NuSTAR hard X-ray data and Gemini 3D spectra reveal powerful AGN and outflow histories in two low-redshift Lyman-α\alpha blobs

We have shown that Lyman-$\alpha$ blobs (LABs) may still exist even at $z\sim0.3$, about 7 billion years later than most other LABs known (Schirmer et al. 2016). Their luminous Ly$\alpha$ and [OIII] emitters at $z\sim0.3$ offer new insights into the ionization mechanism. This paper focuses on the two X-ray brightest LABs at $z\sim0.3$, SDSS J0113$+$0106 (J0113) and SDSS J1155$-$0147 (J1155), comparable in size and luminosity to `B1', one of the best-studied LABs at $z \gtrsim$ 2. Our NuSTAR hard X-ray (3--30 keV) observations reveal powerful active galactic nuclei (AGN) with $L_{2-10{\;\rm keV}}=(0.5$--$3)\times10^{44}$ erg cm$^{-2}$ s$^{-1}$. J0113 also faded by a factor of $\sim 5$ between 2014 and 2016, emphasizing that variable AGN may cause apparent ionization deficits in LABs. Joint spectral analyses including Chandra data constrain column densities of $N_{\rm H}=5.1^{+3.1}_{-3.3}\times10^{23}$ cm$^{-2}$ (J0113) and $N_{\rm H}=6.0^{+1.4}_{-1.1}\times10^{22}$ cm$^{-2}$ (J1155). J0113 is likely buried in a torus with a narrow ionization cone, but ionizing radiation is also leaking in other directions as revealed by our Gemini/GMOS 3D spectroscopy. The latter shows a bipolar outflow over $10$ kpc, with a peculiar velocity profile that is best explained by AGN flickering. X-ray analysis of J1155 reveals a weakly absorbed AGN that may ionize over a wide solid angle, consistent with our 3D spectra. Extinction corrected [OIII] log-luminosities are high, $\sim43.6$. The velocity dispersions are low, $\sim100$--$150$ km s$^{-1}$, even at the AGN positions. We argue that this is a combination of high extinction hiding the turbulent gas, and previous outflows that have cleared the escape paths for their successors.Comment: 15 pages, 17 Figures, accepted for publication in Ap

3.4 Million Real-World Learning Management System Logins Reveal the Majority of Students Experience Social Jet Lag Correlated with Decreased Performance

Misalignments between endogenous circadian rhythms and the built environment (i.e., social jet lag, SJL) result in learning and attention deficits. Currently, there is no way to assess the impact of SJL on learning outcomes of large populations as a response to schedule choices, let alone to assess which individuals are most negatively impacted by these choices. We analyzed two years of learning management system login events for 14,894 Northeastern Illinois University (NEIU) students to investigate the capacity of such systems as tools for mapping the impact of SJL over large populations while maintaining the ability to generate insights about individuals. Personal daily activity profiles were validated against known biological timing effects, and revealed a majority of students experience more than 30 minutes of SJL on average, with greater amplitude correlating strongly with a significant decrease in academic performance, especially in people with later apparent chronotypes. Our findings demonstrate that online records can be used to map individual- and population-level SJL, allow deep mining for patterns across demographics, and could guide schedule choices in an effort to minimize SJL’s negative impact on learning outcomes

Strong gametocytocidal effect of methylene blue-based combination therapy against falciparum malaria

With the availability of new preventive and curative interventions, global malaria control has been strengthened significantly in recent years. Drugs effective in reducing malaria gametocytaemia might contribute to local elimination and possible long-term eradication. We here report on the effects of methylene blue (MB)-based malaria combination therapy on gametocytaemia during a randomised-controlled trial in Burkina Faso. An open-label randomised controlled phase II study in 180 children aged 6-10 years with uncomplicated falciparum malaria was conducted in Nouna, north-western Burkina Faso. Children were randomised to MB-artesunate (AS), MB-amodiaquine (AQ), and AS-AQ (local standard of care). Overall follow-up was for 28 days, follow-up for gametocytaemia was for 14 days. The treatment groups were similar in baseline characteristics and there was only one loss to follow-up. Compared to AS-AQ, both MB-containing regimens were associated with significantly reduced gametocyte carrier rates during follow-up days 3, 7, and 14. This effect was seen both in patients with and without P. falciparum gametocytaemia at baseline. MB reveals pronounced gametocytocidal activity which appears to act against both existing and developing P. falciparum gametocytes. MB-based combination therapy thus has the potential to reduce transmission of P. falciparum malaria in endemic regions, which has important implications for future elimination and eradication strategies

The effect of spatial resolution on optical and near-IR studies of stellar clusters: Implications for the origin of the red excess

Recent ground based near-IR studies of stellar clusters in nearby galaxies have suggested that young clusters remain embedded for 7-10Myr in their progenitor molecular cloud, in conflict with optical based studies which find that clusters are exposed after 1-3Myr. Here, we investigate the role that spatial resolution plays in this apparent conflict. We use a recent catalogue of young ($5000$~\msun) clusters in the nearby spiral galaxy, M83, along with Hubble Space Telescope (HST) imaging in the optical and near-IR, and ground based near-IR imaging, to see how the colours (and hence estimated properties such as age and extinction) are affected by the aperture size employed, in order to simulate studies of differing resolution. We find that the near-IR is heavily affected by the resolution, and when aperture sizes $>40$~pc are used, all young/blue clusters move red-ward in colour space, which results in their appearance as heavily extincted clusters. However, this is due to contamination from nearby sources and nebular emission, and is not an extinction effect. Optical colours are much less affected by resolution. Due to the larger affect of contamination in the near-IR, we find that, in some cases, clusters will appear to show near-IR excess when large ($>20$~pc) apertures are used. Our results explain why few young ($<6$~Myr), low extinction (\av < 1~mag) clusters have been found in recent ground based near-IR studies of cluster populations, while many such clusters have been found in higher resolution HST based studies. Additionally, resolution effects appear to (at least partially) explain the origin of the near-IR excess that has been found in a number of extragalactic YMCs.Comment: 8 pages, 5 figures, accepted for publication in MNRA

A new luminous supersoft X-ray source in NGC 300

Context. We report the discovery of a new luminous supersoft source, XMMU J005455.0−374117, in the nearby spiral galaxy GC 300, in XMM-Newton observations performed on 2005 May 22 and on 2005 November 25. The source is not present in ROSAT data nor in the previous XMM-Newton observations of 2000 December/2001 January. The unique luminous supersoft source,XMMU J005510.7−373855, detected in the 1992 May/June ROSAT data and in the 2000/2001 XMM-Newton data, fell below detectability. This source already appeared highly variable in ROSAT observations. Aims. We report on the temporal and spectral analysis of this new supersoft source (SSS) and compare its properties with the previous known SSS. Methods. We present the light curves of the SSS, model its spectrum and estimate the corresponding flux and luminosities. Results. The light curve of XMMU J005455.0−374117 does not show large fluctuations in any of the observations and its spectrum can be modelled with an absorbed blackbody with kT ∼ 60 eV. The corresponding bolometric luminosity is 8.1+1.4 −4.5 × 1038 erg s−1 in the first observation and drops to 2.2+0.5 −1.4 × 1038 erg s−1 six months later. No optical source brighter than mV ∼ 21.7 mag is found coincident with its position. Conclusions. The luminosity of these two SSSs is higher than what has been found for “classical” SSSs. Their nature could be explained by beamed emission from steady nuclear burning of hydrogen onto white dwarfs, or accretion onto stellar-mass black hole with matter outflow or observed at high inclination angle. The presence of an intermediate-mass black hole seems unlikely in our case

The influence of heterogeneous groundwater discharge on the timescales of contaminant mass flux from streambed sediments ? field evidence and long-term predictions

International audienceStreambed sediments can act as long-term storage zones for organic contaminants originating from the stream water. Until the early 1990s, the small man-made stream, subject of our study, in the industrial area of Bitterfeld (Germany), was used for waste water discharge from the chemical industry nearby. The occurrence of contaminants in the streambed is resulting from aqueous-phase transport and particle facilitated deposition. Groundwater discharge through the streambed can otherwise induce a remobilization and an advective contaminant flux so that contaminants are released back from the streambed to the stream water. We investigated the long-term mass flow rates of chlorinated benzenes (MCB, DCBs) from the streambed to the overlying stream water driven by advection of groundwater. The spatial patterns and magnitudes of groundwater discharge were examined along a reach of 220 m length. At 140 locations groundwater discharge was quantified using streambed temperatures and ranged from 11.0 to 455.0 Lm?2d?1. According to locations with high and low groundwater discharge, time-integrating passive samplers were used to monitor current contaminant concentrations in the streambed. Streambed contaminant concentrations at high groundwater discharge locations were found to be lower than at low discharge locations. Based on data from batch experiments and field observations we parameterized and run multiple one-dimensional advective transport models for the observed range of groundwater discharge magnitudes to simulate the timescales of contaminant release and their dependence on the magnitude of groundwater discharge. The results of the long-term predictive modeling revealed that the time required to reduce the concentrations and the resulting mass fluxes to the water to 10% of the initial values will be in the scale of decades for high-discharge locations and centuries for low-discharge locations, respectively

Coulombic Energy Transfer and Triple Ionization in Clusters

Using neon and its dimer as a specific example, it is shown that excited Auger decay channels that are electronically stable in the isolated monomer can relax in a cluster by electron emission. The decay mechanism, leading to the formation of a tricationic cluster, is based on an efficient energy-transfer process from the excited, dicationic monomer to a neighbor. The decay is ultrafast and expected to be relevant to numerous physical phenomena involving core holes in clusters and other forms of spatially extended atomic and molecular matter.Comment: 5 pages, 1 figure, to be published in PR