Nelson Caldwell

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We present early observations of the afterglow of the Gamma-Ray Burst (GRB) 030329 and the spectroscopic discovery of its associated supernova SN 2003dh. We obtained spectra of the afterglow of GRB 030329 each night from March 30.12 (0.6 days after the burst) to April 8.13 (UT) (9.6 days after the burst). The spectra cover a wavelength range of 350 nm to(More)
Observations of the quiescent X-ray nova XTE J1118+480 with the new 6.5 m MMT have revealed that the velocity amplitude of the dwarf secondary is 698 ± 14 km s −1 and the orbital period of the system is 0.17013 ± 0.00010 d. The implied value of the mass function, f(M) = 6.00 ± 0.36 M ⊙ , provides a hard lower limit on the mass of the compact primary that(More)
We present UBVRI photometry of 44 type-Ia supernovae (SN Ia) observed from 1997 to 2001 as part of a continuing monitoring campaign at the Fred Lawrence Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics. The data set comprises 2190 observations and is the largest homogeneously observed and reduced sample of SN Ia to date, nearly(More)
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. ABSTRACT We present multiband photometry of 185 type-Ia supernovae (SNe Ia),(More)
We present optical and near-infrared photometry and spectroscopy of the type Ia SN 1998bu in the Leo I Group galaxy M96 (NGC 3368). The data set consists of 356 photometric measurements and 29 spectra of SN 1998bu between UT 1998 May 11 and July 15. The well-sampled light curve indicates the supernova reached maximum light in Application of a revised(More)
The M81 group is one of the nearest groups of galaxies, but its properties are quite different from those of the Local Group. It has therefore provided a different environment for the evolution of its member galaxies. We have carried out a CCD survey of the M81 group to search for analogs to Local Group dwarf elliptical (dE) galaxies. All the M81 dwarfs(More)
We present an updated catalog of 1300 objects in the field of M31, including 670 likely star clusters of various types, the rest being stars or background galaxies once thought to be clusters. The coordinates in the catalog are accurate to 0.2˝, and are based on images from the Local Group Survey (LGS, Massey et al. 2006) or from the DSS. Archival HST(More)
Mid-infrared photometry provides a robust technique for identifying active galaxies. While the ultraviolet to mid-infrared (λ ∼ < 5µm) continuum of normal galaxies is dominated by the composite stellar black body curve and peaks at approximately 1.6 µm, the ultraviolet to mid-infrared continuum of active galaxies is dominated by a power law. Consequently,(More)
We present a new photometric catalogue of the Coma galaxy cluster in the Johnson U-and V-bands. We cover an area of 3360arcmin 2 of sky, to a depth of V = 20 mag in a 13 arcsec diameter aperture, and produce magnitudes for ∼ 1400 extended objects in metric apertures from 8.8 to 26arcsec diameters. The mean internal RMS scatter in the photometry is 0.014 mag(More)