Search Publications
The Herschel Orion Protostar Survey: Far-infrared Photometry and Colors of Protostars and Their Variations across Orion A and B
Henning, Thomas; Manoj, P.; Di Francesco, James +10 more
The degree to which the properties of protostars are affected by environment remains an open question. To investigate this, we look at the Orion A and B molecular clouds, home to most of the protostars within 500 pc. At ∼400 pc, Orion is close enough to distinguish individual protostars across a range of environments in terms of both the stellar a…
X-Ray Emission Evolution of the Galactic Ultraluminous X-Ray Pulsar Swift J0243.6+6124 during the 2017-2018 Outburst Observed by the MAXI GSC
Makishima, Kazuo; Kawai, Nobuyuki; Oeda, Motoki +3 more
This paper reports on the X-ray emission evolution of the ultraluminous Galactic X-ray pulsar Swift J0243.6+6124 during the giant outburst from 2017 October to 2018 January as observed by the MAXI GSC all-sky survey. The 2-30 keV light curve and the energy spectra confirm the source luminosity LX assuming an isotropic emission reached 2…
A New Parameter of the Photospheric Magnetic Field to Distinguish Eruptive-flare Producing Solar Active Regions
Leka, K. D.; Kusano, Kanya; Lin, Pei Hsuan +3 more
Solar flares and coronal mass ejections (CMEs) are eruptive phenomena caused by coronal magnetic fields. In particular, large eruptive events originate in active regions (AR) with strong surface magnetic fields. However, it is still unclear what determines the capability of an AR to specifically produce eruptive flares and CMEs, and this hinders o…
SOFIA-EXES Observations of Betelgeuse during the Great Dimming of 2019/2020
Harper, Graham M.; Guinan, Edward F.; Ryde, Nils +5 more
In 2019 October Betelgeuse began a decline in V-band brightness that went beyond the minimum expected from its quasi-periodic ∼420 day cycle, becoming the faintest in recorded photometric history. Observations obtained in 2019 December with Very Large Telescope/SPHERE have shown that the southern half of the star has become markedly fainter than i…
Initial Evaluation of SNEMO2 and SNEMO7 Standardization Derived from Current Light Curves of Type Ia Supernovae
Galbany, L.; Sako, M.; Rubin, D. +7 more
To determine if the SuperNova Empirical Model (SNEMO) can improve Type Ia supernova (SN Ia) standardization of several currently available photometric data sets, we perform an initial test, comparing results with the much-used SALT2 approach. We fit the SNEMO light-curve parameters and pass them to the Bayesian hierarchical model UNITY1.2 to estim…
Insights into the Formation and Evolution History of the Galactic Disk System
Beers, Timothy C.; Lee, Young Sun; Kim, Young Kwang +1 more
We present a kinematic analysis of a sample of 23,908 G- and K-type dwarfs in the Galactic disk. Based on the α-abundance ratio, [α/Fe], we separated our sample into low-α thin-disk and high-α thick-disk stars. We find a ${V}_{\phi }$ gradient of -28.2 km s-1 dex-1 over [Fe/H] for the thin disk and an almost flat trend of the…
2016 Outburst of H 1743-322: XMM-Newton and NuSTAR View
Dewangan, G. C.; Chand, Swadesh; Tripathi, Prakash +2 more
We report the detection of a type C quasi-periodic oscillation (QPO) along with an upper harmonic in the commensurate ratio of 1:2 in two observations of the low-mass black hole transient H 1743-322 jointly observed by XMM-Newton and NuSTAR during the 2016 outburst. We find that the QPO and the upper harmonic exhibit shifts in their centroid frequ…
The Age Dependence of Mid-infrared Emission around Young Star Clusters
Calzetti, Daniela; Lin, Zesen; Kong, Xu +9 more
Using the star cluster catalogs from the Hubble Space Telescope program Legacy Extragalactic UV survey (LEGUS) and 8 µm images from the IRAC camera on the Spitzer Space Telescope for five galaxies within 5 Mpc, we investigate how the 8 µm dust luminosity correlates with the stellar age on the 30-50 pc scale of star-forming regions. We …
Relations between Coronal Mass Ejections and the Photospheric Magnetic Field in Cycles 23 and 24
Bilenko, Irina A.
The number of coronal mass ejections (CMEs) and their parameters and cycle variations were investigated and compared to the photospheric magnetic field evolution in cycles 23 and 24. The Coordinated Data Analysis Workshops (CDAW) catalog of white-light CMEs detected by the Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagrap…
Characterizing X-Ray Properties of the Gamma-Ray Pulsar PSR J1418-6058 in the Rabbit Pulsar Wind Nebula
An, Hongjun; Kim, Minjun
We report on X-ray studies of the gamma-ray pulsar PSR J1418-6058 in the Rabbit pulsar wind nebula (PWN) carried out using archival Chandra and XMM-Newton observations. A refined timing analysis performed with the 120 ks XMM-Newton data finds significant (p ≈ 10-7) pulsation at P ≈ 110 ms which is consistent with that measured with the …