Search Publications
Non-potential Field Formation in the X-shaped Quadrupole Magnetic Field Configuration
Shimizu, T.; Inoue, S.; Kawabata, Y.
Some types of solar flares are observed in X-shaped quadrupolar field configuration. To understand the magnetic energy storage in such a region, we studied non-potential field formation in an X-shaped quadrupolar field region formed in the active region NOAA 11967, which produced three X-shaped M-class flares on 2014 February 2. Nonlinear force-fr…
Angular Momentum Evolution of Young Stars in the nearby Scorpius-Centaurus OB Association
Oberst, Thomas E.; Mamajek, Eric E.; Mellon, Samuel N. +1 more
We report the results of a study of archival SuperWASP light curves for stars in Scorpius-Centaurus (Sco-Cen), the nearest OB association. We use SuperWASP time-series photometry to extract rotation periods for 189 candidate members of the Sco-Cen complex and verify that 162 of those are members of the classic Sco-Cen subgroups of Upper Scorpius (…
HST/COS Far-ultraviolet Spectroscopic Analysis of U Geminorum Following a Wide Outburst
Sion, Edward M.; Godon, Patrick; Shara, Michael M. +1 more
We used the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST) to obtain a series of four far-ultraviolet (FUV; 915-2148 Å) spectroscopic observations of the prototypical dwarf nova U Geminorum during its cooling following a two-week outburst. Our FUV spectral analysis of the data indicates that the white dwarf (WD) cools from a…
The Unusually High Halo Concentration of the Fossil Group NGC 6482: Evidence for Weak Adiabatic Contraction
Buote, David A.
Although fossil galaxy systems are thought to be very old, and thus should possess above-average halo concentrations, typically fossils have unexceptional concentrations of their masses. We revisit the massive isolated elliptical galaxy/fossil group NGC 6482 for which previous X-ray studies of a modest Chandra observation obtained a very uncertain…
Phase Relations between the Sunspot Numbers and Total Solar Irradiance
Xu, J. C.; Xie, J. L.; Qu, Z. N.
Understanding the effect of sunspot activities on the variations in the total solar irradiance (TSI) is essential for the interpretation of the variability of TSI as well as its reconstruction. Phase relations between the sunspot numbers (SN) and two TSI composite data are investigated. It is found that TSI and SN are positively correlated, and th…
INTEGRAL Observations of GW170104
Sunyaev, R.; Hanlon, L.; Mereghetti, S. +16 more
We used data from the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) to set upper limits on the γ-ray and hard X-ray prompt emission associated with the gravitational-wave event GW170104, discovered by the Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo collaboration. The unique omnidirectional viewing capability of th…
The Survey of Lines in M31 (SLIM): The Drivers of the [C II]/TIR Variation
Schinnerer, Eva; Groves, Brent; Glover, Simon +7 more
The ratio of the [C II] 158 µ {{m}} emission line over the total infrared emission (TIR) is often used as a proxy for the photoelectric (PE) heating efficiency ({ɛ }{PE}) of the far-ultraviolet (FUV) photons absorbed by dust in the interstellar medium. In the nearby galaxy M31, we measure a strong radial variation of [C II]/TIR th…
Red Supergiants in the Inner Galaxy: Stellar Properties
Menten, Karl M.; Zhu, Qingfeng; Kudritzki, Rolf-Peter +4 more
Red supergiants (RSGs) are luminous cool stars detectable in disks of distant spirals. About a thousand are known in the Galaxy. Here, we analyze a sample of late-type stars recently observed by Messineo et al. in the inner Galaxy (10^\circ < l< 60^\circ ). A total of 58 targets (25% of previously known RSGs) were reported as supergiants bas…
CO Spectral Line Energy Distributions in Galactic Sources: Empirical Interpretation of Extragalactic Observations
Schilke, P.; Lis, D. C.; Bergin, E. A. +5 more
The relative populations in rotational transitions of CO can be useful for inferring gas conditions and excitation mechanisms at work in the interstellar medium. We present CO emission lines from rotational transitions observed with Herschel/HIFI in the star-forming cores Orion S, Orion KL, Sgr B2(M), and W49N. Integrated line fluxes from these ob…
The Panchromatic Hubble Andromeda Treasury. XVII. Examining Obscured Star Formation with Synthetic Ultraviolet Flux Maps in M31.
Bell, Eric F.; Dolphin, Andrew E.; Skillman, Evan D. +10 more
We present synthetic far- and near-ultraviolet ({FUV} and {NUV}) maps of M31, both with and without dust reddening. These maps were constructed from spatially resolved star formation histories (SFHs) derived from optical Hubble Space Telescope imaging of resolved stars, taken as part of the Panchromatic Hubble Andromeda Treasury program. We use st…