40538809
Asteroid rotation periods from the Palomar Transient Factory survey
The Palomar Transient Factory (PTF) is a synoptic survey designed to explore the transient and variable sky in a wide variety of cadences. We use PTF observations of fields that were observed multiple times (≳10) per night, for several nights, to find asteroids, construct their light curves and measure their rotation periods. Here we describe the pipeline we use to achieve these goals and present the results from the first four (overlapping) PTF fields analysed as part of this programme. These fields, which cover an area of 21 deg^2, were observed on four nights with a cadence of ∼20 min. Our pipeline was able to detect 624 asteroids, of which 145 (≈20 per cent) were previously unknown. We present high-quality rotation periods for 88 main-belt asteroids and possible period or lower limit on the period for an additional 85 asteroids. For the remaining 451 asteroids, we present lower limits on their photometric amplitudes. Three of the asteroids have light curves that are characteristic of binary asteroids. We estimate that implementing our search for all existing high-cadence PTF data will provide rotation periods for about 10 000 asteroids mainly in the magnitude range ≈14 to ≈20.
28576228
CORE-COLLAPSE SUPERNOVAE FROM THE PALOMAR TRANSIENT FACTORY: INDICATIONS FOR A DIFFERENT POPULATION IN DWARF GALAXIES
We use the first compilation of 72 core-collapse supernovae (SNe) from the Palomar Transient Factory (PTF) to study their observed subtype distribution in dwarf galaxies compared to giant galaxies. Our sample is the largest single-survey, untargeted, spectroscopically classified, homogeneous collection of core-collapse events ever assembled, spanning a wide host-galaxy luminosity range (down to M_r ≈ –14 mag) and including a substantial fraction (>20%) of dwarf (M_r ≥ –18 mag) hosts. We find more core-collapse SNe in dwarf galaxies than expected and several interesting trends emerge. We use detailed subclassifications of stripped-envelope core-collapse SNe and find that all Type I core-collapse events occurring in dwarf galaxies are either SNe Ib or broad-lined SNe Ic (SNe Ic-BL), while "normal" SNe Ic dominate in giant galaxies. We also see a significant excess of SNe IIb in dwarf hosts. We hypothesize that in lower metallicity hosts, metallicity-driven mass loss is reduced, allowing massive stars that would have appeared as "normal" SNe Ic in metal-rich galaxies to retain some He and H, exploding as Ib/IIb events. At the same time, another mechanism allows some stars to undergo extensive stripping and explode as SNe Ic-BL (and presumably also as long-duration gamma-ray bursts). Our results are still limited by small-number statistics, and our measurements of the observed N(Ib/c)/N(II) number ratio in dwarf and giant hosts (0.25^(+0.3)_(–0.15) and 0.23^(+0.11)_(–0.08), respectively; 1σ uncertainties) are consistent with previous studies and theoretical predictions. As additional PTF data accumulate, more robust statistical analyses will be possible, allowing the evolution of massive stars to be probed via the dwarf-galaxy SN population.
8913778
Spitzer Observations of the New Luminous Red Nova M85 OT2006-1
M85 OT2006-1 is the latest and most brilliant addition to the small group of known luminous red novae (LRNe). An identifying characteristic of the previously detected events (M31 RV, V4332 Sgr, and V838 Mon) was a spectral redward evolution connected with an emerging infrared component following the optical decay. Here we report on the discovery of a similar feature in Keck NIRC and Spitzer photometry of M85 OT2006-1 6 months posteruption. We find that its 2.1-22 μm spectral energy distribution is best described by a blackbody with effective temperature T_(eff) = 950 ± 150 K and bolometric luminosity L = 2.9^(+0.4)_(-0.5) × 10^5 L_⊙. Assuming spherical geometry, the blackbody effective radius, R = 2.0^(+0.6)_(-0.4) × 10^4 R_⊙, and corresponding expansion velocity, v = 870^(+260)_(-180) km s^(-1), are remarkably similar to the properties of M31 RV 70 days after its eruption. Furthermore, we propose a search strategy for LRNe in the local universe making use of the longevity of their infrared excess emission and discuss the expected number of events in the Spitzer Infrared Nearby Galaxies Survey.
14167939
Detecting Outer Planets in Edge-on Orbits: Combining Radial Velocity and Astrometric Techniques
The astrometric and radial velocity techniques of extrasolar planet detection attempt to detect the periodic reflex motion of the parent star by extracting this periodic signal from a time-sampled set of observations. The extraction is generally accomplished using periodogram analysis or the functionally equivalent technique of least-squares fitting of sinusoids. In this paper, we use a frequentist approach to examine the sensitivity of the least-squares technique when applied to a combination of radial velocity and astrometric observations. We derive an analytical expression for the sensitivity and show that the combined approach yields significantly better sensitivity than either technique on its own. We discuss the ramifications of this result to upcoming astrometric surveys with the Full-Sky Astrometric Mapping Explorer, the Keck Interferometer, and the Space Interferometry Mission.
20207808
DISCOVERY OF A COSMOLOGICAL, RELATIVISTIC OUTBURST VIA ITS RAPIDLY FADING OPTICAL EMISSION
We report the discovery by the Palomar Transient Factory (PTF) of the transient source PTF11agg, which is distinguished by three primary characteristics: (1) bright (Rpeak = 18.3mag), rapidly fading (ΔR = 4mag in Δt = 2 days) optical transient emission; (2) a faint (R = 26.2 ± 0.2mag), blue (g � − R = 0.17 ± 0.29mag) quiescent optical counterpart; and (3) an associated year-long, scintillating radio transient. We argue that these observed properties are inconsistent with any known class of Galactic transients (flare stars, X-ray binaries, dwarf novae), and instead suggest a cosmological origin. The detection of incoherent radio emission at such distances implies a large emitting region, from which we infer the presence of relativistic ejecta. The observed properties are allconsistentwiththepopulationoflong-durationgamma-raybursts(GRBs),markingthefirsttimesuchanoutburst has been discovered in the distant universe independent of a high-energy trigger. We searched for possible highenergy counterparts to PTF11agg, but found no evidence for associated prompt emission. We therefore consider three possible scenarios to account for a GRB-like afterglow without a high-energy counterpart: an “untriggered” GRB (lack of satellite coverage), an “orphan” afterglow (viewing-angle effects), and a “dirty fireball” (suppressed high-energy emission). The observed optical and radio light curves appear inconsistent with even the most basic predictions for off-axis afterglow models. The simplest explanation, then, is that PTF11agg is a normal, on-axis long-durationGRBforwhichtheassociatedhigh-energyemissionwassimplymissed.However,wehavecalculated the likelihood of such a serendipitous discovery by PTF and find that it is quite small (≈2.6%). While not definitive, we nonetheless speculate that PTF11agg may represent a new, more common (>4 times the on-axis GRB rate at 90% confidence) class of relativistic outbursts lacking associated high-energy emission. If so, such sources will be uncovered in large numbers by future wide-field optical and radio transient surveys.
11026035
The Incidence of Dwarf Novae in Large Area Transient Searches
Understanding and quantifying the contribution of known classes of transient and variable sources is an important lesson to be learned from the manifold of precursor programs of the near-future large synoptic sky survey programs such as SkyMapper, Pan-STARRS, and LSST. With this goal in mind, we undertook photometric and spectroscopic follow-up observations of four recently reported unidentified transients. For two sources, WFI J132813.7-214237 and WFI J161953.3+031909, we show that unfortunate coincidences led to their previous designation as transients. While the former is now interpreted as the spatial coincidence of a solar system object with a faint background star, the latter is merely a cataclysmic variable unfortunately caught in and out of eclipse. The third candidate, ROTSE3 J160213.1-021311.7, is identified as an SU UMa type dwarf nova with quiescent brightness of R ~ 22.7 and an outburst amplitude of ~5 mag. The fourth event, SDSS-SN 15207, similarly shows evidence for a dwarf nova origin. Our main conclusion is that cataclysmic variables in their various avatars will contribute moderately to the population of transient objects.
123813842
Black Hole Entropy from Covariant Anomalies
15809457
Hawking radiation, effective actions and covariant boundary conditions
From an appropriate expression for the effective action, the Hawking radiation from charged black holes is derived, using only covariant boundary conditions at the event horizon. The connection of our approach with the Unruh vacuum and the recent analysis [S.P. Robinson, F. Wilczek, Phys. Rev. Lett. 95 (2005) 011303, gr-qc/0502074; S. Iso, H. Umetsu, F. Wilczek, Phys. Rev. Lett. 96 (2006) 151302, hep-th/0602146; R. Banerjee, S. Kulkarni, arXiv: 0707.2449 [hep-th]] of Hawking radiation using anomalies is established.
119245317
Toward a public analysis database for LHC new physics searches using MADANALYSIS 5
We present the implementation, in the MadAnalysis 5 framework, of several ATLAS and CMS searches for supersymmetry in data recorded during the first run of the LHC. We provide extensive details on the validation of our implementations and propose to create a public analysis database within this framework.
118523006
Modelling the clustering of dark matter haloes in resummed perturbation theories
We address the issue of the cosmological bias between matter and galaxy distributions, looking at dark matter haloes as a first step to characterize galaxy clustering. Starting from the linear density field at high redshift, we follow the centre-of-mass trajectory of the material that will form each halo at late times (protohalo). We adopt a fluid-like description for the evolution of perturbations in the protohalo distribution, which is coupled to the matter density field via gravity. We present analytical solutions for the density and velocity fields, in the context of renormalized perturbation theory. We start from the linear solution, then compute one-loop corrections for the propagator and the power spectrum. Finally, we analytically resum the propagator, and we use a suitable extension of the time-renormalization-group method to resum the power spectrum. For halo masses M < 1014 h−1 M⊙, our results at z= 0 are in good agreement with N-body simulations. Our model is able to predict the halo–matter cross-spectrum with an accuracy of 5 per cent up to k≈ 0.1 h Mpc−1 approaching the requirements of future galaxy redshift surveys.
116599063
Hawking fluxes and covariant anomalies
A non-destructive, direct method and apparatus for producing stretch blow molded articles having at least one physical dimension within a preselected range. The apparatus includes an injection mold defining an injection mold interior surface having a first differentially dimensioned portion disposed at a preselected location thereon and capable of producing a parison having a parison exterior surface including a first marker formed by contact with the first differentially dimensioned portion, and a stretch blow mold defining a stretch blow mold interior surface having a second differentially dimensioned portion disposed at a predetermined location thereon and capable of producing the article from the parison including a second marker formed by contact with the second differentially dimensioned portion. Relative position of the first marker with respect to the second marker indicates whether a dimension is within a preselected range. The method includes injection molding a parison so that a parison exterior surface includes a first marker disposed at a preselected position thereon and formed by contact with a first differentially dimensioned portion disposed at a preselected location on an injection mold interior surface, and stretch blow molding an article from the parison so that an article exterior surface includes a second marker disposed at a predetermined position thereon and formed by contact with a second differentially dimensioned portion disposed at a predetermined location on a stretch blow mold interior surface.