We present the discovery of ASASSN-18ey (MAXI J1820+070), a new black hole low-mass X-ray binary (LMXB) discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN). A week after ASAS-SN ...discovered ASASSN-18ey as an optical transient, it was detected as an X-ray transient by MAXI/GCS. Here, we analyze ASAS-SN and Asteroid Terrestrial-impact Last Alert System pre-outburst optical light curves, finding evidence of intrinsic variability for several years prior to the outburst. While there was no long-term rise leading to the outburst, as has been seen in several other systems, the start of the outburst in the optical preceded that in the X-rays by 7.20 0.97 days. We analyze the spectroscopic evolution of ASASSN-18ey from pre-maximum to >100 days post-maximum. The spectra of ASASSN-18ey exhibit broad, asymmetric, double-peaked H emission. The Bowen blend (λ 4650 ) in the post-maximum spectra shows highly variable double-peaked profiles, likely arising from irradiation of the companion by the accretion disk, typical of low-mass X-ray binaries. The optical and X-ray luminosities of ASASSN-18ey are consistent with black hole low-mass X-ray binaries, both in outburst and quiescence.
We present the fifth portion of an unbiased survey of the Galactic plane, |b| ≤ 2°, for 6668-MHz methanol masers. This section of the survey completes the Galactic longitude range visible to the ...Parkes radio telescope, incorporating the longitude range 20°–60°. Within this section of the survey we find 265 methanol masers, 64 new to the survey, bringing the total number of methanol masers detected across the full longitude coverage (186°, through 0°, to 60°) to 972 sources.
Entanglement--one of the most delicate phenomena in nature--is an essential resource for quantum information applications. Scalable photonic quantum devices must generate and control qubit ...entanglement on-chip, where quantum information is naturally encoded in photon path. Here we report a silicon photonic chip that uses resonant-enhanced photon-pair sources, spectral demultiplexers and reconfigurable optics to generate a path-entangled two-qubit state and analyse its entanglement. We show that ring-resonator-based spontaneous four-wave mixing photon-pair sources can be made highly indistinguishable and that their spectral correlations are small. We use on-chip frequency demultiplexers and reconfigurable optics to perform both quantum state tomography and the strict Bell-CHSH test, both of which confirm a high level of on-chip entanglement. This work demonstrates the integration of high-performance components that will be essential for building quantum devices and systems to harness photonic entanglement on the large scale.
ABSTRACT
We present observations of ASASSN-19dj, a nearby tidal disruption event (TDE) discovered in the post-starburst galaxy KUG 0810+227 by the All-Sky Automated Survey for Supernovae (ASAS-SN) at ...a distance of d ≃ 98 Mpc. We observed ASASSN-19dj from −21 to 392 d relative to peak ultraviolet (UV)/optical emission using high-cadence, multiwavelength spectroscopy and photometry. From the ASAS-SN g-band data, we determine that the TDE began to brighten on 2019 February 6.8 and for the first 16 d the rise was consistent with a flux ∝t2 power law. ASASSN-19dj peaked in the UV/optical on 2019 March 6.5 (MJD = 58548.5) at a bolometric luminosity of L = (6.2 ± 0.2) × 1044 erg s−1. Initially remaining roughly constant in X-rays and slowly fading in the UV/optical, the X-ray flux increased by over an order of magnitude ∼225 d after peak, resulting from the expansion of the X-ray emitting region. The late-time X-ray emission is well fitted by a blackbody with an effective radius of ∼1 × 1012 cm and a temperature of ∼6 × 105 K. The X-ray hardness ratio becomes softer after brightening and then returns to a harder state as the X-rays fade. Analysis of Catalina Real-Time Transient Survey images reveals a nuclear outburst roughly 14.5 yr earlier with a smooth decline and a luminosity of LV ≥ 1.4 × 1043 erg s−1, although the nature of the flare is unknown. ASASSN-19dj occurred in the most extreme post-starburst galaxy yet to host a TDE, with Lick HδA = 7.67 ± 0.17 Å.
We have conducted a Galactic plane survey of methanol masers at 6668 MHz using a seven-beam receiver on the Parkes telescope. Here we present results from the first part, which provides sensitive ...unbiased coverage of a large region around the Galactic Centre. Details are given for 183 methanol maser sites in the longitude range 345° through the Galactic Centre to 6°. Within 6° of the Galactic Centre, we found 88 maser sites, of which more than half (48) are new discoveries. The masers are confined to a narrow Galactic latitude range, indicative of many sources at the Galactic Centre distance and beyond, and confined to a thin disc population; there is no high-latitude population that might be ascribed to the Galactic bulge. Within 2° of the Galactic Centre the maser velocities all lie between −60 and +77 km s−1, a range much smaller than the 540 km s−1 range observed in CO. Elsewhere, the maser with highest positive velocity (+107 km s−1) occurs, surprisingly, near longitude 355° and is probably attributable to the Galactic bar. The maser with the most negative velocity (−127 km s−1) is near longitude 346°, within the longitude–velocity locus of the near side of the ‘3-kpc arm’. It has the most extreme velocity of a clear population of masers associated with the near and far sides of the 3-kpc arm. Closer to the Galactic Centre the maser space density is generally low, except within 0.25 kpc of the Galactic Centre itself, the ‘Galactic Centre zone’, where it is 50 times higher, which is hinted at by the longitude distribution, and confirmed by the unusual velocities.
Neoadjuvant anti-PD-1 may improve outcomes for patients with resectable NSCLC and provides a critical window for examining pathologic features associated with response. Resections showing major ...pathologic response to neoadjuvant therapy, defined as ≤10% residual viable tumor (RVT), may predict improved long-term patient outcome. However, %RVT calculations were developed in the context of chemotherapy (%cRVT). An immune-related %RVT (%irRVT) has yet to be developed.
The first trial of neoadjuvant anti-PD-1 (nivolumab, NCT02259621) was just reported. We analyzed hematoxylin and eosin-stained slides from the post-treatment resection specimens of the 20 patients with non-small-cell lung carcinoma who underwent definitive surgery. Pretreatment tumor biopsies and preresection radiographic ‘tumor’ measurements were also assessed.
We found that the regression bed (the area of immune-mediated tumor clearance) accounts for the previously noted discrepancy between CT imaging and pathologic assessment of residual tumor. The regression bed is characterized by (i) immune activation—dense tumor infiltrating lymphocytes with macrophages and tertiary lymphoid structures; (ii) massive tumor cell death—cholesterol clefts; and (iii) tissue repair—neovascularization and proliferative fibrosis (each feature enriched in major pathologic responders versus nonresponders, P<0.05). This distinct constellation of histologic findings was not identified in any pretreatment specimens. Histopathologic features of the regression bed were used to develop ‘Immune-Related Pathologic Response Criteria’ (irPRC), and these criteria were shown to be reproducible amongst pathologists. Specifically, %irRVT had improved interobserver consistency compared with %cRVT median per-case %RVT variability 5% (0%–29%) versus 10% (0%–58%), P=0.007 and a twofold decrease in median standard deviation across pathologists within a sample (4.6 versus 2.2, P=0.002).
irPRC may be used to standardize pathologic assessment of immunotherapeutic efficacy. Long-term follow-up is needed to determine irPRC reliability as a surrogate for recurrence-free and overall survival.
The 6-GHz multibeam maser survey – I. Techniques Green, J. A.; Caswell, J. L.; Fuller, G. A. ...
Monthly notices of the Royal Astronomical Society,
January 2009, Letnik:
392, Številka:
2
Journal Article
Recenzirano
Odprti dostop
A new seven-beam 6–7 GHz receiver has been built to survey the Galaxy and the Magellanic Clouds for newly forming high-mass stars that are pinpointed by strong methanol maser emission at 6668 MHz. ...The receiver was jointly constructed by Jodrell Bank Observatory (JBO) and the Australia Telescope National Facility (ATNF) and allows simultaneous coverage at 6668 and 6035 MHz. It was successfully commissioned at Parkes in 2006 January and is now being used to conduct the Parkes–Jodrell multibeam maser survey of the Milky Way. This will be the first systematic survey of the entire Galactic plane for masers of not only 6668-MHz methanol, but also 6035-MHz excited-state hydroxyl. The survey is two orders of magnitude faster than most previous systematic surveys and has an rms noise level of ∼0.17 Jy. This paper describes the observational strategy, techniques and reduction procedures of the Galactic and Magellanic Cloud surveys, together with deeper, pointed, follow-up observations and complementary observations with other instruments. It also includes an estimate of the survey detection efficiency. The 111 d of observations with the Parkes telescope have so far yielded >800 methanol sources, of which ∼350 are new discoveries. The whole project will provide the first comprehensive Galaxy-wide catalogue of 6668-MHz and 6035-MHz masers.
We present ground-based and Swift photometric and spectroscopic observations of the candidate tidal disruption event (TDE) ASASSN-14li, found at the centre of PGC 043234 (d ... 90 Mpc) by the All-Sky ...Automated Survey for SuperNovae (ASAS-SN). The source had a peak bolometric luminosity of ... and a total integrated energy of ... erg radiated over the ~6 months of observations presented. The UV/optical emission of the source is well fitted by a blackbody with roughly constant temperature of T ... 35,000 K, while the luminosity declines by roughly a factor of 16 over this time. The optical/UV luminosity decline is broadly consistent with an exponential decline, ..., with t0 ... 60 d. ASASSN-14li also exhibits soft X-ray emission comparable in luminosity to the optical and UV emission but declining at a slower rate, and the X-ray emission now dominates. Spectra of the source show broad Balmer and helium lines in emission as well as strong blue continuum emission at all epochs. We use the discoveries of ASASSN-14li and ASASSN-14ae to estimate the TDE rate implied by ASAS-SN, finding an average rate of ... per galaxy with a 90 per cent confidence interval of ... per galaxy. ASAS-SN found roughly 1 TDE for every 70 Type Ia supernovae in 2014, a rate that is much higher than that of other surveys. (ProQuest: ... denotes formulae/symbols omitted.)
ASASSN-15lh: A highly super-luminous supernova Dong, Subo; Shappee, B. J.; Prieto, J. L. ...
Science (American Association for the Advancement of Science),
01/2016, Letnik:
351, Številka:
6270
Journal Article
Recenzirano
Odprti dostop
We report the discovery of ASASSN-15lh (SN 2015L), which we interpret as the most luminous supernova yet found. At redshift z = 0.2326, ASASSN-15lh reached an absolute magnitude of Mu,AB = −23.5 ± ...0.1 and bolometric luminosity Lbol = (2.2 ± 0.2) × 10⁴⁵ ergs s⁻¹, which is more than twice as luminous as any previously known supernova. It has several major features characteristic of the hydrogen-poor super-luminous supernovae (SLSNe-l), whose energy sources and progenitors are currently poorly understood. In contrast to most previously known SLSNe-l that reside in star-forming dwarf galaxies, ASASSN-15lh appears to be hosted by a luminous galaxy (MK ≈ −25.5) with little star formation. In the 4 months since first detection, ASASSN-15lh radiated (1.1 ± 0.2) × 10⁵² ergs, challenging the magnetar model for its engine.
Chip-based quantum key distribution Sibson, P; Erven, C; Godfrey, M ...
Nature communications,
02/2017, Letnik:
8, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Improvement in secure transmission of information is an urgent need for governments, corporations and individuals. Quantum key distribution (QKD) promises security based on the laws of physics and ...has rapidly grown from proof-of-concept to robust demonstrations and deployment of commercial systems. Despite these advances, QKD has not been widely adopted, and large-scale deployment will likely require chip-based devices for improved performance, miniaturization and enhanced functionality. Here we report low error rate, GHz clocked QKD operation of an indium phosphide transmitter chip and a silicon oxynitride receiver chip-monolithically integrated devices using components and manufacturing processes from the telecommunications industry. We use the reconfigurability of these devices to demonstrate three prominent QKD protocols-BB84, Coherent One Way and Differential Phase Shift-with performance comparable to state-of-the-art. These devices, when combined with integrated single photon detectors, pave the way for successfully integrating QKD into future telecommunications networks.
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