SN 2005ap: A Most Brilliant Explosion Quimby, Robert M; Aldering, Greg; Wheeler, J. Craig ...
The Astrophysical journal,
10/2007, Letnik:
668, Številka:
2
Journal Article
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We present unfiltered photometric observations with ROTSE-III and optical spectroscopic follow-up with HET and the Keck telescope of the most luminous supernova yet identified, SN 2005ap. The spectra ...taken about 3 days before and 6 days after maximum light show narrow emission lines (likely originating in the dwarf host) and absorption lines at a redshift of z = 0.2832, which puts the peak unfiltered magnitude at -22.7 plus or minus 0.1 absolute. Broad P Cygni features corresponding to Ha, C III, N III, and O III are further detected with a photospheric velocity of similar to 20,000 km s sub(-1). Unlike other highly luminous supernovae such as 2006gy and 2006tf that show slow photometric evolution, the light curve of SN 2005ap indicates a 1-3 week rise to peak followed by a relatively rapid decay. The spectra also lack the distinct emission peaks from moderately broadened (FWHM similar to 2000 km s sub(-1)) Balmer lines seen in SN 2006gy and SN 2006tf. We briefly discuss the origin of the extraordinary luminosity from a strong interaction as may be expected from a pair instability eruption or a GRB-like engine encased in a H/He envelope.
Background: Voriconazole has a broader spectrum of activity in comparison to fluconazole, itraconazole, and amphotericin B. Little documentation regarding appropriate dosing, efficacy, or adverse ...effects exists for cats. Neurologic adverse effects have been reported as a result of administration in other species.
Hypothesis: Voriconazole administration resulted in neurologic abnormalities in 3 cats.
Animals: Three cats that received voriconazole.
Methods: Observational study of adverse effects associated with voriconazole administration.
Results: All 3 cats had ataxia, which in 2 cats progressed to paraplegia of the rear limbs. Two of the cats had visual abnormalities including mydriasis, decreased to absent pupillary light responses, and decreased menace response. Arrhythmia and hypokalemia were noted in 2 separate cats.
Conclusions and Clinical Importance: Voriconazole has potential neurologic adverse effects in cats. Additional information regarding pharmacokinetics of the drug in this species must be gathered to help determine how it can be dosed most effectively with minimal adverse effects.
HET optical spectroscopy and unfiltered ROTSE-III photometry spanning the first 11 months since explosion of the Type II-P SN 2006bp are presented. The data suggest that the supernova was first ...detected just hours after shock breakout. Optical spectra obtained about 2 days after breakout exhibit narrow emission lines corresponding to He II lambda 4200, He II lambda 4686, and C IV lambda 5805 in the rest frame. These emission features persist in a second observation obtained 5 hr later but are not detected the following night or in subsequent observations. These lines probably emanate from material close to the explosion site, possibly in the outer layers of the progenitor that have been ionized by the high-energy photons released at shock breakout. A P Cygni profile is observed around 4450 AA in the +2 and +3 day spectra. We propose that this line is due to He II lambda 4687 rather than high-velocity H beta , as previously suggested. Further HET spectra cover the evolution across the photometric plateau up to 73 days after breakout and during the nebular phase around day +340. Expansion velocities are derived for key features. The measured decay slope for the unfiltered light curve is 0.0073 plus or minus 0.0004 mag day super(-1) between days +121 and +335, which is significantly slower than the decay of rate super(56)Co. We present a quasi-bolometric light curve through day +60. We see a slow cooling over the first 25 days but no sign of an early sharp peak; any such feature from the shock breakout must have lasted less than similar to 1 day.
We present a multi-wavelength study of GRB 081008, at redshift 1.967, by Swift, ROTSE-III, and Gamma-Ray Burst Optical/NearInfrared Detector. Compared to other Swift GRBs, GRB 081008 has a typical ...gamma-ray isotropic equivalent energy output ({approx}10{sup 53} erg) during the prompt phase, and displayed two temporally separated clusters of pulses. The early X-ray emission seen by the Swift X-Ray Telescope was dominated by the softening tail of the prompt emission, producing multiple flares during and after the Swift Burst Alert Telescope detections. Optical observations that started shortly after the first active phase of gamma-ray emission showed two consecutive peaks. We interpret the first optical peak as the onset of the afterglow associated with the early burst activities. A second optical peak, coincident with the later gamma-ray pulses, imposes a small modification to the otherwise smooth light curve and thus suggests a minimal contribution from a probable internal component. We suggest the early optical variability may be from continuous energy injection into the forward shock front by later shells producing the second epoch of burst activities. These early observations thus provide a potential probe for the transition from the prompt phase to the afterglow phase. The later light curve of GRB 081008 displays a smooth steepening in all optical bands and X-ray. The temporal break is consistent with being achromatic at the observed wavelengths. Our broad energy coverage shortly after the break constrains a spectral break within optical. However, the evolution of the break frequency is not observed. We discuss the plausible interpretations of this behavior.
We report spectroscopic observations of the nova M31N-2007-06b, which was found to be spatially coincident with the M31 globular cluster Bol 111. This nova is the first out of more than 700 ...discovered in M31 over the past century to be associated with one of the galaxy's globular clusters. A total of three spectra of the nova were obtained 3, 6, and 36 days after discovery. The data reveal broad (FWHM similar to 3000 km s super(-1)) Balmer, N II, and N III emission lines and show that the nova belongs to the He/N spectroscopic class. The He/N class of novae are relatively rare, making up roughly 15% of the novae with measured spectra in M31 and roughly 20%-25% of the Galactic novae for which spectroscopic data are available. The implications of a nova, particularly an He/N nova, occurring in a globular cluster are discussed.
Aims.
We study PTF11mnb, a He-poor supernova (SN) whose light curves resemble those of SN 2005bf, a peculiar double-peaked stripped-envelope (SE) SN, until the declining phase after the main peak. We ...investigate the mechanism powering its light curve and the nature of its progenitor star.
Methods.
Optical photometry and spectroscopy of PTF11mnb are presented. We compared light curves, colors and spectral properties to those of SN 2005bf and normal SE SNe. We built a bolometric light curve and modeled this light curve with the SuperNova Explosion Code (SNEC) hydrodynamical code explosion of a MESA progenitor star and semi-analytic models.
Results.
The light curve of PTF11mnb turns out to be similar to that of SN 2005bf until ~50 d when the main (secondary) peaks occur at −18.5 mag. The early peak occurs at ~20 d and is about 1.0 mag fainter. After the main peak, the decline rate of PTF11mnb is remarkably slower than what was observed in SN 2005bf, and it traces well the
56
Co decay rate. The spectra of PTF11mnb reveal a SN Ic and have no traces of He unlike in the case of SN Ib 2005bf, although they have velocities comparable to those of SN 2005bf. The whole evolution of the bolometric light curve is well reproduced by the explosion of a massive (
M
ej
= 7.8
M
⊙
), He-poor star characterized by a double-peaked
56
Ni distribution, a total
56
Ni mass of 0.59
M
⊙
, and an explosion energy of 2.2 × 10
51
erg. Alternatively, a normal SN Ib/c explosion (
M
(
56
Ni) = 0.11
M
⊙
,
E
K
= 0.2 × 10
51
erg,
M
ej
= 1
M
⊙
) can power the first peak while a magnetar, with a magnetic field characterized by
B
= 5.0 × 10
14
G, and a rotation period of
P
= 18.1 ms, provides energy for the main peak. The early
g
-band light curve can be fit with a shock-breakout cooling tail or an extended envelope model from which a radius of at least 30
R
⊙
is obtained.
Conclusions.
We presented a scenario where PTF11mnb was the explosion of a massive, He-poor star, characterized by a double-peaked
56
Ni distribution. In this case, the ejecta mass and the absence of He imply a large ZAMS mass (~85
M
⊙
) for the progenitor, which most likely was a Wolf-Rayet star, surrounded by an extended envelope formed either by a pre-SN eruption or due to a binary configuration. Alternatively, PTF11mnb could be powered by a SE SN with a less massive progenitor during the first peak and by a magnetar afterward.
We present follow-up observations of an optical transient (OT) discovered by ROTSE on 2009 January 21. Photometric monitoring was carried out with ROTSE-IIIb in the optical and Swift in the UV up to ...+70 days after discovery. The light curve showed a fast rise time of ∼10 days followed by a steep decline over the next 60 days, which was much faster than that implied by {sup 56}Ni—{sup 56}Co radioactive decay. The Sloan Digital Sky Survey Data Release 10 database contains a faint, red object at the position of the OT, which appears slightly extended. This and other lines of evidence suggest that the OT is of extragalactic origin, and this faint object is likely the host galaxy. A sequence of optical spectra obtained with the 9.2 m Hobby-Eberly Telescope between +8 and +45 days after discovery revealed a hot, blue continuum with no visible spectral features. A few weak features that appeared after +30 days probably originated from the underlying host. Fitting synthetic templates to the observed spectrum of the host galaxy revealed a redshift of z = 0.19. At this redshift, the peak magnitude of the OT is close to –22.5, similar to the brightest super-luminous supernovae; however, the lack of identifiable spectral features makes the massive stellar death hypothesis less likely. A more plausible explanation appears to be the tidal disruption of a Sun-like star by the central supermassive black hole. We argue that this transient likely belongs to a class of super-Eddington tidal disruption events.
We present the results of a search for untriggered gamma-ray burst (GRB) afterglows with the Robotic Optical Transient Search Experiment-III (ROTSE-III) telescope array. This search covers ...observations from 2003 September to 2005 March. We have an effective coverage of 1.74 deg super(2) yr for rapidly fading transients that remain brighter than 617.5 mag for more than 30 minutes. This search is the first large-area survey to be able to detect typical untriggered GRB afterglows. Our background rate is very low and purely astrophysical. We have found four previously unknown cataclysmic variables (CVs) and one new flare star. We have not detected any candidate afterglow events or other unidentified transients. We can place an upper limit on the rate of fading optical transients with quiescent counterparts dimmer than 620th magnitude at a rate of less than 1.9 deg super(-2) yr super(-1) with 95% confidence. This places limits on the optical characteristics of off-axis (orphan) GRB afterglows. As a by-product of this search, we have an effective 652 deg super(2) yr of coverage for very slowly decaying transients, such as CVs. This implies an overall rate of outbursts from high Galactic latitude CVs of 0.1 deg super(-2) yr super(-1).
We present broad-band multiwavelength observations of GRB 080310 at redshift z= 2.43. This burst was bright and long-lived, and unusual in having extensive optical and near-infrared (IR) follow-up ...during the prompt phase. Using these data we attempt to simultaneously model the gamma-ray, X-ray, optical and IR emission using a series of prompt pulses and an afterglow component. Initial attempts to extrapolate the high-energy model directly to lower energies for each pulse reveal that a spectral break is required between the optical regime and 0.3 keV to avoid overpredicting the optical flux. We demonstrate that afterglow emission alone is insufficient to describe all morphology seen in the optical and IR data. Allowing the prompt component to dominate the early-time optical and IR and permitting each pulse to have an independent low-energy spectral indices we produce an alternative scenario which better describes the optical light curve. This, however, does not describe the spectral shape of GRB 080310 at early times. The fit statistics for the prompt- and afterglow-dominated models are nearly identical making it difficult to favour either. However one enduring result is that both models require a low-energy spectral index consistent with self-absorption for at least some of the pulses identified in the high-energy emission model.
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