Now showing items 1-10 of 10

    • The Collimated Jet Source in IRAS 16547-4247: Time Variation, Possible Precession, and Upper Limits to the Proper Motions along the Jet Axis 

      Rodríguez, Luis F.; Moran, James M.; Franco-Hernández, Ramiro; Garay, Guido; Brooks, Kate J.; Mardones, Diego (American Astronomical Society, 2008)
      The triple radio source detected in association with the luminous infrared source IRAS 16547-4247 has previously been studied with high angular resolution and high sensitivity with the Very Large Array at 3.6 cm wavelength. ...
    • Dynamical Masses of Young M Dwarfs: Masses and Orbital Parameters of Gj 3305 Ab, the Wide Binary Companion to the Imaged Exoplanet Host 51 Eri 

      Montet, Benjamin T.; Bowler, Brendan P.; Shkolnik, Evgenya L.; Deck, Katherine M.; Wang, Ji; Horch, Elliott P.; Liu, Michael C.; Hillenbrand, Lynne A.; Kraus, Adam L.; Charbonneau, David (IOP Publishing, 2015)
      We combine new high resolution imaging and spectroscopy from Keck/NIRC2, Discovery Channel Telescope/DSSI, and Keck/HIRES with published astrometry and radial velocities to measure individual masses and orbital elements ...
    • High-Precision Radio and Infrared Astrometry of Lspm J1314+1320ab. Ii. Testing Pre-Main-Sequence Models at the Lithium Depletion Boundary With Dynamical Masses 

      Dupuy, Trent J.; Forbrich, Jan; Rizzuto, Aaron; Mann, Andrew W.; Aller, Kimberly; Liu, Michael C.; Kraus, Adam L.; Berger, Edo (American Astronomical Society, 2016)
      We present novel tests of pre-main-sequence models based on individual dynamical masses for the M7 binary LSPM J1314+1320AB. Joint analysis of Keck adaptive optics astrometric monitoring along with Very Long Baseline Array ...
    • A Parallax Distance to the Microquasar Grs 1915+105 and a Revised Estimate of Its Black Hole Mass 

      Reid, M. J.; McClintock, J. E.; Steiner, J. F.; Steeghs, D.; Remillard, R. A.; Dhawan, V.; Narayan, Ramesh (IOP Publishing, 2014)
      Using the Very Long Baseline Array, we have measured a trigonometric parallax for the microquasar GRS 1915+105, which contains a black hole and a K-giant companion. This yields a direct distance estimate of 8.6 +2.0 −1.6 ...
    • A Photometricity and Extinction Monitor at the Apache Point Observatory 

      Hogg, David W.; Finkbeiner, Douglas; Schlegel, David J.; Gunn, James E. (IOP Publishing, 2001)
      An unsupervised software "robot" that automatically and robustly reduces and analyzes CCD observations of photometric standard stars is described. The robot measures extinction coefficients and other photometric parameters ...
    • A Reassessment of the Kinematics of PV Cephei Based on Accurate Proper Motion Measurements 

      Loinard, Laurent; Rodríguez, Luis F.; Gómez, Laura; Cantó, Jorge; Raga, Alejandro C.; Goodman, Alyssa; Arce, Héctor G. (Universidad Nacional Autónoma de México, 2010)
      We present two Very Large Array observations of the pre-main-sequence star PV Cephei, taken with a separation of 10.5 years. These data show that the proper motions of this star are \(\mu_{\alpha} = +10.9 \pm 3.0 \ mas \ ...
    • The Trigonometric Parallax of Cygnus X-1 

      Reid, Mark J.; McClintock, Jeffrey E.; Narayan, Ramesh; Gou, Lijun; Remillard, Ronald A.; Orosz, Jerome A. (IOP Publishing, 2011)
      We report a direct and accurate measurement of the distance to the X-ray binary Cygnus X-1, which contains the first black hole to be discovered. The distance of 1.86+0.12 – 0.11 kpc was obtained from a trigonometric ...
    • Trigonometric Parallaxes for 1,507 Nearby Mid-to-late M-dwarfs 

      Dittmann, Jason Adam; Irwin, Jonathan; Charbonneau, David; Berta-Thompson, Zachory K. (IOP Publishing, 2014)
      The MEarth survey is a search for small rocky planets around the smallest, nearest stars to the Sun as identified by high proper motion with red colors. We augmented our planetary search time series with lower cadence ...
    • VLBI for Gravity Probe B. I. Overview 

      Shapiro, Irwin Ira; Bartel, N.; Bietenholz, M. F.; Lebach, D. E.; Lestrade, J.-F.; Ransom, R. R.; Ratner, M. I. (IOP Publishing, 2012)
      We describe the NASA/Stanford gyroscope relativity mission, Gravity Probe B (GP-B), and provide an overview of the following series of six astrometric and astrophysical papers that report on our radio observations and ...
    • VLBI for Gravity Probe B: the guide star, IM Pegasi 

      Bartel, N; Bietenholz, MF; Lebach, DE; Ransom, RR; Ratner, MI; Shapiro, Irwin I. (IOP Publishing, 2015)
      We review the radio very long baseline interferometry (VLBI) observations of the guide star, IM Peg, and three compact extragalactic reference sources, made in support of the NASA/Stanford gyroscope relativity mission, ...