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Far Infrared Variability of Sagittarius A*: 25.5 hr of Monitoring with Herschel
Heinke, C. O.; Dowell, C. D.; Schulz, B. +3 more
Variable emission from Sgr A*, the luminous counterpart to the super-massive black hole at the center of our Galaxy, arises from the innermost portions of the accretion flow. Better characterization of the variability is important for constraining models of the low-luminosity accretion mode powering Sgr A*, and could further our ability to use var…
New Debris Disks in Nearby Young Moving Groups
Ábrahám, P.; Kóspál, Á.; Henning, Th. +5 more
A significant fraction of nearby young moving group members harbor circumstellar debris dust disks. Due to their proximity and youth, these disks are attractive targets for studying the early evolution of debris dust and planetesimal belts. Here we present 70 and 160 µm observations of 31 systems in the β Pic moving group, and in the Tucana-…
Determining Type Ia Supernova Host Galaxy Extinction Probabilities and a Statistical Approach to Estimating the Absorption-to-reddening Ratio RV
Marleau, Francine; Deustua, Susana; Cikota, Aleksandar
We investigate limits on the extinction values of Type Ia supernovae (SNe Ia) to statistically determine the most probable color excess, E(B - V), with galactocentric distance, and use these statistics to determine the absorption-to-reddening ratio, RV, for dust in the host galaxies. We determined pixel-based dust mass surface density m…
The Circum-Galactic Medium of MASsive Spirals. I. An Overview and a Case Study of NGC 5908
Bregman, Joel N.; Anderson, Michael E.; Crain, Robert A. +2 more
The Circum-Galactic Medium of MASsive Spirals is a project studying the overall content, physical and chemical properties, and spatial distributions of the multi-phase circumgalactic medium around a small sample of the most massive ({M}* ≳ 2× {10}11 {M}⊙ , {v}{rot}\gt 300 {km} {{{s}}}-1) isola…
GeMS/GSAOI Photometric and Astrometric Performance in Dense Stellar Fields
Dalessandro, E.; Saracino, S.; Marchetti, E. +7 more
Ground-based imagers at 8 m class telescopes assisted by multi-conjugate adaptive optics are primary facilities with which to obtain accurate photometry and proper motions in dense stellar fields. We observed the central region of the globular clusters Liller 1 and NGC 6624 with the Gemini Multi-conjugate Adaptive Optics System (GeMS) feeding the …
Discovery of Ubiquitous Fast-Propagating Intensity Disturbances by the Chromospheric Lyman Alpha Spectropolarimeter (CLASP)
Auchère, F.; Giono, G.; Kubo, M. +25 more
High-cadence observations by the slit-jaw (SJ) optics system of the sounding rocket experiment known as the Chromospheric Lyman Alpha Spectropolarimeter (CLASP) reveal ubiquitous intensity disturbances that recurrently propagate in either the chromosphere or the transition region or both at a speed much higher than the speed of sound. The CLASP/SJ…
An Investigation of the Sources of Earth-directed Solar Wind during Carrington Rotation 2053
van Driel-Gesztelyi, L.; Fazakerley, A. N.; Harra, L. K.
In this work we analyze multiple sources of solar wind through a full Carrington Rotation (CR 2053) by analyzing the solar data through spectroscopic observations of the plasma upflow regions and the in situ data of the wind itself. Following earlier authors, we link solar and in situ observations by a combination of ballistic backmapping and pote…
The Dimensionless Age of the Universe: A Riddle for Our Time
Kirshner, Robert P.; Avelino, Arturo
We present the interesting coincidence of cosmology and astrophysics that points toward a dimensionless age of the Universe H 0 t 0 that is close to one. Despite cosmic deceleration for 9 Gyr and acceleration since then, we find H 0 t 0 = 0.96 ± 0.01 for the ΛCDM model that fits SN Ia data from Pan-STARR…
Sodium Absorption Systems toward SN Ia 2014J Originate on Interstellar Scales
Foley, R. J.; Sato, B.; Tanaka, M. +21 more
Na I D absorbing systems toward Type Ia supernovae (SNe Ia) have been intensively studied over the last decade with the aim of finding circumstellar material (CSM), which is an indirect probe of the progenitor system. However, it is difficult to deconvolve CSM components from non-variable, and often dominant, components created by interstellar mat…
The Discovery of Lensed Radio and X-Ray Sources behind the Frontier Fields Cluster MACS J0717.5+3745 with the JVLA and Chandra
Churazov, E.; Zitrin, A.; Rosati, P. +24 more
We report on high-resolution JVLA and Chandra observations of the Hubble Space Telescope (HST) Frontier Cluster MACS J0717.5+3745. MACS J0717.5+3745 offers the largest contiguous magnified area of any known cluster, making it a promising target to search for lensed radio and X-ray sources. With the high-resolution 1.0-6.5 GHz JVLA imaging in A and…