The Phoenix galaxy as seen by NuSTAR

Aims. We study the long-term variability of the well-known Seyfert 2 galaxy Mrk 1210 (a.k.a. UGC 4203, or the Phoenix galaxy). Methods. The source was observed by many X-ray facilities in the last 20 years. Here we present a NuSTAR observation and put the results in context of previously published observations. Results. NuSTAR observed Mrk 1210 in 2012 for 15.4 ks. The source showed Compton-thin obscuration similar to that observed by Chandra, Suzaku, BeppoSAX and XMM-Newton over the past two decades, but different from the first observation by ASCA in 1995, in which the active nucleus was caught in a low flux state - or obscured by Compton-thick matter, with a reflection-dominated spectrum. Thanks to the high-quality hard X-ray spectrum obtained with NuSTAR and exploiting the long-term spectral coverage spanning 16.9 years, we can precisely disentangle the transmission and reflection components and put constraints on both the intrinsic long-term variability and hidden nucleus scenarios. In the former case, the distance between the reflector and the source must be at least ~ 2 pc, while in the latter one the eclipsing cloud may be identified with a water maser-emitting clump.<br/

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 &gt;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

The NuSTAR Serendipitous Survey: Hunting for the Most Extreme Obscured AGN at >10 keV

We identify sources with extremely hard X-ray spectra (i.e., with photon indices of ${\rm{\Gamma }}\lesssim 0.6$) in the 13 deg2 NuSTAR serendipitous survey, to search for the most highly obscured active galactic nuclei (AGNs) detected at $\gt 10\,\mathrm{keV}$. Eight extreme NuSTAR sources are identified, and we use the NuSTAR data in combination with lower-energy X-ray observations (from Chandra, Swift XRT, and XMM-Newton) to characterize the broadband (0.5–24 keV) X-ray spectra. We find that all of the extreme sources are highly obscured AGNs, including three robust Compton-thick (CT; ${N}_{{\rm{H}}}\gt 1.5\times {10}^{24}$ cm−2) AGNs at low redshift ($z\lt 0.1$) and a likely CT AGN at higher redshift (z = 0.16). Most of the extreme sources would not have been identified as highly obscured based on the low-energy ($\lt 10$ keV) X-ray coverage alone. The multiwavelength properties (e.g., optical spectra and X-ray–mid-IR luminosity ratios) provide further support for the eight sources being significantly obscured. Correcting for absorption, the intrinsic rest-frame 10–40 keV luminosities of the extreme sources cover a broad range, from $\approx 5\times {10}^{42}$ to 1045 erg s−1. The estimated number counts of CT AGNs in the NuSTAR serendipitous survey are in broad agreement with model expectations based on previous X-ray surveys, except for the lowest redshifts ($z\lt 0.07$), where we measure a high CT fraction of ${f}_{\mathrm{CT}}^{\mathrm{obs}}={30}_{-12}^{+16} \%$. For the small sample of CT AGNs, we find a high fraction of galaxy major mergers (50% ± 33%) compared to control samples of "normal" AGNs

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 &#956;g 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 &#956;g 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

The NuSTAR view of reflection and absorption in NGC 7582

NGC 7582 is a well-studied X-ray bright Seyfert 2 with moderately heavy (NH ~ 1023 - 1024 cm-2), highly variable absorption and strong reflection spectral features. The spectral shape changed around the year 2000, dropping in observed flux and becoming much more highly absorbed. Two scenarios have been put forth to explain this spectral change: (1) the central X-ray source partially "shut off" around this time, decreasing in intrinsic luminosity, with a delayed decrease in reflection features due to the light-crossing time of the Compton-thick material or (2) the source became more heavily obscured, with only a portion of the power law continuum leaking through. NuSTAR observed NGC 7582 twice in 2012, two weeks apart, in order to quantify the reflection using high-quality data above 10 keV. We find that the most plausible scenario is that NGC 7582 has recently become more heavily absorbed by a patchy torus with a covering fraction of ~80%–90% and an equatorial column density of ~ 3 ×1024 cm-2. We find the need for an additional highly variable full-covering absorber with NH = (4–6) × 1023 cm-2 in the line of sight, possibly associated with a hidden broad line region

NuSTAR catches the unveiling nucleus of NGC 1068

We present a NuSTAR and XMM–Newton monitoring campaign in 2014/2015 of the Compton-thick Seyfert 2 galaxy, NGC 1068. During the 2014 August observation, we detect with NuSTAR a flux excess above 20 keV (32 ± 6 per cent) with respect to the 2012 December observation and to a later observation performed in 2015 February. We do not detect any spectral variation below 10 keV in the XMM–Newton data. The transient excess can be explained by a temporary decrease of the column density of the obscuring material along the line of sight (from NH ≃ 1025 cm−2 to NH = 6.7 ± 1.0 × 1024 cm−2), which allows us for the first time to unveil the direct nuclear radiation of the buried active galactic nucleus in NGC 1068 and to infer an intrinsic 2–10 keV luminosity LX=7+7−4×1043X=7−4+7×1043 erg s−1

BASS. XXIII. A new mid-infrared diagnostic for absorption in active galactic nuclei

Galaxie