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Wide band, tunable gamma-ray lenses
Lund, Niels
A new concept for an astronomical telescope in the MeV energy band is presented. The concept builds on Bragg diffraction in crystals, which has been discussed in the past, but so far a design with good sensitivity over a wide energy range has seemed out of reach. In this paper we point out that if we find ways to adjust, in orbit, the individual t…
Physical Characterization of Serendipitously Uncovered Millimeter-wave Line-emitting Galaxies at z 2.5 behind the Local Luminous Infrared Galaxy VV 114
Tamura, Yoichi; Kohno, Kotaro; Yun, Min S. +11 more
We present a detailed investigation of millimeter-wave line emitters ALMA J010748.3-173028 (ALMA-J0107a) and ALMA J010747.0-173010 (ALMA-J0107b), which were serendipitously uncovered in the background of the nearby galaxy VV 114 with spectral scan observations at λ = 2-3 mm. Via Atacama Large Millimeter/submillimeter Array (ALMA) detection of CO(4…
Evolution of Saturn's north polar color and cloud structure between 2012 and 2017 inferred from Cassini VIMS and ISS observations
Baines, K. H.; Sromovsky, L. A.; Fry, P. M.
Cassini/ISS imagery and Cassini/VIMS spectral imaging observations from 0.35 to 5.12 µm show that Saturn's north polar region (70 °-90 ° N) evolved significantly between 2012 and 2017, with the region poleward of the hexagon changing from dark blue/green to a moderately brighter gold color, except for the inner eye region (88.2 °-90 ° N), wh…
ALMA Observations of the Inner Cavity in the Protoplanetary Disk around Sz 84
Dong, Ruobing; Tamura, Motohide; Takami, Michihiro +5 more
We present Atacama Large Millimeter/submillimeter Array observations of a protoplanetary disk around the T Tauri star Sz 84 and analyses of the structures of the inner cavity in the central region of the dust disk. Sz 84's spectral energy distribution (SED) has been known to exhibit negligible infrared excess at λ ≲ 10 µm due to the disk's c…
The Role of Dust, UV Luminosity and Large-scale Environment on the Escape of Lyα Photons: A Case Study of a Protocluster Field at z = 3.1
Dey, Arjun; Lee, Kyoung-Soo; Huang, Yun +3 more
We present a detailed characterization of the Lyα properties for 93 Lyα emitters (LAEs) at z ~ 3.1 selected from the D1 field of the Canada-France-Hawaii Telescope Legacy Survey, including 24 members of a massive protocluster. The median-stacked Lyα image shows an extended Lyα halo (LAH) surrounding the galaxy with the exponential scale length 4.9…
A new framework for understanding systematic errors in cluster lens modelling - II. Constraint selection
Keeton, Charles R.; Raney, Catie A.; Zimmerman, Dhruv T.
Cluster lens models are affected by a variety of choices in the lens modelling process. We have begun a programme to develop a systematic error budget for cluster lens modelling. Here, we examine the selection of image constraints as a potential systematic effect. For constraining the mass model, we find that it is more important to have images be…
Cold Ionospheric Ions in the Magnetosphere
André, Mats; Toledo-Redondo, Sergio; Yau, Andrew W.
Cold (eV) ions of ionospheric origin are a major source of magnetospheric plasma. These ions dominate the number density for most of the volume of the magnetosphere, most of the time. This affects large-scale physics, including plasma temperature and pressure (and thus instability thresholds) and the Alfvén velocity (and thus energy transport with…
Observational Kinematic Characteristics of Blobs in Solar Coronal Helmet and Pseudo Streamers
Kumar, Pankaj; Cho, Kyung-Suk; Kim, Yeon-Han +4 more
We examine two helmet and two pseudo streamers (HSs and PSs) observed on 2018 and 2019. The HSs (PSs) have dark coronal cavities and stretched loop structures (twin coronal cavities and narrow plasma sheet) at their bases, which are well observed in K-Coronagraph (K-Cor). Their outer-corona structures (top of core, cusp, and stalk) are also clearl…
The Highly Self-absorbed Blazar PKS 1351-018
Frey, Sándor; Chen, Sina; Punsly, Brian +5 more
PKS 1351-018 at a redshift of z = 3.71 is one of the most luminous, steady synchrotron sources with a luminosity >1047 erg s-1. The synchrotron luminosity does not seem to have varied by more than ~25% over 35 yr. In order to appreciate this remarkable behavior, if it were at z = 0.5, it would have a flux density at 15 GHz…
Redshift evolution of X-ray spectral index of quasars observed by XMM-NEWTON/SDSS
Misra, R.; Hayman, Z. M.; Shehata, SH. M. +2 more
We study the X-ray spectral evolution of quasars with red-shift using a sample of 1280 quasars constructed by cross-referencing the XMM-Newton 3 XMM - DR 7 and the optical SDSS-DR14 catalogues. The sources were selected to have a minimum detected X-ray counts >600 and which were not affected by high background. The sample redshift distribution …