VI band images from the ESO Very Large Telescope (VLT) for 15 dwarf galaxy candidates in the Centaurus group of galaxies. We confirm nine dwarfs to be members of Cen A by measuring their distances using a Bayesian approach to determine the tip of the red giant branch luminosity. We have also fit theoretical isochrones to measure their mean metallicities. The properties of the new dwarfs are similar to those in the Local Group in terms of their sizes, luminosities, and mean metallicities. Within our photometric precision, there is no evidence of a metallicity spread, but we do observe possible extended star formation in several galaxies, as evidenced by a population of asymptotic giant branch stars brighter than the red giant branch tip. The new dwarfs do not show any signs of tidal disruption. Together with the recently reported dwarf galaxies by the complementary PISCeS survey, we study the luminosity function and 3D structure of the group. By comparing the observed luminosity function to the high-resolution cosmological simulation IllustrisTNG, we find agreement within a 90% confidence interval. However, Cen A seems to be missing its brightest satellites and has an overabundance of the faintest dwarfs in comparison to its simulated analogs. In terms of the overall 3D distribution of the observed satellites, we find that the whole structure is flattened along the line-of-sight, with a root-mean-square (rms) height of 130 kpc and an rms semi-major axis length of 330 kpc. Future distance measurements of the remaining dwarf galaxy candidates are needed to complete the census of dwarf galaxies in the Centaurus group.
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Yniguez, Basilio, Shea Garrison-Kimmel, Michael Boylan-Kolchin, and James S. Bullock. "On the stark difference in satellite distributions around the Milky Way and Andromeda." Monthly Notices of the Royal Astronomical Society 439, no. 1 (February 4, 2014): 73–82. http://dx.doi.org/10.1093/mnras/stt2058.

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Abstract We compare spherically averaged radial number counts of bright (≳105 L⊙) dwarf satellite galaxies within 400 kpc of the Milky Way (MW) and M31 and find that the MW satellites are much more centrally concentrated. Remarkably, the two satellite systems are almost identical within the central 100 kpc, while M31 satellites outnumber MW satellites by about a factor of 4 at deprojected distances spanning 100–400 kpc. We compare the observed distributions to those predicted for Λ cold dark matter (ΛCDM) subhaloes using a suite of 44 high-resolution ∼1012 M⊙ halo zoom simulations, 22 of which are in pairs like the MW and M31. We find that the radial distribution of satellites around M31 is fairly typical of those predicted for subhaloes, while the MW's distribution is more centrally concentrated than any of our simulated ΛCDM haloes. One possible explanation is that our census of bright (≳105 L⊙) MW dwarf galaxies is significantly incomplete beyond ∼100 kpc of the Sun. If there were ∼8–20 more bright dwarfs orbiting undetected at 100–400 kpc distance, then the MW's radial distribution would fall within the range expected from subhalo distributions and also look very much like the known M31 system. We use our simulations to demonstrate that there is enough area left unexplored by the Sloan Digital Sky Survey and its extensions that the discovery of ∼10 new bright dwarfs is not implausible given the expected range of angular anisotropy of subhaloes in the sky.
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Більше джерел

Дисертації з теми "Dwarf Satellites"

1

Coleman, Matthew Grant, and coleman@mso anu edu au. "Tidal Structure in Galactic Satellites." The Australian National University. Research School of Astronomy and Astrophysics, 2005. http://thesis.anu.edu.au./public/adt-ANU20050602.112738.

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Анотація:
The dynamical histories of three Galactic satellite systems have been investigated. These include the Fornax and Sculptor dwarf spheroidal galaxies, and the globular cluster Omega Centauri. Wide-field CCD photometry was obtained for these objects in two colours, V and I, covering a total sky area of 30 square degrees. These data were used to construct a colour-magnitude diagram for each system, which then provided a filter to select probable member stars. This technique reduced contamination from foreground stars, allowing a comprehensive examination of the poorly-known outer regions of these three Galactic satellites.¶ An initial analysis of the central region of Fornax was made using the deep photometric data provided by Stetson et al. The analysis revealed a shell-like feature located approximately 1.5 core radii southeast from the centre of the dwarf galaxy, with an integrated luminosity of M_V ~ -4. The colour-magnitude data for this shell indicate it to be dominated by stars with an age ~2 Gyr.¶ The complete analysis of Fornax utilised two colour data covering a 3.2 deg times 3.2 deg area on the sky. The colour-magnitude selection technique revealed a second shell-like feature situated 1.3 deg northwest from the Fornax centre, approximately 30' beyond the nominal tidal radius at this position angle. This feature displays an integrated luminosity of M_V ~ -7. The alignment of this second shell is parallel to the original shell, and both are situated on the minor axis. Additionally, a statistical analysis of the extra-tidal region of Fornax revealed two large, faint surface brightness structures located on the minor axis. These structures, combined with the two shells, present strong evidence for shell structure in Fornax. This is the first such structure observed in a dwarf galaxy, and implies that Fornax has experienced a merger event in the recent past.¶ The photometric survey of Sculptor was complete to the depth of the horizontal branch stars. The red horizontal branch stars were found to be significantly more concentrated than the blue horizontal branch stars. An analysis of the distribution of red giant branch-selected stars revealed no significant extra-tidal structure. To further test this result, spectra at far red wavelengths were obtained for over 700 candidate red giant stars over the 10 sq deg region using the 2dF instrument on the Anglo-Australian Telescope. Radial velocities and metallicities for these stars were measured using Ca ii triplet lines, providing additional constraints to select Sculptor members beyond the nominal tidal radius. The distribution of the 179 probable Sculptor members indicated a lack of extra-tidal stars. These results support, at most, a mild level of interaction between this system and the Galaxy. An upper mass limit for extra-tidal material was measured to be 10% of the Sculptor luminous mass.¶ The analysis of Omega Centauri was similar to that of Sculptor. V and I band photometry was obtained to search for the tidal tails proposed by a previous study. As noted by others, dust correction was found to remove these structures. Spectra covering the region 370-450 nm were obtained for approximately 4000 candidate cluster members, and radial velocities were used to distinguish members from field stars. A total of 24 probable members of Omega Cen were found in the extra-tidal regions. Hence, if Omega Cen does possess tidal tails, they comprise at most 1% of the cluster mass.
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2

Willman, Beth. "A survey for resolved Milky Way dwarf galaxy satellites /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/5445.

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3

Cheng, Wing-hong, and 鄭穎康. "Tidal evolution of Pluto-Charon and the implications for the origin ofthe satellites Nix and Hydra." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B45846856.

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4

Minelli, Alice <1994&gt. "Chemical composition of Milky Way satellites: Magellanic Clouds and Sagittarius dwarf galaxy." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10313/1/PhDThesis_AliceMinelli.pdf.

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Анотація:
This PhD project is aimed at investigating the chemical composition of the stellar populations in the closest satellites of the Milky Way (MW), namely the Large and Small Magellanic Cloud (LMC and SMC, respectively) and the remnant of the Sagittarius (Sgr) dwarf spheroidal galaxy. Their proximity allows us to resolve their individual stars both with spectroscopy and photometry, studying in detail the characteristics of their stellar populations. All these objects are interacting galaxies: LMC and SMC are in an early stage of a minor merger event, and Sgr is being disrupted by the tidal field of the MW. There is a plenty of literature regarding the chemical composition of these systems, however, the extension of these galaxies prevents a complete and homogeneous analysis. Therefore, we homogeneously analysed stellar spectra belonging to MW and its satellites galaxies and we derived their chemical compositions. We highlighted the importance of a homogeneous analysis in the comparison among different galaxies or different samples, to avoid systematics due to different methods or physical assumptions.
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5

Rackham, Benjamin V., Dániel Apai, and Mark S. Giampapa. "The Transit Light Source Effect: False Spectral Features and Incorrect Densities for M-dwarf Transiting Planets." IOP PUBLISHING LTD, 2018. http://hdl.handle.net/10150/627040.

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Transmission spectra are differential measurements that utilize stellar illumination to probe transiting exoplanet atmospheres. Any spectral difference between the illuminating light source and the disk-integrated stellar spectrum due to starspots and faculae will be imprinted in the observed transmission spectrum. However,. few constraints exist for the extent of photospheric heterogeneities in M dwarfs. Here we model spot and faculae covering fractions consistent with observed photometric variabilities for M dwarfs and the associated 0.3-5.5. mu m stellar contamination spectra. We find that large ranges of spot and faculae covering fractions are consistent with observations and corrections assuming a linear relation between variability amplitude, and covering fractions generally underestimate the stellar contamination. Using realistic estimates for spot and faculae covering fractions, we find that stellar contamination can be more than 10x. larger than the transit depth changes expected for atmospheric features in rocky exoplanets. We also find that stellar spectral contamination can lead to systematic errors in radius and therefore the derived density of small planets. In the case of the TRAPPIST-1 system, we show that TRAPPIST-1 ' s rotational variability is consistent with spot covering fractions f(spot) = 8(7)(+18)% and faculae covering fractions f(fac) = 54(-46)(+16)%. The associated stellar contamination signals alter the transit depths of the TRAPPIST-1 planets at wavelengths of interest for planetary atmospheric species by roughly 1-15x. the strength of planetary features, significantly complicating JWST follow-up observations of this system. Similarly, we find that stellar contamination can lead to underestimates of the bulk densities of the TRAPPIST-1 planets of Delta(rho) = -8(-20)(+7)%, thus leading to overestimates of their volatile contents.
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6

Pinilla, P., L. H. Quiroga-Nuñez, M. Benisty, A. Natta, L. Ricci, Th Henning, der Plas G. van, T. Birnstiel, L. Testi, and K. Ward-Duong. "Millimeter Spectral Indices and Dust Trapping By Planets in Brown Dwarf Disks." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/625749.

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Анотація:
Disks around brown dwarfs (BDs) are excellent laboratories to study the first steps of planet formation in cold and low-mass disk conditions. The radial-drift velocities of dust particles in BD disks higher than in disks around more massive stars. Therefore, BD disks are expected to be more depleted in millimeter-sized grains compared to disks around T Tauri or Herbig Ae/Be stars. However, recent millimeter observations of BD disks revealed low millimeter spectral indices, indicating the presence of large grains in these disks and challenging models of dust evolution. We present 3 mm photometric observations carried out with the IRAM/Plateau de Bure Interferometer (PdBI) of three BD disks in the Taurus star-forming region, which have been observed with ALMA at 0.89 mm. The disks were not resolved and only one was detected with enough confidence (similar to 3.5 sigma) with PdBI. Based on these observations, we obtain the values and lower limits of the spectral index and find low values (alpha(mm) less than or similar to 3.0). We compare these observations in the context of particle trapping by an embedded planet, a promising mechanism to explain the observational signatures in more massive and warmer disks. We find, however, that this model cannot reproduce the current millimeter observations for BD disks, and multiple-strong pressure bumps globally distributed in the disk remain as a favorable scenario to explain observations. Alternative possibilities are that the gas masses in the BD disk are very low (similar to 2 x 10(-3) M-Jup) such that the millimeter grains are decoupled and do not drift, or fast growth of fluffy aggregates.
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7

Salomon, Jean-Baptiste. "Morphologie intrinsèque et cinématique globale des galaxies satellites d’Andromède." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAE042/document.

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Анотація:
A l’échelle galactique, le paradigme lambda-CDM n’est pas prédictif. Afin d’approfondir nos connaissances dans cette gamme de taille, les satellites du Groupe Local (GL) sont les systèmes galactiques les plus simples et les plus proches pour tester nos différentes hypothèses. Ainsi, nous présentons d’abord une méthode permettant d’obtenir analytiquement l’ellipticité intrinsèque des galaxies naines. Les résultats de cette technique appliquée sur un échantillon de 25 satellites de la galaxie Andromède (M31) laissent présumer que le GL est plus perturbé qu’il n’était envisagé jusqu’alors. Après cette approche individuelle, nous exposons un résultat sur la cinématique globale du système M31. Cette estimation montre pour la première fois que la vitesse transverse de ce système par rapport à la Voie Lactée est élevée. Cela peut mener à de fortes implications sur le GL, notamment quant à la détermination de sa masse et de son évolution passée et future
The Lambda-CDM cosmological model represents nowadays the best understanding of the formation and the evolution of large scale structures in our Universe. Nevertheless, this paradigm is not predictive and successful yet at smaller scales. In this context, satellites in the Local Group (LG), the simpler and closer galactic systems, are one of our best chance to test this model and to improve our comprehension of galaxy formation. Thus, we present here a method to derive analytically the intrinsic (3D) morphology of dwarf galaxies. Results of this technic applied to 25 Andromeda (M31) satellites suggest that the LG is in fact more disturbed than what was previously thought. After this individual approach, we further expose a recent result on the global kinematics of the M31 system. This new estimation suggests for the first time a high transverse velocity for this system with respect to the Milky Way. These values could lead to redefine the entire dynamic of the LG and its surroundings
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8

Ricci, L., H. Rome, P. Pinilla, S. Facchini, T. Birnstiel, and L. Testi. "VLA Observations of the Disk around the Young Brown Dwarf 2MASS J044427+2512." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/625755.

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We present multi-wavelength radio observations obtained with the VLA of the protoplanetary disk surrounding the young brown dwarf 2MASS J04442713+2512164 (2M0444) in the Taurus star-forming region. 2M0444 is the brightest known brown dwarf disk at millimeter wavelengths, making this an ideal target to probe radio emission from a young brown dwarf. Thermal emission from dust in the disk is detected at 6.8 and 9.1 mm, whereas the 1.36 cm measured flux is dominated by ionized gas emission. We combine these data with previous observations at shorter sub-mm and mm wavelengths to test the predictions of dust evolution models in gas-rich disks after adapting their parameters to the case of 2M0444. These models show that the radial drift mechanism affecting solids in a gaseous environment has to be either completely made inefficient, or significantly slowed down by very strong gas pressure bumps in order to explain the presence of mm/cm-sized grains in the outer regions of the 2M0444 disk. We also discuss the possible mechanisms for the origin of the ionized gas emission detected at 1.36 cm. The inferred radio luminosity for this emission is in line with the relation between radio and bolometric luminosity valid for for more massive and luminous young stellar objects, and extrapolated down to the very low luminosity of the 2M0444 brown dwarf.
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9

Conn, Anthony Rhys. "Structure of the M31 satellite system : bayesian distances from the tip of the red giant branch." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01012081.

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This study focuses on the spatial distribution of the M31 satellite system. A new Bayesian technique for determining object distances from the Tip of their Red Giant Branch is developed and used to obtain distance probability distributions for M31and 27 of its satellite galaxies. These distances are then used to calculate the satellite positions in three dimensions. Subsequent analysis of the resulting spatial distribution reveals striking inhomogeneity, with roughly half of the satellites confined to a curiously oriented thin disk. The distribution is also markedly asymmetric, with the majority of satellites lying on the Milky Way side of M31.
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10

Dashyan, Gohar. "Processus de rétroaction baryonique dans les galaxies naines et satellites." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS518.

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Comprendre l’évolution des galaxies suppose d’expliquer leur apparence, qui résulte de leur contenu stellaire. Or les étoiles se forment à partir de gaz froid. Les processus de rétroaction baryonique peuvent empêcher la formation d’étoiles en chauffant le gaz, en générant des vents galactiques qui expulsent le gaz ou l’empêchent de parvenir dans la galaxie. Sans ces processus, les modèles peinent à reproduire les observations. Certaines étoiles, lorsqu’elles explosent en supernovae (SNe), sont considérées comme la source principale de rétroaction dans les plus petites galaxies – les galaxies naines. Cependant, selon des travaux récents, leur capacité de rétroaction est insuffisante. Par ailleurs, les galaxies naines font l'objet de divergences entre théorie et observations concernant la nature de la matière noire, qui reste méconnue. Il se peut que ces divergences soient résolues en invoquant des processus de rétroaction. En parallèle, les noyaux actifs – des trous noirs massifs qui croissent –, constituent une autre source de rétroaction. Des observations récentes suggèrent qu’ils pourraient avoir de l’importance dans les galaxies naines. Premièrement, je montre analytiquement que la capacité des noyaux actifs à générer des vents galactiques dépasse souvent celle des SNe. Ensuite, je montre numériquement que le noyau actif d’une galaxie peut impacter l’évolution galaxie voisine. Enfin, je montre par une série de simulations numériques que l’injection de rayonnement cosmique par les SNe réduit la formation d’étoiles et augmente la génération de vents, qui sont alors en bien meilleur accord avec les observations, bien qu'encore en deçà
Understanding galaxies calls for the understanding of their appearance, which results from their stellar content, and stars form out of cold gas. Feedback processes can impede star formation: by heating the gas or preventing it from cooling and forming stars; by triggering galactic outflows that eject the gas; and by preventing the inflow of gas. In the lowest mass galaxies – dwarf galaxies –powerful and luminous stellar explosions, supernovae (SNe), are thought to be the predominant feedback process. However, recent work suggests that SN feedback is too weak. Moreover, several puzzles surrounding dwarf galaxies challenge our understanding of dark matter – of which the exact nature that is still unknown –, and these discrepancies might be solved by feedback processes. Besides, Active Galactic Nuclei (AGN) – i.e. growing massive black holes –, are another source of feedback in galaxies. The effect of AGN in dwarf galaxies is often thought to be minimal, because their growth is suppressed. But there is growing evidence that their presence in dwarf galaxies might be stronger than once thought. First, I show, using analytical methods, that the capacity of AGN to trigger outflows in dwarf galaxies is stronger than that of SNe in most of the parameter space. I then show numerically, that the AGN of a galaxy can influence the evolution of a neighboring galaxy. Finally, I assess the impact of the injection of cosmic rays by SNe: I find that it reduces the rate of star formation and increases the efficiency of SNe at driving winds, bringing simulated wind properties of dwarf galaxies much closer to observations, but the effect is not sufficient to fully match the observations
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Книги з теми "Dwarf Satellites"

1

Pluto and Charon: Ice worlds on the ragged edge of the solar system. 2nd ed. Weinheim, Germany: Wiley-VCH, 2006.

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2

Michael, Anderson. The nature of planets, dwarf planets, and space objects. New York: Britannica Educational Pub., 2012.

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3

United States. National Aeronautics and Space Administration., ed. Final report: Temperature and gravity dependence of trace element abundances in hot DA white dwarfs (94-EUVE-094). [Washington, DC: National Aeronautics and Space Administration, 1998.

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4

United States. National Aeronautics and Space Administration., ed. Ultraviolet spectra of subluminous objects found in the Kiso Schmidt survey and systematic reanalysis of the archived ultraviolet spectra of white dwarfs observed with the IUE satellite under the Astrophysics Data Program (ADP): Semi-annual report. Hanover, NH: Trustees of Dartmouth College, 1988.

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5

Outer Solar System: Jupiter, Saturn, Uranus, Neptune, and the Dwarf Planets. Rosen Publishing Group, 2010.

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6

Determining the atmospheric structure and dynamics of the FK Comae Star HD32918: Final report. [Washington, D.C: National Aeronautics and Space Administration, 1995.

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7

Orbiting The Moons Of Pluto Complex Solutions To The Einstein Maxwell Schrdinger And Dirac Equations. World Scientific Publishing Company, 2011.

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8

Cappellaro, Enrico. IUE-ULDA access guide no. 6: International Ultraviolet Explorer-Uniform Low Dispersion Archive : Supernovae (ESA SP). European Space Agency, 1995.

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9

Mee, Nicholas. The Cosmic Mystery Tour. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198831860.001.0001.

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The Cosmic Mystery Tour is a brief account of modern physics and astronomy presented in a broad historical and cultural context. The book is attractively illustrated and aimed at the general reader. Part I explores the laws of physics including general relativity, the structure of matter, quantum mechanics and the Standard Model of particle physics. It discusses recent discoveries such as gravitational waves and the project to construct LISA, a space-based gravitational wave detector, as well as unresolved issues such as the nature of dark matter. Part II begins by considering cosmology, the study of the universe as a whole and how we arrived at the theory of the Big Bang and the expanding universe. It looks at the remarkable objects within the universe such as red giants, white dwarfs, neutron stars and black holes, and considers the expected discoveries from new telescopes such as the Extremely Large Telescope in Chile, and the Event Horizon Telescope, currently aiming to image the supermassive black hole at the galactic centre. Part III considers the possibility of finding extraterrestrial life, from the speculations of science fiction authors to the ongoing search for alien civilizations known as SETI. Recent developments are discussed: space probes to the satellites of Jupiter and Saturn; the discovery of planets in other star systems; the citizen science project SETI@Home; Breakthrough Starshot, the project to develop technologies to send spacecraft to the stars. It also discusses the Fermi paradox which argues that we might actually be alone in the cosmos
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Частини книг з теми "Dwarf Satellites"

1

Walker, Matthew. "Dark Matter in the Galactic Dwarf Spheroidal Satellites." In Planets, Stars and Stellar Systems, 1039–89. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-5612-0_20.

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2

Martínez-Delgado, D., A. Aparicio, and M. A. Gómez-Flechoso. "Searching for Tidal Tails in Galactic Dwarf Spheroidal Satellites." In The Evolution of Galaxies, 425–28. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-017-3313-7_102.

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3

Gómez-Flechoso, M. A. "Ram Pressure Stripping of Dwarf Satellites in Disc Galaxies." In The Evolution of Galaxies, 463. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-017-3313-7_114.

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4

Gatto, A., F. Fraternali, F. Marinacci, J. Read, and H. Lux. "Estimating the Galactic Coronal Density via Ram-Pressure Stripping from Dwarf Satellites." In The Labyrinth of Star Formation, 167–69. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-03041-8_31.

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5

Allard, N. F., S. Bourdreux, J. F. Kielkopf, G. Hébrard, J. M. Désert, R. Ferlet, A. Vidal-Madjar, I. Hubeny, and J. M. Peek. "Lyman Gamma Satellites Due to H-H+ Collisions: Application to FUSE Observations of Hot White Dwarfs." In White Dwarfs, 161–62. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0215-8_47.

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6

Raven, John A., and Sean Donnelly. "Brown Dwarfs and Black Smokers: The Potential for Photosynthesis Using Radiation from Low-Temperature Black Bodies." In Habitability of Other Planets and Satellites, 267–84. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-6546-7_15.

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7

Gómez-Flechoso, M. A., and D. Martínez-Delgado. "Tidal Tails of the Dwarf Satellite Galaxies and the Milky Way Halo." In Highlights of Spanish Astrophysics III, 476. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-1778-6_119.

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8

Voloshina, Irina. "Results of Optical Monitoring of the Dwarf Nova SS Cyg During the 1993 Campaign of Coordinated Observations with the Asca Satellite." In Cataclysmic Variables and Related Objects, 73–74. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-0325-8_21.

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9

MARSAKOV, V. A., M. L. GOZHA, and V. V. KOVAL. "How many thick disk subsystems are there in the Milky Way Galaxy?" In Astronomical and Astrophysical Transactions, Vol. 32, No. 2, 117–22. Cambridge Scientific Publishers, 2021. http://dx.doi.org/10.17184/eac.5239.

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It was shown that stellar populations of the Galaxy with the thick disk kinematics, namely globular clusters, field RR Lyrae variables (lyrids), and nearby field F - G stars, have different chemical compositions. Based on the analysis of the nature of the dependencies of [alpha/Fe] on [Fe/H] for these objects, it was concluded that the thick disk subsystem in the Galaxy is composite, and at least three components independently exist inside it. The oldest subsystem consists of the metal-rich globular clusters which were formed from a single protogalactic cloud shortly after onset of the explosions of type Ia supernova in it. Then a subsystem of the field thick disk stars was formed as a result of the "heating" of the stars of the primary thin disk already formed in the Galaxy by a rather massive dwarf satellite galaxy which fell onto the Galaxy. And, finally, the subsystem of field stars (including the lyrids) with the kinematics of not only the thick, but even the thin disk that fell onto the Galaxy from this captured satellite galaxy.
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Тези доповідей конференцій з теми "Dwarf Satellites"

1

Medoff, Jonah. "Searching for Dwarf Galaxies Satellites of Isolated, Low-Mass Hosts." In Searching for Dwarf Galaxies Satellites of Isolated, Low-Mass Hosts. US DOE, 2023. http://dx.doi.org/10.2172/1993257.

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2

Spitoni, Emanuele, Fiorenzo Vincenzo, Francesca Matteucci, and Donatella Romano. "The connection between the Galactic halo and ancient Dwarf Satellites." In Frontier Research in Astrophysics – II. Trieste, Italy: Sissa Medialab, 2017. http://dx.doi.org/10.22323/1.269.0024.

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3

Allard, N. F., I. Drira та J. F. Kielkopf. "Quasi-molecular satellites in the Lyman β profile: application to the white dwarf stars". У SPECTRAL LINE SHAPES. ASCE, 1999. http://dx.doi.org/10.1063/1.58317.

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4

Rinchiuso, Lucia, Emmanuel Moulin, Celine Armand, and Vincent Poireau. "Dark Matter Search with H.E.S.S. Towards Ultra-faint Dwarf Nearby DES Satellites of the Milky Way." In 36th International Cosmic Ray Conference. Trieste, Italy: Sissa Medialab, 2019. http://dx.doi.org/10.22323/1.358.0542.

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5

Ticleanu, Mircea. "THE POSSIBLE FUTURE OF INTERNAL TELLURIC PLANETS AND OF TRANS-NEPTUNIAN DWARF PLANETS: SATELLITES OF THE LARGE PLANETS." In 16th International Multidisciplinary Scientific GeoConference SGEM2016. Stef92 Technology, 2016. http://dx.doi.org/10.5593/sgem2016/b13/s05.086.

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6

Barnstedt, J., N. Kappelmann, K. Werner, Klaus Werner, and T. Rauch. "HIRDES—The main instrument of the WSO∕UV satellite." In 17TH EUROPEAN WHITE DWARF WORKSHOP. AIP, 2010. http://dx.doi.org/10.1063/1.3527787.

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7

Krueger, Arlin J., and Luce Morin. "Improvements in Remote Sensing of Volcanic Sulfur Dioxide." In Optical Remote Sensing of the Atmosphere. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/orsa.1990.mc6.

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Sulfur dioxide in volcanic eruption clouds was detected from space using data from the Total Ozone Mapping Spectrometer (TOMS) instrument on the Nimbus 7 satellite (Krueger, 1983) and confirmed in data from the SBUV instrument on the same satellite (McPeters and Heath, 1984). The detection was possible because sulfur dioxide has strong absorption bands in the same wavelength region of the near ultraviolet that was selected for measuring total ozone with these satellite instruments. The background levels of sulfur dioxide are so low that the measurement of ozone can normally be made without accounting for any interference from this gas. However, volcanic eruptions can produce millions of tons of sulfur dioxide in compact clouds which locally dwarf the absorption by ozone. Even as the eruption cloud is dispersing the absorption by sulfur dioxide can be comparable to that of ozone.
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8

Yuasa, Takayuki. "Mass Estimation of White Dwarfs in Intermediate Polar systems using the Suzaku satellite." In The Extreme sky: Sampling the Universe above 10 keV. Trieste, Italy: Sissa Medialab, 2010. http://dx.doi.org/10.22323/1.096.0071.

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9

Maggio, Camilla, Daniel Kerszberg, Daniele Ninci, Vincenzo Vitale, Victor A. Acciari, Stefano Ansoldi, Lucio Angelo Antonelli, et al. "Upper limits on the WIMP annihilation cross section from a joint analysis of dwarf spheroidal satellite galaxy observations with the MAGIC telescopes." In 37th International Cosmic Ray Conference. Trieste, Italy: Sissa Medialab, 2021. http://dx.doi.org/10.22323/1.395.0512.

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Звіти організацій з теми "Dwarf Satellites"

1

España Fontán, Paula, and Maria Angeles Gomez Flechoso. Effects of the orbit orientation on the evolution of dwarf satellite galaxies. Fundación Avanza, May 2023. http://dx.doi.org/10.60096/fundacionavanza/2492022.

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Cosmological models propose a hierarchical scenario for galaxy evolution, where dwarf galaxies are accreted in the halo of larger ones. We study the effect of the satellite’s orbital orientation on the planar alignment of satellite galaxies.
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2

Baird, Robin W. Movements and Habitat use of Dwarf and Pygmy Sperm Whales using Remotely-Deployed LIMPET Satellite Tags. Fort Belvoir, VA: Defense Technical Information Center, September 2013. http://dx.doi.org/10.21236/ada597799.

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3

Baird, Robin W. Movements and Habitat Use of Dwarf and Pygmy Sperm Whales using Remotely-Deployed LIMPET Satellite Tags. Fort Belvoir, VA: Defense Technical Information Center, September 2014. http://dx.doi.org/10.21236/ada617026.

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