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Constraints on positron annihilation kinematics in the inner Galaxy
Diehl, Roland; Siegert, Thomas; Panther, Fiona H. +4 more
Context. The annihilation of cosmic positrons with electrons in the interstellar medium results in the strongest persistent γ-ray line signal in the sky. For the past 50 yr, this 511 keV emission - predominantly from the galactic bulge region and from a low surface-brightness disk - has puzzled observers and theoreticians. A key issue for understa…
Molecular gas in radio galaxies in dense megaparsec-scale environments at z = 0.4-2.6
Castignani, G.; De Zotti, G.; Benoist, C. +4 more
Context. Low luminosity radio galaxies (LLRGs) typically reside in dense megaparsec-scale environments and are often associated with brightest cluster galaxies (BCGs). They are an excellent tool to study the evolution of molecular gas reservoirs in giant ellipticals, even close to the active galactic nucleus.
Aims: We investigate the role of …
Investigation of the origin of the anomalous microwave emission in Lambda Orionis
Doi, Yasuo; Onaka, Takashi; Kaneda, Hidehiro +5 more
The anomalous microwave emission (AME) still lacks a conclusive explanation. This excess of emission, roughly between 10 and 50 GHz, tends to defy attempts to explain it as synchrotron or free-free emission. The overlap with frequencies important for cosmic microwave background explorations, combined with a strong correlation with interstellar dus…
Spatial and seasonal variations in C3Hx hydrocarbon abundance in Titan's stratosphere from Cassini CIRS observations
Lombardo, Nicholas A.; Nixon, Conor A.; Achterberg, Richard K. +4 more
Of the C3Hx hydrocarbons, propane (C3H8) and propyne (methylacetylene, CH3C2H) were first detected in Titan's atmosphere during the Voyager 1 flyby in 1980. Propene (propylene, C3H6) was first detected in 2013 with data from the Composite InfraRed Spectrometer …
Outgassing-induced acceleration of comet 67P/Churyumov-Gerasimenko
Kramer, T.; Läuter, M.
Context. Cometary activity affects the orbital motion and rotation state through sublimation-induced forces. The availability of precise rotation-axis orientation and position data from the Rosetta mission allows us to accurately determine the outgassing of comet Churyumov-Gerasimenko/67P (67P).
Aims: We derived the observed non-gravitational…
Interplay between pulsation, mass loss, and third dredge-up: More about Miras with and without technetium
Bernhard, K.; Cristallo, S.; McDonald, I. +2 more
Context. We follow-up on a previous finding that AGB Mira variables containing the third dredge-up indicator technetium (Tc) in their atmosphere form a different sequence of K - [22] colour as a function of pulsation period than Miras without Tc. A near- to mid-infrared colour such as K - [22] is a good probe for the dust mass-loss rate of the sta…
Discovery of the first resolved triple white dwarf
Hermes, J. J.; Gänsicke, B. T.; Tremblay, P. -E. +4 more
We report the discovery of J1953-1019, the first resolved triple white dwarf system. The triplet consists of an inner white dwarf binary and a wider companion. Using Gaia DR2 photometry and astrometry combined with our follow-up spectroscopy, we derive effective temperatures, surface gravities, masses, and cooling ages of the three components. All…
A new line on the wide binary test of gravity
Banik, Indranil
The relative velocity distribution of wide binary (WB) stars is sensitive to the law of gravity at the low accelerations typical of galactic outskirts. I consider the feasibility of this wide binary test using the `line velocity' method. This involves considering only the velocity components along the direction within the sky plane orthogonal to t…
2D Isotropic Feature of Solar Wind Turbulence as Shown by Self-correlation Level Contours at Hour Timescales
He, Jiansen; Wang, Xin; Tu, Chuanyi
The slow wind anisotropy is observed by Dasso et al. as elongation along the magnetic field direction in the magnetic self-correlation contours calculated from data sets of two-day-long data and averaged for five years in 1998-2002, which is consistent with prediction by the “critical balance cascade theory.” More pronounced elongation at smaller …
Phase Curves from the Kuiper Belt: Photometric Properties of Distant Kuiper Belt Objects Observed by New Horizons
Buratti, Bonnie J.; Singer, Kelsi N.; Stern, S. Alan +17 more
Prior to its close encounter with the Kuiper Belt object (KBO) (486958) 2014 MU69 on 2019 January 1, NASA’s New Horizons spacecraft observed other KBOs from distances greater than 0.1 au at solar phase angles far larger than those attainable from Earth. The expanded range in phase angle afforded by these distant KBO (DKBO) observations …