Energy input and response from prompt and early optical afterglow emission in gamma-ray bursts

The taxonomy of optical emission detected during the critical first few minutes after the onset of a gamma-ray burst (GRB) defines two broad classes: prompt optical emission correlated with prompt gamma-ray emission, and early optical afterglow emission uncorrelated with the gamma-ray emission. The standard theoretical interpretation attributes prompt emission to internal shocks in the ultra-relativistic outflow generated by the internal engine; early afterglow emission is attributed to shocks generated by interaction with the surrounding medium. Here we report on observations of a bright GRB that, for the first time, clearly show the temporal relationship and relative strength of the two optical components. The observations indicate that early afterglow emission can be understood as reverberation of the energy input measured by prompt emission. Measurements of the early afterglow reverberations therefore probe the structure of the environment around the burst, whereas the subsequent response to late-time impulsive energy releases reveals how earlier flaring episodes have altered the jet and environment parameters. Many GRBs are generated by the death of massive stars that were born and died before the Universe was ten per cent of its current age, so GRB afterglow reverberations provide clues about the environments around some of the first stars.Comment: 13 pages, 4 figures, 1 table. Note: This paper has been accepted for publication in Nature, but is embargoed for discussion in the popular press until formal publication in Natur

Rotation Curves of Spiral Galaxies

Rotation curves of spiral galaxies are the major tool for determining the distribution of mass in spiral galaxies. They provide fundamental information for understanding the dynamics, evolution and formation of spiral galaxies. We describe various methods to derive rotation curves, and review the results obtained. We discuss the basic characteristics of observed rotation curves in relation to various galaxy properties, such as Hubble type, structure, activity, and environment.Comment: 40 pages, 6 gif figures; Ann. Rev. Astron. Astrophys. Vol. 39, p.137, 200

A Pipeline for the ROTSE-IIId Archival Data

We have constructed a new, fast, robust and reliable pipeline to detect variable stars from the ROTSE-IIId archival data. Turkish share of ROTSE-III archive contains approximately one million objects from a large field of view (1.85\dgr) and it considerably covers a large portion of northern sky (\delta>-25\dgr). The unfiltered ROTSE-III magnitude of the objects ranges from 7.7 to 16.9. The main stages of the new pipeline are as follows: Source extraction, astrometry of the objects, light curve generation and inhomogeneous ensemble photometry. A high performance computing (HPC) algorithm has also been implemented into the pipeline where we had a good performance even on a personal computer. Running the algorithms of the pipeline on a cluster decreases analysis time significantly from weeks to hours. The pipeline is especially tested against long period variable stars with periods of a few hundred days (e.g Mira and SR) and variables having periods starting from a few days to a few hundred days were detected.Comment: 8 pages, 5 figures 2 tables; last revision before publishe

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 Automated Survey for SuperNovae (ASAS-SN). The source had a peak bolometric luminosity of L ' 1044 ergs

Confined dense circumstellar material surrounding a regular type II supernova

With the advent of new wide-field, high-cadence optical transient surveys, our understanding of the diversity of core-collapse supernovae has grown tremendously in the last decade. However, the pre-supernova evolution of massive stars, which sets the physical backdrop to these violent events, is theoretically not well understood and difficult to probe observationally. Here we report the discovery of the supernova iPTF 13dqy = SN 2013fs a mere ∼3 h after explosion. Our rapid follow-up observations, which include multiwavelength photometry and extremely early (beginning at ∼6 h post-explosion) spectra, map the distribution of material in the immediate environment (≲1015 cm) of the exploding star and establish that it was surrounded by circumstellar material (CSM) that was ejected during the final ∼1 yr prior to explosion at a high rate, around 10-3 solar masses per year. The complete disappearance of flash-ionized emission lines within the first several days requires that the dense CSM be confined to within ≲1015 cm, consistent with radio non-detections at 70–100 days. The observations indicate that iPTF 13dqy was a regular type II supernova; thus, the finding that the probable red supergiant progenitor of this common explosion ejected material at a highly elevated rate just prior to its demise suggests that pre-supernova instabilities may be common among exploding massive stars. © 2017 Nature Publishing Grou

ASASSN-15lh: The Most Luminous Supernova Ever Discovered

We report the discovery and early evolution of ASASSN-15lh, the most luminous supernova ever found. At redshift z=0.2326, ASASSN-15lh reached an absolute magnitude of M_{u,AB} ~ -23.5 and bolometric luminosity L_bol ~ 2.2x10^45 ergs/s, which is >~ 2 times more luminous than any previously known supernova. Its spectra match the hydrogen-poor sub-class of super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are poorly understood. In contrast to known SLSNe-I, most of which reside in star-forming, dwarf galaxies, its host appears to be a luminous galaxy (M_V ~ -22; M_K ~ -25.1) with little star formation. In the two months since its first detection, ASASSN-15lh has radiated ~7.5x10^51 ergs, challenging the popular magnetar model for the engine of SLSNe-I

The ASAS-SN bright supernova catalogue - III. 2016

This catalogue summarizes information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (mpeak ≤ 17), spectroscopically confirmed supernovae discovered in 2016. We then gather the near-infrared through ultraviolet magnitudes of all host galaxies and the offsets of the supernovae from the centres of their hosts from public data bases. We illustrate the results using a sample that now totals 668 supernovae discovered since 2014 May 1, including the supernovae from our previous catalogues, with type distributions closely matching those of the ideal magnitude limited sample from Li et al. This is the third of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team

Effect of a single acupuncture treatment on surgical wound healing in dogs: a randomized, single blinded, controlled pilot study

<p>Abstract</p> <p>Background</p> <p>The aim of the study was to investigate the effect of acupuncture on wound healing after soft tissue or orthopaedic surgery in dogs.</p> <p>Methods</p> <p>29 dogs were submitted to soft tissue and/or orthopaedic surgeries. Five dogs had two surgical wounds each, so there were totally 34 wounds in the study. All owners received instructions for post operative care as well as antibiotic and pain treatment. The dogs were randomly assigned to treatment or control groups. Treated dogs received one dry needle acupuncture treatment right after surgery and the control group received no such treatment. A veterinary surgeon that was blinded to the treatment, evaluated the wounds at three and seven days after surgery in regard to oedema (scale 0-3), scabs (yes/no), exudate (yes/no), hematoma (yes/no), dermatitis (yes/no), and aspect of the wound (dry/humid).</p> <p>Results</p> <p>There was no significant difference between the treatment and control groups in the variables evaluated three and seven days after surgery. However, oedema reduced significantly in the group treated with acupuncture at seven days compared to three days after surgery, possibly due the fact that there was more oedema in the treatment group at day three (although this difference was nor significant between groups).</p> <p>Conclusions</p> <p>The use of a single acupuncture treatment right after surgery in dogs did not appear to have any beneficial effects in surgical wound healing.</p

Observation of associated near-side and away-side long-range correlations in √sNN=5.02 TeV proton-lead collisions with the ATLAS detector

Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁡2Δϕ modulation for all ΣETPb ranges and particle pT

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente