• Publications
  • Influence
A New Cepheid Distance to the Maser-Host Galaxy NGC 4258 and Its Implications for the Hubble Constant*
We present initial results from a time series BVI survey of two fields in NGC 4258 using the HST ACS. This galaxy was selected because of its accurate maser-based distance, which is anticipated to
Spectroscopic Discovery of the Supernova 2003dh Associated with GRB 030329
We present early observations of the afterglow of GRB 030329 and the spectroscopic discovery of its associated supernova SN 2003dh. We obtained spectra of the afterglow of GRB 030329 each night from
Long γ-ray bursts and core-collapse supernovae have different environments
When massive stars exhaust their fuel, they collapse and often produce the extraordinarily bright explosions known as core-collapse supernovae. On occasion, this stellar collapse also powers an even
Supernova SN 2011fe from an exploding carbon–oxygen white dwarf star
Early observations of type Ia supernova SN 2011fe in the galaxy M101 at a distance from Earth of 6.4 megaparsecs find that the exploding star was probably a carbon–oxygen white dwarf, and from the lack of an early shock it is concluded that the companion was likely a main-sequence star.
A New Calibration Of Galactic Cepheid Period-Luminosity Relations From B To K Bands, And A Comparison To LMC Relations
Context. The universality of the Cepheid Period-Luminosity relations has been under discussion since metallicity effects have been assumed to play a role in the value of the intercept and, more
No supernovae associated with two long-duration γ-ray bursts
It is now accepted that long-duration γ-ray bursts (GRBs) are produced during the collapse of a massive star1,2. The standard ‘collapsar’ model3 predicts that a broad-lined and luminous type Ic
Six months of multiwavelength follow-up of the tidal disruption candidate asassn-14li and implied tde rates from asas-sn
We present ground-based and Swift photometric and spectroscopic observations of the candidate tidal disruption event (TDE) ASASSN-14li, found at the center of PGC043234 (d ' 90 Mpc) by the All-Sky
Bolometric light curves and explosion parameters of 38 stripped-envelope core-collapse supernovae
Literature data are collated for 38 stripped-envelope core-collapse supernovae (SE SNe; i.e. SNe IIb, Ib, Ic and Ic-BL) that have good light curve coverage in more than one optical band. Using
Using Cepheids to determine the galactic abundance gradient I. The solar neighbourhood
A number of studies of abundance gradients in the galactic disk have been performed in recent years. The results obtained are rather disparate: from no detectable gradient to a rather signicant slope
ASASSN-15oi: a rapidly evolving, luminous tidal disruption event at 216 Mpc
We present ground-based and Swift photometric and spectroscopic observations of the tidal disruption event (TDE) ASASSN-15oi, discovered at the center of 2MASX J20390918-3045201 ($d\simeq216$ Mpc) by