Search Publications
Molecular Oxygen in Oort Cloud Comet 1P/Halley
Altwegg, K.; Rubin, M.; van Dishoeck, E. F. +1 more
Recently, the ROSINA mass spectrometer suite on board the European Space Agency's Rosetta spacecraft discovered an abundant amount of molecular oxygen, O2, in the coma of Jupiter family comet 67P/Churyumov-Gerasimenko of O2/H2O = 3.80 ± 0.85%. It could be shown that O2 is indeed a parent species and that…
Spectroscopic Observations of an Evolving Flare Ribbon Substructure Suggesting Origin in Current Sheet Waves
Qiu, J.; Longcope, D. W.; Brannon, S. R.
We present imaging and spectroscopic observations from the Interface Region Imaging Spectrograph of the evolution of the flare ribbon in the SOL2014-04-18T13:03 M-class flare event, at high spatial resolution and time cadence. These observations reveal small-scale substructure within the ribbon, which manifests as coherent quasi-periodic oscillati…
Gamma-rays from Type Ia Supernova SN2014J
Sunyaev, R.; Churazov, E.; Bikmaev, I. +8 more
The whole set of INTEGRAL observations of Type Ia supernova SN 2014J, covering the period 19-162 days after the explosion, has been analyzed. For spectral fitting the data are split into early and late periods covering days 19-35 and 50-162, respectively, optimized for 56Ni and 56Co lines. As expected for the early period, mu…
Small-scale and Global Dynamos and the Area and Flux Distributions of Active Regions, Sunspot Groups, and Sunspots: A Multi-database Study
DeLuca, Edward E.; Pevtsov, Alexei A.; Longcope, Dana W. +12 more
In this work, we take advantage of 11 different sunspot group, sunspot, and active region databases to characterize the area and flux distributions of photospheric magnetic structures. We find that, when taken separately, different databases are better fitted by different distributions (as has been reported previously in the literature). However, …
Discovery of Molecular Gas around HD 131835 in an APEX Molecular Line Survey of Bright Debris Disks
Pascucci, I.; Ábrahám, P.; Kóspál, Á. +11 more
Debris disks are considered to be gas-poor, but recent observations revealed molecular or atomic gas in several 10-40 Myr old systems. We used the APEX and IRAM 30 m radio telescopes to search for CO gas in 20 bright debris disks. In one case, around the 16 Myr old A-type star HD 131835, we discovered a new gas-bearing debris disk, where the CO 3-…
Red Supergiants as Cosmic Abundance Probes: The Sculptor Galaxy NGC 300
Bender, Ralf; Bonanos, Alceste Z.; Bresolin, Fabio +9 more
We present a quantitative spectroscopic study of 27 red supergiants (RSGs) in the Sculptor Galaxy NGC 300. J-band spectra were obtained using KMOS on the Very Large Telescope and studied with state of the art synthetic spectra including NLTE corrections for the strongest diagnostic lines. We report a central metallicity of [Z] = -0.03 ± 0.05 with …
A Probable Milli-parsec Supermassive Binary Black Hole in the Nearest Quasar Mrk 231
Lu, Youjun; Yan, Chang-Shuo; Dai, Xinyu +1 more
Supermassive binary black holes (BBHs) are unavoidable products of galaxy mergers and are expected to exist in the cores of many quasars. Great effort has been made during the past several decades to search for BBHs among quasars; however, observational evidence for BBHs remains elusive and ambiguous, which is difficult to reconcile with theoretic…
Measurements of E-Mode Polarization and Temperature-E-Mode Correlation in the Cosmic Microwave Background from 100 Square Degrees of SPTpol Data
Ade, P. A. R.; Chiang, H. C.; Hanson, D. +63 more
We present measurements of E-mode polarization and temperature-E-mode correlation in the cosmic microwave background using data from the first season of observations with SPTpol, the polarization-sensitive receiver currently installed on the South Pole Telescope (SPT). The observations used in this work cover 100 {{deg }2} of sky with a…
The Fast Filament Eruption Leading to the X-flare on 2014 March 29
Krucker, Säm; Young, Peter R.; Kleint, Lucia +3 more
We investigate the sequence of events leading to the solar X1 flare SOL2014-03-29T17:48. Because of the unprecedented joint observations of an X-flare with the ground-based Dunn Solar Telescope and the spacecraft IRIS, Hinode, RHESSI, STEREO, and the Solar Dynamics Observatory, we can sample many solar layers from the photosphere to the corona. A …
Action-space Clustering of Tidal Streams to Infer the Galactic Potential
Hogg, David W.; Helmi, Amina; Sanderson, Robyn E.
We present a new method for constraining the Milky Way halo gravitational potential by simultaneously fitting multiple tidal streams. This method requires three-dimensional positions and velocities for all stars to be fit, but does not require identification of any specific stream or determination of stream membership for any star. We exploit the …