The Afterglow and Kilonova of the Short GRB 160821B Troja, E.; Castro-Tirado, A. J.; Gonzalez, J Becerra ...
Monthly notices of the Royal Astronomical Society,
08/2019, Letnik:
489, Številka:
2
Journal Article
Recenzirano
Odprti dostop
GRB 160821B is a short duration gamma-ray burst (GRB) detected and localized by the Neil Gehrels Swift Observatory in the outskirts of a spiral galaxy at z = 0.1613, at a projected physical offset of ...16 kpc from the galaxy’s center. We present X-ray, optical/nIR, and radio observations of its counterpart and model them with two distinct components of emission: a standard afterglow, arising from the interaction of the relativistic jet with the surrounding medium, and a kilonova, powered by the radioactive decay of the sub-relativistic ejecta. Broadband modelling of the afterglow data reveals a weak reverse shock propagating backward into the jet, and a likely jet-break at 3.5 d. This is consistent with a structured jet seen slightly off-axis (θview ∼ θcore) while expanding into a low-density medium (n ≈ 10−3 cm−3). Analysis of the kilonova properties suggests a rapid evolution towards red colours, similar toAT2017gfo, and a low-nIR luminosity, possibly due to the presence of a long-lived neutron star. The global properties of the environment, the inferred low mass (Mej <~ 0.006 Msun) and velocities (vej >~ 0.05c) of lanthanide-rich ejecta are consistent with a binary neutron star merger progenitor.
Short gamma-ray bursts within 200 Mpc Dichiara, S; Troja, E; O’Connor, B ...
Monthly notices of the Royal Astronomical Society,
03/2020, Letnik:
492, Številka:
4
Journal Article
Recenzirano
Odprti dostop
ABSTRACT
We present a systematic search for short-duration gamma-ray bursts (GRBs) in the local Universe based on 14 yr of observations with the Neil Gehrels Swift Observatory. We cross-correlate the ...GRB positions with the GLADE catalogue of nearby galaxies, and find no event at a distance ≲100 Mpc and four plausible candidates in the range 100 Mpc ≲ D ≲ 200 Mpc. Although affected by low statistics, this number is higher than the one expected for chance alignments to random galaxies, and possibly suggests a physical association between these bursts and nearby galaxies. By assuming a local origin, we use these events to constrain the range of properties for X-ray counterparts of neutron star mergers. Optical upper limits place tight constraints on the onset of a blue kilonova, and imply either low masses ($\lesssim 10^{-3}\, \mathrm{M}_{\odot }$) of lanthanide-poor ejecta or unfavorable orientations (θobs ≳ 30 deg). Finally, we derive that the all-sky rate of detectable short GRBs within 200 Mpc is $1.3^{+1.7}_{-0.8}$ yr−1 (68 per cent confidence interval), and discuss the implications for the GRB outflow structure. If these candidates are instead of cosmological origin, we set a upper limit of ≲2.0 yr−1 (90 per cent confidence interval) to the rate of nearby events detectable with operating gamma-ray observatories, such as Swift and Fermi.
The largest glitch observed in the Crab pulsar Shaw, B; Lyne, A G; Stappers, B W ...
Monthly notices of the Royal Astronomical Society,
08/2018, Letnik:
478, Številka:
3
Journal Article
Abstract
We study the high-energy properties of GRB 181123B, a short gamma-ray burst (sGRB) at redshift
z
≈ 1.75. We show that, despite its nominal short duration with
T
90
< 2 s, this burst displays ...evidence of a temporally extended emission (EE) at high energies and that the same trend is observed in the majority of sGRBs at
z
≳ 1. We discuss the impact of instrumental selection effects on the GRB classification, stressing that the measured
T
90
is not an unambiguous indicator of the burst physical origin. By examining their environment (e.g., stellar mass, star formation, offset distribution), we find that these high-
z
sGRBs share many properties of long GRBs at a similar distance and are consistent with a short-lived progenitor system. If produced by compact binary mergers, these sGRBs with EE may be easier to localize at large distances and herald a larger population of sGRBs in the early universe.
Asthma is a chronic inflammatory airway disease accounting for severe morbidity and mortality in children. To determine the characteristics of traditional Chinese medicine (TCM) used to treat ...pediatric asthma, we conducted a nationwide population‐based study by analyzing a cohort of one million randomly sampled patients from the beneficiaries of the National Health Insurance Program in Taiwan from 2002 to 2010. Children under 18 years of age with newly diagnosed asthma (ICD‐9‐CM code: 493, N = 45 833) were enrolled, and 57.95% (N = 26 585) of them had used TCM. The number of TCM users was significantly more than that of non‐TCM users in school‐age children. The most commonly prescribed TCM formula is Ding‐chuan‐tang, or Xing‐ren (Semen Armeniacae Amarum) for the single herb. Our study is the first to reveal characteristics and prescription patterns of the use of TCM in children with asthma. Further research is needed to elucidate the efficacy and safety of these Chinese herbal products.
The early afterglow of GRB 190829A Dichiara, S; Troja, E; Lipunov, V ...
Monthly notices of the Royal Astronomical Society,
03/2022, Letnik:
512, Številka:
2
Journal Article
Recenzirano
Odprti dostop
ABSTRACT
GRB 190829A at z = 0.0785 is the fourth closest long GRB ever detected by the Neil Gehrels Swift observatory, and the third confirmed case with a very high-energy component. We present our ...multiwavelength analysis of this rare event, focusing on its early stages of evolution, and including data from Swift, the MASTER global network of optical telescopes, ALMA, and ATCA. We report sensitive limits on the linear polarization of the optical emission, disfavouring models of off-axis jets to explain the delayed afterglow peak. The study of the multiwavelength light curves and broad-band spectra supports a model with at least two emission components: a bright reverse shock emission, visible at early times in the optical and X-rays and, later, in the radio band; and a forward shock component dominating at later times and lower radio frequencies. A combined study of the prompt and afterglow properties shows many similarities with cosmological long GRBs, suggesting that GRB 190829A is an example of classical GRBs in the nearby universe.
During its first observing run, in late 2015, the advanced Laser Interferometer Gravitational-wave Observatory facility announced three gravitational wave (GW) triggers to electromagnetic follow-up ...partners. Two of these have since been confirmed as being of astrophysical origin: both are binary black hole mergers at ∼500 Mpc; the other trigger was later found not to be astrophysical. In this paper, we report on the Swift follow-up observations of the second and third triggers, including details of 21 X-ray sources detected; none of which can be associated with the GW event. We also consider the challenges that the next GW observing run will bring as the sensitivity and hence typical distance of GW events will increase. We discuss how to effectively use galaxy catalogues to prioritize areas for follow-up, especially in the presence of distance estimates from the GW data. We also consider two galaxy catalogues and suggest that the high completeness at larger distances of the 2MASS Photometric Redshift catalogue makes it very well suited to optimize Swift follow-up observations.
Hard X-Ray Emission in Centaurus A Rani, B.; Mundo, S. A.; Mushotzky, R. ...
The Astrophysical journal,
06/2022, Letnik:
932, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Abstract
We use 13 yr of Swift/BAT observations to probe the nature and origin of the hard X-ray (14–195 KeV) emission in Centaurus A. Since the beginning of the Swift operation in 2004, significant ...X-ray variability in the 14–195 KeV band has been detected, with mild changes in the source spectrum. Spectral variations became more eminent after 2013, following a softer-when-brighter trend. Using the power spectral density (PSD) method, we find that the observed hard X-ray photon flux variations are consistent with a red-noise process of slope, −1.3, with no evidence for a break in the PSD. We find a significant correlation between the hard X-ray and 230 GHz radio flux variations, with no time delay longer than 30 days. The temporal and spectral analysis confirms that the X-ray emission generated by the accretion in the ADAF model is sub-dominant as compared with the emission arising from that produced by the inner regions of the radio jet.
We present Hubble Space Telescope (HST) and Chandra imaging, combined with Very Large Telescope MUSE integral field spectroscopy of the counterpart and host galaxy of the first binary neutron star ...merger detected via gravitational-wave emission by LIGO and Virgo, GW170817. The host galaxy, NGC 4993, is an S0 galaxy at z = 0.009783. There is evidence for large, face-on spiral shells in continuum imaging, and edge-on spiral features visible in nebular emission lines. This suggests that NGC 4993 has undergone a relatively recent ( 1 Gyr) "dry" merger. This merger may provide the fuel for a weak active nucleus seen in Chandra imaging. At the location of the counterpart, HST imaging implies there is no globular or young stellar cluster, with a limit of a few thousand solar masses for any young system. The population in the vicinity is predominantly old with 1% of any light arising from a population with ages < 500 Myr . Both the host galaxy properties and those of the transient location are consistent with the distributions seen for short-duration gamma-ray bursts, although the source position lies well within the effective radius ( r e ∼ 3 kpc), providing an re-normalized offset that is closer than ∼ 90 % of short GRBs. For the long delay time implied by the stellar population, this suggests that the kick velocity was significantly less than the galaxy escape velocity. We do not see any narrow host galaxy interstellar medium features within the counterpart spectrum, implying low extinction, and that the binary may lie in front of the bulk of the host galaxy.
Summary
Background
Generic instruments measuring health‐related quality of life (HRQoL), like EQ5D™, enable comparison of skin diseases with healthy populations and nondermatological medical ...conditions, as well as calculation of utility data.
Objectives
To measure HRQoL in patients with common skin diseases and healthy controls across Europe using the EQ5D.
Methods
This multicentre observational cross‐sectional study was conducted in 13 European countries. Each dermatology clinic recruited at least 250 consecutive adult outpatients to complete questionnaires, including the EQ5D.
Results
There were 5369 participants (4010 patients and 1359 controls). Mean ± SD self‐rated health state reported by patients was 69·9 ± 19·7; for controls it was 82·2 ± 15·5. When adjusted for confounding factors, including comorbidity, mean patient EQ visual analogue scores were 10·5 points lower than for controls (standardized β = −0·23). Odds ratio with 95% confidence interval for impairment in all five dimensions of EQ5D adjusted for confounders was doubled for patients compared with controls. Patients with hidradenitis suppurativa (HS), blistering conditions, leg ulcers, psoriasis and eczemas had the highest risk for reduction in HRQoL in most dimensions (2–10‐fold). Data on differences of impairment by dimensions offer new insights.
Conclusions
This study confirms the large impact skin conditions have on patients’ well‐being, differentiating between aspects of HRQoL. Patients with HS, blistering diseases, leg ulcers, infections and most chronic skin diseases reported reduced HRQoL compared with patients with chronic obstructive lung disease, diabetes mellitus, cardiovascular disease and cancers. These findings are important in the prioritization of resource allocation between medical fields and within dermatological subspecialities.
What is already known about this topic?
The EQ5D™ can be used to compare life quality impairment from diseases across a range of specialties and to generate utility data.
The EQ5D has previously been little used in dermatology.
What does this study add?
This study has generated EQ5D data across a range of dermatological diagnoses in a large cohort of patients across Europe.
Skin diseases affect quality of life differently across different dimensions.
This EQ5D information may assist appropriate care and resource allocation.
Respond to this article
PDF
