Search

Background Microvascular obstruction (MVO) and intramyocardial haemorrhage (IMH) are associated with adverse prognosis, independently of infarct size after reperfused ST-elevation myocardial infarction (STEMI). Mitral annular plane systolic excursion (MAPSE) is a well-established parameter of longitudinal function on echocardiography. Objective We aimed to investigate how acute MAPSE, assessed by a four-chamber cine-cardiovascular MR (CMR), is associated with MVO, IMH and convalescent left ventricular (LV) remodelling. Methods 54 consecutive patients underwent CMR at 3T (Intera CV, Philips Healthcare, Best, The Netherlands) within 3 days of reperfused STEMI. Cine, T2-weighted, T2* and late gadolinium enhancement (LGE) imaging were performed. Infarct and MVO extent were measured from LGE images. The presence of IMH was investigated by combined analysis of T2w and T2* images. Averaged-MAPSE (medial-MAPSE+lateral-MAPSE/2) was calculated from 4-chamber cine imaging. Results 44 patients completed the baseline scan and 38 patients completed 3-month scans. 26 (59%) patients had MVO and 25 (57%) patients had IMH. Presence of MVO and IMH were associated with lower averaged-MAPSE (11.7±0.4 mm vs 9.3±0.3 mm; p

We present a novel method for the light-curve characterization of Pan-STARRS1 Medium Deep Survey (PS1 MDS) extragalactic sources into stochastic variables (SV) and burst-like (BL) transients, using multi-band image-differencing time-series data. We select detections in difference images associated with galaxy hosts using a star/galaxy catalog extracted from the deep PS1 MDS stacked images, and adopt a maximum a posteriori formulation to model their difference-flux time-series in four Pan-STARRS1 photometric bands g,r,i, and z. We use three deterministic light-curve models to fit burst-like transients and one stochastic light curve model, the Ornstein-Uhlenbeck process, in order to fit variability that is characteristic of active galactic nuclei (AGN). We assess the quality of fit of the models band-wise source-wise, using their estimated leave-out-one cross-validation likelihoods and corrected Akaike information criteria. We then apply a K-means clustering algorithm on these statistics, to determine the source classification in each band. The final source classification is derived as a combination of the individual filter classifications. We use our clustering method to characterize 4361 extragalactic image difference detected sources in the first 2.5 years of the PS1 MDS, into 1529 BL, and 2262 SV, with a purity of 95.00% for AGN, and 90.97% for SN based on our verification sets. We combine our light-curve classifications with their nuclear or off-nuclear host galaxy offsets, to define a robust photometric sample of 1233 active galactic nuclei and 812 supernovae. We use these samples to identify simple photometric priors that would enable their real-time identification in future wide-field synoptic surveys., Comment: Accepted for publication in ApJ

Optical and near-infrared observations of the Type Ic supernova (SN) 2004aw are presented, obtained from day -3 to day +413 with respect to the B-band maximum. The photometric evolution is characterised by a comparatively slow post-maximum decline of the light curves. The peaks in redder bands are significantly delayed relative to the bluer bands, the I-band maximum occurring 8.4 days later than that in B. With an absolute peak magnitude of -18.02 in the V band the SN can be considered fairly bright, but not exceptional. This also holds for the U through I bolometric light curve, where SN 2004aw has a position intermediate between SNe 2002ap and 1998bw. Spectroscopically SN 2004aw provides a link between a normal Type Ic supernova like SN 1994I and the group of broad-lined SNe Ic. The spectral evolution is rather slow, with a spectrum at day +64 being still predominantly photospheric. The shape of the nebular [O I] 6300,6364 line indicates a highly aspherical explosion. Helium cannot be unambiguously identified in the spectra, even in the near-infrared. Using an analytical description of the light curve peak we find that the total mass of the ejecta in SN 2004aw is 3.5-8.0 M_Sun, significantly larger than in SN 1994I, although not as large as in SN 1998bw. The same model suggests that about 0.3 M_Sun of {56}Ni has been synthesised in the explosion. No connection to a GRB can be firmly established., 22 pages, 15 figures, 6tables, LaTeX, MNRAS online-early, references and affiliations updated, style corrections

The rapid succession of discovery of short--duration hard--spectrum GRBs has led to unprecedented insights into the energetics of the explosion and nature of the progenitors. Yet short of the detection of a smoking gun, like a burst of coincident gravitational radiation or a Li-Paczynski mini-supernova, it is unlikely that a definitive claim can be made for the progenitors. As was the case with long--duration soft--spectrum GRBs, however, the expectation is that a systematic study of the hosts and the locations of short GRBs could begin to yield fundamental clues about their nature. We present the first aggregate study of the host galaxies of short--duration hard--spectrum GRBs. In particular, we present the Gemini--North and Keck discovery spectra of the galaxies that hosted three short GRBs and a moderate--resolution (R~6000) spectrum of a fourth host. We find that these short--hard GRBs originate in a variety of low-redshift (z, 8 pages, 2 figures. Accepted to ApJ

Introduction Left bundle branch block (LBBB) is common following trans-catheter aortic valve implantation (TAVI) and has been linked to increased mortality, although whether this is due to the development of a TAVI-induced LBBB cardiomyopathy is unclear. Methods 48 patients undergoing TAVI for severe aortic stenosis were evaluated. 24 patients with TAVI-induced LBBB (LBBB-T) were matched with 24 patients with a narrow post-procedure QRS (nQRS). Patients underwent comprehensive Cardiovascular Magnetic Resonance (CMR) imaging prior to and 6m post-TAVI. Measured cardiac reverse remodelling parameters included left ventricular ejection fraction (LVEF), global longitudinal strain (GLS) and left sided chamber size. Inter and intraventricular dyssynchrony was determined using time to peak radial strain derived from CMR Feature Tracking. Results In the nQRS group there was no change in QRSd (93 ± 17 to 96 ± 11 ms, p = 0.098). In the LBBB-T group, QRSd increased by a mean of 55 ms from 96 ± 14 to 151 ± 12 (p= 18.6 ± 5.8 mm, p = 0.773). Post-procedure aortic regurgitant fraction was similar between groups (nQRS 5.4 ± 5.7 vs LBBB-T 5.5 ± 3.3%, p = 0.948). There was an inverse correlation between QRS duration and change in LVEF (r=-0.46, p = 0.001) and QRS duration and change in LV GLS (r=-0.37, p = 0.010). Conclusion LBBB-T is associated with less favourable cardiac reverse remodelling at medium term follow up. In view of this, every effort should be made to prevent TAVI-induced LBBB, especially as TAVI is extended to a younger, lower risk population.

Background Transcatheter aortic valve implantation is an established therapeutic option for patients with severe symptomatic aortic stenosis unsuitable for surgery. CMR has a lower intra-observer and inter-observer variability than echocardiography in the assessment of aortic regurgitation (AR), offering full volumetric quantitation independent of the number or eccentricity of regurgitant jets. Moderate AR following TAVI is an independent predictor of mortality in the postoperative period and has prompted development of novel bioprostheses designed to facilitate precise deployment and minimise paravalvular regurgitation (Figure 1). Aim To compare the degree of early post-procedure aortic regurgitation following implantation of the Medtronic CoreValve and Boston Scientific Lotus Valve systems in patients treated for severe symptomatic aortic stenosis. Methods All patients underwent an identical 1.5T CMR scan (Intera, Phillips Healthcare, Best, Netherlands) post-procedure prior to discharge. Through-plane phase contrast velocity encoded imaging was performed perpendicular to the aortic valve jet at a level above the aortic prosthesis. Aortic flow was subsequently quantified offline (QFlow version 7.2, Medis Medical Imaging Systems, Leiden, The Netherlands) and regurgitant fraction (%) derived. AR was defined as regurgitant fraction of none/trivial ≤ 5%, mild 6 – 15%, moderate 16 – 25%, moderate-severe 26 – 48%, and severe > 48% The invasive AR index derived at the time of TAVI was also recorded ([(Diastolic BP-LVEDP)/Systolic BP] x100). Results 18 Medtronic CoreValve patients (age 79.6 ± 6.3 years, 67% male, EuroSCORE II 4.59 ± 3.59%) and 24 Boston Lotus TAVI patients (age 78.6 ± 8.7years, 54% male, EuroSCORE II 4.07 ± 3.37%) were studied at a median interval of 6 days following implantation. The residual peak aortic pressure gradient observed following Boston Lotus implantation was higher than that following Medtronic CoreValve (25.8 ± 12.1 vs.15.0 ± 5.5mmHg, p = 0.001). The absolute regurgitant fraction was significantly lower following Boston Lotus implantation than following Medtronic CoreValve (Lotus: 4.0 ± 3.5% vs. CoreValve: 11.7 ± 7.2%, p = 0.001). The classification of AR severity is summarised in Figure 2. Overall, 39% of patients with CoreValve had moderate AR compared to no reported cases in the Lotus group. There was a negative correlation between invasive AR index and regurgitant fraction from CMR imaging (Spearman’s coefficient − 0.4, p = 0.016). Conclusions CMR directly quantifies AR following TAVI and there is agreement with invasive AR measurements. There was significantly less aortic regurgitation in the immediate post-implant period using the Boston Lotus valve compared with the Medtronic CoreValve. However the residual peak pressure gradient was lower with the Medtronic CoreValve. Further work is required to assess the longer term differences in AR and whether this translates into a mortality benefit.

We describe a method for measuring the integrated Comptonization (YSZ) of clusters of galaxies from measurements of the Sunyaev-Zel'dovich (SZ) effect in multiple frequency bands and use this method to characterize a sample of galaxy clusters detected in South Pole Telescope (SPT) data. We test this method on simulated cluster observations and verify that it can accurately recover cluster parameters with negligible bias. In realistic simulations of an SPT-like survey, with realizations of cosmic microwave background anisotropy, point sources, and atmosphere and instrumental noise at typical SPT-SZ survey levels, we find that YSZ is most accurately determined in an aperture comparable to the SPT beam size. We demonstrate the utility of this method to measure YSZ and to constrain mass scaling relations using X-ray mass estimates for a sample of 18 galaxy clusters from the SPT-SZ survey. Measuring YSZ within a 0.75' radius aperture, we find an intrinsic log-normal scatter of 21+/-11% in YSZ at a fixed mass. Measuring YSZ within a 0.3 Mpc projected radius (equivalent to 0.75' at the survey median redshift z = 0.6), we find a scatter of 26+/-9%. Prior to this study, the SPT observable found to have the lowest scatter with mass was cluster detection significance. We demonstrate, from both simulations and SPT observed clusters, that YSZ measured within an aperture comparable to the SPT beam size is equivalent, in terms of scatter with cluster mass, to SPT cluster detection significance., Submitted to ApJ. 13 pages, 10 figures

Clusters of galaxies are expected to gravitationally lens the cosmic microwave background (CMB) and thereby generate a distinct signal in the CMB on arcminute scales. Measurements of this effect can be used to constrain the masses of galaxy clusters with CMB data alone. Here we present a measurement of lensing of the CMB by galaxy clusters using data from the South Pole Telescope (SPT). We develop a maximum likelihood approach to extract the CMB cluster lensing signal and validate the method on mock data. We quantify the effects on our analysis of several potential sources of systematic error and find that they generally act to reduce the best-fit cluster mass. It is estimated that this bias to lower cluster mass is roughly $0.85\sigma$ in units of the statistical error bar, although this estimate should be viewed as an upper limit. We apply our maximum likelihood technique to 513 clusters selected via their SZ signatures in SPT data, and rule out the null hypothesis of no lensing at $3.1\sigma$. The lensing-derived mass estimate for the full cluster sample is consistent with that inferred from the SZ flux: $M_{200,\mathrm{lens}} = 0.83_{-0.37}^{+0.38}\, M_{200,\mathrm{SZ}}$ (68% C.L., statistical error only)., Comment: 14 pages, 3 figures. Published in ApJ. Replaced to match published version

We describe an algorithm for identifying point-source transients and moving objects on reference-subtracted optical images containing artifacts of processing and instrumentation. The algorithm makes use of the supervised machine learning technique known as Random Forest. We present results from its use in the Dark Energy Survey Supernova program (DES-SN), where it was trained using a sample of 898,963 signal and background events generated by the transient detection pipeline. After reprocessing the data collected during the first DES-SN observing season (Sep. 2013 through Feb. 2014) using the algorithm, the number of transient candidates eligible for human scanning decreased by a factor of 13.4, while only 1 percent of the artificial Type Ia supernovae (SNe) injected into search images to monitor survey efficiency were lost, most of which were very faint events. Here we characterize the algorithm's performance in detail, and we discuss how it can inform pipeline design decisions for future time-domain imaging surveys, such as the Large Synoptic Survey Telescope and the Zwicky Transient Facility. An implementation of the algorithm and the training data used in this paper are available at http://portal.nersc.gov/project/dessn/autoscan., Comment: 24 pages, 9 figures, 4 tables v3: added link to training data / implementation

We present the first year of Hubble Space Telescope imaging of the unique supernova (SN) 'Refsdal', a gravitationally lensed SN at z=1.488$\pm$0.001 with multiple images behind the galaxy cluster MACS J1149.6+2223. The first four observed images of SN Refsdal (images S1-S4) exhibited a slow rise (over ~150 days) to reach a broad peak brightness around 20 April, 2015. Using a set of light curve templates constructed from SN 1987A-like peculiar Type II SNe, we measure time delays for the four images relative to S1 of 4$\pm$4 (for S2), 2$\pm$5 (S3), and 24$\pm$7 days (S4). The measured magnification ratios relative to S1 are 1.15$\pm$0.05 (S2), 1.01$\pm$0.04 (S3), and 0.34$\pm$0.02 (S4). None of the template light curves fully captures the photometric behavior of SN Refsdal, so we also derive complementary measurements for these parameters using polynomials to represent the intrinsic light curve shape. These more flexible fits deliver fully consistent time delays of 7$\pm$2 (S2), 0.6$\pm$3 (S3), and 27$\pm$8 days (S4). The lensing magnification ratios are similarly consistent, measured as 1.17$\pm$0.02 (S2), 1.00$\pm$0.01 (S3), and 0.38$\pm$0.02 (S4). We compare these measurements against published predictions from lens models, and find that the majority of model predictions are in very good agreement with our measurements. Finally, we discuss avenues for future improvement of time delay measurements -- both for SN Refsdal and for other strongly lensed SNe yet to come., Comment: 19 pages, 9 figures; ApJ in press; v4: corrected layout errors and bibliography arXiv identifiers

Background NICE 2010 guidelines (CG95) proposed investigation according to pre-test likelihood (PTL) of coronary artery disease (CAD) in patients presenting with stable chest pain; low risk patients are referred for CT coronary angiography (CTCA), intermediate risk should have a functional test (stress echocardiography, MPS, CMR) with invasive angiography reserved for high risk patients and those with a PTL>90% having no investigation and treated prospectively as angina. The 2016 update to CG95 now recommends referral for CTCA in all patients with typical or atypical chest pain and in those with non-anginal pain but with ECG changes, with functional imaging reserved for those who have previously documented coronary disease or revascularisation. Our aim was to compare imaging resource utilisation between the 2010 and 2016 guideline recommendations to highlight the potential service implications if followed explicitly. Methods Consecutive patients referred over 4 weeks to the Leeds General Infirmary rapid access chest pain clinic (RACPC) with stable chest pain symptoms were prospectively evaluated. Non identifiable data was collected on demographics, typicality of chest pain symptoms and ECG findings and subsequently requested 1st line investigation. Patient notes were reviewed and PTL for patients was calculated in accordance with CG95 and hypothetical investigative strategies calculated according to both 2010 and 2016 guidelines. Results 157 consecutive patients were evaluated between 17th October and 17th November 2016. Patient demographics are displayed in table 1. 37 (23.5%) patients had typical angina, 55 (35.0%) had atypical angina, 65 (41.4%) had non-anginal symptoms. 16 (10.2%) patients had previous infarction/revascularisation. 25 (15.9%) patients had a PTL 90%. Table 2 shows diagnostic tests requested and hypothetical investigative strategies according to NICE 2010 CG95 and the 2016 update. Conclusion/Implications Our results show that if implemented in proposed 2016 form there will be a significant increase in the referral rate for CTCA with a corresponding decrease in referral for functional imaging and angiography. Furthermore the number of patients that are not investigated would more than double following the introduction of the proposed NICE 2016 guidelines. CTCA has high sensitivity for the diagnosis of CAD but more limited specificity and concerns are that increased usage in intermediate/high risk patients may lead to increased rates of unnecessary angiography due to the overestimation of severity of CAD. The change in guidelines would lead to a significant shift in practice that has implications for both workforce planning and provision of resources.

Introduction Pre-test likelihood models recommended in current UK and US guidelines have been shown to overestimate the probability of coronary artery disease(CAD). We aimed to develop a UK population-based multivariable risk model from CE-MARC(a contemporary study of stable CAD where all patients underwent X-ray coronary angiography) and validate it prospectively in the CE-MARC 2 trial population. Methods CE-MARC (development population) enrolled patients between 2006–9 with suspected angina. Multivariable logistic regression modelled presence of significant stenosis (QCA≥70% in epicardial arteries or ≥50% in Left Main Stem) as a function of baseline demographic and clinical characteristics. The validation population were from the CE-MARC 2 trial (2012–16) that underwent angiography, plus additional low and high-risk patients from Leeds General Infirmary (2014–2016) to ensure adequate numbers across the full risk spectrum. Discrimination and calibration were assessed and compared to existing CAD consortium models(ESC 2013 guidelines) and the Duke Score(NICE CG95 2010 and US 2012 guidelines). Results There were 675 patients in the development population, and 369 patients in the validation population(Table 1). A multivariable model was developed that included age, sex, angina type, smoking, diabetes, dyslipidaemia, hypertension, ECG Q-waves and ST segment abnormalities.The validation population had a similar CV risk profile. The new CE-MARC model discriminated well (c-statistic: 0.78 (95%CI 0.73–0.82)) and was well-calibrated (Table 2, Figure 1). In comparison, the Duke clinical model was very poorly calibrated (−1.016; −1.265 to −0.766; p Conclusion The CE-MARC risk model, developed from a large contemporary UK population undergoing angiography, performed very well in the independent validation sample, without needing any adjustment for different risk prevalence or for miscalibration. In contrast, the earlier Duke risk score substantially over-predicted CAD risk, and remained poorly-calibrated even when this was corrected. The CAD consortium model (ESC 2013 guidelines), slightly under-estimated average CAD risk, but performed well once this was accounted for lower margin presents histogram of number of patients with each predicted risk score

Background Prognosis and treatment of patients with chronic heart failure (CHF) differs according to whether it is ischaemic (ICM) or non-ischaemic cardiomyopathy (NICM). Multi-parametric cardiovascular magnetic resonance (CMR) can distinguish these aetiologies; strain imaging however may confer incremental diagnostic and prognostic information over left ventricular ejection fraction (LVEF). We hypothesised in a prospectively recruited sample of CHF patients, ICM and NICM have different myocardial strain patterns. Methods The VINDICATE trial investigated efficacy of high dose vitamin D in patients with CHF. A subgroup of the trial underwent CMR, blood and cardiopulmonary exercise tests at baseline. 53 patients (31 ICM, 22 NICM) underwent identical 3.0T CMR protocols (Achieva, Philips Healthcare, Best, The Netherlands). Tissue tagging by spatial modulation of magnetization (SPAMM) (spatial resolution 1.51 × 1.57×10mm3, tag separation 7 mm, 18 phases, typical TR/TE 5.8/3.5 ms, flip angle 10°, typical temporal resolution 55 ms) was acquired in short axis slices acquired at the apex, mid-ventricle, and base. Late gadolinium enhancement (LGE) was performed 15 min following administration of 0.15 mmol/kg gadolinium DTPA. CMR data were analysed quantitatively using commercially available software (CVI42, Circle Cardiovascular Imaging Inc. Calgary, Canada and inTag v1.0, CREATIS lab, Lyon, France). Endocardial and epicardial contours were drawn on SPAMM sequences using a semi-automated process. Peak circumferential LV strain (Ecc) was measured at apex, mid-ventricle, and base. LV twist was calculated by subtracting basal from apical rotation. Torsion was determined by: Torsion = Peak Twist x (Apical Radius+Basal Radius)/2xApex to Base length Results The two groups were comparable for baseline demographics (Table 1). The ICM group had significantly more prior revascularisation (CABG/PCI). There was no significant difference between the 2 groups in both LV dimensions and LVEF, however ICM had significantly more LGE (Table 2). There was no significant difference between the 2 groups in Ecc. NICM patients had significantly lower LV twist and torsion compared to the ICM group 6.0±3.68° vs 8.8±4.32° p=0.020 and 6.3±3.79° vs 8.8±4.69° p=0.048 respectively. Conclusion Despite similar EF and Ecc, patients with NICM had significantly less LV torsion than ICM. Myocyte dysfunction in ICM is more sub-endocardial due to the wave-front of ischaemia and more global in NICM. Relative perseveration of LV torsion of ICM over NICM is likely a result of sparing of sub-epicardial fibres and an increased compensatory recruitment of sub-epicardial fibres that are predominantly responsible for LV torsion. Recognition of different torsion patterns of ICM and NICM gives insight into aetiology of CHF, which may assist patient diagnosis and management, especially in those unable to have contrast agents.

Background Validation of four-dimensional (4D) flow CMR accelerated acquisition methods is needed to make them more robust for clinical applications.1 Our aim was to compare three widely-used acceleration methods in 4D flow CMR: 4D segmented fast-gradient-echo (4D- turbo-field-echo, 4D-TFE), 4D non-segmented gradient-echo with echo-planar imaging (4D- EPI) and 4D-k-t Broad-use Linear Acquisition Speed-up Technique accelerated TFE (4D-k-t BLAST). Methods CMR was performed in two institutions on identical 1.5T systems. Acceleration methods were compared in static/pulsatile phantoms (Figure 1) and 25 volunteers. In volunteers, the CMR protocol included: cines, 2D phase contrast (PC) at the aortic valve (AV) and mitral valve (MV) and three whole-heart free-breathing (no respiratory motion correction) 4D flow CMR pulse sequences. Field-of-view, slices, phases (30), voxel size and VENC were the same for each subject. In volunteers, net acquisition time for each 4D flow sequence was recorded, as well as a visual grading of image quality on a four-point scale: 0, no artefacts to 3, non-evaluable. Results For the pulsatile phantom experiments, the mean error against the reference flow by time beaker measurements for 4D-TFE was 4.9%±1.3%, for 4D-EPI 7.6%±1.3% and for 4D-k-t BLAST 4.4%±1.9%. In vivo, acquisition time was shortest for 4D-EPI at 7 min59s±2 min30s. 4D- EPI and 4D-k-t BLAST had minimal artefacts, while for 4D-TFE, 40% of AV and MV assessments were non-evaluable because of phase dispersion artefacts. Peak velocity assessment using 4D-EPI demonstrated best correlation to 2D PC (AV: r=0.78, p Conclusion Of the three 4D flow CMR methods tested, 4D-EPI demonstrated the least susceptibility to artefacts, good image quality, modest agreement with the current reference standard for peak intra-cardiac velocities and the highest consistency of intra-cardiac flow quantifications. Competing interests The authors declare that they have no competing interests. Acknowledgement We thank Gavin Bainbridge, Caroline Richmond, Margaret Saysell and Petra Bijsterveld for their invaluable assistance in recruiting and collecting data for this study. Funding Sources This work was supported by the British Heart Foundation [FS/10/62/28409 to S.P.] and Dutch ZonMw [Project Number: 104003001 to J.W]. References . Dyverfeldt P, Bissell M, Barker AJ, Bolger AF, et al. 4D flow cardiovascular magnetic resonance consensus statement. J Cardiovasc Magn Reson2015;17:72.

(Abridged) We present the results of an X-ray analysis of 80 galaxy clusters selected in the 2500 deg^2 South Pole Telescope survey and observed with the Chandra X-ray Observatory. We divide the full sample into subsamples of ~20 clusters based on redshift and central density, performing an X-ray fit to all clusters in a subsample simultaneously, assuming self-similarity of the temperature profile. This approach allows us to constrain the shape of the temperature profile over 0R500) regions than their low-z (0.3R500 in our high-z subsample. This flattening is consistent with a temperature bias due to the enhanced (~3x) rate at which group-mass (~2 keV) halos, which would go undetected at our survey depth, are accreting onto the cluster at z~1. This work demonstrates a powerful method for inferring spatially-resolved cluster properties in the case where individual cluster signal-to-noise is low, but the number of observed clusters is high., Comment: 17 pages, 13 figures, submitted to ApJ. Updated following referee report

We present UV through NIR broad-band photometry, and optical and NIR spectroscopy of Type Iax supernova 2012Z. The data set consists of both early and late-time observations, including the first late phase NIR spectrum obtained for a spectroscopically classified SN Iax. Simple model calculations of its bolometric light curve suggest SN 2012Z produced ~0.3 M_sun of (56)Ni, ejected about a Chandrasekhar mass of material, and had an explosion energy of ~10^51 erg, making it one of the brightest and most energetic SN Iax yet observed. The late phase NIR spectrum of SN 2012Z is found to broadly resemble similar epoch spectra of normal SNe Ia; however, like other SNe Iax, corresponding visual-wavelength spectra differ substantially compared to all supernova types. Constraints from the distribution of IMEs, e.g. silicon and magnesium, indicate that the outer ejecta did not experience significant mixing during or after burning, and the late phase NIR line profiles suggests most of the (56)Ni is produced during high density burning. The various observational properties of SN 2012Z are found to be consistent with the theoretical expectations of a Chandrasekhar mass white dwarf progenitor that experiences a pulsational delayed detonation, which produced several tenths of a solar mass of (56)Ni during the deflagration burning phase and little (or no) (56)Ni during the detonation phase. Within this scenario only a moderate amount of Rayleigh-Taylor mixing occurs both during the deflagration and fallback phase of the pulsation, and the layered structure of the IMEs is a product of the subsequent denotation phase. The fact that the SNe Iax population does not follow a tight brightness-decline relation similar to SNe Ia can then be understood in the framework of variable amounts of mixing during pulsational rebound and variable amounts of (56)Ni production during the early subsonic phase of expansion., Submitted to A&A, manuscript includes response to referee's comments. 39 pages, including 16 figures, 9 tables

We present extensive multi-wavelength observations of the extremely rapidly declining Type Ic supernova, SN 2005ek. Reaching a peak magnitude of M_R = -17.3 and decaying by ~3 mag in the first 15 days post-maximum, SN 2005ek is among the fastest Type I supernovae observed to date. The spectra of SN 2005ek closely resemble those of normal SN Ic, but with an accelerated evolution. There is evidence for the onset of nebular features at only nine days post-maximum. Spectroscopic modeling reveals an ejecta mass of ~0.3 Msun that is dominated by oxygen (~80%), while the pseudo-bolometric light curve is consistent with an explosion powered by ~0.03 Msun of radioactive Ni-56. Although previous rapidly evolving events (e.g., SN 1885A, SN 1939B, SN 2002bj, SN 2010X) were hypothesized to be produced by the detonation of a helium shell on a white dwarf, oxygen-dominated ejecta are difficult to reconcile with this proposed mechanism. We find that the properties of SN 2005ek are consistent with either the edge-lit double detonation of a low-mass white dwarf or the iron-core collapse of a massive star, stripped by binary interaction. However, if we assume that the strong spectroscopic similarity of SN 2005ek to other SN Ic is an indication of a similar progenitor channel, then a white-dwarf progenitor becomes very improbable. SN 2005ek may be one of the lowest mass stripped-envelope core-collapse explosions ever observed. We find that the rate of such rapidly declining Type I events is at least 1-3% of the normal SN Ia rate., Comment: Accepted for publication in ApJ. Please visit http://www.cfa.harvard.edu/~mdrout to hear a sonification of SN2005ek

We use measurements from the South Pole Telescope (SPT) Sunyaev-Zel'dovich (SZ) cluster survey in combination with X-ray measurements to constrain cosmological parameters. We present a statistical method that fits for the scaling relations of the SZ and X-ray cluster observables with mass while jointly fitting for cosmology. The method is generalizable to multiple cluster observables, and self-consistently accounts for the effects of the cluster selection and uncertainties in cluster mass calibration on the derived cosmological constraints. We apply this method to a data set consisting of an SZ-selected catalog of 18 galaxy clusters at z > 0.3 from the first 178 deg^2 of the 2500 deg^2 SPT-SZ survey, with 14 clusters having X-ray observations from either Chandra or XMM-Newton. Assuming a spatially flat ΛCDM cosmological model, we find the SPT cluster sample constrains σ_8(Ω_m /0.25)^(0.30) = 0.785 ± 0.037. In combination with measurements of the cosmic microwave background (CMB) power spectrum from the SPT and the seven-year Wilkinson Microwave Anisotropy Probe data, the SPT cluster sample constrains σ_8 = 0.795 ± 0.016 and Ω_m = 0.255 ± 0.016, a factor of 1.5 improvement on each parameter over the CMB data alone. We consider several extensions beyond the ΛCDM model by including the following as free parameters: the dark energy equation of state (w), the sum of the neutrino masses (Σm ν), the effective number of relativistic species (N_(eff)), and a primordial non-Gaussianity (f_(NL)). We find that adding the SPT cluster data significantly improves the constraints on w and Σm_ν beyond those found when using measurements of the CMB, supernovae, baryon acoustic oscillations, and the Hubble constant. Considering each extension independently, we best constrain w = –0.973 ± 0.063 and the sum of neutrino masses Σm_ν < 0.28 eV at 95% confidence, a factor of 1.25 and 1.4 improvement, respectively, over the constraints without clusters. Assuming a ΛCDM model with a free N_(eff) and Σm_ν, we measure N_(eff) = 3.91 ± 0.42 and constrain Σm_ν < 0.63 eV at 95% confidence. We also use the SPT cluster sample to constrain f_(NL) = –220 ± 317, consistent with zero primordial non-Gaussianity. Finally, we discuss the current systematic limitations due to the cluster mass calibration, and future improvements for the recently completed 2500 deg^2 SPT-SZ survey. The survey has detected ~500 clusters with a median redshift of ~0.5 and a median mass of ~2.3 × 10^(14) M_☉ h^(–1) and, when combined with an improved cluster mass calibration and existing external cosmological data sets will significantly improve constraints on w.

The galaxy cluster SPT-CL J0205-5829 currently has the highest spectroscopically-confirmed redshift, z=1.322, in the South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) survey. XMM-Newton observations measure a core-excluded temperature of Tx=8.7keV producing a mass estimate that is consistent with the Sunyaev-Zel'dovich derived mass. The combined SZ and X-ray mass estimate of M500=(4.9+/-0.8)e14 h_{70}^{-1} Msun makes it the most massive known SZ-selected galaxy cluster at z>1.2 and the second most massive at z>1. Using optical and infrared observations, we find that the brightest galaxies in SPT-CL J0205-5829 are already well evolved by the time the universe was 3 Gyr, and low rates of star formation (, 11 pages, 5 figures, submitted to ApJ

Introduction Aortic stenosis (AS) results in left ventricular hypertrophy, myocyte dysfunction and fibrosis as a physiological response to excessive afterload. Transcatheter Aortic Valve implantation (TAVI) is an effective treatment for severe AS, however controversy exists whether gender predisposes to improved myocardial function post procedure. Feature-tracking cardiovascular magnetic resonance (FT-CMR) is a novel method for quantification of myocardial strain and strain rate that can identify subtle changes in left ventricular (LV) mechanics prior to overt changes in LV ejection fraction (EF). Our aim was to compare the acute impact of TAVI on LV function between males and females defined by strain measurements. Methods 59 patients, 34 males and 25 females matched for age (78.4 ± 7.19 years vs 78.8 ± 9.7 years p = 0.876), EuroSCORE II (5.19 ± 4.33% vs 4.26 ± 2.99% p = 0.788) and presence of baseline myocardial fibrosis (p = 0.829) with severe, symptomatic AS were prospectively enrolled prior to TAVI. All patients underwent an identical 1.5T CMR protocol (Intera or Ingenia, Phillips Healthcare, Best, The Netherlands) at baseline and at a median of 4 days following TAVI. Endocardial and epicardial borders were traced manually on the end-diastolic slice, then strain and strain rate measurements were obtained using commercially available post-processing software (CVI42, Circle Cardiovascular Imaging, Calgary, Alberta, Canada). Results TAVI was associated with a significant and comparable reduction in peak aortic pressure gradient and LV mass index in both men and women (Table 1). There was no significant difference in extent of pressure drop (p = 0.374) or extent of regression of LV mass index (p = 0.095) between men and women. There was no significant change in left ventricular end diastolic volume indexed (LVEDVI) or LVEF observed acutely following TAVI, in men or women (Table 1). Longitudinal strain (Ell), circumferential strain (Ecc) and circumferential strain rate (SRcc) did not change significantly in men or women (Table 2). However, TAVI was associated with a significant increase in longitudinal strain rate (SRll) in males (p = 0.012) that was not observed in females (p = 0.184) (Table 2). Conclusion TAVI was associated with structural reverse remodelling that was comparable between males and females. Functional recovery in LV mechanics following TAVI may occur earlier in males than in females, although this may reflect the higher LVMI that men have at baseline prior to TAVI.

Introduction Left ventricular end-diastolic filling pressure (LVEDP) is an invasive measure of LV function obtained at cardiac catheterisation (CC) that predicts prognosis and guides therapeutic strategy. Echocardiographic E/E’ ratio has been shown to be inaccurate for estimation of LVEDP. Feature-tracking cardiovascular magnetic resonance (FT-CMR) is a novel method for quantification of myocardial deformation and can be used to quantitatively assess left atrial (LA) function. Currently there is no validated MRI parameter that estimates LVEDP. We hypothesised that LA strain correlates to LVEDP. Methods 14 patients in sinus rhythm, with severe AS underwent a 1.5T CMR protocol (Ingenia, Phillips Healthcare, Best, The Netherlands). LVEDP was recorded at the time of CC by standard techniques. 4 chamber and mid ventricular short axis steady state free procession cine images were obtained: LA endocardial and epicardial borders were traced manually on the end-diastolic slice and strain measurements were calculated using commercially available post-processing software (CVI42, Circle Cardiovascular Imaging, Calgary, Alberta, Canada). Results Patients were divided into 2 groups: low EDP (13 ± 2.4mmHg) and high EDP (36.1 ± 3.4mmHg) (p Conclusion LA function (PALS) as measured by FT-CMR is independently associated with LVEDP and may have a role in predicting LV filling pressures via a routine CMR protocol.

Objectives Chronic myocardial infarction (MI) detected by late gadolinium enhancement (LGE) is associated with significant mortality and morbidity. Limited subendocardial infarction may not lead to reduction in ejection fraction (EF) and a regional wall motion abnormality (RWMA) may not be evident. Global longitudinal strain (GLS) is impaired independently of EF in a number of conditions, enabling early detection of disease. Strain imaging predicts final infarct size in MI and is superior to LVEF in predicting morbidity and mortality. We hypothesised subjects with chronic MI but normal EF would have impaired GLS compared to healthy volunteers. Methods Twenty patients with chronic MI (defined as subendocardial hyperenhancement on LGE) and normal LVEF and 20 healthy volunteers underwent CMR at either 1.5T or 3.0T (Philips Achieva TX). Standard bSSFP cine images were used to calculate LV dimensions and GLS by feature tracking (CVI 42, Circle Cardiovascular Imaging Calgary, Canada). LGE imaging was performed in all patients (0.2mmol/kg Gadolinium DTPA). Results Patients were matched for age (59.8 ± 12 vs 59.6 ± 5.4 p = 0.95) and EF (60.4 ± 3.8 vs 62.2 ± 3.5 p = 0.11). Visual evidence of RWMA was present in 13/20 (65%) of chronic MI patients and 0/20 healthy volunteers. GLS was significantly lower in patients with chronic MI than in those without (−16.07 ± 3.9 vs −19.79 ± 2.3 p = 0.001) (Figure 1). Conclusion GLS is impaired in patients with chronic MI but normal LVEF. GLS identifies abnormalities in LV systolic contraction not apparent with EF alone. It may reveal chronic MI in patients with contraindications to gadolinium-based contrast or prognostication of this subset of chronic MI patients. GLS could be used to detect chronic MI by alternative imaging modalities.

Objectives Rheumatoid arthritis (RA) is associated with increased cardiovascular mortality. Proposed mechanisms include coronary microvascular dysfunction due to immune dysregulation and systemic inflammation. First pass myocardial perfusion CMR allows quantification of myocardial blood flow (MBF) and myocardial perfusion reserve (MPR). In the absence of coronary artery disease (CAD), reduced MPR represents coronary microvascular dysfunction. We hypothesised MPR would be reduced in RA and that abnormalities in left ventricular (LV) deformation would be evident in RA, as LV mass has been reported to be reduced in established disease. Methods Twelve patients with newly diagnosed, treatment naive RA and 12 healthy volunteers (HV) underwent CMR at 3.0T (Phillips Achieva TX). Both groups had no history of CAD. Dual bolus resting and stress perfusion imaging was performed (0.1mmol/kg Gadolinium DTPA) and MBF estimated for the mid ventricular slice using Fermi constrained convolution (PMI v 0.4 [Sourbron, 2009]). Left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) by feature tracking were calculated using bSSFP images (CVI 42 , Circle Cardiovascular Imaging, Calgary, Canada). Results Mean age of RA patients was 48 ± 16 and mean age of HV 47 ± 14. Of the RA patients, 4 were male and 8 female. Of the HV, 2 were male and 10 female. Mean MPR values were 1.98 ± 0.79 and 1.99 ± 0.72 (P = 0.88) for RA and HV respectively (Figure 1). Mean values for LVEF were 63 ± 4 and 62 ± 4% (P = 0.48) respectively for RA patients and HV. Mean values for GLS were −20.2 and −21 ± 0.4 (P = 0.396) for RA and HV respectively. Conclusion These findings suggest treatment naive RA patients have no detectable abnormalities on perfusion CMR. Therefore, whilst present in established RA, coronary microvascular dysfunction may not yet have developed in early RA. No abnormalities of LV systolic function were evident and may be a later manifestation of RA.

We report the first investigation of cool-core properties of galaxy clusters selected via their Sunyaev--Zel'dovich (SZ) effect. We use 13 galaxy clusters uniformly selected from 178 deg^2 observed with the South Pole Telescope (SPT) and followed up by the Chandra X-ray Observatory. They form an approximately mass-limited sample (> 3 x 10^14 M_sun h^-1_70) spanning redshifts 0.3 < z < 1.1. Using previously published X-ray-selected cluster samples, we compare two proxies of cool-core strength: surface brightness concentration (cSB) and cuspiness (��). We find that cSB is better constrained. We measure cSB for the SPT sample and find several new z > 0.5 cool-core clusters, including two strong cool cores. This rules out the hypothesis that there are no z > 0.5 clusters that qualify as strong cool cores at the 5.4�� level. The fraction of strong cool-core clusters in the SPT sample in this redshift regime is between 7% and 56% (95% confidence). Although the SPT selection function is significantly different from the X-ray samples, the high-z cSB distribution for the SPT sample is statistically consistent with that of X-ray-selected samples at both low and high redshifts. The cool-core strength is inversely correlated with the offset between the brightest cluster galaxy and the X-ray centroid, providing evidence that the dynamical state affects the cool-core strength of the cluster. Larger SZ-selected samples will be crucial in understanding the evolution of cluster cool cores over cosmic time., 9 pages, 5 figures. Version as published in December 20th, 2012 issue of ApJ

We present a catalog of 224 galaxy cluster candidates, selected through their Sunyaev-Zel'dovich (SZ) effect signature in the first 720 deg2 of the South Pole Telescope (SPT) survey. This area was mapped with the SPT in the 2008 and 2009 austral winters to a depth of 18 uK-arcmin at 150 GHz; 550 deg2 of it was also mapped to 44 uK-arcmin at 95 GHz. Based on optical imaging of all candidates and near-infrared imaging of the majority of candidates, we have found optical and/or infrared counterparts for 158 clusters. Of these, 135 were first identified as clusters in SPT data, including 117 new discoveries reported in this work. This catalog triples the number of confirmed galaxy clusters discovered through the SZ effect. We report photometrically derived (and in some cases spectroscopic) redshifts for confirmed clusters and redshift lower limits for the remaining candidates. The catalog extends to high redshift with a median redshift of z = 0.55 and maximum redshift of z = 1.37. Based on simulations, we expect the catalog to be nearly 100% complete above M500 ~ 5e14 Msun h_{70}^-1 at z > 0.6. There are 121 candidates detected at signal-to-noise greater than five, at which the catalog purity is measured to be 95%. From this high-purity subsample, we exclude the z < 0.3 clusters and use the remaining 100 candidates to improve cosmological constraints following the method presented by Benson et al., 2011. Adding the cluster data to CMB+BAO+H0 data leads to a preference for non-zero neutrino masses while only slightly reducing the upper limit on the sum of neutrino masses to sum mnu < 0.38 eV (95% CL). For a spatially flat wCDM cosmological model, the addition of this catalog to the CMB+BAO+H0+SNe results yields sigma8=0.807+-0.027 and w = -1.010+-0.058, improving the constraints on these parameters by a factor of 1.4 and 1.3, respectively. [abbrev], 22 pages, 7 figures, submitted to ApJ

We present the results of the ground- and space-based optical and near-infrared (NIR) follow-up of 224 galaxy cluster candidates detected with the Sunyaev-Zel'dovich (SZ) effect in the 720 deg^2 of the South Pole Telescope (SPT) survey completed in the 2008 and 2009 observing seasons. We use the optical/NIR data to establish whether each candidate is associated with an overdensity of galaxies and to estimate the cluster redshift. Most photometric redshifts are derived through a combination of three different cluster redshift estimators using red-sequence galaxies, resulting in an accuracy of ��z/(1+z)=0.017, determined through comparison with a subsample of 57 clusters for which we have spectroscopic redshifts. We successfully measure redshifts for 158 systems and present redshift lower limits for the remaining candidates. The redshift distribution of the confirmed clusters extends to z=1.35 with a median of z_{med}=0.57. Approximately 18% of the sample with measured redshifts lies at z>0.8. We estimate a lower limit to the purity of this SPT SZ-selected sample by assuming that all unconfirmed clusters are noise fluctuations in the SPT data. We show that the cumulative purity at detection significance ��>5 (��>4.5) is >= 95 (>= 70%). We present the red brightest cluster galaxy (rBCG) positions for the sample and examine the offsets between the SPT candidate position and the rBCG. The radial distribution of offsets is similar to that seen in X-ray-selected cluster samples, providing no evidence that SZ-selected cluster samples include a different fraction of recent mergers than X-ray-selected cluster samples., 22 pages, 7 figures, 1 multi-page table at the end of the article

We use weak gravitational lensing to measure the masses of five galaxy clusters selected from the South Pole Telescope (SPT) survey, with the primary goal of comparing these with the SPT Sunyaev--Zel'dovich (SZ) and X-ray based mass estimates. The clusters span redshifts 0.28 < z < 0.43 and have masses M_500 > 2 x 10^14 h^-1 M_sun, and three of the five clusters were discovered by the SPT survey. We observed the clusters in the g'r'i' passbands with the Megacam imager on the Magellan Clay 6.5m telescope. We measure a mean ratio of weak lensing (WL) aperture masses to inferred aperture masses from the SZ data, both within an aperture of R_500,SZ derived from the SZ mass, of 1.04 +/- 0.18. We measure a mean ratio of spherical WL masses evaluated at R_500,SZ to spherical SZ masses of 1.07 +/- 0.18, and a mean ratio of spherical WL masses evaluated at R_500,WL to spherical SZ masses of 1.10 +/- 0.24. We explore potential sources of systematic error in the mass comparisons and conclude that all are subdominant to the statistical uncertainty, with dominant terms being cluster concentration uncertainty and N-body simulation calibration bias. Expanding the sample of SPT clusters with WL observations has the potential to significantly improve the SPT cluster mass calibration and the resulting cosmological constraints from the SPT cluster survey. These are the first WL detections using Megacam on the Magellan Clay telescope., Main body: 18 pages, 7 figures, 6 tables. Appendix: 6 pages, 10 figures. Accepted by ApJ. New version incorporates changes from accepted article

The South Pole Telescope (SPT) is a 10 meter telescope operating at mm wavelengths. It has recently completed a three-band survey covering 2500 sq. degrees. One of the survey's main goals is to detect galaxy clusters using Sunyaev-Zeldovich effect and use these clusters for a variety of cosmological and astrophysical studies such as the dark energy equation of state, the primordial non-gaussianity and the evolution of galaxy populations. Since 2005, we have been engaged in a comprehensive optical and near-infrared followup program (at wavelengths between 0.4 and 5 {\mu}m) to image high-significance SPT clusters, to measure their photometric redshifts, and to estimate the contamination rate of the candidate lists. These clusters are then used for various cosmological and astrophysical studies., Comment: For TAUP 2011 proceedings

We present results of X-ray observations of a sample of 15 clusters selected via their imprint on the cosmic microwave background from the thermal Sunyaev-Zel'dovich (SZ) effect. These clusters are a subset of the first SZ-selected cluster catalog, obtained from observations of 178 deg^2 of sky surveyed by the South Pole Telescope (SPT). Using X-ray observations with Chandra and XMM-Newton, we estimate the temperature, T_X, and mass, M_g, of the intracluster medium within r_500 for each cluster. From these, we calculate Y_X = M_(g)T_X and estimate the total cluster mass using an M_(500)-Y_X scaling relation measured from previous X-ray studies. The integrated Comptonization, Y SZ, is derived from the SZ measurements, using additional information from the X-ray-measured gas density profiles and a universal temperature profile. We calculate scaling relations between the X-ray and SZ observables and find results generally consistent with other measurements and the expectations from simple self-similar behavior. Specifically, we fit a Y_(SZ)-Y_X relation and find a normalization of 0.82 ± 0.07, marginally consistent with the predicted ratio of Y_(SZ)/Y_X = 0.91 ± 0.01 that would be expected from the density and temperature models used in this work. Using the Y_X-derived mass estimates, we fit a Y_(SZ)-M_500 relation and find a slope consistent with the self-similar expectation of Y_(SZ) ∝ M^(5/3) with a normalization consistent with predictions from other X-ray studies. We find that the SZ mass estimates, derived from cosmological simulations of the SPT survey, are lower by a factor of 0.78 ± 0.06 relative to the X-ray mass estimates. This offset is at a level of 1.3σ when considering the ~15% systematic uncertainty for the simulation-based SZ masses. Overall, the X-ray measurements confirm that the scaling relations of the SZ-selected clusters are consistent with the properties of other X-ray-selected samples of massive clusters, even allowing for the broad redshift range (0.29 < z < 1.08) of the sample.

Gamma-ray bursts (GRBs) serve as powerful probes of the early Universe, with their luminous afterglows revealing the locations and physical properties of star forming galaxies at the highest redshifts, and potentially locating first generation (Population III) stars. Since GRB afterglows have intrinsically very simple spectra, they allow robust redshifts from low signal to noise spectroscopy, or photometry. Here we present a photometric redshift of z~9.4 for the Swift-detected GRB 090429B based on deep observations with Gemini-North, the Very Large Telescope, and the GRB Optical and Near-infrared Detector. Assuming a Small Magellanic Cloud dust law (which has been found in a majority of GRB sight-lines), the 90% likelihood range for the redshift is 9.06 < z < 9.52, although there is a low-probability tail to somewhat lower redshifts. Adopting Milky Way or Large Magellanic Cloud dust laws leads to very similar conclusions, while a Maiolino law does allow somewhat lower redshift solutions, but in all cases the most likely redshift is found to be z>7. The non-detection of the host galaxy to deep limits (Y_AB >~ 28 mag, which would correspond roughly to 0.001 L* at z=1) in our late time optical and infrared observations with the Hubble Space Telescope strongly supports the extreme redshift origin of GRB 090429B, since we would expect to have detected any low-z galaxy, even if it were highly dusty. Finally, the energetics of GRB 090429B are comparable to those of other GRBs, and suggest that its progenitor is not greatly different to those of lower redshift bursts., Accepted for publication on The Astrophysical Journal

We report the discovery of a supernova (SN) with the highest apparent energy output to date and conclude that it represents an extreme example of the Type IIn subclass. The SN, which was discovered behind the Large Magellanic Cloud at z = 0.289 by the SuperMACHO microlensing survey, peaked at M_R = -21.5 mag and only declined by 2.9 mag over 4.7 years after the peak. Over this period, SN 2003ma had an integrated bolometric luminosity of 4 x 10^51 ergs, more than any other SN to date. The radiated energy is close to the limit allowed by conventional core-collapse explosions. Optical spectra reveal that SN 2003ma has persistent single-peaked intermediate-width hydrogen lines, a signature of interaction between the SN and a dense circumstellar medium. The light curves show further evidence for circumstellar interaction, including a long plateau with a shape very similar to the classic SN IIn 1988Z -- however, SN 2003ma is ten times more luminous at all epochs. The fast velocity measured for the intermediate-width H_alpha component (~6000 km/s) points towards an extremely energetic explosion (> 10^52 ergs), which imparts a faster blast-wave speed to the post-shock material and a higher luminosity from the interaction than is observed in typical SNe IIn. Mid-infrared observations of SN 2003ma suggest an infrared light echo is produced by normal interstellar dust at a distance ~0.5 pc from the SN., 21 pages, 15 figures, accepted for publication in ApJ

Long-duration gamma-ray bursts (GRBs) are thought to result from the explosions of certain massive stars, and some are bright enough that they should be observable out to redshifts of z > 20 using current technology. Hitherto, the highest redshift measured for any object was z = 6.96, for a Lyman-alpha emitting galaxy. Here we report that GRB 090423 lies at a redshift of z approximately 8.2, implying that massive stars were being produced and dying as GRBs approximately 630 Myr after the Big Bang. The burst also pinpoints the location of its host galaxy.

The bright Type II-plateau supernova (SN) 2004dj occurred within the young, massive stellar cluster Sandage-96 in a spiral arm of NGC 2403. New multi-wavelength observations obtained with several ground-based and space-based telescopes are combined to study the radiation from Sandage-96 after SN 2004dj faded away. Sandage-96 started to dominate the flux in the optical bands starting September 2006 (~800 d after explosion). The optical fluxes are equal to the pre-explosion ones within the observational uncertainties. An optical Keck spectrum obtained ~900 d after explosion shows the dominant blue continuum from the cluster stars shortward of 6000 ��as well as strong SN nebular emission lines redward. The integrated spectral energy distribution (SED) of the cluster has been extended into the ultraviolet region by archival XMM-Newton and new Swift observations, and compared with theoretical models. The outer parts of the cluster have been resolved by the Hubble Space Telescope, allowing the construction of a color-magnitude diagram. The fitting of the cluster SED with theoretical isochrones results in cluster ages between 10--40 Myr, depending on metallicity and the model family. The isochrone fitting indicates that the resolved part of the cluster has a bimodal age distribution: a younger population at ~10--16 Myr, and an older one at ~32--100 Myr which is similar to the age distribution of the nearby field stars. These stars may have been captured from the field during the cluster formation. The young age of Sandage-96 suggest 12 < M_prog < 20 M_\odot as the most probable mass range for the progenitor of SN 2004dj. This is consistent with, but perhaps slightly higher than, most of the other Type II-plateau SN progenitor masses determined so far., accepted in ApJ

The first gamma-ray burst (GRB) confirmed to be bright enough to be seen with the naked eye, GRB 080319B at redshift z = 0.937, allowed for exquisite follow-up observations across the electromagnetic spectrum. We present our detailed optical and infrared observations of the afterglow, consisting of over 5000 images starting 51 s after the GRB trigger, in concert with our own analysis of the Swift data. The event is extreme not only in observed properties but intrinsically: it was the most luminous event ever recorded at optical and infrared wavelengths and had an exceedingly high isotropic-equivalent energy release in gamma-rays. At early times, the afterglow evolution is broadly consistent with being reverse-shock dominated, but then is subsumed by a forward shock at around 1000 s. The overall spectral energy distribution, spanning from ultraviolet through near-infrared wavelengths, shows no evidence for a significant amount of dust extinction in the host frame. The afterglow evolution, however, is highly chromatic: starting at about 1000 s the index shifts blueward before shifting back to the red at late times. In our deepest late-time observations, we find tentative evidence for an optical jet break and a luminous supernova. Finally, we examine the detectability of such events with current and future facilities and find that such an event could be detected in gamma-rays by BAT out to z = 10.7 (8 sigma), while the nominal EXIST sensitivity would allow detection to z ~ 32. At K band, this source would have been easily detected with meter-class telescopes to z ~ 17., Comment: Accepted to ApJ (18 Sept 2008), 45 pages, 9 figures. Updated following referee comments. Added photometry from early-time (saturated) IR imaging starting at 51 s post trigger. A full machine-readable table of all photometry used in our plots, figures, and analysis is given at http://astro.berkeley.edu/~dperley/grbpub/080319b/photometry.txt

We present optical and infrared observations of the unusual Type Ia supernova (SN) 2004eo. The light curves and spectra closely resemble those of the prototypical SN 1992A, and the luminosity at maximum (M_B = -19.08) is close to the average for a SN Ia. However, the ejected 56Ni mass derived by modelling the bolometric light curve (about 0.45 solar masses) lies near the lower limit of the 56Ni mass distribution observed in normal SNe Ia. Accordingly, SN 2004eo shows a relatively rapid post-maximum decline in the light curve (Delta m_(B) = 1.46), small expansion velocities in the ejecta, and a depth ratio Si II 5972 / Si II 6355 similar to that of SN 1992A. The physical properties of SN 2004eo cause it to fall very close to the boundary between the faint, low velocity gradient, and high velocity gradient subgroups proposed by Benetti et al. (2005). Similar behaviour is seen in a few other SNe Ia. Thus, there may in fact exist a few SNe Ia with intermediate physical properties., Comment: 28 pages, 17 figures, accepted for publication in MNRAS

We present VRIJHK photometry, and optical and near-infrared spectroscopy, of the heavily extinguished Type Ia supernova (SN) 2002cv, located in NGC 3190, which is also the parent galaxy of the Type Ia SN 2002bo. SN 2002cv, not visible in the blue, has a total visual extinction of 8.74 +- 0.21 mag. In spite of this we were able to obtain the light curves between -10 and +207 days from the maximum in the I band, and also to follow the spectral evolution, deriving its key parameters. We found the peak I-band brightness to be Imax = 16.57 +- 0.10 mag, the maximum absolute I magnitude to be MmaxI = -18.79 +- 0.20, and the parameter dm15(B) specifying the width of the B-band light curve to be 1.46 +- 0.17 mag. The latter was derived using the relations between this parameter and dm40(I) and the time interval dtmax(I) between the two maxima in the I-band light curve. As has been found for previously observed, highly extinguished SNe Ia, a small value of 1.59 +- 0.07 was obtained here for the ratio Rv of the total-to-selective extinction ratio for SN 2002cv, which implies a small mean size for the grains along the line of sight toward us. Since it was found for SN 2002bo a canonical value of 3.1, here we present a clear evidence of different dust properties inside NGC 3190., Comment: 18 pages, 18 figures. Accepted for publication in MNRAS. Added co-authors

The nebular spectra of the broad-lined, SN 1998bw-like Type Ic SN 2002ap are studied by means of synthetic spectra. Two different modelling techniques are employed. In one technique, the SN ejecta are treated as a single zone, while in the other a density and abundance distribution in velocity is used from an explosion model. In both cases, heating caused by gamma-ray and positron deposition is computed (in the latter case using a Monte Carlo technique to describe the propagation of gamma-rays and positrons), as is cooling via forbidden-line emission. The results are compared, and although general agreement is found, the stratified models are shown to reproduce the observed line profiles much more accurately than the single-zone model. The explosion produced ~ 0.1 Msun of 56Ni. The distribution in velocity of the various elements is in agreement with that obtained from the early-time models, which indicated an ejected mass of ~ 2.5 Msun with a kinetic energy of 4 x 10^{51} erg. Nebular spectroscopy confirms that most of the ejected mass (~ 1.2 Msun) was oxygen. The presence of an oxygen-rich inner core, combined with that of 56Ni at high velocities as deduced from early-time models, suggests that the explosion was asymmetric, especially in the inner part., Comment: 24 pages, 6 figures, 2 Tables. Accepted by the Astrophysical Journal

Introduction Refractory angina describes those patients with persistence of symptoms despite revascularisation and routine pharmacotherapy with β-blockers, calcium channel antagonists and nitrates. Ranolazine offers adjunct therapy in such cohorts, by providing anti-ischaemic effects complementary to existing agents. It is thought to be well-tolerated, without significant effects on haemodynamic parameters including heart rate and blood pressure. This prospective study aimed to establish the short-term effectiveness and safety profile of ranolazine in patients with refractory angina. Methods Bradford Royal Infirmary has a specialised cardiology service to manage refractory angina (BRAS). From their database, 50 consecutive patients were selected for inclusion between May 2013 and February 2014. All patients were commenced on ranolazine 375 mg twice daily at initial review, and therapy was continued for 1 month. Those who required up-titration of anti-anginals or revascularisation on clinical grounds were excluded from the study. Results of 6 min walks, Canadian Cardiovascular Society (CCS) grading of angina severity and QTc interval on resting ECG was tabulated, both pre-intervention and at 1 month. Wilcoxon signed rank sum testing was applied to measure differences in outcome. Patients were surveyed to assess for tolerability and adverse events. Results 45 patients were eligible for inclusion. 87% (39/45) were male, with a mean age of 65.2 years (SD 12.3). At 1 month, there was a median increase in 6 min walk of 30 metres (95% CI: 25 – 60; p = 0.0002). CCS grading class for angina severity reduced by 0.5 (95% CI: 0 – 0.86; p Conclusions These findings suggest that ranolazine offers effective additive therapy in patients with persistent anginal symptoms who have been otherwise optimised. Despite our small sample size, results demonstrated a statistically significant improvement in performance on 6 min walk, CCS grading score and usage of GTN spray. Overall, ranolazine was well-tolerated without QTc prolongation or overt side-effects. Further studies are indicated to establish whether effects are maintained in the longer term.

We present Hubble Space Telescope (HST) rest-frame ultraviolet imaging of the host galaxies of 16 hydrogen-poor superluminous supernovae (SLSNe), including 11 events from the Pan-STARRS Medium Deep Survey. Taking advantage of the superb angular resolution of HST, we characterize the galaxies' morphological properties, sizes and star formation rate (SFR) densities. We determine the supernova (SN) locations within the host galaxies through precise astrometric matching, and measure physical and host-normalized offsets, as well as the SN positions within the cumulative distribution of UV light pixel brightness. We find that the host galaxies of H-poor SLSNe are irregular, compact dwarf galaxies, with a median half-light radius of just 0.9 kpc. The UV-derived SFR densities are high ( ~ 0.1 M_sun/yr/kpc^2), suggesting that SLSNe form in overdense environments. Their locations trace the UV light of their host galaxies, with a distribution intermediate between that of long-duration gamma-ray bursts (LGRBs) (which are strongly clustered on the brightest regions of their hosts) and a uniform distribution (characteristic of normal core-collapse SNe), though cannot be statistically distinguished from either with the current sample size. Taken together, this strengthens the picture that SLSN progenitors require different conditions than those of ordinary core-collapse SNe to form, and that they explode in broadly similar galaxies as do LGRBs. If the tendency for SLSNe to be less clustered on the brightest regions than are LGRBs is confirmed by a larger sample, this would indicate a different, potentially lower-mass progenitor for SLSNe than LRGBs., Comment: ApJ in press; matches published version. Minor changes following referee's comments; conclusions unchanged

Background LA function is conventionally assessed by bi-plane method to compute LA end diastolic volume (LAEDV), end systolic volume (LAESV), stroke volume (LA SV), ejection fraction (LA EF). Voxel feature tracking (FT) is a novel technique for the assessment of LA function. We aimed to investigate if voxel FT derived longitudinal or radial strains are superior to traditionally derived parameters of LA function (LA SV and LA EF) in predicting LV function. Methods Twelve-patients underwent CMR at 3T (Achieva CV, Philips Healthcare, Best, The Netherlands) within 3 days following AMI. CMR protocol included: cines and late gadolinium enhancement (LGE) imaging (0.1 mmol/kg gadolinium DTPA). Indexed LAEDV (LAEDVi), end-systolic volume (LAESVi) and ejection fraction were computed by bi-plane method. Voxel FT for the LA in the long axis 4-chamber cines was analysed offline using commercially available software (cvi42 v5.1, Circle Cardiovascular Imaging Inc., Calgary, Canada). Results Demographics and basic CMR parameters are mentioned in Table 1. Analysis time was longer for manual contouring and computation of LA EF and SV compared to 4-CH strain analysis (4 ± 2 min versus 2 ± 1.5 min, p = 0.01). On univariate analysis, LV EF was correlated to peak longitudinal strain (PLS) (p = 0.01) and peak radial strain (PRS) (p = 0.02). On multivariate regression analysis, PLS of LA was most strongly correlated to LV EF (R=0.68; p = 0.015). All other parameters did not achieve statistical significance. Conclusion Peak left atrial longitudinal strain (PLS) is the only parameter of LA function, which independently correlates to LV ejection fraction. PLS of the LA is easily assessed on 4-chamber cines alone and takes less time to compute than the manually generated parameters of LA function.

We report observations of GRB 050525A, for which a Gemini North spectrum shows its redshift to be z = 0.606. This is the third closest long GRB discovered by Swift. We observed its afterglow using the VLT, Gemini and TNG telescopes to search for an associated SN. We find that the early-time light curve is described by a broken power law with a break at t ~ 0.3 d after the burst. About 5 d after the burst, a flattening is apparent, followed by a further dimming. Both the magnitude and the shape of the light curve suggest that a supernova was emerging during the late decay of the afterglow. This supernova, dubbed SN 2005nc, had a rise time faster than SN 1998bw and a long-lasting maximum. A spectrum obtained about 20 d (rest-frame) after the GRB resembles the spectrum of SN 1998bw obtained close to maximum light., 5 pages, 4 ps figures. Accepted for publication in ApJ Letters

The localization of the short-duration, hard-spectrum GRB 050509b was a watershed event. Thanks to the nearly immediate relay of the GRB position by Swift, we began imaging the GRB field 8 minutes after the burst and continued for the following 8 days. No convincing optical/infrared candidate afterglow or supernova was found for the object. We present a re-analysis of the XRT afterglow and find an absolute position that is ~4" to the west of the XRT position reported previously. Close to this position is a bright elliptical galaxy with redshift z=0.2248, about 1' from the center of a rich cluster of galaxies. Based on positional coincidences, the GRB and the bright elliptical are likely to be physically related. We thus have discovered evidence that at least some short-duration, hard-spectra GRBs arise at cosmological distances. However, while GRB 050509b was underluminous compared to long-duration GRBs, we demonstrate that the ratio of the blast-wave energy to the gamma-ray energy is consistent with that of long-duration GRBs. Based on this analysis, on the location of the GRB (40 +- 13 kpc from a bright galaxy), on the galaxy type (elliptical), and the lack of a coincident supernova, we suggest that there is now observational consistency with the hypothesis that short-hard bursts arise during the merger of a compact binary. We limit the properties of a Li-Paczynski ''mini-supernova.'' Other progenitor models are still viable, and additional rapidly localized bursts from the Swift mission will undoubtedly help to further clarify the progenitor picture. (abridged), Comment: ApJ, in press. 35 pages, 9 figures

We present a catalog of galaxy clusters selected via their Sunyaev-Zel'dovich (SZ) effect signature from 2500 deg$^2$ of South Pole Telescope (SPT) data. This work represents the complete sample of clusters detected at high significance in the 2500-square-degree SPT-SZ survey, which was completed in 2011. A total of 677 (409) cluster candidates are identified above a signal-to-noise threshold of $��$ =4.5 (5.0). Ground- and space-based optical and near-infrared (NIR) imaging confirms overdensities of similarly colored galaxies in the direction of 516 (or 76%) of the $��$>4.5 candidates and 387 (or 95%) of the $��$>5 candidates; the measured purity is consistent with expectations from simulations. Of these confirmed clusters, 415 were first identified in SPT data, including 251 new discoveries reported in this work. We estimate photometric redshifts for all candidates with identified optical and/or NIR counterparts; we additionally report redshifts derived from spectroscopic observations for 141 of these systems. The mass threshold of the catalog is roughly independent of redshift above $z$~0.25 leading to a sample of massive clusters that extends to high redshift. The median mass of the sample is $M_{\scriptsize 500c}(��_\mathrm{crit})$ ~ 3.5 x 10$^{14} M_\odot h^{-1}$, the median redshift is $z_{med}$ =0.55, and the highest-redshift systems are at $z$>1.4. The combination of large redshift extent, clean selection, and high typical mass makes this cluster sample of particular interest for cosmological analyses and studies of cluster formation and evolution., Minor changes to match accepted version; Associated data products available at http://pole.uchicago.edu/public/data/sptsz-clusters/index.html

We present optical observations of the newly discovered accretion powered millisecond pulsar IGR J00291+5934, undertaken in the weeks following its outburst on 2 d December 2004. The decay to quiescence is seen to be highly variable with no indication of a modulation on the ∼2.46 hr orbital period apparent in the data, consistent with a system at low inclination. We also have a single Keck LRIS spectrum of the companion to IGR J00291+5934 taken 10 days after outburst. Strong hydrogen and helium emission lines are observed confirming the identity of the counterpart.

To evaluate the safety and cost effectiveness of laparoscopic cholecystectomy as a day case procedure.District hospital, England.103 patients undergoing laparoscopic cholecystectomy.Laparoscopic cholecystectomy by a standard four cannula technique. Propofol anaesthesia, prophylactic antiemetics and pre-emptive analgesia were given in all cases.Morbidity and cost.103 patients have undergone laparoscopic cholecystectomy, 51 of them as day cases. Patients were selected for day treatment if they were under 60 years old, they wanted to go home the same day, they had no history of jaundice or any anaesthetic contraindication, and if there was an adult at home to look after them. Three of those selected as day cases required overnight admission, one because of severe pain and two who required a drain overnight. The median hospital stay was 12 hours (range 10-28 hours) and the cost of the operation was about pounds 419.This is a safe and cost-effective procedure and should be considered in selected patients.

We present spectroscopic observations of GRB091127 (z=0.490) at the peak of the putative associated supernova, SN2009nz. Subtracting a late-time spectrum of the host galaxy, we isolate the contribution of SN2009nz and uncover broad features typical of nearby GRB-SNe. This establishes unambiguously that GRB091127 was accompanied by a broad-lined Type Ic SN, and links a cosmological long burst with a standard energy release (E_gamma,iso ~ 1.1e52 erg) to a massive star progenitor. The spectrum of SN2009nz closely resembles that of SN2006aj, with SN2003dh 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 SiII 6355 absorption feature, v_ph ~ 17,000 km/s, 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 explosion parameters: M_Ni ~ 0.35 M_sun, E_K ~ 2.3e51 erg, and M_ej ~ 1.4 M_sun, similar to those of SN2006aj. These properties indicate that SN2009nz follows a trend of lower M_Ni for GRB-SNe with lower E_K and M_ej. Equally important, since GRB091127 is a typical cosmological burst, the similarity of SN2009nz to SN2006aj either casts doubt on the claim that XRF060218/SN2006aj 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, including proper subtraction of the host galaxy contribution, 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., Submitted to ApJ; 11 pages; 2 tables; 4 figures; emulateapj style

Introduction Catheter ablation (CA) for atrial fibrillation (AF) is growing exponentially. Although ablation for paroxysmal AF (PAF) is associated with shorter procedure times and less extensive left atrial ablation vs persistent AF thromboembolic complications can occur in both sub-groups. Inadequate anticoagulation leads to thrombotic complications and excessive anticoagulation can lead to bleeding risks. Many centres adopt a policy of discontinuing warfarin in the immediate run-up to the procedure, covering the procedure with unfractionated heparin and “bridging” postoperative patients with low molecular weight heparins (LMWH) back onto warfarin. We wished to determine the safety of CA for AF with a therapeutic INR using both the single transseptal approach and duty cycled radiofrequency energy (RF) with non irrigated PVAC catheters and the double transseptal puncture technique using irrigated RF catheters and either CARTO or NAVX electroanatomical mapping. Methods A retrospective analysis of 173 patients who underwent CA for AF while taking uninterrupted warfarin. Procedural target International Normalised Ratio (INR) was 2–3 with a peri-procedural target ACT of 300–350 s. In sub therapeutic INR patients weight adjusted LMWH was used post procedure with warfarin until INR was >2. Standard technique employed was large area circumferential ablation using conventional RF energy or pulmonary vein isolation using duty cycled RF energy. Data was gathered for demographics, procedural INR, total dose of unfractionated heparin, fluoroscopy time, and type of radiofrequency energy used. Endpoints were minor bleeding, major bleeding (requiring transfusion), vascular complications, pericardial tamponade and stroke/TIA within 28 days of the procedure. Results There were 128/173 male patients, age range between 21 and 73 years (mean 57 years). 122 underwent ablation for PAF and 51 for persistent AF. Mean procedural INR was 2.4 (range 1.7–3.9). Mean unfractionated heparin dose was 6000 units (range 1000–14 500). Mean fluoroscopy time for the PVAC group was 23.4 mins (range 8.3–50.1 mins). Mean fluoroscopy time for CARTO/NAVX group was 31mins (range 14.10–58.44 mins). There were no major bleeding complications. There was 1 minor bleeding complication with a groin pseudoaneurysm. There were 2 cases of pericardial tamponade (2/173%–1.2%) both managed with percutaneous pericardial drainage. There were no stroke/TIAs. Conclusion These data demonstrate that CA for AF by both single and double transseptal technique using both standard RF and duty cycled RF while maintaining a therapeutic INR is a safe procedure. Maintaining a therapeutic INR reduces the risk of embolic events associated with “bridging” heparin without an increase in bleeding complications. This technique is convenient for patients and avoids switching between LMWH and warfarin and ensures patient safety by maintaining therapeutic anticoagulation before, during and after the procedure.

SN2009ku, discovered by Pan-STARRS-1, is a Type Ia supernova (SNIa), and a member of the distinct SN2002cx-like class of SNeIa. Its light curves are similar to the prototypical SN2002cx, but are slightly broader and have a later rise to maximum in g. SN2009ku is brighter (~0.6 mag) than other SN2002cx-like objects, peaking at M_V = -18.4 mag - which is still significantly fainter than typical SNeIa. SN2009ku, which had an ejecta velocity of ~2000 kms^-1 at 18 days after maximum brightness is spectroscopically most similar to SN2008ha, which also had extremely low-velocity ejecta. However, SN2008ha had an exceedingly low luminosity, peaking at M_V = -14.2 mag, ~4 mag fainter than SN2009ku. The contrast of high luminosity and low ejecta velocity for SN2009ku is contrary to an emerging trend seen for the SN2002cx class. SN2009ku is a counter-example of a previously held belief that the class was more homogeneous than typical SNeIa, indicating that the class has a diverse progenitor population and/or complicated explosion physics. As the first example of a member of this class of objects from the new generation of transient surveys, SN2009ku is an indication of the potential for these surveys to find rare and interesting objects., Comment: 7 pages, 3 figures