K. Sakamoto

Publications (3)6.02 Total impact

• Article: SMA High Angular Resolution Imaging of the Lensed Quasar APM 08279+5255

  M. Krips, A. B. Peck, K. Sakamoto, G. B. Petitpas, D. J. Wilner, S. Matsushita, and D. Iono
  [show abstract] [hide abstract]
  ABSTRACT: We present Submillimeter Array observations of the z = 3.91 gravitationally lensed broad absorption line quasar APM 08279+5255 which spatially resolve the 1.0 mm (200 μm rest frame) dust continuum emission. At 0.4'' resolution, the emission is separated into two components, a stronger, extended one to the northeast (46 ± 5 mJy) and a weaker, compact one to the southwest (15 ± 2 mJy). We have carried out simulations of the gravitational lensing effect responsible for the two submillimeter components in order to constrain the intrinsic size of the submillimeter continuum emission. Using an elliptical lens potential, the best-fit lensing model yields an intrinsic (projected) diameter of ~80 pc, which is not as compact as the optical/near-infrared (NIR) emission and agrees with previous size estimates of the gas and dust emission in APM 08279+5255. Based on our estimate, we favor a scenario in which the 200 μm (rest frame) emission originates from a warm dust component (Td = 150-220 K) that is mainly heated by the AGN rather than by a starburst. The flux is boosted by a factor of ~90 in our model, consistent with recent estimates for APM 08279+5255.
  The Astrophysical Journal 12/2008; 671(1):L5. · 6.02 Impact Factor
• Source

  Available from: ArXiv

  Article: SMA High Angular Resolution Imaging of the Lensed Quasar APM08279+5255

  M. Krips, A. B. Peck, K. Sakamoto, G. B. Petitpas, D. J. Wilner, S Matsushita, D. Iono
  [show abstract] [hide abstract]
  ABSTRACT: We present Submillimeter Array observations of the z=3.91 gravitationally lensed broad absorption line quasar APM08279+5255 which spatially resolve the 1.0mm (0.2mm rest-frame) dust continuum emission. At 0.4" resolution, the emission is separated into two components, a stronger, extended one to the northeast (46+/-5mJy) and a weaker, compact one to the southwest (15+/-2mJy). We have carried out simulations of the gravitational lensing effect responsible for the two submm components in order to constrain the intrinsic size of the submm continuum emission. Using an elliptical lens potential, the best fit lensing model yields an intrinsic (projected) diameter of ~80pc, which is not as compact as the optical/near-infrared (NIR) emission and agrees with previous size estimates of the gas and dust emission in APM08279+5255. Based on our estimate, we favor a scenario in which the 0.2mm (rest-frame) emission originates from a warm dust component (T_d=150-220K) that is mainly heated by the AGN rather than by a starburst (SB). The flux is boosted by a factor of ~90 in our model, consistent with recent estimates for APM08279+5255. Comment: 6 pages, 2 figures, accepted for publication in ApJL, in emulateApJ format
  10/2007;
• Source

  Available from: Rui-Qing Mao

  Article: SMA CO(J=3-2) interferometric observations of the central region of M51

  S Matsushita, K. Sakamoto, C. -Y. Kuo, P. -Y. Hsieh, Dinh-V-Trung, R. -Q. Mao, D. Iono, A. B. Peck, M. C. Wiedner, S. -Y. Liu, N. Ohashi, J. Lim
  [show abstract] [hide abstract]
  ABSTRACT: We present the first interferometric CO(J=3-2) observations (beam size of 3.9"x1.6" or 160pc x 65pc) with the Submillimeter Array (SMA) toward the center of the Seyfert 2 galaxy M51. The image shows a strong concentration at the nucleus and weak emission from the spiral arm to the northwest. The integrated intensity of the central component in CO(J=3-2) is almost twice as high as that in CO(J=1-0), indicating that the molecular gas within an ~80 pc radius of the nucleus is warm (>~100 K) and dense (~10^4 cm^-3). Similar intensity ratios are seen in shocked regions in our Galaxy, suggesting that these gas properties may be related to AGN or starburst activity. The central component shows a linear velocity gradient (~1.4 km/s/pc) perpendicular to the radio continuum jet, similar to that seen in previous observations and interpreted as a circumnuclear molecular disk/torus around the Seyfert 2 nucleus. In addition, we identify a linear velocity gradient (~0.7 km/s/pc) along the jet. Judging from the energetics, the velocity gradient can be explained by supernova explosions or energy and momentum transfer from the jet to the molecular gas via interaction, which is consistent with the high intensity ratio. Comment: 12 pages, 3 figures, accepted for publication in ApJL
  07/2004;