Browsing by Author "Centre for Astrophysics Research"

Now showing items 281-300 of 3207

    • Binaries discovered by the SPY survey VI : Discovery of a low mass companion to the hot subluminous planetary nebula central star EGB5-a recently ejected common envelope? 

      Geier, S.; Napiwotzki, R.; Heber, U.; Nelemans, G. (2011)
      Hot subdwarf B stars (sdBs) in close binary systems are assumed to be formed via common envelope ejection. According to theoretical models, the amount of energy and angular momentum deposited in the common envelope scales ...

    • The binary fraction of planetary nebula central stars - III. the promise of VPHAS+ 

      Barker, Helen; Zijlstra, Albert; Marco, Orsola De; Frew, David J.; Drew, J. E.; Corradi, R. L. M.; Eislöffel, Jochen; Parker, Quentin A. (2018-04-21)
      The majority of planetary nebulae (PNe) are not spherical, and current single-star models cannot adequately explain all the morphologies we observe. This has led to the Binary Hypothesis, which states that PNe are ...

    • The Binary Frequency Among Carbon-enhanced, s-Process-rich, Metal-poor Stars 

      Lucatello, S.; Tsangarides, S.; Beers, T.C.; Carretta, E.; Gratton, R.G.; Ryan, Sean G. (2005)
      We discuss radial velocities for a sample of carbon-enhanced, s-process–rich, very metal-poor (CEMP-s) stars, analyzed with high-resolution spectroscopy obtained over multiple epochs. We find that ~68% of the stars in the ...

    • Binary sdB Stars with Massive Compact Companions 

      Geier, S.; Karl, C.; Edelmann, H.; Heber, U.; Napiwotzki, R. (Astronomical Society of the Pacific, 2008)
      The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close ...

    • Binary star formation : Primary disks and secondary stars 

      Wheelwright, H.E.; Vink, J.S.; Oudmaijer, R.D.; Drew, J.E. (American Institute of Physics (AIP), 2012)
      Most intermediate mass, pre-main-sequence Herbig Ae/Be stars reside in binary systems. As they are young, the properties of these systems allow us to constrain how they form. We have investigated the formation of Herbig ...

    • Binary White Dwarfs in the Supernova Ia Progenitor Survey 

      Napiwotzki, R.; Karl, C.; Nelemans, G.; Yungelson, L.; Christlieb, N.; Drechsel, H.; Heber, U.; Homeier, D.; Koester, D.; Leibundgut, B.; Marsh, T.R.; Moehler, S.; Renzini, A.; Reimers, D. (Astronomical Society of the Pacific, 2007)
      We report results of a systematic radial velocity survey for double degenerate (DD) binaries as potential progenitors of type Ia supernovae: SPY (ESO Supernovae Ia Progenitor surveY). More than 1000 white dwarfs (WDs) and ...

    • A Bird's Eye View of Ocular Galaxies 

      Brinks, E.; Kaufman, M.; Elmegreen, D.M.; Struck, C.; Elmegreen, B.; Thomasson, M.; Klaric, M. (Astronomical Society of the Pacific, 2000)
      Ocular galaxies are systems undergoing an in-plane, near grazing, prograde encounter. In addition to the interaction causing the formation of two long, symmetrically opposite tidal tails, during a short period after ...

    • Black hole masses, accretion rates and hot- and cold-mode accretion in radio galaxies at z ~ 1 

      Fernandes, Cristina A. C.; Jarvis, M.J.; Martínez-Sansigre, Alejo M. S.; Rawlings, Steve G.; Afonso, José M.; Hardcastle, M.J.; Lacy, Mark; Stevens, Jason A.; Vardoulaki, Eleni (2015-02-21)
      Understanding the evolution of accretion activity is fundamental to our understanding of how galaxies form and evolve over the history of the Universe. We analyse a complete sample of 27 radio galaxies which includes both ...

    • The BLAST 250 μm-selected galaxy population in GOODS-South 

      Dunlop, J.S.; Ade, P.A.R.; Bock, J.J.; Chapin, E.L.; Cirasuolo, M.; Coppin, Kristen; Devlin, M.J.; Griffin, M.; Greve, T.R.; Gundersen, J.O.; Halpern, M.; Hargrave, P.C.; Hughes, D.H.; Ivison, R.J.; Klein, J.; Kovacs, A.; Marsden, G.; Mauskopf, P.; Netterfield, Calvin B.; Olmi, L.; Pascale, E.; Patanchon, G.; Rex, M.; Scott, D.; Semisch, C.; Smail, I.; Targett, T.A.; Thomas, N.; Truch, M.D.P.; Tucker, C.; Tucker, G.S.; Viero, M.P.; Walter, F.; Wardlow, J. L.; Weiss, A.; Wiebe, D.V. (2010-11-01)
      We identify and investigate the nature of the 20 brightest 250 μm sources detected by the Balloon-borne Large Aperture Submillimetre Telescope (BLAST) within the central 150 arcmin of the Great Observatories Origins Deep ...

    • BLAST : the far-infrared/radio correlation in distant galaxies 

      Ivison, R.J.; Alexander, David M.; Biggs, Andy D.; Brandt, W.N.; Chapin, E.L.; Coppin, Kristen; Devlin, Mark J.; Dickinson, Mark; Dunlop, James; Dye, Simon; Eales, Stephen A.; Frayer, David T.; Halpern, Mark; Hughes, David H.; Ibar, Edo; Kovacs, A.; Marsden, Gaelen; Moncelsi, L.; Netterfield, Calvin B.; Pascale, Enzo; Patanchon, Guillaume; Rafferty, D. A.; Rex, Marie; Schinnerer, Eva; Scott, Douglas; Semisch, C.; Smail, Ian; Swinbank, A. M.; Truch, Matthew D.P.; Tucker, Gregory S.; Viero, M.P.; Walter, Fabian; Weiss, Axel; Wiebe, Donald V.; Xue, Y.Q. (2010)
      We investigate the correlation between far-infrared (FIR) and radio luminosities in distant galaxies, a lynchpin of modern astronomy. We use data from the Balloon-borne Large Aperture Submillimetre Telescope (BLAST), ...

    • Blazars in the LOFAR Two-Metre Sky Survey First Data Release 

      Mooney, S.; Quinn, J.; Callingham, J. R.; Morganti, R.; Duncan, K.; Morabito, Leah K.; Best, P. N.; Gürkan, G.; Hardcastle, M. J.; Prandoni, I.; Röttgering, H. J. A.; Sabater, J.; Shimwell, T. W.; Shulevski, A.; Tasse, C.; Williams, W. L. (2018-11-19)
      Historically, the blazar population has been poorly understood at low frequencies because survey sensitivity and angular resolution limitations have made it difficult to identify megahertz counterparts. We used the LOFAR ...

    • A blind CO detection of a distant red galaxy in the HS1700+64 protocluster 

      Chapman, S.C.; Bertoldi, F.; Smail, Ian; Blain, A. W.; Geach, J. E.; Gurwell, M.; Ivison, R. J.; Petitpas, G. R.; Reddy, N.; Steidel, C. C. (2015-05-01)

    • Blind detections of CO J=1-0 IN 11 H-ATLAS Galaxies at z=2.1-3.5 with the GBT/Zpectrometer 

      Harris, A.I.; Baker, A. J.; Frayer, D. T.; Smail, Ian; Swinbank, A.M.; Riechers, D. A.; van der Werf, P. P.; Auld, R.; Baes, M.; Bussmann, R. S.; Buttiglione, S.; Cava, A.; Clements, D. L.; Cooray, A.; Dannerbauer, H.; Dariush, A.; De Zotti, G.; Dunne, L.; Dye, S.; Eales, S.; Fritz, J.; Gonzalez-Nuevo, J.; Hopwood, R.; Ibar, E.; Ivison, R. J.; Jarvis, M.J.; Maddox, S.; Negrello, M.; Rigby, E.; Smith, Daniel; Temi, P.; Wardlow, J. (2012-06-20)
      We report measurements of the carbon monoxide ground state rotational transition ((CO)-C-12-O-16 J = 1-0) with the Zpectrometer ultrawideband spectrometer on the 100 m diameter Green Bank Telescope. The sample comprises ...

    • Bloated Dwarfs: The Thickness of the HI Disks in Irregular Galaxies 

      Brinks, E.; Walter, F.; Ott, J. (Astronomical Society of the Pacific, 2002)
      Somewhat counterintuitively, the gas disks of (dwarf) irregular galaxies, such as the LMC, are thicker than those of normal disk galaxies, both in relative as well as in absolute terms. In retrospect, this is easily ...

    • A blue depression in the optical spectra of M dwarfs 

      Jones, Hugh R. A.; Pavlenko, Yakiv; Lyubchik, Yuri; Bessell, Mike; Allard, Nicole; Pinfield, David J. (2023-05-12)
      A blue depression is found in the spectra of M dwarfs from 4000 to 4500A. This depression shows an increase toward lower temperatures though is particularly sensitive to gravity and metallicity. It is the single most ...

    • Blue not brown: UKIRT Infrared Deep Sky Survey T dwarfs with suppressed K-band flux 

      Murray, D. N.; Burningham, B.; Jones, H.R.A.; Pinfield, D.J.; Lucas, P.W.; Leggett, S. K.; Tinney, C. G.; Day-Jones, A. C.; Weights, D. J.; Lodieu, N.; Perez Prieto, J. A.; Nickson, E.; Zhang, Z. H.; Clarke, J. R. A.; Jenkins, J. S.; Tamura, M. (2011-06)
      We have used blue near-infrared colours to select a group of 12 spectroscopically confirmed United Kingdom InfraRed Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS) T dwarfs later than T4. From amongst these, we identify ...

    • The blue straggler stars of galactic clusters 

      Schonberner, D.; Napiwotzki, R. (Astronomical Society of the Pacific, 1993)
      The origin and evolution of blue straggler stars (BS) in clusters is still an unsolved problem for our understanding of stellar evolution. Several rivalling theories exist, of which that of Saio & Wheeler (1980) is the ...

    • Boron depletion in 9 to 15 M(circle dot) stars with rotation 

      Frischknecht, U.; Hirschi, R.; Meynet, G.; Ekstroem, S.; Georgy, C.; Rauscher, T.; Winteler, C.; Thielemann, F-K. (Cambridge University Press, 2010)
      The treatment of mixing is still one of the major uncertainties in stellar evolution models. One open question is how well the prescriptions for rotational mixing describe the real effects. We tested the mixing prescriptions ...

    • Boron in the very metal-poor star BD-13 3442 

      Duncan, D.K.; Rebull, L.M.; Primas, F.; Boesgaard, A.M.; Deliyannis, C.P.; Hobbs, L.M.; King, J.R.; Ryan, Sean G. (1998)
      The Goddard High Resolution Spectrograph (GHRS) of the Hubble Space Telescope (HST) has been used to observe the boron 2500 °A region of BD −13 3442. At a metallicity of [Fe/H]=−3.00 this is the most metal- poor star ever ...

    • Branchings in the gamma process path revisited 

      Rauscher, T. (2006-01)
      The location of the (gamma,p)/(gamma,n) and (gamma,alpha)/(gamma,n) line at gamma process temperatures is discussed, using updated reaction rates based on global Hauser-Feshbach calculations. The results can be directly ...