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Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548
Im, M.; Fox, O. D.; Malkan, M. A. +153 more
We present the results of an optical spectroscopic monitoring program targeting NGC 5548 as part of a larger multiwavelength reverberation mapping campaign. The campaign spanned 6 months and achieved an almost daily cadence with observations from five ground-based telescopes. The Hβ and He II λ4686 broad emission-line light curves lag that of the …
The Chemical Composition of an Extrasolar Kuiper-Belt-Object
Zuckerman, B.; Xu, S.; Dufour, P. +3 more
The Kuiper Belt of our solar system is a source of short-period comets that may have delivered water and other volatiles to Earth and the other terrestrial planets. However, the distribution of water and other volatiles in extrasolar planetary systems is largely unknown. We report the discovery of an accretion of a Kuiper-Belt-Object analog onto t…
The Colour and Stereo Surface Imaging System (CaSSIS) for the ExoMars Trace Gas Orbiter
Mangold, N.; Hansen, C. J.; Cremonese, G. +58 more
The Colour and Stereo Surface Imaging System (CaSSIS) is the main imaging system onboard the European Space Agency's ExoMars Trace Gas Orbiter (TGO) which was launched on 14 March 2016. CaSSIS is intended to acquire moderately high resolution (4.6 m/pixel) targeted images of Mars at a rate of 10-20 images per day from a roughly circular orbit 400 …
Seasonal mass transfer on the nucleus of comet 67P/Chuyumov-Gerasimenko
Jorda, L.; Bertaux, J. -L.; Lamy, P. +47 more
We collect observational evidence that supports the scheme of mass transfer on the nucleus of comet 67P/Churyumov-Gerasimenko. The obliquity of the rotation axis of 67P causes strong seasonal variations. During perihelion the southern hemisphere is four times more active than the north. Northern territories are widely covered by granular material …
The production and escape of Lyman-Continuum radiation from star-forming galaxies at z ∼ 2 and their redshift evolution
Sobral, David; Khostovan, Ali Ahmad; Bouwens, Rychard +4 more
We study the production rate of ionizing photons of a sample of 588 Hα emitters (HAEs) and 160 Lyman-α emitters (LAEs) at z = 2.2 in the COSMOS field in order to assess the implied emissivity from galaxies, based on their ultraviolet (UV) luminosity. By exploring the rest-frame Lyman Continuum (LyC) with GALEX/NUV data, we find fesc <…
Winds measured by the Rover Environmental Monitoring Station (REMS) during the Mars Science Laboratory (MSL) rover's Bagnold Dunes Campaign and comparison with numerical modeling using MarsWRF
Bridges, Nathan T.; Sullivan, Robert; Newman, Claire E. +9 more
A high density of REMS wind measurements were collected in three science investigations during MSL's Bagnold Dunes Campaign, which took place over ∼80 sols around southern winter solstice (Ls∼90°) and constituted the first in situ analysis of the environmental conditions, morphology, structure, and composition of an active dune field on Mars. The …
IACHEC Cross-calibration of Chandra, NuSTAR, Swift, Suzaku, XMM-Newton with 3C 273 and PKS 2155-304
Miller, Eric D.; Guainazzi, Matteo; Madsen, Kristin K. +5 more
On behalf of the International Astronomical Consortium for High Energy Calibration, we present results from the cross-calibration campaigns in 2012 on 3C 273 and in 2013 on PKS 2155-304 between the then active X-ray observatories Chandra, NuSTAR, Suzaku, Swift, and XMM-Newton. We compare measured fluxes between instrument pairs in two energy bands…
A Spectroscopic Search for AGN Activity in the Reionization Era
Stark, Daniel P.; Ellis, Richard S.; Zitrin, Adi +4 more
The ubiquity of Lyman alpha (Lyα) emission in a sample of four bright [O III]-strong star-forming galaxies with redshifts above seven has led to the suggestion that such luminous sources represent a distinct population compared with their fainter, more numerous counterparts. The presence of Lyα emission within the reionization era could indicate t…
A Neutron Star Binary Merger Model for GW170817/GRB 170817A/SSS17a
Lee, W. H.; Rest, A.; Foley, R. J. +14 more
The merging neutron star gravitational-wave event GW170817 has been observed throughout the entire electromagnetic spectrum from radio waves to γ-rays. The resulting energetics, variability, and light curves are shown to be consistent with GW170817 originating from the merger of two neutron stars, in all likelihood followed by the prompt gravitati…
Bulge-forming Galaxies with an Extended Rotating Disk at z ~ 2
Übler, Hannah; Tamura, Yoichi; Kohno, Kotaro +24 more
We present 0.″2-resolution Atacama Large Millimeter/submillimeter Array observations at 870 µm for 25 Hα-seleced star-forming galaxies around the main sequence at z = 2.2-2.5. We detect significant 870 µm continuum emission in 16 (64%) of these galaxies. The high-resolution maps reveal that the dust emission is mostly radiated from a s…