Search Publications
High-resolution Observations of a White-light Flare with NST
Cho, K. -S.; Xu, Y.; Yurchyshyn, V. +4 more
Using high-resolution data from the New Solar Telescope, we studied fine spatial and temporal details of an M1.3 white-light (WL) flare, which was one of three homologous solar flares (C6.8, M1.3, and M2.3) observed in close proximity to the west solar limb on 2014 October 29 in NOAA active region 12192. We report that the TiO WL flare consists of…
Development of a Full Ice-cream Cone Model for Halo Coronal Mass Ejections
Moon, Y. -J.; Lee, Harim; Na, Hyeonock
It is essential to determine three-dimensional parameters (e.g., radial speed, angular width, and source location) of coronal mass ejections (CMEs) for the space weather forecast. In this study, we investigate which cone type represents a halo CME morphology using 29 CMEs (12 Solar and Heliospheric Observatory (SOHO)/Large Angle and Spectrometric …
On the Binary Nature of Massive Blue Hypergiants: High-resolution X-Ray Spectroscopy Suggests That Cyg OB2 12 is a Colliding Wind Binary
Hamann, W. -R.; Oskinova, L. M.; Ignace, R. +5 more
The blue hypergiant Cyg OB2 12 (B3Ia+) is a representative member of the class of very massive stars in a poorly understood evolutionary stage. We obtained its high-resolution X-ray spectrum using the Chandra observatory. PoWR model atmospheres were calculated to provide realistic wind opacities and to establish the wind density structu…
The First Detection of a Pulsar with ALMA
de Luca, A.; Possenti, A.; Burgay, M. +8 more
Although there is a general consensus on the fact that pulsars’ radio emission is coherent in nature, whereas the emission from the optical to high-energy γ-rays is due to incoherent processes, it has not been established yet at which wavelengths the transition occurs, which is key information for all emission models of pulsar magnetospheres. Of c…
A Tale of Two Impostors: SN2002kg and SN1954J in NGC 2403
Van Dyk, Schuyler D.; Humphreys, Roberta M.; Davidson, Kris +1 more
We describe new results on two supernova impostors in NGC 2403, SN 1954J(V12) and SN 2002kg(V37). For the famous object SN 1954J, we combine four critical observations: its current SED, its Hα emission line profile, the Ca II triplet in absorption in its red spectrum, and the brightness compared to its pre-event state. Together, these strongly sug…
ALMA Observations of the Gravitational Lens SDP.9
Tamura, Yoichi; Oguri, Masamune; Matsushita, Satoki +3 more
We present long-baseline ALMA observations of the strong gravitational lens H-ATLAS J090740.0-004200 (SDP.9), which consists of an elliptical galaxy at {z}{{L}}=0.6129 lensing a background submillimeter galaxy into two extended arcs. The data include Band 6 continuum observations, as well as CO J = 6-5 molecular line observations, from …
Discovery of a Metal-poor, Luminous Post-AGB Star that Failed the Third Dredge-up.
Wood, P. R.; Asplund, M.; Van Winckel, H. +3 more
Post-asymptotic giant branch (post-AGB) stars are known to be chemically diverse. In this paper we present the first observational evidence of a star that has failed the third dredge-up (TDU). J005252.87-722842.9 is an A-type (T eff = 8250 ± 250 K) luminous (8200 ± 700 L ⊙) metal-poor ([Fe/H] = -1.18 ± 0.10) low-mass (M …
GRAVITY Spectro-interferometric Study of the Massive Multiple Stellar System HD 93206 A
Henning, Th.; van Boekel, R.; Brandner, W. +9 more
Characterization of the dynamics of massive star systems and the astrophysical properties of the interacting components are a prerequisite for understanding their formation and evolution. Optical interferometry at milliarcsecond resolution is a key observing technique for resolving high-mass multiple compact systems. Here, we report on Very Large …
2004 TT357: A Potential Contact Binary in the Trans-Neptunian Belt
Noll, Keith S.; Thirouin, Audrey; Sheppard, Scott S.
We report photometric observations of the trans-Neptunian object 2004 TT357 obtained in 2015 and 2017 using the 4.3 m Lowell’s Discovery Channel Telescope. We derive a rotational period of 7.79 ± 0.01 hr and a peak-to-peak lightcurve amplitude of 0.76 ± 0.03 mag. 2004 TT357 displays a large variability that can be explained b…
Novel Analysis of the Multiwavelength Structure of the Relativistic Jet in Quasar 3C 273
Jamrozy, Marek; Stawarz, Łukasz; Harris, D. E. +4 more
We present a detailed analysis of the best-quality multiwavelength data gathered for the large-scale jet in the core-dominated quasar 3C 273. We analyze all the archival observations of the target with the Chandra X-ray Observatory, the far-ultraviolet observations with the Hubble Space Telescope, and the 8.4 GHz map obtained with the Very Large A…