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The SUrvey for Pulsars and Extragalactic Radio Bursts - IV. Discovery and polarimetry of a 12.1-s radio pulsar
Ray, P. S.; Kramer, M.; Johnston, S. +19 more
We report the discovery of PSR J2251-3711, a radio pulsar with a spin period of 12.1 s, the second longest currently known. Its timing parameters imply a characteristic age of 15 Myr, a surface magnetic field of 1.3 × 1013 G, and a spin-down luminosity of 2.9 × 1029 erg s-1. Its dispersion measure of 12.12(1) pc cm…
Global helium abundance measurements in the solar corona
Telloni, Daniele; Antonucci, Ester; Fineschi, Silvano +24 more
Solar abundances have been historically assumed to be representative of cosmic abundances. However, our knowledge of the solar abundance of helium, the second most abundant element, relies mainly on models1 and indirect measurements through helioseismic observations2, because actual measurements of helium in the solar atmosph…
Core-collapse supernovae in binaries as the origin of galactic hyper-runaway stars
Rossi, E. M.; Renzo, M.; Evans, F. A.
Several stars detected moving at velocities near to or exceeding the Galactic escape speed likely originated in the Milky Way disc. We quantitatively explore the 'binary supernova scenario' hypothesis, wherein these 'hyper-runaway' stars are ejected at large peculiar velocities when their close, massive binary companions undergo a core-collapse su…
MKT J170456.2-482100: the first transient discovered by MeerKAT
Heywood, I.; Wijers, R. A. M. J.; Woudt, P. A. +19 more
We report the discovery of the first transient with MeerKAT, MKT J170456.2-482100, discovered in ThunderKAT images of the low-mass X-ray binary GX339-4. MKT J170456.2-482100 is variable in the radio, reaching a maximum flux density of 0.71± 0.11 mJy on 2019 October 12, and is undetected in 15 out of 48 ThunderKAT epochs. MKT J170456.2-482100 is co…
Limits to Rest-frame Ultraviolet Emission from Far-infrared-luminous z ≃ 6 Quasar Hosts
Jahnke, K.; Koekemoer, A. M.; Fan, X. +20 more
We report on a Hubble Space Telescope search for rest-frame ultraviolet emission from the host galaxies of five far-infrared-luminous z ≃ 6 quasars and the z = 5.85 hot-dust-free quasar SDSS J0005-0006. We perform 2D surface brightness modeling for each quasar using a Markov Chain Monte Carlo estimator, to simultaneously fit and subtract the quasa…
The Villafranca catalog of Galactic OB groups. I. Systems with O2-O3.5 stars
Maíz Apellániz, J.; Barbá, R. H.; Sota, A. +2 more
Context. The spectral classifications of the Galactic O-Star Spectroscopic Survey (GOSSS) and the astrometric and photometric data from Gaia have significantly improved our ability to measure distances and determine memberships of stellar groups (clusters, associations, or parts thereof) with OB stars. In the near future, the situation will be fur…
Blanco DECam Bulge Survey (BDBS) II: project performance, data analysis, and early science results
Clarkson, William I.; Kunder, Andrea; Johnson, Christian I. +7 more
The Blanco DECam Bulge Survey (BDBS) imaged more than 200 sq deg of the Southern Galactic bulge using the ugrizY filters of the Dark Energy Camera, and produced point spread function photometry of approximately 250 million unique sources. In this paper, we present details regarding the construction and collation of survey catalogues, and also disc…
Solving Grain Size Inconsistency between ALMA Polarization and VLA Continuum in the Ophiuchus IRS 48 Protoplanetary Disk
Henning, Thomas; Hull, Charles L. H.; Kataoka, Akimasa +6 more
The protoplanetary disk around Ophiuchus IRS 48 shows an azimuthally asymmetric dust distribution in (sub)millimeter observations, which is interpreted as a vortex, where millimeter/centimeter-sized particles are trapped at the location of the continuum peak. In this paper, we present 860 µm ALMA observations of polarized dust emission from …
Runaway OB Stars in the Small Magellanic Cloud: Dynamical versus Supernova Ejections
Oey, M. S.; Castro, N.; Moe, M. +2 more
Runaway OB stars are ejected from their parent clusters via two mechanisms, both involving multiple stars: the dynamical ejection scenario (DES) and the binary supernova scenario (BSS). We constrain the relative contributions from these two ejection mechanisms in the Small Magellanic Cloud (SMC) using data for 304 field OB stars from the spatially…
A First Spectroscopic Measurement of the Magnetic-field Strength for an Active Region of the Solar Corona
Brage, Tomas; Si, Ran; Li, Wenxian +3 more
For all involved in astronomy, the importance of monitoring and determining astrophysical magnetic-field strengths is clear. It is also a well-known fact that the corona magnetic fields play an important part in the origin of solar flares and the variations of space weather. However, after many years of solar corona studies, there is still no dire…