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We present observations and analysis of PS1-10bzj, a superluminous supernova (SLSN) discovered in the Pan-STARRSMedium Deep Survey at a redshift z = 0.650. Spectroscopically, PS1-10bzj is similar to the hydrogenpoor SLSNe 2005ap and SCP 06F6, though with a steeper rise and lower peak luminosity (Mbol ≃ -21.4 mag) than previous events. We construct a bolometric light curve, and show that while PS1-10bzj's energetics were less extreme than previous events, its luminosity still cannot be explained by radioactive nickel decay alone.We explore both a magnetar spin-down and circumstellar interaction scenario and find that either can fit the data. PS1-10bzj is located in the Extended Chandra Deep Field South and the host galaxy is imaged in a number of surveys, including with the Hubble Space Telescope. The host is a compact dwarf galaxy (MB ≈ -18 mag, diameter ≲800 pc), with a low stellar mass (M" ≈ 2.4 × 107M☉), young stellar population (τ" ≈ 5 Myr), and a star formation rate of ~2-3M☉ yr-1. The specific star formation rate is the highest seen in an SLSN host so far (~100 Gyr-1).We detect the [OIII] λ4363 line, and find a low metallicity: 12 + (O/H) = 7.8 ± 0.2 (≃ 0.1Z☉). Together, this indicates that at least some of the progenitors of SLSNe come from young, low-metallicity populations. [ABSTRACT FROM AUTHOR]

We present spectroscopic observations of GRB 091127 (z = 0.490) at the peak of the putative associated supernova SN 2009nz. Subtracting a late-time spectrum of the host galaxy, we isolate the contribution of SN 2009nz and uncover broad features typical of nearby gamma-ray-burst-supernovae (GRB-SNe). This establishes unambiguously that GRB 091127 was accompanied by a broad-lined Type Ic SN, and links a cosmological long burst with a standard energy release (Eγ,iso ~ 1.1 X 1052 erg) to a massive star progenitor. The spectrum of SN 2009nz closely resembles that of SN 2006aj, with SN 2003dh also providing an acceptable match, but has significantly narrower features than SNe 1998bw and 2010bh, indicative of a lower expansion velocity. The photospheric velocity inferred from the Si II λ6355 absorption feature, Vph ≈ 17,000 km s-1, is indeed closer to that of SNe 2006aj and 2003dh than to the other GRB-SNe. Combining the measured velocity with the light curve peak brightness and width, we estimate the following nominal (maximal) explosion parameters: MNi ≈ 0.35 (0.6) M⊙, EK ≈ 2.3 X 1051 (8.4 X 1051) erg, and Mej ≈ 1.4 (3.5) M⊙, similar to those of SN 2006aj. These properties indicate that SN 2009nz follows a trend of lower MNi for GRB-SNe with lower Ek and Mej. Equally important, since GRB 091127 is a typical cosmological burst, the similarity of SN 2009nz to SN 2006aj either casts doubt on the claim that XRF 060218/SN 2006aj was powered by a neutron star or indicates that the nature of the central engine is encoded in the SN properties but not in the prompt emission. Future spectra of GRB-SNe at z ≳ 0.3 will shed light on the full dispersion of SN properties for standard long GRBs, on the relation between SNe associated with sub-energetic and standard GRBs, and on a potential dispersion in the associated SN types. [ABSTRACT FROM AUTHOR]

The Gemini Observatories primarily operate a multi-instrument queue, with observers selecting observations that are best suited to weather and seeing conditions. The Target of Opportunity (ToO) observing mode is intended to allow observation of targets that cannot be specified in advance but which have a well defined external trigger such as distant supernovae or Gamma Ray bursts. In addition, the instrument and configuration best suited to observe the ToO may depend on properties of the event, such as brightness and redshift which again are impossible to know in advance. Queue observing naturally lends itself to Target of Opportunity (ToO) support since the time required to switch between programs and instruments is very short, and the staff observer is trained to operate all the available instruments and modes. Gemini Observatory has supported pre-approved ToO programs since beginning queue operations, and has implemented a rapid (less than 15 minutes response time) ToO mode since 2005. ToOs comprise a significant fraction of the queue (20–25% of the highest ranking band) nowadays. We discuss the ToO procedures, the statistics of rapid ToOs observing at Gemini North Observatory, the science related to GRBs and supernovae that this important mode has enabled. [ABSTRACT FROM PUBLISHER]