NuSTAR unveils a Compton-thick type 2 quasar in MrK 34

We present Nuclear Spectroscopic Telescope Array (NuSTAR) 3-40 keV observations of the optically selected Type 2 quasar (QSO2) SDSS J1034+6001 or Mrk 34. The high-quality hard X-ray spectrum and archival XMM-Newton data can be fitted self-consistently with a reflection-dominated continuum and a strong Fe K? fluorescence line with equivalent width >1 keV. Prior X-ray spectral fitting below 10 keV showed the source to be consistent with being obscured by Compton-thin column densities of gas along the line of sight, despite evidence for much higher columns from multiwavelength data. NuSTAR now enables a direct measurement of this column and shows that N H lies in the Compton-thick (CT) regime. The new data also show a high intrinsic 2-10 keV luminosity of L 2-10 ~ 1044 erg s–1, in contrast to previous low-energy X-ray measurements where L 2-10 lesssim 1043 erg s–1 (i.e., X-ray selection below 10 keV does not pick up this source as an intrinsically luminous obscured quasar). Both the obscuring column and the intrinsic power are about an order of magnitude (or more) larger than inferred from pre-NuSTAR X-ray spectral fitting. Mrk 34 is thus a "gold standard" CT QSO2 and is the nearest non-merging system in this class, in contrast to the other local CT quasar NGC 6240, which is currently undergoing a major merger coupled with strong star formation. For typical X-ray bolometric correction factors, the accretion luminosity of Mrk 34 is high enough to potentially power the total infrared luminosity. X-ray spectral fitting also shows that thermal emission related to star formation is unlikely to drive the observed bright soft component below ~3 keV, favoring photoionization instead

NuSTAR J033202-2746.8: Direct Constraints on the Compton Reflection in a Heavily Obscured Quasar at z ≈ 2

We report Nuclear Spectroscopic Telescope Array (NuSTAR) observations of NuSTAR J033202-2746.8, a heavily obscured, radio-loud quasar detected in the Extended Chandra Deep Field-South, the deepest layer of the NuSTAR extragalactic survey (~400 ks, at its deepest). NuSTAR J033202-2746.8 is reliably detected by NuSTAR only at E > 8 keV and has a very flat spectral slope in the NuSTAR energy band ($\Gamma =0.55^{+0.62}_{-0.64}$; 3-30 keV). Combining the NuSTAR data with extremely deep observations by Chandra and XMM-Newton (4 Ms and 3 Ms, respectively), we constrain the broad-band X-ray spectrum of NuSTAR J033202-2746.8, indicating that this source is a heavily obscured quasar ($N_{\rm H}=5.6^{+0.9}_{-0.8}\times 10^{23}$ cm–2) with luminosity L 10-40 keV ≈ 6.4 × 1044 erg s–1. Although existing optical and near-infrared (near-IR) data, as well as follow-up spectroscopy with the Keck and VLT telescopes, failed to provide a secure redshift identification for NuSTAR J033202-2746.8, we reliably constrain the redshift z = 2.00 ± 0.04 from the X-ray spectral features (primarily from the iron K edge). The NuSTAR spectrum shows a significant reflection component ($R=0.55^{+0.44}_{-0.37}$), which was not constrained by previous analyses of Chandra and XMM-Newton data alone. The measured reflection fraction is higher than the R ~ 0 typically observed in bright radio-loud quasars such as NuSTAR J033202-2746.8, which has L 1.4 GHz ≈ 1027 W Hz–1. Constraining the spectral shape of active galactic nuclei (AGNs), including bright quasars, is very important for understanding the AGN population, and can have a strong impact on the modeling of the X-ray background. Our results show the importance of NuSTAR in investigating the broad-band spectral properties of quasars out to high redshift

Determination of nicarbazin as dinitrocarbanilide residues in chicken feed, breast and litter.

Abstract: To control coccidiosis, a common disease in commercial broiler production, anticoccidials are added to feed. However, concerns about the deposition of anticoccidial residues in chicken breast do exist. Brazilian law allows 200 μg kg-1 of nicarbazin (main chicken anticoccidial) residue in chicken breast, but demands its withdrawal from feed 10 days before slaughter, to avoid its presence in chicken breast. The present research aimed at raising chickens for 42 days and subject them to three treatments with anticoccidials by analyzing nicarbazin residues as dinitrocarbanilide (DNC) in feed, breast and poultry litter. The results showed that feed and breast had DNC levels within the legislation, therefore chicken breast is safe for human consumption. Also, shortly after nicarbazin removal from feed, DNC concentration dropped in poultry litter by about 50% in all treatments. Resumo ? Para controlar a coccidiose, doença comum na produção comercial de frangos de corte, são adicionados anticoccidianos à ração. No entanto, preocupações sobre a deposição de resíduos de anticoccidianos no peito de frango existem. A legislação brasileira permite 200 μg kg-1 de resíduo de nicarbazina (principal anticoccidiano) no peito de frango, porém exige que seja retirado da ração 10 dias antes do abate, para evitar sua presença no peito de frango. A presente pesquisa objetivou criar frangos por 42 dias e submete-los a três tratamentos com anticoccidianos, analisando resíduos de nicarbazina na forma de dinitrocarbanilida (DNC) na ração, peito e cama de aviário. Os resultados mostraram que na ração e no peito, todos níveis de DNC se mantiveram dentro da legislação, sendo o peito de frango seguro para consumo humano. Ainda, logo após a retirada da nicarbazina da ração, a concentração de DNC na cama de aviário caiu cerca de 50% em todos tratamentos.bitstream/item/219013/1/final9387.pd