Search Publications
A Highly Magnified Supernova at z = 1.703 behind the Massive Galaxy Cluster A1689
Kneib, J. -P.; Dahle, H.; Lidman, C. +17 more
Our ability to study the most remote supernova explosions, crucial for the understanding of the evolution of the high-redshift universe and its expansion rate, is limited by the light collection capabilities of telescopes. However, nature offers unique opportunities to look beyond the range within reach of our unaided instruments thanks to the lig…
Hubble Space Telescope Studies of Nearby Type Ia Supernovae: The Mean Maximum Light Ultraviolet Spectrum and its Dispersion
Cenko, S. Bradley; Law, Nicholas M.; Ellis, Richard S. +11 more
We present the first results of an ongoing campaign using the STIS spectrograph on board the Hubble Space Telescope (HST), whose primary goal is the study of near-ultraviolet (UV) spectra of local Type Ia supernovae (SNe Ia). Using events identified by the Palomar Transient Factory and subsequently verified by ground-based spectroscopy, we demonst…
Arp 220: Extinction and Merger-induced Star Formation
Genzel, R.; Sturm, E.; Tacconi, L. J. +3 more
We analyze new spatially resolved integral field spectroscopic H- and K-band data at a resolution of 0farcs3 (100 pc) and reanalyze interferometric CO(2-1) line observations of the prototypical merging system Arp 220. We find that the majority of the K-band luminosity is due to a 10 Myr old starburst, with a significant contribution from an underl…
Eclipses during the 2010 Eruption of the Recurrent Nova U Scorpii
Maehara, Hiroyuki; Schaefer, Bradley E.; Worters, Hannah L. +34 more
The eruption of the recurrent nova U Scorpii on 2010 January 28 is now the all-time best observed nova event. We report 36,776 magnitudes throughout its 67 day eruption, for an average of one measure every 2.6 minutes. This unique and unprecedented coverage is the first time that a nova has had any substantial amount of fast photometry. With this,…
Nonlinear Color-Metallicity Relations of Globular Clusters. II. A Test on the Nonlinearity Scenario for Color Bimodality Using the u-band Colors: The Case of M87 (NGC 4486)
Blakeslee, John P.; Sohn, Sangmo T.; Kim, Hak-Sub +4 more
The optical color distributions of globular clusters (GCs) in most large elliptical galaxies are bimodal. Based on the assumed linear relationship between GC colors and their metallicities, the bimodality has been taken as evidence of two GC subsystems with different metallicities in each galaxy and has led to a number of theories in the context o…
Exploring Dust Extinction at the Edge of Reionization
Fynbo, Johan P. U.; Tanvir, Nial R.; Levan, Andrew J. +3 more
The brightness of gamma-ray burst (GRB) afterglows and their occurrence in young, blue galaxies make them excellent probes to study star-forming regions in the distant universe. We here elucidate dust extinction properties in the early universe through the analysis of the afterglows of all known z > 6 GRBs: GRB 090423, 080913, and 050904, at z …
Anatomy of a Post-starburst Minor Merger: A Multi-wavelength WFC3 Study of NGC 4150
Mutchler, Max; McCarthy, Patrick J.; Calzetti, Daniela +22 more
We present a spatially resolved near-UV/optical study, using the Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope, of NGC 4150, a sub-L *, early-type galaxy (ETG) of around 6 × 109 M sun, which has been observed as part of the WFC3 Early-Release Science Programme. Previous work indicates that this gal…
Twelve and a Half Years of Observations of Centaurus a with the Rossi X-Ray Timing Explorer
Wilms, J.; Pottschmidt, K.; Kadler, M. +5 more
The Rossi X-ray Timing Explorer (RXTE) has observed the nearest radio galaxy, Centaurus A (Cen A), in 13 intervals from 1996 August to 2009 February over the 3-200 keV band. Spectra accumulated over the 13 intervals were well described with an absorbed power law and an iron line. Cutoff power laws and Compton reflection from cold matter did not pr…
Discovery of an Energetic 38.5 ms Pulsar Powering the Gamma-ray Source IGR J18490-0000/HESS J1849-000
Gotthelf, E. V.; Terrier, R.; Halpern, J. P. +1 more
We report the discovery of a 38.5 ms X-ray pulsar in observations of the soft γ-ray source IGR J18490-0000 with the Rossi X-ray Timing Explorer (RXTE). PSR J1849-0001 is spinning down rapidly with period derivative 1.42 × 10-14 s s-1, yielding a spin-down luminosity \dot{E} = 9.8 × 1036 erg s-1, characte…
Observing Evolution in the Supergranular Network Length Scale During Periods of Low Solar Activity
McIntosh, Scott W.; Ulrich, Roger K.; Leamon, Robert J. +2 more
We present the initial results of an observational study into the variation of the dominant length scale of quiet solar emission: supergranulation. The distribution of magnetic elements in the lanes that from the network affects, and reflects, the radiative energy in the plasma of the upper solar chromosphere and transition region at the magnetic …