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On the Absence of High-redshift AGNs: Little Growth in the Supermassive Black Hole Population at High Redshifts
Bauer, F. E.; Barger, A. J.; Cowie, L. L. +1 more
We search for high-redshift (z > 4.5) X-ray active galactic nuclei (AGNs) in the deep central (off-axis angle < 5'7) region of the 7 Ms Chandra Deep Field-South X-ray image. We compile an initial candidate sample from direct X-ray detections. We then probe more deeply in the X-ray data by using preselected samples with high spatial resolutio…
HATS-47b, HATS-48Ab, HATS-49b, and HATS-72b: Four Warm Giant Planets Transiting K Dwarfs
Latham, David W.; Jordán, Andrés; Butler, R. P. +43 more
We report the discovery of four transiting giant planets around K dwarfs. The planets HATS-47b, HATS-48Ab, HATS-49b, and HATS-72b have masses of ${0.369}_{-0.021}^{+0.031} ${M}_{{\rm{J}}}, ${0.243}_{-0.030}^{+0.022} ${M}_{{\rm{J}}}, ${0.353}_{-0.027}^{+0.038} ${M}_{{\rm{J}}}, and $0.1254\pm 0.0039 ${M}_{{\rm{J}}}, respectively, and radii of $1.117…
Robust diffraction-limited near-infrared-to-near-ultraviolet wide-field imaging from stratospheric balloon-borne platforms—Super-pressure Balloon-borne Imaging Telescope performance
Jauzac, Mathilde; Tam, Sut-Ieng; Benton, Steven J. +26 more
At a fraction of the total cost of an equivalent orbital mission, scientific balloon-borne platforms, operating above 99.7% of the Earth's atmosphere, offer attractive, competitive, and effective observational capabilities—namely, space-like seeing, transmission, and backgrounds—which are well suited for modern astronomy and cosmology. The Super-p…
A Magnetic White Dwarf Accretion Model for the Anomalous X-Ray Pulsar 4U 0142+61
Rodrigues, Claudia V.; Coelho, Jaziel G.; Castro, Manuel +2 more
The quiescent emission of the anomalous X-ray pulsar (AXP) 4U 0142+61 extends over a broad range of energy, from radio up to hard X-rays. In particular, this object is unique among soft gamma-ray repeaters (SGRs) and AXPs in presenting simultaneously mid-infrared emission and pulsed optical emission. In spite of the many propositions to explain th…
Relativistic reflection spectra of super-spinning black holes
Tripathi, Ashutosh; Zhou, Biao; Abdikamalov, Askar B. +4 more
We construct a relativistic reflection model in a non-Kerr spacetime in which, depending on the value of the deformation parameter of the metric, there are black hole solutions with spin parameter | a∗|>1 . We apply our model to fit Suzaku data of four Seyfert galaxies (Ton S180, Ark 120, 1H0419-577, and Swift J0501.9-3239). These ga…
The nature of 500 micron risers I: SMA observations
Pérez-Fournon, I.; Clements, D. L.; Conley, A. +4 more
We present SMA observations at resolutions from 0.35 to 3 arcsec of a sample of 34 candidate high redshift dusty star forming galaxies (DSFGs). These sources were selected from the HerMES Herschel survey catalogues to have SEDs rising from 250 to 350 to 500 µm, a population termed 500-risers. We detect counterparts to 24 of these sources, wi…
Accurate mass estimates from the proper motions of dispersion-supported galaxies
Bullock, James S.; Lazar, Alexandres
We derive a new mass estimator that relies on internal proper motion measurements of dispersion-supported stellar systems, one that is distinct and complementary to existing estimators for line-of-sight velocities. Starting with the spherical Jeans equation, we show that there exists a radius where the mass enclosed depends only on the projected t…
MADX - a simple technique for source detection and measurement using multiband imaging from the Herschel-ATLAS survey
Dunne, L.; Maddox, S. J.
We describe the method used to detect sources for the Herschel-ATLAS (Herschel Astrophysical Terahertz Large Area Survey) survey. The method is to filter the individual bands using a matched filter, based on the point spread function (PSF) and confusion noise, and then form the inverse variance-weighted sum of the individual bands, including weigh…
Evolution of supersonic downflows in a sunspot
Mathioudakis, M.; Krishna Prasad, S.; Nelson, C. J.
Context. Supersonic downflows have been observed in transition region spectra above numerous sunspots, however, little research has been conducted to date into how persistent these signatures are within sunspots on timescales longer than a few hours.
Aims: We aim to analyse the lead sunspot of AR 12526 to infer the properties and evolution of…
The Demagnetization of the Venusian Ionosphere under Nearly Flow-aligned Interplanetary Magnetic Fields
Xu, Qi; Zhang, Tielong; Xu, Xiaojun +4 more
Previous studies suggested that the interplanetary magnetic field (IMF) has a significant influence on the Venusian-induced magnetosphere. We present observations by Venus Express under a nearly flow-aligned IMF condition to investigate the demagnetization of the Venusian ionosphere. Our results show that the magnetic barrier becomes weak and narr…