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Color is a fundamental image feature of facial expressions. For example, when we furrow our eyebrows in anger, blood rushes in, turning some face areas red; or when one goes white in fear as a result of the drainage of blood from the face. Surprisingly, these image properties have not been exploited to recognize the facial action units (AUs) associated with these expressions. Herein, we present the first system to do recognition of AUs and their intensities using these functional color changes. These color features are shown to be robust to changes in identity, gender, race, ethnicity, and skin color. Specifically, we identify the chromaticity changes defining the transition of an AU from inactive to active and use an innovative Gabor transform-based algorithm to gain invariance to the timing of these changes. Because these image changes are given by functions rather than vectors, we use functional classifiers to identify the most discriminant color features of an AU and its intensities. We demonstrate that, using these discriminant color features, one can achieve results superior to those of the state-of-the-art. Finally, we define an algorithm that allows us to use the learned functional color representation in still images. This is done by learning the mapping between images and the identified functional color features in videos. Our algorithm works in realtime, i.e., $>$ > 30 frames/second/CPU thread. [ABSTRACT FROM AUTHOR]

Facial expressions of emotion are thought to have evolved from the development of facial muscles used in sensory regulation and later adapted to express moral judgment. Negative moral judgment includes the expressions of anger, disgust and contempt. Here, we study the hypothesis that these facial expressions of negative moral judgment have further evolved into a facial expression of negation regularly used as a grammatical marker in human language. Specifically, we show that people from different cultures expressing negation use the same facial muscles as those employed to express negative moral judgment. We then show that this nonverbal signal is used as a co-articulator in speech and that, in American Sign Language, it has been grammaticalized as a non-manual marker. Furthermore, this facial expression of negation exhibits the theta oscillation (3-8 Hz) universally seen in syllable and mouthing production in speech and signing. These results provide evidence for the hypothesis that some components of human language have evolved from facial expressions of emotion, and suggest an evolutionary route for the emergence of grammatical markers. [ABSTRACT FROM AUTHOR]

To fully define the grammar of American Sign Language (ASL), a linguistic model of its nonmanuals needs to be constructed. While significant progress has been made to understand the features defining ASL manuals, after years of research, much still needs to be done to uncover the discriminant nonmanual components. The major barrier to achieving this goal is the difficulty in correlating facial features and linguistic features, especially since these correlations may be temporally defined. For example, a facial feature (e.g., head moves down) occurring at the end of the movement of another facial feature (e.g., brows moves up), may specify a Hypothetical conditional, but only if this time relationship is maintained. In other instances, the single occurrence of a movement (e.g., brows move up) can be indicative of the same grammatical construction. In the present paper, we introduce a linguistic–computational approach to efficiently carry out this analysis. First, a linguistic model of the face is used to manually annotate a very large set of 2,347 videos of ASL nonmanuals (including tens of thousands of frames). Second, a computational approach is used to determine which features of the linguistic model are more informative of the grammatical rules under study. We used the proposed approach to study five types of sentences – Hypothetical conditionals, Yes/no questions, Wh-questions, Wh-questions postposed, and Assertions – plus their polarities – positive and negative. Our results verify several components of the standard model of ASL nonmanuals and, most importantly, identify several previously unreported features and their temporal relationship. Notably, our results uncovered a complex interaction between head position and mouth shape. These findings define some temporal structures of ASL nonmanuals not previously detected by other approaches. [ABSTRACT FROM AUTHOR]

We review several aspects of RNAi and gene silencing with baculovirus. We show that the potency of RNAi in Spodoptera frugiperda (Sf21) insect cells correlates well with the efficiency of transfection of the siRNA. Using a fluorescein-labeled siRNA we found that the siRNA localized in areas surrounding the endoplasmic reticulum (ER). Both long (700 nucleotides long) and small (∼25 nucleotides long) interfering RNAs were equally effective in initiating RNA interference (RNAi), and the duration of the interfering effect was indistinguishable. Even though RNAi in Sf21 cells is very effective, in vitro experiments show that these cells fragment the long dsRNA into siRNA poorly, when compared to HEK cells.Finally, we show that in vivo inhibition of baculovirus infection with dsRNA homologous to genes that are essential for baculovirus infectivity depends strongly on the amount of dsRNA used in the assays. Five hundred nanogram of dsRNA directly injected into the haemolymph of insects prevent animal death to over 95%. In control experiments, over 96% of insects not injected with dsRNA or injected with an irrelevant dsRNA died within a week. These results demonstrate the efficiency of dsRNA for in vivo prevention of a viral infection by virus that is very cytotoxic and lytic in animals. [Copyright &y& Elsevier]

Examines the changes in NAD phosphate diaphorase (NADPH-d) stained neurons following certain neurological disorders. Use of computerized image analyzer in measuring stain neurons; Increase in striatal NADPH-d cell measurements in patients with Huntington's disease; Effects of perinatal asphyxia in rats monitored with cerebral microdialysis.

Interesting among possible mechanisms responsible for X-ray emission from active galactic nuclei (AGNs) is ionized relativistic reflection (IRR). Since it arises close to the central black hole it can test strong gravity. Its characteristic features include a high energy Compton hump, a broad Fe Kα line, and a soft excess. Therefore, using the Swift-Burst Alert Telescope (BAT) catalog we looked for hard X-ray selected AGNs that may exhibit at least one of these characteristic features. Among the possibly interesting targets found is Seyfert I Galaxy LEDA 168563. We obtained a broadband 100 ks Suzaku observation of this source, and careful analysis of the data was carried out. The results support the presence of these IRR distinct features. Moreover, the comparison of the earlier combined XMM-Newton and Swift-BAT and more recent Suzaku data showed interesting long-term spectral variability. The soft excess decreased while higher energy features relatively increased and the power-law component became flatter—the behavior predicted by the IRR model. [ABSTRACT FROM AUTHOR]

The relativistic jets created by some active galactic nuclei are important agents of AGN feedback. In spite of this, our understanding of what produces these jets is still incomplete. X-ray observations, which can probe the processes operating in the central regions in the immediate vicinity of the supermassive black hole, the presumed jet launching point, are potentially particularly valuable in illuminating the jet formation process. Here, we present the hard X-ray NuSTAR observations of the radio-loud quasar 4C 74.26 in a joint analysis with quasi-simultaneous, soft X-ray Swift observations. Our spectral analysis reveals a high-energy cutoff of keV and confirms the presence of ionized reflection in the source. From the average spectrum we detect that the accretion disk is mildly recessed, with an inner radius of Rin = 4–180 Rg. However, no significant evolution of the inner radius is seen during the three months covered by our NuSTAR campaign. This lack of variation could mean that the jet formation in this radio-loud quasar differs from what is observed in broad-line radio galaxies. [ABSTRACT FROM AUTHOR]

We present an analysis of ionized X-ray disk winds found in the Fe K band of four stellar-mass black holes observed with Chandra, including 4U 1630−47, GRO J1655−40, H 1743−322, and GRS 1915+105. High-resolution photoionization grids were generated in order to model the data. Third-order gratings spectra were used to resolve complex absorption profiles into atomic effects and multiple velocity components. The Fe xxv line is found to be shaped by contributions from the intercombination line (in absorption), and the Fe xxvi line is detected as a spin–orbit doublet. The data require 2–3 absorption zones, depending on the source. The fastest components have velocities approaching or exceeding increasing mass outflow rates and wind kinetic power by orders of magnitude over prior single-zone models. The first-order spectra require re-emission from the wind, broadened by a degree that is loosely consistent with Keplerian orbital velocities at the photoionization radius. This suggests that disk winds are rotating with the orbital velocity of the underlying disk, and provides a new means of estimating launching radii—crucial to understanding wind driving mechanisms. Some aspects of the wind velocities and radii correspond well to the broad-line region in active galactic nuclei (AGNs), suggesting a physical connection. We discuss these results in terms of prevalent models for disk wind production and disk accretion itself, and implications for massive black holes in AGNs. [ABSTRACT FROM AUTHOR]

We present a spectral study of the ultraluminous Be/X-ray transient pulsar Swift J0243.6+6124 using Neutron Star Interior Composition Explorer (NICER) observations during the system’s 2017–2018 giant outburst. The 1.2–10 keV energy spectrum of the source can be approximated with an absorbed cutoff power-law model. We detect strong, luminosity-dependent emission lines in the 6–7 keV energy range. A narrow 6.42 keV line, observed in the sub-Eddington regime, is seen to evolve into a broad Fe-line profile in the super-Eddington regime. Other features are found at 6.67 and 6.97 keV in the Fe-line complex. An asymmetric broad-line profile, peaking at 6.67 keV, is possibly due to Doppler effects and gravitational redshift. The 1.2–79 keV broadband spectrum from Nuclear Spectroscopic Telescope Array (NuSTAR) and NICER observations at the outburst peak is well described by an absorbed cutoff power law plus multiple Gaussian lines and a blackbody component. Physical reflection models are also tested to probe the broad iron-line feature. Depending on the mass accretion rate, we found emission sites that are evolving from ∼5000 km to a range closer to the surface of the neutron star. Our findings are discussed in the framework of the accretion disk and its implication on the magnetic field, the presence of optically thick accretion curtain in the magnetosphere, jet emission, and the massive, ultrafast outflow expected at super-Eddington accretion rates. We do not detect any signatures of a cyclotron absorption line in the NICER or NuSTAR data. [ABSTRACT FROM AUTHOR]

We present a multi-wavelength study of four high redshift blazars, S5 0014+81 (z = 3.37), CGRaBS J0225+1846 (z = 2.69), BZQ J1430+4205 (z = 4.72), and 3FGL J1656.2−3303 (z = 2.40) using quasi-simultaneous data from the Swift, Nuclear Spectroscopic Telescope Array (NuSTAR) and the Fermi-Large Area Telescope (LAT) and also archival XMM-Newton observations. Other than 3FGL J1656.2−3303, none of the sources were known as γ-ray emitters, and our analysis of ∼7.5 yr of LAT data reveals the first time detection of statistically significant γ-ray emission from CGRaBS J0225+1846. We generate the broadband spectral energy distributions (SED) of all the objects, centering at the epoch of NuSTAR observations and reproduce them using a one-zone leptonic emission model. The optical−UV emission in all the objects can be explained by radiation from the accretion disk, whereas the X-ray to γ-ray windows of the SEDs are found to be dominated by inverse Compton scattering off the broad line region photons. All of them host black holes that are billions of solar masses. Comparing the accretion disk luminosity and the jet power of these sources with a large sample of blazars, we find them to occupy a high disk luminosity–jet power regime. We also investigate the X-ray spectral properties of the sources in detail with a major focus on studying the causes of soft X-ray deficit, a feature generally seen in high redshift radio-loud quasars. We summarize that this feature could be explained based on the intrinsic curvature in the jet emission rather than being due to the external effects predicted in earlier studies, such as host galaxy and/or warm absorption. [ABSTRACT FROM AUTHOR]

Infection by Shiga toxin-producing Escherichia coli causes hemorrhagic colitis, hemolytic uremic syndrome (HUS), acute renal failure, and also central nervous system complications in around 30% of the children affected. Besides, neurological deficits are one of the most unrepairable and untreatable outcomes of HUS. Study of the striatum is relevant because basal ganglia are one of the brain areas most commonly affected in patients that have suffered from HUS and since the deleterious effects of a sub-lethal dose of Shiga toxin have never been studied in the striatum, the purpose of this study was to attempt to simulate an infection by Shiga toxin-producing E. coli in a murine model. To this end, intravenous administration of a sub-lethal dose of Shiga toxin 2 (0.5 gg per mouse) was used and the correlation between neurological manifestations and ultrastructural changes in striatal brain cells was studied in detail. Neurological manifestations included significant motor behavior abnormalities in spontaneous motor activity, gait, pelvic elevation and hind limb activity eight days after administration of the toxin. Transmission electron microscopy revealed that the toxin caused early perivascular edema two days after administration, as well as significant damage in astrocytes four days after administration and significant damage in neurons and oligodendrocytes eight days after administration. Interrupted synapses and mast cell extravasation were also found eight days after administration of the toxin. We thus conclude that the chronological order of events observed in the striatum could explain the neurological disorders found eight days after administration of the toxin. [ABSTRACT FROM AUTHOR]

AbstractBackground:Routine intracranial pressure monitor (ICP) prophylaxis is not practiced at our institution. Nevertheless, some patients receive de facto prophylaxis as a result of the use of antibiotics for injuries such as open or facial fractures. We tested the hypothesis that prophylactic antibiotics do not reduce the incidence of central nervous system (CNS) infections but instead are associated with the acquisition of multi-drug resistant (MDR) bacterial infections.Methods:Patients admitted to the trauma intensive care unit (TICU) from January, 2001 through December, 2004 with blunt, non-operative traumatic brain injury who were managed solely with an ICP monitor were identified from our trauma registry and divided into two groups: (1) Those receiving no antibiotics prior to or during ICP monitoring (NONE; n 71); and (2) those already receiving antibiotics at the time of ICP monitor insertion (PRO; n 84). Groups were stratified on the basis of age, Injury Severity Score (ISS), Glasgow Coma Scale (GCS) Score, base excess (BE), ICP days, transfusions in 24 h, ICU days, ventilator days, head Abbreviated Injury Score (AIS), and chest AIS. The study groups did not differ with respect to age, ISS, GCS, BE, ICP days, 24-h transfusions, ICU days, ventilator days, head AIS, or length of stay. In all, 183 patients were identified, of whom 28 died within seven days and were excluded from the analysis. All patients were followed until discharge for both CNS infections and subsequent infectious complications.Results:Only two patients, both in the PRO group, developed CNS infection. Both infectious complications (0.7 vs 1.4 per patient; p < 0.05) and infections secondary to MDR pathogens (0.03 vs. 0.33 per patient; p < 0.01) were significantly more common in the PRO group. Twenty-nine percent of the ventilator-associated pneumonias and 33 of the blood stream infections in the PRO group were MDR, whereas only two blood stream infections in the NONE group (4 of the total infections) were MDR.Conclusions:The routine use of prophylactic antibiotics for ICP monitor insertion is not warranted. This practice does not reduce the CNS infection rate and is associated with more MDR pathogens in any subsequent infectious complications. [ABSTRACT FROM AUTHOR]

Background Ventilator-associated pneumonia (VAP) is a frequent complication during recovery of severely traumatized patients. The primary objective of this study was to determine if prophylactic administration of aerosolized ceftazidime reduced the incidence of VAP in high-risk injured patients without altering the incidence of other infectious complications.Patients and Methods This was a single-institution double-blind, randomized trial that compared a seven-day course of aerosolized ceftazidime with placebo. Intubated high-risk patients admitted to the trauma intensive care unit at a large regional trauma center between February 2003 and September 2005 were eligible for enrollment. The main outcome evaluated was the incidence of VAP at two weeks and 30 days. The incidences of multi-drug-resistant infections and other infectious complications were secondary outcomes.Results A total of 105 patients were randomized, resulting in 52 patients in the placebo arm and 53 patients in the ceftazidime arm. There was no statistical difference between the groups with regard to demographic data, injury severity, calculated risk of VAP, or the number of doses received. In the intention-to-treat analysis, the incidence of VAP at two weeks was 2452 (46) in the placebo group and 2153 (40) in the ceftazidime group. The number of patients with VAP at 30 days was 2652 (50) in the placebo group and 2653 (49) in the ceftazidime group. There was no statistical difference in the development of multi-drug-resistant VAP or other infectious complications in the two groups.Conclusion The use of aerosolized ceftazidime did not reduce the rate of VAP in high-risk patients admitted after traumatic injury, but neither did it increase the incidence of other infectious complications. Routine use of prophylactic aerosolized ceftazidime to prevent VAP in trauma patients cannot be recommended. [ABSTRACT FROM AUTHOR]

We present results from NuSTAR and XMM-Newton observations of the new black hole X-ray binary MAXI J1820+070 at low accretion rates (below 1% of the Eddington luminosity). We detect a narrow Fe Kα emission line, in contrast to the broad and asymmetric Fe Kα line profiles commonly present in black hole binaries at high accretion rates. The narrow line, with weak relativistic broadening, indicates that the Fe Kα line is produced at a large disk radius. Fitting with disk reflection models assuming standard disk emissivity finds a large disk truncation radius (a few tens to a few hundreds of gravitational radii, depending on the disk inclination). In addition, we detect a quasi-periodic oscillation (QPO) varying in frequency between 11.6 ± 0.2 mHz and 2.8 ± 0.1 mHz. The very low QPO frequencies suggest a large size for the optically thin Comptonization region according to the Lense–Thirring precession model, supporting that the accretion disk recedes from the innermost stable circular orbit and is replaced by advection-dominated accretion flow at low accretion rates. We also discuss the possibility of an alternative accretion geometry that the narrow Fe Kα line is produced by a lamppost corona with a large height illuminating the disk. [ABSTRACT FROM AUTHOR]

Axions/axion-like particles (ALPs) are a well-motivated extension of the Standard Model and are generic within String Theory. The X-ray transparency of the intracluster medium (ICM) in galaxy clusters is a powerful probe of light ALPs (with mass ); as X-ray photons from an embedded or background source propagate through the magnetized ICM, they may undergo energy-dependent quantum mechanical conversion into ALPs (and vice versa), imprinting distortions on the X-ray spectrum. We present Chandra data for the active galactic nucleus NGC 1275 at the center of the Perseus cluster. Employing a 490 ks High Energy Transmission Gratings exposure, we obtain a high-quality 1–9 keV spectrum free from photon pileup and ICM contamination. Apart from iron-band features, the spectrum is described by a power-law continuum, with any spectral distortions at the <3% level. We compute photon survival probabilities as a function of ALP mass ma and ALP-photon coupling constant for an ensemble of ICM magnetic field models, and then use the NGC 1275 spectrum to constrain the -plane. Marginalizing over magnetic field realizations, the 99.7% credible region limits the ALP-photon coupling to (depending upon magnetic field model) for masses . These are the most stringent limit to date on for these light ALPs, and have already reached the sensitivity limits of next-generation helioscopes and light-shining-through-wall experiments. We highlight the potential of these studies with the next-generation X-ray observatories Athena and Lynx, but note the critical importance of advances in relative calibration of these future X-ray spectrometers. [ABSTRACT FROM AUTHOR]

The mechanisms that drive disk winds are a window into the physical processes that underlie the disk. Stellar-mass black holes are an ideal setting in which to explore these mechanisms, in part because their outbursts span a broad range in mass accretion rate. We performed a spectral analysis of the disk wind found in six Chandra/HETG observations of the black hole candidate 4U 1630−472, covering a range of luminosities over two distinct spectral states. We modeled both wind absorption and extended wind re-emission components using PION, a self-consistent photoionized absorption model. In all but one case, two photoionization zones were required in order to obtain acceptable fits. Two independent constraints on launching radii, obtained via the ionization parameter formalism and the dynamical broadening of the re-emission, helped characterize the geometry of the wind. The innermost wind components () tend toward small volume filling factors, high ionization, densities up to , and outflow velocities of ∼0.003c. These small launching radii and large densities require magnetic driving, as they are inconsistent with numerical and analytical treatments of thermally driven winds. Outer wind components () are significantly less ionized and have filling factors near unity. Their larger launching radii, lower densities (), and outflow velocities (∼0.0007c) are nominally consistent with thermally driven winds. The overall wind structure suggests that these components may also be part of a broader MHD outflow and perhaps better described as magneto-thermal hybrid winds. [ABSTRACT FROM AUTHOR]

We report on X-ray and radio observations of the ultra-compact X-ray binary 4U 1543−624 taken in August 2017 during an enhanced accretion episode. We obtained Neutron Star Interior Composition Explorer (NICER) monitoring of the source over a ∼10 day period during which target-of-opportunity observations were also conducted with Swift, INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL), and the Australia Telescope Compact Array. Emission lines were measured in the NICER X-ray spectrum at ∼0.64 keV and ∼6.4 keV that correspond to O and Fe, respectively. By modeling these line components, we are able to track changes in the accretion disk throughout this period. The innermost accretion flow appears to move inwards from hundreds of gravitational radii (Rg = GM/c2) at the beginning of the outburst to <8.7 Rg at peak intensity. We do not detect the source in radio, but are able to place a 3σ upper limit on the flux density at 27 μJy beam−1. Comparing the radio and X-ray luminosities, we find that the source lies significantly away from the range typical of black holes in the – plane, suggesting a neutron star primary. This adds to the evidence that neutron stars (NSs) do not follow a single track in the – plane, limiting its use in distinguishing between different classes of NSs based on radio and X-ray observations alone. [ABSTRACT FROM AUTHOR]

We present new, deep (245 ks) Chandra observations of the galaxy cluster Abell 1664 (z = 0.1283). These images reveal rich structure, including elongation and accompanying compressions of the X-ray isophotes in the NE–SW direction, suggesting that the hot gas is sloshing in the gravitational potential. This sloshing has resulted in cold fronts, at distances of 50, 110, and 325 kpc from the cluster center. Our results indicate that the core of A1664 is highly disturbed, as the global metallicity and cooling time flatten at small radii, implying mixing on a range of scales. The central active galactic nucleus (AGN) appears to have recently undergone a mechanical outburst, as evidenced by our detection of cavities. These cavities are the X-ray manifestations of radio bubbles inflated by the AGN and may explain the motion of cold molecular CO clouds previously observed with the Atacama Large Millimeter Array (ALMA). The estimated mechanical power of the AGN, using the minimum energy required to inflate the cavities as a proxy, is erg s−1, which may be enough to drive the molecular gas flows, and offset the cooling luminosity of the intracluster medium, at erg s−1. This mechanical power is orders of magnitude higher than the measured upper limit on the X-ray luminosity of the central AGN, suggesting that its black hole may be extremely massive and/or radiatively inefficient. We map temperature variations on the same spatial scale as the molecular gas and find that the most rapidly cooling gas is mostly coincident with the molecular gas reservoir centered on the brightest cluster galaxy’s systemic velocity observed with ALMA and may be fueling cold accretion onto the central black hole. [ABSTRACT FROM AUTHOR]

We present the results of a detailed multiwavelength study of a sample of 16 narrow-line Seyfert 1 (NLSy1) galaxies known in γ-rays so far. This includes a focused X-ray spectral analysis, to compare them with a more general NLSy1 population, and a broadband spectral energy distribution (SED) modeling considering the leptonic radiative processes to understand their similarity/dissimilarity with blazars. The X-ray spectra of γ-NLSy1 galaxies exhibit similarities to both typical NLSy1 sources below ≲2 keV and blazars at higher energies. We also find weak evidences of excess absorption in the soft X-ray spectra of three sources and a tentative detection of the Fe line in 1H 0323+342. A comparison of the broadband parameters derived from the SED modeling reveals the similarity of γ-NLSy1 objects to blazars, in particular to flat-spectrum radio quasars. The γ-NLS1 galaxies host relatively low power jets with small bulk Lorentz factors with respect to blazars, and this explains the paucity of such sources in the γ-ray catalogs and identification of even fewer parent population members. Many of the observed features of these intriguing objects suggest that they host low-mass black holes. The accretion rate in Eddington units can be considered as the driving factor to explain the physical properties of γ-NLSy1 sources, similar to that which is known for the general blazar population. [ABSTRACT FROM AUTHOR]

We present recent Chandra X-ray observations of the RX J0821.0+0752 galaxy cluster, in addition to ALMA observations of the CO(1–0) and CO(3–2) line emission tracing the molecular gas in its central galaxy. All of the CO line emission, originating from a molecular gas reservoir, is located several kiloparsecs away from the nucleus of the central galaxy. The cold gas is concentrated into two main clumps surrounded by a diffuse envelope. They form a wide filament coincident with a plume of bright X-ray emission emanating from the cluster core. This plume encompasses a putative X-ray cavity that is only large enough to have uplifted a small percent of the molecular gas. Unlike other brightest cluster galaxies, stimulated cooling, where X-ray cavities lift low-entropy cluster gas until it becomes thermally unstable, cannot have produced the observed gas reservoir. Instead, the molecular gas has likely formed as a result of sloshing motions in the intracluster medium induced by a nearby galaxy. Sloshing can emulate uplift by dislodging gas from the galactic center. This gas has the shortest cooling time, so it will condense if disrupted for long enough. [ABSTRACT FROM AUTHOR]

We present an analysis of the narrow Fe Kα line in Chandra/HETGS observations of the Seyfert active galactic nucleus (AGN) NGC 4151. The sensitivity and resolution afforded by the gratings reveal asymmetry in this line. Models including weak Doppler boosting, gravitational redshifts, and scattering are generally preferred over Gaussians at the 5σ level of confidence, and generally measure radii consistent with . Separate fits to “high/unobscured” and “low/obscured” phases reveal that the line originates at smaller radii in high-flux states; model-independent tests indicate that this effect is significant at the 4–5σ level. Some models and Δt ≃ 2 × 104 s variations in line flux suggest that the narrow Fe Kα line may originate at radii as small as in high-flux states. These results indicate that the narrow Fe Kα line in NGC 4151 is primarily excited in the innermost part of the optical broad line region (BLR), or X-ray BLR. Alternatively, a warp could provide the solid angle needed to enhance Fe Kα line emission from intermediate radii, and might resolve an apparent discrepancy in the inclination of the innermost and outer disk in NGC 4151. Both warps and the BLR may originate through radiation pressure, so these explanations may be linked. We discuss our results in detail, and consider the potential for future observations with Chandra, XARM, and ATHENA to measure black hole masses and to study the intermediate disk in AGNs using narrow Fe Kα emission lines. [ABSTRACT FROM AUTHOR]

We present a spectral and timing analysis of the newly reported Galactic X-ray transient Swift J1658.2–4242 observed by Nuclear Spectroscopic Telescope Array (NuSTAR) and Swift. The broadband X-ray continuum is typical of a black hole binary in the bright hard state, with a photon index of Γ = 1.63 ± 0.02 and a low coronal temperature of kTe = 22 ± 1 keV, corresponding to a low spectral cutoff well constrained by NuSTAR. Spectral modeling of the relativistic disk reflection features, consisting of a broad Fe Kα line and the Compton reflection hump, reveals that the black hole is rapidly spinning with the spin parameter of a* > 0.96, and the inner accretion disk is viewed at a high inclination angle of (statistical errors, 90% confidence). The high inclination is independently confirmed by dips in the light curves, which can be explained by absorbing material located near the disk plane temporarily obscuring the central region. In addition, we detect an absorption line in the NuSTAR spectra centered at keV. If associated with ionized Fe K absorption lines, this provides evidence for the presence of outflowing material in the low/hard state of a black hole binary candidate. A timing analysis shows the presence of a type-C quasi-periodic oscillation in the power spectrum, with the frequency increasing from ∼0.14 to ∼0.21 Hz during the single NuSTAR exposure. Our analysis reveals that Swift J1658.2–4242 displays characteristics typical for a black hole binary that is viewed at a high inclination angle, making it a good system for studying the accretion geometry in black hole binaries. [ABSTRACT FROM AUTHOR]

We present recent ALMA observations of the CO (1–0) and CO (3–2) emission lines in the brightest cluster galaxy of RXC J1504.1−0248, which is one of the most extreme cool core clusters known. The central galaxy contains of molecular gas. The molecular gas morphology is complex and disturbed, showing no evidence for a rotationally supported structure in equilibrium. A total of 80% of the gas is situated within the central 5 kpc of the galactic center, while the remaining gas is located in a 20 kpc long filament. The cold gas has likely condensed out of the hot atmosphere. The filament is oriented along the edge of a putative X-ray cavity, suggesting that active galactic nucleus activity has stimulated condensation. This is energetically feasible, although the morphology is not as conclusive as systems whose molecular filaments trail directly behind buoyant radio bubbles. The velocity gradient along the filament is smooth and shallow. It is only consistent with freefall if it lies within 20° of the plane of the sky. The abundance of clusters with comparably low velocities suggests that the filament is not freefalling. Both the central gas and filamentary gas are coincident with bright UV emission from ongoing star formation. Star formation near the cluster core is consistent with the Kennicutt–Schmidt law. The filament exhibits increased star formation surface densities, possibly resulting from either the consumption of a finite molecular gas supply or spatial variations in the CO-to-H2 conversion factor. [ABSTRACT FROM AUTHOR]

Galaxy cluster cores are pervaded by hot gas which radiates at far too high a rate to maintain any semblance of a steady state; this is referred to as the cooling flow problem. Of the many heating mechanisms that have been proposed to balance radiative cooling, one of the most attractive is the dissipation of acoustic waves generated by active galactic nuclei. Fabian et al. showed that if the waves are nearly adiabatic, wave damping due to heat conduction and viscosity must be well below standard Coulomb rates in order to allow the waves to propagate throughout the core. Because of the importance of this result, we have revisited wave dissipation under galaxy cluster conditions in a way that accounts for the self-limiting nature of dissipation by electron thermal conduction, allows the electron and ion temperature perturbations in the waves to evolve separately, and estimates kinetic effects by comparing to a semicollisionless theory. While these effects considerably enlarge the toolkit for analyzing observations of wavelike structures and developing a quantitative theory for wave heating, the drastic reduction of transport coefficients proposed in Fabian et al. remains the most viable path to acoustic wave heating of galaxy cluster cores. [ABSTRACT FROM AUTHOR]

We present broadband X-ray analyses of a sample of bright ultraluminous X-ray sources (ULX) with the goal of investigating the spectral similarity of this population to the known ULX pulsars, M82 X-2, NGC 7793 P13, and NGC 5907 ULX. We perform a phase-resolved analysis of the broadband XMM-Newton+NuSTAR data set of NGC 5907 ULX, finding that the pulsed emission from the accretion column in this source exhibits a similar spectral shape to that seen in both M82 X-2 and NGC 7793 P13, and that this is responsible for the excess emission observed at the highest energies when the spectra are fit with accretion disk models. We then demonstrate that similar “hard” excesses are seen in all ULXs in the broadband sample. Finally, for ULXs where the nature of the accretor is currently unknown, we test whether the hard excesses are all consistent with being produced by an accretion column similar to those present in M82 X-2, NGC 7793 P13, and NGC 5907 ULX. Based on the average shape of the pulsed emission, we find that in all cases a similar accretion column can successfully reproduce the observed data, consistent with the hypothesis that this ULX sample may be dominated by neutron star accretors. Compared to the known pulsar ULXs, our spectral fits for the remaining ULXs suggest that the non-pulsed emission from the accretion flow beyond the magnetosphere makes a stronger relative contribution than the component associated with the accretion column. If these sources do also contain neutron star accretors, this may help to explain the lack of detected pulsations. [ABSTRACT FROM AUTHOR]

We present ALMA Cycle 4 observations of CO(1-0), CO(3-2), and 13CO(3-2) line emission in the brightest cluster galaxy (BCG) of RXJ0821+0752. This is one of the first detections of 13CO line emission in a galaxy cluster. Half of the CO(3-2) line emission originates from two clumps of molecular gas that are spatially offset from the galactic center. These clumps are surrounded by diffuse emission that extends 8 kpc in length. The detected 13CO emission is confined entirely to the two bright clumps, with any emission outside of this region lying below our detection threshold. Two distinct velocity components with similar integrated fluxes are detected in the 12CO spectra. The narrower component (60 km s−1 FWHM) is consistent in both velocity centroid and linewidth with 13CO(3-2) emission, while the broader (130–160 km s−1), slightly blueshifted wing has no associated 13CO(3-2) emission. A simple local thermodynamic model indicates that the 13CO emission traces 2.1 × 109M⊙ of molecular gas. Isolating the 12CO velocity component that accompanies the 13CO emission yields a CO-to-H2 conversion factor of αCO = 2.3 M⊙ (K km s−1)−1, which is a factor of two lower than the Galactic value. Adopting the Galactic CO-to-H2 conversion factor in BCGs may therefore overestimate their molecular gas masses by a factor of two. This is within the object-to-object scatter from extragalactic sources, so calibrations in a larger sample of clusters are necessary in order to confirm a sub-Galactic conversion factor. [ABSTRACT FROM AUTHOR]

We present first results from a series of NuSTAR observations of the black hole X-ray binary V404 Cyg obtained during its summer 2015 outburst, primarily focusing on observations during the height of this outburst activity. The NuSTAR data show extreme variability in both the flux and spectral properties of the source. This is partly driven by strong and variable line-of-sight absorption, similar to previous outbursts. The latter stages of this observation are dominated by strong flares, reaching luminosities close to Eddington. During these flares, the central source appears to be relatively unobscured and the data show clear evidence for a strong contribution from relativistic reflection, providing a means to probe the geometry of the innermost accretion flow. Based on the flare properties, analogies with other Galactic black hole binaries, and also the simultaneous onset of radio activity, we argue that this intense X-ray flaring is related to transient jet activity during which the ejected plasma is the primary source of illumination for the accretion disk. If this is the case, then our reflection modeling implies that these jets are launched in close proximity to the black hole (as close as a few gravitational radii), consistent with expectations for jet launching models that tap either the spin of the central black hole, or the very innermost accretion disk. Our analysis also allows us to place the first constraints on the black hole spin for this source, which we find to be (99% statistical uncertainty, based on an idealized lamp-post geometry). [ABSTRACT FROM AUTHOR]

We present results from four new broadband X-ray observations of the extreme ultraluminous X-ray source Holmberg IX X-1 ( erg s−1), performed by Suzaku and NuSTAR in coordination. Combined with the archival data, we now have broadband observations of this remarkable source from six separate epochs. Two of these new observations probe lower fluxes than seen previously, allowing us to extend our knowledge of the broadband spectral variability exhibited. The spectra are well fit by two thermal blackbody components that dominate the emission below 10 keV, as well as a steep () power-law tail that dominates above ∼15 keV. Remarkably, while the 0.3–10.0 keV flux varies by a factor of ∼3 between all these epochs, the 15–40 keV flux varies by only ∼20%. Although the spectral variability is strongest in the ∼1–10 keV band, both of the thermal components are required to vary when all epochs are considered. We also revisit the search for iron absorption features by leveraging the high-energy NuSTAR data to improve our sensitivity to extreme velocity outflows in light of the ultra-fast outflow recently detected in NGC 1313 X-1. Iron absorption from a similar outflow along our line of sight can be ruled out in this case. We discuss these results in the context of super-Eddington accretion models that invoke a funnel-like geometry for the inner flow, and propose a scenario in which we have an almost face-on view of a funnel that expands to larger radii with increasing flux, resulting in an increasing degree of geometrical collimation for the emission from intermediate-temperature regions. [ABSTRACT FROM AUTHOR]

We report new ALMA observations of the CO(3-2) line emission from the molecular gas reservoir in the central galaxy of the Phoenix cluster. The cold molecular gas is fueling a vigorous starburst at a rate of and powerful black hole activity in the forms of both intense quasar radiation and radio jets. The radio jets have inflated huge bubbles filled with relativistic plasma into the hot, X-ray atmospheres surrounding the host galaxy. The ALMA observations show that extended filaments of molecular gas, each long with a mass of several billion solar masses, are located along the peripheries of the radio bubbles. The smooth velocity gradients and narrow line widths along each filament reveal massive, ordered molecular gas flows around each bubble, which are inconsistent with gravitational free-fall. The molecular clouds have been lifted directly by the radio bubbles, or formed via thermal instabilities induced in low-entropy gas lifted in the updraft of the bubbles. These new data provide compelling evidence for close coupling between the radio bubbles and the cold gas, which is essential to explain the self-regulation of feedback. The very feedback mechanism that heats hot atmospheres and suppresses star formation may also paradoxically stimulate production of the cold gas required to sustain feedback in massive galaxies. [ABSTRACT FROM AUTHOR]

Continuum and reflection spectral models have each been widely employed in measuring the spins of accreting black holes. However, the two approaches have not been implemented together in a photon-conserving, self-consistent framework. We develop such a framework using the black hole X-ray binary GX 339–4 as a touchstone source, and we demonstrate three important ramifications. (1) Compton scattering of reflection emission in the corona is routinely ignored, but is an essential consideration given that reflection is linked to the regimes with strongest Comptonization. Properly accounting for this causes the inferred reflection fraction to increase substantially, especially for the hard state. Another important impact of the Comptonization of reflection emission by the corona is the downscattered tail. Downscattering has the potential to mimic the relativistically broadened red wing of the Fe line associated with a spinning black hole. (2) Recent evidence for a reflection component with a harder spectral index than the power-law continuum is naturally explained as Compton-scattered reflection emission. (3) Photon conservation provides an important constraint on the hard state’s accretion rate. For bright hard states, we show that disk truncation to large scales is unlikely as this would require accretion rates far in excess of the observed of the brightest soft states. Our principal conclusion is that when modeling relativistically broadened reflection, spectral models should allow for coronal Compton scattering of the reflection features, and when possible, take advantage of the additional constraining power from linking to the thermal disk component. [ABSTRACT FROM AUTHOR]

Disk and wind signatures are seen in the soft state of Galactic black holes, while the jet is seen in the hard state. Here we study the disk–wind connection in the ρ class of variability in GRS 1915+105 using a joint NuSTAR–Chandra observation. The source shows 50 s limit cycle oscillations. By including new information provided by the reflection spectrum and using phase-resolved spectroscopy, we find that the change in the inner disk inferred from the blackbody emission is not matched by reflection measurements. The latter is almost constant, independent of the continuum model. The two radii are comparable only if the disk temperature color correction factor changes, an effect that could be due to the changing opacity of the disk caused by changes in metal abundances. The disk inclination is similar to that inferred from the jet axis, and oscillates by ∼10°. The simultaneous Chandra data show the presence of two wind components with velocities between 500 and 5000 km s−1, and possibly two more with velocities reaching 20,000 km s−1 (∼0.06 c). The column densities are ∼5 × 1022 cm−2. An upper limit to the wind response time of 2 s is measured, implying a launch radius of <6 × 1010 cm. The changes in wind velocity and absorbed flux require the geometry of the wind to change during the oscillations, constraining the wind to be launched from a distance of 290–1300 rg from the black hole. Both data sets support fundamental model predictions in which a bulge originates in the inner disk and moves outward as the instability progresses. [ABSTRACT FROM AUTHOR]

We present ALMA CO(1–0) and CO(3–2) observations of the brightest cluster galaxy (BCG) in the 2A 0335+096 galaxy cluster (z = 0.0346). The total molecular gas mass of 1.13 ± 0.15 × 109M⊙ is divided into two components: a nuclear region and a 7 kpc long dusty filament. The central molecular gas component accounts for 3.2 ± 0.4 × 108M⊙ of the total supply of cold gas. Instead of forming a rotationally supported ring or disk, it is composed of two distinct, blueshifted clumps south of the nucleus and a series of low-significance redshifted clumps extending toward a nearby companion galaxy. The velocity of the redshifted clouds increases with radius to a value consistent with the companion galaxy, suggesting that an interaction between these galaxies <20 Myr ago disrupted a pre-existing molecular gas reservoir within the BCG. Most of the molecular gas, 7.8 ± 0.9 × 108M⊙, is located in the filament. The CO emission is co-spatial with a 104 K emission-line nebula and soft X-rays from 0.5 keV gas, indicating that the molecular gas has cooled out of the intracluster medium over a period of 25–100 Myr. The filament trails an X-ray cavity, suggesting that the gas has cooled from low-entropy gas that has been lifted out of the cluster core and become thermally unstable. We are unable to distinguish between inflow and outflow along the filament with the present data. Cloud velocities along the filament are consistent with gravitational free-fall near the plane of the sky, although their increasing blueshifts with radius are consistent with outflow. [ABSTRACT FROM AUTHOR]

Observation shows that nebular emission, molecular gas, and young stars in giant galaxies are associated with rising X-ray bubbles inflated by radio jets launched from nuclear black holes. We propose a model where molecular clouds condense from low-entropy gas caught in the updraft of rising X-ray bubbles. The low-entropy gas becomes thermally unstable when it is lifted to an altitude where its cooling time is shorter than the time required to fall to its equilibrium location in the galaxy, i.e., . The infall speed of a cloud is bounded by the lesser of its free-fall and terminal speeds, so that the infall time here can exceed the free-fall time by a significant factor. This mechanism is motivated by Atacama Large Millimeter Array observations revealing molecular clouds lying in the wakes of rising X-ray bubbles with velocities well below their free-fall speeds. Our mechanism would provide cold gas needed to fuel a feedback loop while stabilizing the atmosphere on larger scales. The observed cooling time threshold of —the clear-cut signature of thermal instability and the onset of nebular emission and star formation—may result from the limited ability of radio bubbles to lift low-entropy gas to altitudes where thermal instabilities can ensue. Outflowing molecular clouds are unlikely to escape, but instead return to the central galaxy in a circulating flow. We contrast our mechanism to precipitation models where the minimum value of triggers thermal instability, which we find to be inconsistent with observation. [ABSTRACT FROM AUTHOR]

We present a multi-epoch hard X-ray analysis of Cygnus X-1 in its soft state based on four observations with the Nuclear Spectroscopic Telescope Array (NuSTAR). Despite the basic similarity of the observed spectra, there is clear spectral variability between epochs. To investigate this variability, we construct a model incorporating both the standard disk-corona continuum and relativistic reflection from the accretion disk, based on prior work on Cygnus X-1, and apply this model to each epoch independently. We find excellent consistency for the black hole spin and the iron abundance of the accretion disk, which are expected to remain constant on observational timescales. In particular, we confirm that Cygnus X-1 hosts a rapidly rotating black hole, , in broad agreement with the majority of prior studies of the relativistic disk reflection and constraints on the spin obtained through studies of the thermal accretion disk continuum. Our work also confirms the apparent misalignment between the inner disk and the orbital plane of the binary system reported previously, finding the magnitude of this warp to be ∼10°–15°. This level of misalignment does not significantly change (and may even improve) the agreement between our reflection results and the thermal continuum results regarding the black hole spin. The spectral variability observed by NuSTAR is dominated by the primary continuum, implying variability in the temperature of the scattering electron plasma. Finally, we consistently observe absorption from ionized iron at ∼6.7 keV, which varies in strength as a function of orbital phase in a manner consistent with the absorbing material being an ionized phase of the focused stellar wind from the supergiant companion star. [ABSTRACT FROM AUTHOR]

We report on observations of the neutron star (NS) residing in the low-mass X-ray binary 1RXS J180408.9-34205 taken 2015 March by NuSTAR and XMM-Newton while the source was in the hard spectral state. We find multiple reflection features (Fe detected with NuSTAR; N vii, O vii, and O viii detected in the RGS) from different ionization zones. Through joint fits using the self-consistent relativistic reflection model relxill, we determine the inner radius to be ≤11.1 Rg. For a 1.4 NS with a spin of , this is an inner disk radius of km. We find the inclination of the system to be between 18° and 29°. If the disk is truncated at a radius greater than the NS radius, it could be truncated by a boundary layer on the NS surface. It is also possible that the disk is truncated at the magnetospheric radius; conservative estimates would then imply G at the magnetic poles, though coherent pulsations have not been detected and the source is not identified as a pulsar. [ABSTRACT FROM AUTHOR]

Broad Fe K emission lines have been widely observed in the X-ray spectra of black hole systems as well as in neutron star systems. The intrinsically narrow Fe K fluorescent line is generally believed to be part of the reflection spectrum originating in an illuminated accretion disk which is broadened by strong relativistic effects. However, the nature of the lines in neutron star low-mass X-ray binaries (LMXBs) has been a matter of debate. We therefore obtained the longest, high-resolution X-ray spectrum of a neutron star LMXB to date with a 300 ks Chandra High Energy Transmission Grating Spectrometer (HETGS) observation of Serpens X-1. The observation was taken under the “continuous clocking” mode, and thus was free of photon pile-up effects. We carry out a systematic analysis and find that the blurred reflection model fits the Fe line of Serpens X-1 significantly better than a broad Gaussian component does, implying that the relativistic reflection scenario is much preferred. Chandra HETGS also provides a highest spectral resolution view of the Fe K region and we find no strong evidence for additional narrow lines. [ABSTRACT FROM AUTHOR]

We present a multi-epoch X-ray spectral analysis of the Seyfert 1 galaxy Fairall 9. Our analysis shows that Fairall 9 displays unique spectral variability in that its ratio residuals to a simple absorbed power law in the 0.5–10 keV band remain constant with time in spite of large variations in flux. This behavior implies an unchanging source geometry and the same emission processes continuously at work at the timescale probed. With the constraints from NuSTAR on the broad-band spectral shape, it is clear that the soft excess in this source is a superposition of two different processes, one being blurred ionized reflection in the innermost parts of the accretion disk, and the other a continuum component such as a spatially distinct Comptonizing region. Alternatively, a more complex primary Comptonization component together with blurred ionized reflection could be responsible. [ABSTRACT FROM AUTHOR]

We present the first direct measurements of the rest-frame 10–40 keV X-ray luminosity function (XLF) of active galactic nuclei (AGNs) based on a sample of 94 sources at 0.1 < z < 3, selected at 8–24 keV energies from sources in the Nuclear Spectroscopic Telescope Array (NuSTAR) extragalactic survey program. Our results are consistent with the strong evolution of the AGN population seen in prior, lower-energy studies of the XLF. However, different models of the intrinsic distribution of absorption, which are used to correct for selection biases, give significantly different predictions for the total number of sources in our sample, leading to small, systematic differences in our binned estimates of the XLF. Adopting a model with a lower intrinsic fraction of Compton-thick sources and a larger population of sources with column densities cm−2 or a model with stronger Compton reflection component (with a relative normalization of R ∼ 2 at all luminosities) can bring extrapolations of the XLF from 2–10 keV into agreement with our NuSTAR sample. Ultimately, X-ray spectral analysis of the NuSTAR sources is required to break this degeneracy between the distribution of absorbing column densities and the strength of the Compton reflection component and thus refine our measurements of the XLF. Furthermore, the models that successfully describe the high-redshift population seen by NuSTAR tend to over-predict previous, high-energy measurements of the local XLF, indicating that there is evolution of the AGN population that is not fully captured by the current models. [ABSTRACT FROM AUTHOR]

We present the results from a joint Suzaku/NuSTAR broadband spectral analysis of 3C 390.3. The high quality data enables us to clearly separate the primary continuum from the reprocessed components allowing us to detect a high energy spectral cut-off ( keV), and to place constraints on the Comptonization parameters of the primary continuum for the first time. The hard over soft compactness is and the optical depth is this leads to an electron temperature of keV. Expanding our study of the Comptonization spectrum to the optical/UV by studying the simultaneous Swift-UVOT data, we find indications that the compactness of the corona allows only a small fraction of the total UV/optical flux to be Comptonized. Our analysis of the reprocessed emission show that 3C 390.3 only has a small amount of reflection (R ∼ 0.3), and of that the vast majority is from distant neutral matter. However, we also discover a soft-X-ray excess in the source, which can be described by a weak ionized reflection component from the inner parts of the accretion disk. In addition to the backscattered emission, we also detect the highly ionized iron emission lines Fe xxv and Fe xxvi. [ABSTRACT FROM AUTHOR]

We present results from a 244 ks NuSTAR observation of 3C 273 obtained during a cross-calibration campaign with the Chandra, INTEGRAL, Suzaku, Swift, and XMM-Newton observatories. We show that the spectrum, when fit with a power-law model using data from all observatories except INTEGRAL over the 1–78 keV band, leaves significant residuals in the NuSTAR data between 30 and 78 keV. The NuSTAR 3–78 keV spectrum is well described by an exponentially cutoff power law ( keV) with a weak reflection component from cold, dense material. There is also evidence for a weak ( eV) neutral iron line. We interpret these features as arising from coronal emission plus reflection off an accretion disk or distant material. Beyond 80 keV INTEGRAL data show clear excess flux relative to an extrapolation of the active galactic nucleus model fit to NuSTAR. This high-energy power law is consistent with the presence of a beamed jet, which begins to dominate over emission from the inner accretion flow at 30–40 keV. Modeling the jet locally (in the NuSTAR + INTEGRAL band) as a power law, we find that the coronal component is fit by and jet photon index by We also consider Fermi/LAT observations of 3C 273, and here the broadband spectrum of the jet can be described by a log-parabolic model, peaking at ∼2 MeV. Finally, we investigate the spectral variability in the NuSTAR band and find an inverse correlation between flux and Γ. [ABSTRACT FROM AUTHOR]

We present new ultraviolet, optical, and X-ray data on the Phoenix galaxy cluster (SPT-CLJ2344-4243). Deep optical imaging reveals previously undetected filaments of star formation, extending to radii of ∼50–100 kpc in multiple directions. Combined UV-optical spectroscopy of the central galaxy reveals a massive (2 × 109M⊙), young (∼4.5 Myr) population of stars, consistent with a time-averaged star formation rate of 610 ± 50 M⊙ yr−1. We report a strong detection of O vi λλ1032,1038, which appears to originate primarily in shock-heated gas, but may contain a substantial contribution (>1000 M⊙ yr−1) from the cooling intracluster medium (ICM). We confirm the presence of deep X-ray cavities in the inner ∼10 kpc, which are among the most extreme examples of radio-mode feedback detected to date, implying jet powers of 2–7 × 1045 erg s−1. We provide evidence that the active galactic nucleus inflating these cavities may have only recently transitioned from “quasar-mode” to “radio-mode,” and may currently be insufficient to completely offset cooling. A model-subtracted residual X-ray image reveals evidence for prior episodes of strong radio-mode feedback at radii of ∼100 kpc, with extended “ghost” cavities indicating a prior epoch of feedback roughly 100 Myr ago. This residual image also exhibits significant asymmetry in the inner ∼200 kpc (0.15R500), reminiscent of infalling cool clouds, either due to minor mergers or fragmentation of the cooling ICM. Taken together, these data reveal a rapidly evolving cool core which is rich with structure (both spatially and in temperature), is subject to a variety of highly energetic processes, and yet is cooling rapidly and forming stars along thin, narrow filaments. [ABSTRACT FROM AUTHOR]

We present simultaneous Nuclear Spectroscopic Telescope Array (NuSTAR ) and Suzaku observations of the X-ray binary Cygnus X-1 in the hard state. This is the first time this state has been observed in Cyg X-1 with NuSTAR, which enables us to study the reflection and broadband spectra in unprecedented detail. We confirm that the iron line cannot be fit with a combination of narrow lines and absorption features, instead requiring a relativistically blurred profile in combination with a narrow line and absorption from the companion wind. We use the reflection models of García et al. to simultaneously measure the black hole spin, disk inner radius, and coronal height in a self-consistent manner. Detailed fits to the iron line profile indicate a high level of relativistic blurring, indicative of reflection from the inner accretion disk. We find a high spin, a small inner disk radius, and a low source height and rule out truncation to greater than three gravitational radii at the 3σ confidence level. In addition, we find that the line profile has not changed greatly in the switch from soft to hard states, and that the differences are consistent with changes in the underlying reflection spectrum rather than the relativistic blurring. We find that the blurring parameters are consistent when fitting either just the iron line or the entire broadband spectrum, which is well modeled with a Comptonized continuum plus reflection model. [ABSTRACT FROM AUTHOR]

We present the results from coordinated X-ray observations of the ultraluminous X-ray source NGC 5204 X-1 performed by the Nuclear Spectroscopic Telescope Array and XMM-Newton in early 2013. These observations provide the first detection of NGC 5204 X-1 above , extending the broadband coverage to . The observations were carried out in two epochs separated by approximately 10 days, and showed little spectral variation with an observed luminosity of erg s−1. The broadband spectrum robustly confirms the presence of a clear spectral downturn above seen in some previous observations. This cutoff is inconsistent with the standard low/hard state seen in Galactic black hole binaries, as would be expected from an intermediate-mass black hole accreting at significantly sub-Eddington rates given the observed luminosity. The continuum is apparently dominated by two optically thick thermal-like components, potentially accompanied by a faint high-energy tail. The broadband spectrum is likely associated with an accretion disk that differs from a standard Shakura & Sunyaev thin disk. [ABSTRACT FROM AUTHOR]

We present X-ray timing and spectral analyses of simultaneous 150 ks Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku X-ray observations of the Seyfert 1.5 galaxy NGC 4151. We disentangle the continuum emission, absorption, and reflection properties of the active galactic nucleus (AGN) by applying inner accretion disk reflection and absorption-dominated models. With a time-averaged spectral analysis, we find strong evidence for relativistic reflection from the inner accretion disk. We find that relativistic emission arises from a highly ionized inner accretion disk with a steep emissivity profile, which suggests an intense, compact illuminating source. We find a preliminary, near-maximal black hole spin accounting for statistical and systematic modeling errors. We find a relatively moderate reflection fraction with respect to predictions for the lamp post geometry, in which the illuminating corona is modeled as a point source. Through a time-resolved spectral analysis, we find that modest coronal and inner disk reflection (IDR) flux variation drives the spectral variability during the observations. We discuss various physical scenarios for the IDR model and we find that a compact corona is consistent with the observed features. [ABSTRACT FROM AUTHOR]

We present the first broadband 0.3–25.0 keV X-ray observations of the bright ultraluminous X-ray source (ULX) Holmberg II X-1, performed by NuSTAR, XMM-Newton, and Suzaku in 2013 September. The NuSTAR data provide the first observations of Holmberg II X-1 above 10 keV and reveal a very steep high-energy spectrum, similar to other ULXs observed by NuSTAR to date. These observations further demonstrate that ULXs exhibit spectral states that are not typically seen in Galactic black hole binaries. Comparison with other sources implies that Holmberg II X-1 accretes at a high fraction of its Eddington accretion rate and possibly exceeds it. The soft X-ray spectrum ( keV) appears to be dominated by two blackbody-like emission components, the hotter of which may be associated with an accretion disk. However, all simple disk models under-predict the NuSTAR data above ∼10 keV and require an additional emission component at the highest energies probed, implying the NuSTAR data does not fall away with a Wien spectrum. We investigate physical origins for such an additional high-energy emission component and favor a scenario in which the excess arises from Compton scattering in a hot corona of electrons with some properties similar to the very high state seen in Galactic binaries. The observed broadband 0.3–25.0 keV luminosity inferred from these epochs is erg s−1, typical for Holmberg II X-1, with the majority of this flux (∼90%) emitted below 10 keV. [ABSTRACT FROM AUTHOR]

We report on a 10 ks simultaneous Chandra/High Energy Transmission Grating (HETG)–Nuclear Spectroscopic Telescope Array (NuSTAR) observation of the Bursting Pulsar, GRO J1744-28, during its third detected outburst since discovery and after nearly 18 yr of quiescence. The source is detected up to 60 keV with an Eddington persistent flux level. Seven bursts, followed by dips, are seen with Chandra, three of which are also detected with NuSTAR. Timing analysis reveals a slight increase in the persistent emission pulsed fraction with energy (from 10% to 15%) up to 10 keV, above which it remains constant. The 0.5–70 keV spectra of the persistent and dip emission are the same within errors and well described by a blackbody (BB), a power-law (PL) with an exponential rolloff, a 10 keV feature, and a 6.7 keV emission feature, all modified by neutral absorption. Assuming that the BB emission originates in an accretion disk, we estimate its inner (magnetospheric) radius to be about 4 × 107 cm, which translates to a surface dipole field B ≈ 9 × 1010 G. The Chandra/HETG spectrum resolves the 6.7 keV feature into (quasi-)neutral and highly ionized Fe xxv and Fe xxvi emission lines. XSTAR modeling shows these lines to also emanate from a truncated accretion disk. The burst spectra, with a peak flux more than an order of magnitude higher than Eddington, are well fit with a PL with an exponential rolloff and a 10 keV feature, with similar fit values compared to the persistent and dip spectra. The burst spectra lack a thermal component and any Fe features. Anisotropic (beamed) burst emission would explain both the lack of the BB and any Fe components. [ABSTRACT FROM AUTHOR]

CGRaBS J0809+5341, a high-redshift blazar at z = 2.144, underwent a giant optical outburst on 2014 April 19 when it brightened by ∼5 mag and reached an unfiltered apparent magnitude of 15.7 mag. This implies an absolute magnitude of −30.5 mag, making it one of the brightest quasars in the universe. This optical flaring triggered us to carry out observations during the decaying part of the flare covering a wide energy range using the Nuclear Spectroscopic Telescope Array, Swift, and ground-based optical facilities. For the first time, the source is detected in γ-rays by the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope. A high optical polarization of ∼10% is also observed. Using the Sloan Digital Sky Survey spectrum, the accretion disk luminosity and black hole mass are estimated as 1.5 × 1045 erg s−1 and 108.4M⊙, respectively. Using a single zone leptonic emission model, we reproduce the spectral energy distribution of the source during the flaring activity. This analysis suggests that the emission region is probably located outside the broad-line region, and the jet becomes radiatively efficient. We also show that the overall properties of CGRaBS J0809+5341 seem to not be in agreement with the general properties observed in high-redshift blazars up to now. [ABSTRACT FROM AUTHOR]