Zobrazeno 1 - 10
of 136
pro vyhledávání: '"SCHMIDT, G. D."'
The optical properties of the z = 0.435 quasar PKS 1222+216 (4C+21.35) are summarized since the discovery of impressive gamma-ray activity in this source by Fermi/LAT. Unlike several other gamma-ray-bright blazars, there appears to be little connecti
Externí odkaz:
http://arxiv.org/abs/1110.6040
We describe the optical spectropolarimetric monitoring program at Steward Observatory centered around gamma-ray-bright blazars and the LAT Monitored Source List planned for Fermi Cycles 2-4. The large number of measurements made during Cycle 1 of the
Externí odkaz:
http://arxiv.org/abs/0912.3621
Autor:
Batcheldor, D., Schneider, G., Hines, D. C., Schmidt, G. D., Axon, D. J., Robinson, A., Sparks, W., Tadhunter, C.
The findings of a nine orbit calibration plan carried out during HST Cycle 15, to fully determine the NICMOS camera 2 (2.0 micron) polarization calibration to high accuracy, are reported. Recently Ueta et al. and Batcheldor et al. have suggested that
Externí odkaz:
http://arxiv.org/abs/0812.4951
Autor:
Batcheldor, D., Schneider, G., Hines, D. C., Schmidt, G. D., Axon, D. J., Robinson, A., Sparks, W., Tadhunter, C.
The ability of NICMOS to perform high accuracy polarimetry is currently hampered by an uncalibrated residual instrumental polarization at a level of 1.2-1.5%. To better quantify and characterize this residual we obtained observations of three polarim
Externí odkaz:
http://arxiv.org/abs/0811.0843
We present a detailed analysis of all the known Hot DQ white dwarfs in the Fourth Data Release of the Sloan Digital Sky Survey (SDSS) recently found to have carbon dominated atmospheres. Our spectroscopic and photometric analysis reveals that these o
Externí odkaz:
http://arxiv.org/abs/0805.0331
Autor:
Sing, D. K., Green, E. M., Howell, S. B., Holberg, J. B., Lopez-Morales, M., Shaw, J. S., Schmidt, G. D.
We report on the discovery of J0644+3344, a bright deeply eclipsing cataclysmic variable (CV) binary. Spectral signatures of both binary components and an accretion disk can be seen at optical wavelengths. The optical spectrum shows broad H I, He I,
Externí odkaz:
http://arxiv.org/abs/0708.0725
Publikováno v:
Astrophys.J.654:499-520,2006
We have conducted a survey of 61 southern white dwarfs searching for magnetic fields using Zeeman spectropolarimetry. Our objective is to obtain a magnetic field distribution for these objects and, in particular, to find white dwarfs with weak fields
Externí odkaz:
http://arxiv.org/abs/astro-ph/0609273
Autor:
Dufour, P., Bergeron, P., Schmidt, G. D., Liebert, James, Harris, H. C., Knapp, G. R., Anderson, S. F., Schneider, D. P.
Publikováno v:
Astrophys.J.651:1112-1119,2006
A reanalysis of the strongly metal-blanketed DZ white dwarf G165-7 is presented. An improved grid of model atmospheres and synthetic spectra is used to analyze BVRI, JHK, and ugriz photometric observations as well as a high quality Sloan Digital Sky
Externí odkaz:
http://arxiv.org/abs/astro-ph/0608065
Autor:
Wilkes, B. J., Pounds, K. A., Schmidt, G. D., Smith, P. S., Cutri, R. M., Ghosh, H., Nelson, B., Hines, D. C.
Publikováno v:
Astrophys.J.634:183-192,2005
XMM-Newton spectra of five red, 2MASS AGN, selected from a sample observed by Chandra to be relatively X-ray bright and to cover a range of hardness ratios, confirm the presence of substantial absorbing material in three sources with optical classifi
Externí odkaz:
http://arxiv.org/abs/astro-ph/0510062
Publikováno v:
Astrophys.J.630:L173-L176,2005
The magnetic white dwarf SDSS J121209.31+013627.7 exhibits a weak, narrow Halpha emission line whose radial velocity and strength are modulated on a period of ~90 minutes. Though indicative of irradiation on a nearby companion, no cool continuum comp
Externí odkaz:
http://arxiv.org/abs/astro-ph/0508043