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Spectroscopy Of Grb 051111 At Z = 1.54948: Kinematics And Elemental Abundances Of The Grb Environment And Host Galaxy, B. E. Penprase, E. Berger, D. B. Fox, S. R. Kulkarni, S. Kadish, L. Kerber, E. Ofek, M. Kasliwal, G. Hill, B. Schaefer, M. Reed
Spectroscopy Of Grb 051111 At Z = 1.54948: Kinematics And Elemental Abundances Of The Grb Environment And Host Galaxy, B. E. Penprase, E. Berger, D. B. Fox, S. R. Kulkarni, S. Kadish, L. Kerber, E. Ofek, M. Kasliwal, G. Hill, B. Schaefer, M. Reed
Faculty Publications
We present a high-resolution, high S/N optical spectrum of the afterglow of GRB 051111 obtained with the HIRES spectrograph on the Keck I 10 m telescope. The spectrum exhibits three redshitted absorption systems with the highest, at z = 1.54948, arising in the GRB host galaxy. While the Lya feature is outside the range of our spectrum, the high column density of weakly depleted Zn suggests that the host is a damped Lyα system with N(H I) ≲ 1021 (Z/Z⊙)-1. The bulk of the gas (>80%) is confined to a narrow velocity range of |v| < 30 km s-1, exhibiting strong dust depletion of refractory elements such as Fe and Cr. The depletion pattern is similar to that observed in warm disk clouds of the Milky Way. We also detect absorption from all ground-level fine-structure states of Fe II, the first such example in a QSO-DLA system or GRB-absorption spectrum, which indicate conditions that are consistent with the "warm disk" depletion pattern. The absorption profiles of Fe II and Mg n extend over several hundred km s -1, with a depletion pattern that more closely resembles that of QSO-DLA systems, suggesting that the sight line to GRB 051111 probes the halo of the host galaxy in addition to the dense disk. Thus, detailed diagnostics of the interstellar medium of GRB host galaxies continue to provide insight into regions that are generally missed in quasar surveys. © 2006. The American Astronomical Society. All rights reserved.
The Anomalous Early Afterglow Of Grb 050801, E. S. Rykoff, V. Mangano, S. A. Yost, R. Sari, F. Aharonian, C. W. Akerlof, M. C.B. Ashley, S. D. Barthelmy, D. N. Burrows, N. Gehrels, E. Göǧüş, T. Güver, D. Horns, Ü Kiziloǧlu, H. A. Krimm, T. A. Mckay, M. Özel, A. Phillips, R. M. Quimby, G. Rowell, W. Rujopakarn, B. E. Schaefer, D. A. Smith, H. F. Swan, W. T. Vestrand, J. C. Wheeler, J. Wren, F. Yuan
The Anomalous Early Afterglow Of Grb 050801, E. S. Rykoff, V. Mangano, S. A. Yost, R. Sari, F. Aharonian, C. W. Akerlof, M. C.B. Ashley, S. D. Barthelmy, D. N. Burrows, N. Gehrels, E. Göǧüş, T. Güver, D. Horns, Ü Kiziloǧlu, H. A. Krimm, T. A. Mckay, M. Özel, A. Phillips, R. M. Quimby, G. Rowell, W. Rujopakarn, B. E. Schaefer, D. A. Smith, H. F. Swan, W. T. Vestrand, J. C. Wheeler, J. Wren, F. Yuan
Faculty Publications
The ROTSE-IIIc telescope at the HESS site, Namibia, obtained the earliest detection of optical emission from a gamma-ray burst (GRB), beginning only 21.8 s from the onset of Swift GRB 050801. The optical light curve does not fade or brighten significantly over the first ∼250 s, after which there is an achromatic break and the light curve declines in typical power-law fashion. The Swift XRT also obtained early observations starting at 69 s after the burst onset. The X-ray light curve shows the same features as the optical light curve. These correlated variations in the early optical and X-ray emission …
Optical Light Curve And Cooling Break Of Grb 050502a, S. A. Yost, K. Alatalo, E. S. Rykoff, F. Aharonian, C. W. Akerlof, M. C.B. Ashley, C. H. Blake, J. S. Bloom, M. Boettcher, E. E. Falco, E. Göǧüş, T. Güver, J. P. Halpern, D. Horns, M. Joshi, Ü Kiziloǧlu, T. A. Mckay, N. Mirabal, M. Özel, A. Phillips, R. M. Quimby, W. Rujopakarn, B. E. Schaefer, J. C. Shields, M. Skrutskie, D. A. Smith, D. L. Starr, H. F. Swan, A. Szentgyorgyi, W. T. Vestrand, J. C. Wheeler, J. Wren
Optical Light Curve And Cooling Break Of Grb 050502a, S. A. Yost, K. Alatalo, E. S. Rykoff, F. Aharonian, C. W. Akerlof, M. C.B. Ashley, C. H. Blake, J. S. Bloom, M. Boettcher, E. E. Falco, E. Göǧüş, T. Güver, J. P. Halpern, D. Horns, M. Joshi, Ü Kiziloǧlu, T. A. Mckay, N. Mirabal, M. Özel, A. Phillips, R. M. Quimby, W. Rujopakarn, B. E. Schaefer, J. C. Shields, M. Skrutskie, D. A. Smith, D. L. Starr, H. F. Swan, A. Szentgyorgyi, W. T. Vestrand, J. C. Wheeler, J. Wren
Faculty Publications
We present light curves of the afterglow of GRB 050502A, including very early data at t - tGRB < 60 s. The light curve is composed of unfiltered ROTSE-IIIb optical observations from 44 s to 6 hr postburst, R-band MDM observations from 1.6 to 8.4 hr postburst, and PAIRITEL JHKs observations from 0.6 to 2.6 hr postburst. The optical light curve is fit by a broken power law, where tα steepens from α = -1.13 ±0.02 to -1.44 ±0.02 at ∼5700 s. This steepening is consistent with the evolution expected for the passage of the cooling frequency v c through the optical band. Even in our earliest observation at 44 s postburst, there is no evidence that the optical flux is brighter than a backward extrapolation of the later power law would suggest. The observed decay indices and spectral index are consistent with either an ISM or a wind fireball model, but slightly favor the ISM interpretation. The expected spectral index in the ISM interpretation is consistent within 1 σ with the observed spectral index β= -0.8 ±0.1; the wind interpretation would imply a spectral index slightly (∼2 σ) shallower than observed. A small amount of dust extinction at the source redshift could steepen an intrinsic spectrum sufficiently to account for the observed value of β. In this picture, the early optical decay, with the peak at or below 4.7 × 1014 Hz at 44 s, requires very small electron and magnetic energy partitions from the fireball. © 2006. The American Astronomical Society. All rights reserved.