S. T. Holland
A5061115115- Gamma-ray bursts and supernovae
- SAS software applications and methods
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- CCD and CMOS Imaging Sensors
- Microbial Metabolites in Food Biotechnology
- Particle Detector Development and Performance
- Astrophysics and Star Formation Studies
- COVID-19 diagnosis using AI
- Galaxies: Formation, Evolution, Phenomena
- Atmospheric Ozone and Climate
- Mechanics and Biomechanics Studies
- Adaptive optics and wavefront sensing
- Statistical and numerical algorithms
- Dark Matter and Cosmic Phenomena
- Computational Physics and Python Applications
- Particle Accelerators and Free-Electron Lasers
- Nuclear Physics and Applications
- Atmospheric and Environmental Gas Dynamics
- Climate Change Policy and Economics
University of North Carolina at Greensboro
2007-2024
University of North Carolina at Chapel Hill
2020-2024
National Bureau of Economic Research
2007-2024
International Paper (United States)
2024
Research Triangle Park Foundation
2024
Duke University
2024
University of Maryland, College Park
2024
Lawrence Berkeley National Laboratory
2022-2024
Dartmouth College
2015-2024
Swiss Federal Office of Energy
2022
The High-z Supernova Search Team has discovered and observed 8 new supernovae in the redshift interval z=0.3-1.2. These independent observations, confirm result of Riess et al. (1998a) Perlmutter (1999) that supernova luminosity distances imply an accelerating universe. More importantly, they extend range consistently SN Ia to z~1, where signature cosmological effects opposite sign some plausible systematic effects. Consequently, these measurements not only provide another quantitative...
We present early observations of the afterglow GRB 030329 and spectroscopic discovery its associated supernova SN 2003dh. obtained spectra each night from March 30.12 (0.6 days after burst) to April 8.13 (UT) (9.6 burst). The cover a wavelength range 350-850 nm. consist power-law continuum (Fν ∝ ν-0.9) with narrow emission lines originating H II regions in host galaxy, indicating low redshift z = 0.1687. However, our taken 2003 5 show broad peaks flux characteristic supernova. Correcting for...
We present the photometric calibration of Swift UltraViolet/Optical Telescope (UVOT) which includes: optimum and background apertures, effective area curves, colour transformations, conversion factors for count rates to flux, zero points (which are accurate better than 4 per cent) each seven UVOT broadband filters. The was performed with observations standard stars star fields that represent a wide range spectral types. results include position dependent uniformity, instrument response over...
We present photometric and spectroscopic observations of 23 high-redshift supernovae (SNe) spanning a range z = 0.34-1.03, nine which are unambiguously classified as Type Ia. These SNe were discovered during the IfA Deep Survey, began in 2001 September observed total 2.5 deg2 to depth approximately m ≈ 25-26 RIZ over 9-17 visits, typically every 1-3 weeks for nearly 5 months, with additional continuing until 2002 April. give brief description survey motivations, observational strategy,...
We report the discovery by Swift hard X-ray monitor of transient source J2058.4+0516 (Sw J2058+05). Our multi-wavelength follow-up campaign uncovered a long-lived (duration ≳ months), luminous (LX, iso ≈ 3 × 1047 erg s−1) and radio (νLν, 1042 counterpart. The associated optical emission, however, from which we measure redshift 1.1853, is relatively faint, this not due to large amount dust extinction in host galaxy. Based on numerous similarities with recently discovered GRB 110328A/Swift...
The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the sky in energy range 15-50 keV. BAT observes 88% each day with a detection sensitivity 5.3 mCrab for full-day observation and time resolution as fine 64 seconds. three main purposes are (1) discovery new sources, (2) outbursts or other changes flux known (3) generation light curves more than 900 sources spanning over eight years. primary interface is public web page. Between 2005...
We present the catalog of sources detected in first 22 months data from hard X-ray survey (14--195 keV) conducted with BAT coded mask imager on \swift satellite. The contains 461 above 4.8 sigma level BAT. High angular resolution for every source Swift XRT or archival have allowed associations to be made known counterparts other wavelength bands over 97% detections, including discovery ~30 galaxies previously unknown as AGN and several new Galactic sources. A total 266 are associated Seyfert...
The Ultraviolet/Optical Telescope (UVOT) is one of three instruments onboard the Swift observatory. photometric calibration has been published, and this paper follows up with details on other aspects including a measurement point spread function an assessment orbital variation effect photometry. A correction for large-scale variations in sensitivity over field view described, as well model coincidence loss which used to assess extended regions. We have provided detector distortion measured...
We present observations of GRB 060124, the first event for which both prompt and afterglow emission could be observed simultaneously in their entirety by three Swift instruments. Indeed, Swift-BAT triggered on a precursor ~570s before main burst peak, this allowed to repoint narrow field instruments position ~350s occurred. 060124 also Konus-Wind, harder gamma-ray band (up 2MeV). Thanks these exceptional circumstances, temporal spectral properties can studied optical, X-ray ranges. While...
We present extensive optical and infrared photometry of the afterglow gamma-ray burst (GRB) 030329 its associated supernova (SN) 2003dh over first two months after detection (2003 March 30-May 29 UT). Optical spectroscopy from a variety telescopes is shown and, when combined with photometry, allows an unambiguous separation between SN contributions. The GRB initially power-law continuum but shows significant color variations during week that are unrelated to presence SN. early light curve...
We present ultravioliet (UV) observations of supernovae (SNe) obtained with the UltraViolet/Optical Telescope (UVOT) on board Swift spacecraft. This is largest sample UV light curves from any single instrument and covers all major SN types most subtypes. The SNe Ia are fairly homogenous while Ib/c IIP show more variety in their curve shapes. UV-optical colors clearly differentiate IIP, particularly at early times. color evolution however, makes similar to about 20 days after explosion. shown...
Aims.We present early optical spectroscopy of the afterglow gamma-ray burst GRB 060206 with aim determining metallicity absorber and physical conditions in circumburst medium. We also discuss how GRBs may be important complementary probes cosmic chemical evolution.
We report the Swift discovery of nearby long, soft gamma-ray burst GRB 100316D, and subsequent unveiling its low redshift host galaxy associated supernova. derive event to be z = 0.0591 +/- 0.0001 provide accurate astrometry for GRB-SN. study extremely unusual prompt emission with time-resolved X-ray spectroscopy, find that spectrum is best modelled a thermal component in addition synchrotron peak energy. The light curve has remarkably shallow decay out at least 800 s. bright, blue highly...
We present the observations of GRB090510 performed by Fermi Gamma-Ray Space Telescope and Swift observatory. This is a bright, short burst that shows an extended emission detected in GeV range. Furthermore, its optical initially rises, feature so far observed only long bursts, while X-ray flux initial shallow decrease, followed steeper decay. exceptional behavior enables us to investigate physical properties GRB outflow, poorly known bursts. discuss internal shock external models for...
We report on the results of a search for Ly-alpha emission from host galaxy z=2.140 GRB 011211 and other galaxies in its surrounding field. detect as well six The restframe equivalent width line is about 21 AA. This fifth detection out five possible detections galaxies, strongly indicating that hosts, at least high redshifts, are emitters. intriguing only 25% Lyman-Break selected similar redshifts have lines with larger than 20 Possible explanations i) preference progenitors to be metal-poor...
We present the discovery and follow-up observations of afterglow gamma-ray burst GRB 011121 its associated supernova SN 2001ke. Images were obtained with Optical Gravitational Lensing Experiment 1.3 m telescope in BVRI passbands, starting 10.3 hr after burst. The temporal analysis our early data indicates a steep decay, independent wavelength, Fν ∝ t-1.72±0.05. There is no evidence for break light curve earlier than 2.5 days spectral energy distribution determined from broadband photometry...