47 research outputs found

    Revival of the magnetar PSR J1622-4950: observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR

    Get PDF
    New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a quiescent state since at least early 2015, reactivated between 2017 March 19 and April 5. The radio flux density, while variable, is approximately 100x larger than during its dormant state. The X-ray flux one month after reactivation was at least 800x larger than during quiescence, and has been decaying exponentially on a 111+/-19 day timescale. This high-flux state, together with a radio-derived rotational ephemeris, enabled for the first time the detection of X-ray pulsations for this magnetar. At 5%, the 0.3-6 keV pulsed fraction is comparable to the smallest observed for magnetars. The overall pulsar geometry inferred from polarized radio emission appears to be broadly consistent with that determined 6-8 years earlier. However, rotating vector model fits suggest that we are now seeing radio emission from a different location in the magnetosphere than previously. This indicates a novel way in which radio emission from magnetars can differ from that of ordinary pulsars. The torque on the neutron star is varying rapidly and unsteadily, as is common for magnetars following outburst, having changed by a factor of 7 within six months of reactivation.Comment: Published in ApJ (2018 April 5); 13 pages, 4 figure

    The 1.28 GHz MeerKAT DEEP2 Image

    Get PDF
    We present the confusion-limited 1.28 GHz MeerKAT DEEP2 image covering one qb » ¢ 68 FWHM primarybeam area with θ = 7 6 FWHM resolution and s = m - n 0.55 0.01 Jy beam 1 rms noise. Its J2000 center position α = 04h 13m 26 4, δ = −80° 00′ 00″ was selected to minimize artifacts caused by bright sources. We introduce the new 64-element MeerKAT array and describe commissioning observations to measure the primary-beam attenuation pattern, estimate telescope pointing errors, and pinpoint (u, v) coordinate errors caused by offsets in frequency or time. We constructed a 1.4 GHz differential source count by combining a power-law count fit to the DEEP2 confusion P(D) distribution from 0.25 to 10 μJy with counts of individual DEEP2 sources between 10 μJy and 2.5 mJy. Most sources fainter than S ∼ 100 μJy are distant star-forming galaxies (SFGs) obeying the far-IR/ radio correlation, and sources stronger than 0.25 μJy account for ∼93% of the radio background produced by SFGs. For the first time, the DEEP2 source count has reached the depth needed to reveal the majority of the star formation history of the universe. A pure luminosity evolution of the 1.4 GHz local luminosity function consistent with the Madau & Dickinson model for the evolution of SFGs based on UV and infrared data underpredicts our 1.4 GHz source count in the range -5 log Jy 4 [ ( )] S

    The MeerKAT Galaxy Cluster Legacy Survey: I. Survey overview and highlights

    Get PDF
    Please abstract in the article.The South African Radio Astronomy Observatory (SARAO), the National Research Foundation (NRF), the National Radio Astronomy Observatory, US National Science Foundation, the South African Research Chairs Initiative of the DSI/NRF, the SARAO HCD programme, the South African Research Chairs Initiative of the Department of Science and Innovation.http://www.aanda.orghj2022Physic

    Hospital readmissions among older people with intellectual disability in comparison with the general population

    No full text
    Background: Older people with intellectual disability have high multimorbidity and poor physical and mental health compared with the general population. Consequently, they have a greater need for health care. Hospital readmissions may be an indicator of the quality of health care. However, so far, only a few studies have investigated this outcome in populations of people with intellectual disability. None has focused on older people. Method: We identified a cohort of people with intellectual disability aged 55+ years and alive at the end of 2012 (n = 7936). Moreover, we established a reference cohort from the general population, one-to-one matched by sex and year of birth. Data on hospital visits during the period 2002–2012 were collected from the Swedish National Patient Register. Readmissions were defined as unplanned visits with the same diagnosis occurring within 30 days of discharge and with no planned visit for the same diagnosis during this time. Results: Compared with the general population, people with intellectual disability had increased risk of readmissions for diseases of the nervous system [relative risk (RR) 2.62], respiratory system (RR 1.48), digestive system (RR 1.40) and musculoskeletal system and connective tissue (RR 2.10). Within these diagnostic groups, increased risks were found for arthropathies (RR 3.73), disorders of gallbladder, biliary tract and pancreas (RR 1.78), other diseases of intestines (RR 1.30), and other forms of heart disease (RR 1.23). Decreased risk of readmissions was found for mental and behavioural disorders (RR 0.78) and diseases of the circulatory system (RR 0.64). Conclusions: The increased risk for readmissions related to diseases of the nervous and musculoskeletal systems has a clear relation to the prevalence of comorbidities in these areas. People with intellectual disability often also have inborn limitations and damages in these systems which with time lead to complications and risk for diseases, which can be difficult to discover. The increased risk for readmissions for disease of the respiratory system, together with the already known increased prevalence of such diagnoses and their occurrence as a cause for death, warrants further investigations and considerations of potential preventive measures. The pattern of readmissions among older people with intellectual disability cannot be explained solely by a higher prevalence of disorders in this group. Our finding of increased risks for readmissions for diseases in the digestive system could be interpreted as communication problems, which sometimes result in too rapid discharges and their consequential early readmissions
    corecore