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Cosmic Explorer is a concept for a new laser interferometric observatory in the United States to extend ground-based gravitational-wave astrophysics into the coming decades. Aiming to begin operation in the 2030s, Cosmic Explorer will extend current and future detector technologies to a 40 km interferometric baseline—ten times larger than the LIGO observatories. Operating as part of a global gravitational-wave observatory network, Cosmic Explorer will have a cosmological reach, detecting black holes and neutron stars back to the times of earliest star formation. It will observe nearby binary collisions with enough precision to reveal details of the dynamics of the ultradense matter in neutron stars and to test the general-relativistic model of black holes. [ABSTRACT FROM AUTHOR]

Sociologicial analyses of artistic practice have long drawn on theoretical traditions grounded in binaries and dualisms. Such analytical strategies, exemplified here by field theoretical approaches, center art objects and their movements in and across markets, where binaristic visions of art worlds do offer significant leverage. But when the analyst moves away from markets for art objects and looks to artistic practices the binaristic lens provides, at best, a blurred image with meaningful blind spots. This article suggests an alternative vision of artistic practice --one based on gravity rather than polarity--that captures the ways individuals and their actions make sense in a specific universe of meaning without forcing them into fundamentally competitive and economistic relationships. It leverages findings enabled by a unique sampling strategy in a four year study of visual artists in the United States to illuminate some limitations of binary theoretical frameworks, and outlines a generative alternative to dualism that promotes new analytical and theoretical directions for sociological analyses of artists and artistic practice. This alternative model provides new leverage on four persistent issues in analyses of artistic work: cultural change in occupational fields; actors' attempts to manage overlapping but incommensurate forms of recognition, reputation, attention, and success; the persistent hegemony of markets for objects in both vernacular and sociological understandings of artistic practice; and questions of visibility and legitimacy central to understanding boundary formation and boundary work in creative fields. The gravitational metaphor promotes a distict set of strategies for the study of artistic work as well as other nontraditional occupations. [ABSTRACT FROM AUTHOR]

The article discusses the developments in the study about black holes, particularly in the U.S. It claims that black holes could be responsible in creating such spectacular phenomena as active galactic nuclei, quasars and massive jets. It cites that the black hole concept was originated by natural scientist and Anglican rector John Michell in 1783. The opinion by Jacob Bekenstein of the Hebrew University of Jerusalem on black holes is also cited.

ABSTRACT We report the result of a new Chandra observation of the black hole X-ray transient H 1705−250 in quiescence. H 1705−250 was barely detected in the new ∼50 ks Chandra observation. With five detected counts, we estimate the source quiescent luminosity to be LX ∼ 9.1 × 1030 erg s−1 in the 0.5-10 keV band (adopting a distance of 8.6 kpc). This value is in line with the quiescent luminosities found among other black hole X-ray binaries with similar orbital periods. By using images taken with the Faulkes Telescope North, we derive a refined position of H 1705−250. We also present the long-term light curve of the optical counterpart from 2006 to 2012, and show evidence for variability in quiescence. [ABSTRACT FROM AUTHOR]

ABSTRACT In this paper we report on Expanded Very Large Array radio and Chandra and Swift X-ray observations of the outburst decay of the transient black hole candidate MAXI J1659-152 in 2011. We discuss the distance to the source taking the high inclination into account and conclude that the source distance is probably 6 ± 2 kpc. The lowest observed flux corresponds to a luminosity of erg s−1. This, together with the orbital period of 2.4 h reported in the literature, suggests that the quiescent X-ray luminosity is higher than predicted on the basis of the orbital period-quiescent X-ray luminosity relationship. It is more in line with that expected for a neutron star, although the outburst spectral and timing properties reported in the literature strongly suggest that MAXI J1659-152 harbours a black hole. This conclusion is subject to confirmation of the lowest observed flux as the quiescent flux. The relation between the accretion and ejection mechanisms can be studied using the observed correlation between the radio and X-ray luminosities as these evolve over an outburst. We determine the behaviour of MAXI J1659-152 in the radio-X-ray diagram at low X-ray luminosities using the observations reported in this paper and at high X-ray luminosities using values reported in the literature. At high X-ray luminosities, the source lies closer to the sources that follow a correlation index steeper than 0.6-0.7. However, when compared to other sources that follow a steeper correlation index, the X-ray luminosity in MAXI J1659-152 is also lower. The latter can potentially be explained by the high inclination of MAXI J1659-152 if the X-ray emission comes from close to the source and the radio emission is originating in a more extended region. However, it is probable that the source was not in the canonical low-hard state during these radio observations and this may affect the behaviour of the source as well. At intermediate X-ray luminosities, the source makes the transition from the radio underluminous sources in the direction of the relation traced by the 'standard' correlation similar to what has been reported for H 1743−322 in the literature. However, MAXI J1659-152 remains underluminous with respect to this 'standard' correlation. [ABSTRACT FROM AUTHOR]

ABSTRACT A new, transient ultraluminous X-ray source (ULX) was recently discovered by Chandra in M31 with a luminosity at ∼5 × 1039 erg s−1. Here we analyse a series of five subsequent XMM-Newton observations. These show a steady decline in X-ray luminosity over 1.5 months, from 1.8 × 1039 to 0.6 × 1039 erg s−1, giving an observed e-fold time-scale of ∼40 d. This is similar to the decay time-scales seen in multiple soft X-ray transients in our own Galaxy, supporting the interpretation of this ULX as a stellar mass black hole in a low-mass X-ray binary (LMXB), accreting at super-Eddington rates. This is further supported by the lack of detection of an O/B star in quiescence and the spectral behaviour of the XMM-Newton data being dominated by a disc-like component rather than the power law expected from a sub-Eddington intermediate-mass black hole. These data give the best sequence of high Eddington fraction spectra ever assembled due to the combination of low absorption column to M31 and well-calibrated bandpass down to 0.3 keV of XMM-Newton in full frame mode. The spectra can be roughly described by our best current disc model, BHSPEC, assuming a 10 M⊙ black hole with best-fitting spin ∼0.4, declining from L/ LEdd= 0.75 to 0.25. However, the data are better described by a two-component model, where the disc emission is significantly affected by advection, and with an additional low-temperature Comptonization component at high energies which becomes more important at high luminosities. This could simply indicate the limitations of our current disc models, though changes in the energy-dependent variability also weakly supports a two-component interpretation of the data. Irrespective of the detailed interpretation of the spectral properties, these data support the presence of accretion on to a stellar mass black hole in a LMXB accreting in the Eddington regime. This allows an unambiguous connection of this object, and, by extension, similar low-luminosity ULXs, to 'standard' X-ray binaries. [ABSTRACT FROM AUTHOR]

The current generation of flagship X-ray missions, Chandra and XMM-Newton, has changed our understanding of the so-called "cool-core" galaxy clusters and groups. Instead of the initial idea that the thermal gas is cooling and flowing toward the center, the new picture envisages a complex dynamical evolution of the intracluster medium (ICM) regulated by the radiative cooling and the nongravitational heating from the active galactic nucleus (AGN). Understanding the physics of the hot gas and its interplay with the relativistic plasma ejected by the AGN is key for understanding the growth and evolution of galaxies and their central black holes, the history of star formation, and the formation of large-scale structures. It has thus become clear that the feedback from the central black hole must be taken into account in any model of galaxy evolution. In this paper, we draw a qualitative picture of the current knowledge of the effects of the AGN feedback on the ICM by summarizing the recent results in this field. [ABSTRACT FROM AUTHOR]

Abstract: Ultraluminous X-ray sources (ULXs) are accreting black holes that may contain the missing population of intermediate mass black holes or reflect super-Eddington accretion physics. Ten years of Chandra and XMM-Newton observations of ULXs, integrated by multiband studies of their counterparts, have produced a wealth of observational data and phenomenological classifications. We review the properties of their host galaxies, list popular spectral models and implications for standard and supercritical accretion physics, demonstrate how X-ray timing of these objects places constraints on their masses. We also review multiwavelength studies of ULXs, including the optical emission of the binary system and nebulosity around them. We summarize that three classes of black holes could power ULXs: normal stellar mass black holes (∼10M ⊙), massive stellar black holes (≲100M ⊙), and intermediate mass black holes (102–104 M ⊙). We collect evidence for the presence of these three types of compact objects, including caveat of each interpretation, and briefly review their formation processes. [Copyright &y& Elsevier]

The possibility is explored that accretion on an intermediate-mass black hole contributes to the ionization of the interstellar medium of the compact blue dwarf galaxy MRK 996. Chandra observations set tight upper limits (99.7 per cent confidence level) in both the X-ray luminosity of the posited active galactic nucleus (AGN), , and the black hole mass, ≲, where λ is the Eddington ratio. The X-ray luminosity upper limit is insufficient to explain the high-ionization line [O ] , which is observed in the mid-infrared spectrum of MRK 996 and is proposed as evidence for AGN activity. This indicates that shocks associated with supernova explosions and winds of young stars must be responsible for this line. It is also found that the properties of the diffuse X-ray emission of MRK 996 are consistent with this scenario, thereby providing direct evidence for shocks that heat the galaxy's interstellar medium and contribute to its ionization. [ABSTRACT FROM AUTHOR]

The exquisite angular resolution of the Chandra x-ray telescope has enabled the detection and study of resolved x-ray jets in a wide variety of astronomical systems. Chandra has detected extended jets in our galaxy from protostars, symbiotic binaries, neutron star pulsars, black hole binaries, extragalactic jets in radio sources, and quasars. The x-ray data play an essential role in deducing the emission mechanism of the jets, in revealing the interaction of jets with the intergalactic or intracluster media, and in studying the energy generation budget of black holes. [ABSTRACT FROM AUTHOR]

Abstract: Motivated by the proposed EXIST mission, a “medium-class” space observatory to survey black holes and the Early Universe proposed to the 2010 NAS/NRC Astronomy and Astrophysics Decadal Survey, we have developed the first “large” area 256cm2 close-tiled (0.6mm gaps) hard X-ray (20–600keV) imaging detector employing pixelated (2.5mm) CdZnTe (CZT) detectors, each 2×2×0.5cm3. We summarize the design, development and operation of this detector array (8×8 CZTs) and its performance as the imager for a coded aperture telescope on a high altitude (40km) balloon flight in October, 2009, as the ProtoEXIST1 payload. We then outline our current development of a second-generation imager, ProtoEXIST2, with 0.6mm pixels on a 32×32 array on each CZT, and how it will lead to the ultimate imaging system needed for EXIST. Other applications of this technology will also be mentioned. [Copyright &y& Elsevier]

The article presents a study on blazars, a black holes of solar masses sending out particle jets to the speed of light, in the U.S. The researchers revealed the detection of teraelectronvolt (TeV) υ-rays. The high-energy υ-ray emission from blazars was discovered using υ-ray telescope EGRET, a new generation of telescope in the National Aeronautics and Space Administration (NASAs) Compton υ-Ray Observatory. The new findings are based on the atmospheric Cerenkov technique in which a υ-ray is detected through a shower of secondary particles that initiates an optical shock wave as it passes through the atmosphere. Furthermore, the investigation of the structure of blazar jets will remain the prerogative of υ-ray observatories.

The article focuses on the study conducted by K. Hada and colleagues regarding the high-resolution radio images of the origin of a high-speed jet launched near the blackhole of elliptical galaxy M87. It states that the image was obtained using the Very Long Baseline Array (VLBA) interferometer, controlled by the U.S. National Radio Astronomy Observatory which probes the black hole-jet connection in the galaxy. Moreover, images show that the jet flows between the black hole and core.

A quiz related to the gravitational energy of a black holes and the number of electrical plants needed in the U.S. if a complete switch to electric cars is made.

This article states that black holes may be harder to create than previously believed, according to an unexpected discovery made with NASA's Chandra X-ray Observatory. When a massive star exhausts its nuclear fuel and goes supernova, it blasts its outer mantle into space. The remaining core collapses into a small, dense neutron star or a black hole, a region of space where gravity is so strong that not even light can escape it. Astrophysicists used theories of stellar evolution to peg 25 solar masses as the threshold above which anything will end up as a black hole. So a team led by Michael Muno of the University of California, Los Angeles, was surprised to find the pulsating x-ray emission of a neutron star in a young, massive, compact star cluster known as Westerlund 1. As there are 35-solarmass stars still around in the cluster, the researchers guess the neutron star progenitor must have been at least 40 solar masses. Frank Verbunt of Utrecht University in the Netherlands says that if the progenitor star had been part of a binary system, its companion could have siphoned off enough mass to keep the giant star from collapsing into a black hole.

The bigger the supermassive black hole at the centre of a galaxy, the faster the stars in the galactic bulge rotate. Why this should be so has been something of a puzzle, but now a mechanism that is both powerful and common enough to do the job has been identified. [ABSTRACT FROM AUTHOR]

The article reports on the Rapid Response Research (RAPID) mechanism and Very Large Telescope in Chile and National Aeronautics and Space Administration (NASA)'s Chandra space observatory. The National Science Foundation (NSF)'s RAPID mechanism is used to enable research on earthquakes, volcanic eruptions, or any other event. The Very Large Telescope and NASA's Chandra space observatory observed a small black hole blowing a vast bubble of hot gas.