ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Exploring the reality of density substructures in the Palomar 5 stellar stream (2016)
    Oxford University Press
    Details
    Publication Date: 2016-06-18
    Description: We present an analysis of the presence of substructures in the stellar stream of the Palomar 5 globular cluster, as derived from Sloan Digital Sky Survey data. Using a matched filter technique, we recover the positions and sizes of overdensities reported in previous studies. To explore the reality of these structures, we also create an artificial model of the stream, in which we construct a realistic background on top of which we add a perfectly smooth stream structure, taking into account the effects of photometric completeness and interstellar extinction. We find that the smooth artificial stream then shows similarly pronounced substructures as the real structure. Interestingly, our best-fitting N -body simulation does display real projected density variations linked to stellar epicyclic motions, but these become less significant when taking into account the SDSS star-count constraints. The substructures found when applying our matched filter technique to the N -body particles converted into observable stars are thus mostly unrelated to these epicyclic motions. This analysis suggests that the majority of the previously detected substructures along the tidal tail of Palomar 5 are artefacts of observational inhomogeneities.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    The transverse velocity of the Andromeda system, derived from the M31 satellite population (2016)
    Oxford University Press
    Details
    Publication Date: 2016-01-21
    Description: We present a dynamical measurement of the tangential motion of the Andromeda system, the ensemble consisting of the Andromeda galaxy (M31) and its satellites. The system is modelled as a structure with cosmologically motivated velocity dispersion and density profiles, and we show that our method works well when tested using the most massive substructures in high-resolution cold dark matter (CDM) simulations. Applied to the sample of 40 currently known galaxies of this system, we find a value for the velocity along the East and North directions of v East = –111.5 ± 70.2 km s –1 and v North = 99.4 ± 60.0 km s –1 , implying a transverse velocity significantly higher than previous estimates of the proper motion of M31 itself. This result has significant implications on estimates of the mass of the Local Group, as well as on its past and future history.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    Sailing under the Magellanic Clouds: a DECam view of the Carina dwarf (2014)
    Oxford University Press
    Details
    Publication Date: 2014-09-17
    Description: We present deep optical photometry from the DECam imager on the 4 m Blanco telescope of over 12 deg 2 around the Carina dwarf spheroidal, with complete coverage out to 1 deg and partial coverage extending out to 2.6 deg. Using a Poisson-based matched-filter analysis to identify stars from each of the three main stellar populations, old, intermediate, and young, we confirm the previously identified radial age gradient, distance, tidal radius, stellar radial profiles, relative stellar population sizes, ellipticity, and position angle. We find an angular offset between the three main elliptical populations of Carina, and find only tentative evidence for tidal debris, suggesting that past tidal interactions could not have significantly influenced the Carina dwarf. We detect stars in the vicinity of, but distinct to, the Carina dwarf, and measure their distance to be 46±2 kpc. We determine this population to be part of the halo of the Large Magellanic Cloud at an angular radius of over 20 deg. Due to overlap in colour–magnitude space with Magellanic stars, previously detected tidal features in the old population of Carina are likely weaker than previously thought.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    The remnants of galaxy formation from a panoramic survey of the region around M31 (2009)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2009-09-04
    Description: In hierarchical cosmological models, galaxies grow in mass through the continual accretion of smaller ones. The tidal disruption of these systems is expected to result in loosely bound stars surrounding the galaxy, at distances that reach 10-100 times the radius of the central disk. The number, luminosity and morphology of the relics of this process provide significant clues to galaxy formation history, but obtaining a comprehensive survey of these components is difficult because of their intrinsic faintness and vast extent. Here we report a panoramic survey of the Andromeda galaxy (M31). We detect stars and coherent structures that are almost certainly remnants of dwarf galaxies destroyed by the tidal field of M31. An improved census of their surviving counterparts implies that three-quarters of M31's satellites brighter than M(v) = -6 await discovery. The brightest companion, Triangulum (M33), is surrounded by a stellar structure that provides persuasive evidence for a recent encounter with M31. This panorama of galaxy structure directly confirms the basic tenets of the hierarchical galaxy formation model and reveals the shared history of M31 and M33 in the unceasing build-up of galaxies.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉McConnachie, Alan W -- Irwin, Michael J -- Ibata, Rodrigo A -- Dubinski, John -- Widrow, Lawrence M -- Martin, Nicolas F -- Cote, Patrick -- Dotter, Aaron L -- Navarro, Julio F -- Ferguson, Annette M N -- Puzia, Thomas H -- Lewis, Geraint F -- Babul, Arif -- Barmby, Pauline -- Bienayme, Olivier -- Chapman, Scott C -- Cockcroft, Robert -- Collins, Michelle L M -- Fardal, Mark A -- Harris, William E -- Huxor, Avon -- Mackey, A Dougal -- Penarrubia, Jorge -- Rich, R Michael -- Richer, Harvey B -- Siebert, Arnaud -- Tanvir, Nial -- Valls-Gabaud, David -- Venn, Kimberly A -- England -- Nature. 2009 Sep 3;461(7260):66-9. doi: 10.1038/nature08327.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉NRC Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, British Columbia, Canada V9E 2E7. alan.mcconnachie@nrc-cnrc.gc.ca〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19727194" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    The cosmic web in our own backyard (2008)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2008-01-05
    Description: On the largest scales, matter is strung out on an intricate pattern known as the cosmic web. The tendrils of this web should reach right into our own cosmic backyard, lacing the Galactic halo with lumps of dark matter. The search for these lumps, lit up by stars that formed within them, is a major astronomical endeavor, although it has failed to find the huge expected population. Is this a dark matter crisis, or does it provide clues to the complexities of gas physics in the early universe? New technologies in the coming decade will reveal the answer.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ibata, Rodrigo A -- Lewis, Geraint F -- New York, N.Y. -- Science. 2008 Jan 4;319(5859):50-2. doi: 10.1126/science.1152008.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Observatoire Astronomique de Strasbourg, 11, rue de l'Universite, 67000 Strasbourg, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18174430" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 6
    facet.materialart.
    Unknown
    A molecular Einstein ring: imaging a starburst disk surrounding a quasi-stellar object (2003)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2003-04-05
    Description: Images of the molecular CO 2-1 line emission and the radio continuum emission from the redshift 4.12 gravitationally lensed quasi-stellar object (QSO) PSS J2322+1944 reveal an Einstein ring with a diameter of 1.5". These observations are modeled as a star-forming disk surrounding the QSO nucleus with a radius of 2 kiloparsecs. The implied massive star formation rate is 900 solar masses per year. At this rate, a substantial fraction of the stars in a large elliptical galaxy could form on a dynamical time scale of 108 years. The observation of active star formation in the host galaxy of a high-redshift QSO supports the hypothesis of coeval formation of supermassive black holes and stars in spheroidal galaxies.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Carilli, C L -- Lewis, G F -- Djorgovski, S G -- Mahabal, A -- Cox, P -- Bertoldi, F -- Omont, A -- New York, N.Y. -- Science. 2003 May 2;300(5620):773-5. Epub 2003 Apr 3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉National Radio Astronomy Observatory, Post Office Box O, Socorro, NM 87801, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12677071" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    Solo dwarfs I: survey introduction and first results for the Sagittarius dwarf irregular galaxy (2016)
    Oxford University Press
    Details
    Publication Date: 2016-03-18
    Description: We introduce the Solitary Local dwarfs survey (Solo), a wide-field photometric study targeting every isolated dwarf galaxy within 3 Mpc of the Milky Way. Solo is based on ( u ) gi multiband imaging from Canada–France–Hawaii Telescope/MegaCam for northern targets, and Magellan/Megacam for southern targets. All galaxies fainter than M V ~= –18 situated beyond the nominal virial radius of the Milky Way and M31 (300 kpc) are included in this volume-limited sample, for a total of 42 targets. In addition to reviewing the survey goals and strategy, we present results for the Sagittarius dwarf irregular galaxy (Sag DIG), one of the most isolated, low-mass galaxies, located at the edge of the Local Group. We analyse its resolved stellar populations and their spatial distributions. We provide updated estimates of its central surface brightness and integrated luminosity, and trace its surface brightness profile to a level fainter than 30 mag arcsec –2 . Sag DIG is well described by a highly elliptical (disc-like) system following a single component Sérsic model. However, a low-level distortion is present at the outer edges of the galaxy that, were Sag DIG not so isolated, would likely be attributed to some kind of previous tidal interaction. Further, we find evidence of an extremely low level, extended distribution of stars beyond ~5 arcmin (〉1.5 kpc) that suggests Sag DIG may be embedded in a very low-density stellar halo. We compare the stellar and H i structures of Sag DIG, and discuss results for this galaxy in relation to other isolated, dwarf irregular galaxies in the Local Group.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    Major substructure in the M31 outer halo: distances and metallicities along the giant stellar stream (2016)
    Oxford University Press
    Details
    Publication Date: 2016-04-04
    Description: We present a renewed look at M31's giant stellar stream along with the nearby structures streams C and D, exploiting a new algorithm capable of fitting to the red giant branch (RGB) of a structure in both colour and magnitude space. Using this algorithm, we are able to generate probability distributions in distance, metallicity and RGB width for a series of subfields spanning these structures. Specifically, we confirm a distance gradient of approximately 20 kpc per degree along a 6 deg extension of the giant stellar stream, with the farthest subfields from M31 lying ~120 kpc more distant than the innermost subfields. Further, we find a metallicity that steadily increases from $-0.7^{+0.1}_{-0.1}$ to $-0.2^{+0.2}_{-0.1}$ dex along the inner half of the stream before steadily dropping to a value of $-1.0^{+0.2}_{-0.2}$ dex at the farthest reaches of our coverage. The RGB width is found to increase rapidly from $0.4^{+0.1}_{-0.1}$ to $1.1^{+0.2}_{-0.1}$ dex in the inner portion of the stream before plateauing and decreasing marginally in the outer subfields of the stream. In addition, we estimate stream C to lie at a distance between 794 and 862 kpc and stream D between 758 and 868 kpc. We estimate the median metallicity of stream C to lie in the range –0.7 to –1.6 dex and a metallicity of $-1.1^{+0.3}_{-0.2}$ dex for stream D. RGB widths for the two structures are estimated to lie in the range 0.4–1.2 dex and 0.3–0.7 dex, respectively. In total, measurements are obtained for 19 subfields along the giant stellar stream, four along stream C, five along stream D and three general M31 spheroid fields for comparison. We thus provide a higher resolution coverage of the structures in these parameters than has previously been available in the literature.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    A vast, thin plane of corotating dwarf galaxies orbiting the Andromeda galaxy (2013)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2013-01-04
    Description: Dwarf satellite galaxies are thought to be the remnants of the population of primordial structures that coalesced to form giant galaxies like the Milky Way. It has previously been suspected that dwarf galaxies may not be isotropically distributed around our Galaxy, because several are correlated with streams of H I emission, and may form coplanar groups. These suspicions are supported by recent analyses. It has been claimed that the apparently planar distribution of satellites is not predicted within standard cosmology, and cannot simply represent a memory of past coherent accretion. However, other studies dispute this conclusion. Here we report the existence of a planar subgroup of satellites in the Andromeda galaxy (M 31), comprising about half of the population. The structure is at least 400 kiloparsecs in diameter, but also extremely thin, with a perpendicular scatter of less than 14.1 kiloparsecs. Radial velocity measurements reveal that the satellites in this structure have the same sense of rotation about their host. This shows conclusively that substantial numbers of dwarf satellite galaxies share the same dynamical orbital properties and direction of angular momentum. Intriguingly, the plane we identify is approximately aligned with the pole of the Milky Way's disk and with the vector between the Milky Way and Andromeda.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ibata, Rodrigo A -- Lewis, Geraint F -- Conn, Anthony R -- Irwin, Michael J -- McConnachie, Alan W -- Chapman, Scott C -- Collins, Michelle L -- Fardal, Mark -- Ferguson, Annette M N -- Ibata, Neil G -- Mackey, A Dougal -- Martin, Nicolas F -- Navarro, Julio -- Rich, R Michael -- Valls-Gabaud, David -- Widrow, Lawrence M -- England -- Nature. 2013 Jan 3;493(7430):62-5. doi: 10.1038/nature11717.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Observatoire Astronomique de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France. rodrigo.ibata@astro.unistra.fr〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23282362" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Velocity anti-correlation of diametrically opposed galaxy satellites in the low-redshift Universe (2014)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2014-07-22
    Description: Recent work has shown that the Milky Way and the Andromeda galaxies both possess the unexpected property that their dwarf satellite galaxies are aligned in thin and kinematically coherent planar structures. It is interesting to evaluate the incidence of such planar structures in the larger galactic population, because the Local Group may not be a representative environment. Here we report measurements of the velocities of pairs of diametrically opposed satellite galaxies. In the local Universe (redshift z 〈 0.05), we find that satellite pairs out to a distance of 150 kiloparsecs from the galactic centre are preferentially anti-correlated in their velocities (99.994 per cent confidence level), and that the distribution of galaxies in the larger-scale environment (out to distances of about 2 megaparsecs) is strongly clumped along the axis joining the inner satellite pair (〉7sigma confidence). This may indicate that planes of co-rotating satellites, similar to those seen around the Andromeda galaxy, are ubiquitous, and their coherent motion suggests that they represent a substantial repository of angular momentum on scales of about 100 kiloparsecs.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ibata, Neil G -- Ibata, Rodrigo A -- Famaey, Benoit -- Lewis, Geraint F -- England -- Nature. 2014 Jul 31;511(7511):563-6. doi: 10.1038/nature13481. Epub 2014 Jul 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Lycee international des Pontonniers, 1 rue des Pontonniers, F-67000 Strasbourg, France. ; Observatoire astronomique de Strasbourg, Universite de Strasbourg, CNRS, UMR 7550, 11 rue de l'Universite, F-67000 Strasbourg, France. ; Sydney Institute for Astronomy, School of Physics, A28, The University of Sydney, New South Wales 2006, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25043008" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...