Search Publications
Study of Extreme-ultraviolet Emission and Properties of a Coronal Streamer from PROBA2/SWAP, Hinode/EIS and Mauna Loa Mk4 Observations
Slemzin, V.; Goryaev, F.; Vainshtein, L. +1 more
Wide-field extreme-ultraviolet (EUV) telescopes imaging in spectral bands sensitive to 1 MK plasma on the Sun often observe extended, ray-like coronal structures stretching radially from active regions to distances of 1.5-2 R ⊙, which represent the EUV counterparts of white-light streamers. To explain this phenomenon, we investigated th…
The Peculiar Galactic Center Neutron Star X-Ray Binary XMM J174457-2850.3
Altamirano, D.; Degenaar, N.; Wijnands, R. +6 more
The recent discovery of a millisecond radio pulsar experiencing an accretion outburst similar to those seen in low mass X-ray binaries, has opened up a new opportunity to investigate the evolutionary link between these two different neutron star manifestations. The remarkable X-ray variability and hard X-ray spectrum of this object can potentially…
Automatic Classification of Time-variable X-Ray Sources
Gaensler, B. M.; Murphy, Tara; Lo, Kitty K. +1 more
To maximize the discovery potential of future synoptic surveys, especially in the field of transient science, it will be necessary to use automatic classification to identify some of the astronomical sources. The data mining technique of supervised classification is suitable for this problem. Here, we present a supervised learning method to automa…
Strong Far-infrared Cooling Lines, Peculiar CO Kinematics, and Possible Star-formation Suppression in Hickson Compact Group 57
Appleton, P. N.; Xu, C. K.; Charmandaris, V. +14 more
We present [C II] and [O I] observations from Herschel and CO(1-0) maps from the Combined Array for Research in Millimeter Astronomy (CARMA) of the Hickson compact group HCG 57, focusing on the galaxies HCG 57a and HCG 57d. HCG 57a has been previously shown to contain enhanced quantities of warm molecular hydrogen consistent with shock or turbulen…
Interaction between Two Coronal Mass Ejections in the 2013 May 22 Large Solar Energetic Particle Event
Li, Gang; Ding, Liu-Guan; Chen, Yao +7 more
We investigate the eruption and interaction of two coronal mass ejections (CMEs) during the large 2013 May 22 solar energetic particle event using multiple spacecraft observations. Two CMEs, having similar propagation directions, were found to erupt from two nearby active regions (ARs), AR11748 and AR11745, at ~08:48 UT and ~13:25 UT, respectively…
NuSTAR J033202-2746.8: Direct Constraints on the Compton Reflection in a Heavily Obscured Quasar at z ≈ 2
Harrison, F. A.; Stern, D.; Zhang, W. W. +25 more
We report Nuclear Spectroscopic Telescope Array (NuSTAR) observations of NuSTAR J033202-2746.8, a heavily obscured, radio-loud quasar detected in the Extended Chandra Deep Field-South, the deepest layer of the NuSTAR extragalactic survey (~400 ks, at its deepest). NuSTAR J033202-2746.8 is reliably detected by NuSTAR only at E > 8 keV and has a …
Confirmation of a High Magnetic Field in GRO J1008-57
Hailey, Charles J.; Chakrabarty, Deepto; Fürst, Felix +11 more
GRO J1008-57 is a high-mass X-ray binary for which several claims of a cyclotron resonance scattering feature near 80 keV have been reported. We use NuSTAR, Suzaku, and Swift data from its giant outburst of 2012 November to confirm the existence of the 80 keV feature and perform the most sensitive search to date for cyclotron scattering features a…
Optical Observations of the Type Ic Supernova 2007gr in NGC 1058
Filippenko, Alexei V.; Li, Weidong; Wang, Xiaofeng +6 more
We present extensive optical observations of the normal Type Ic supernova (SN) 2007gr, spanning from about one week before maximum light to more than one year thereafter. The optical light and color curves of SN 2007gr are very similar to those of the broad-lined Type Ic SN 2002ap, but the spectra show remarkable differences. The optical spectra o…
Shock-Cloud Interaction and Particle Acceleration in the Southwestern Limb of SN 1006
Miceli, M.; Bocchino, F.; Decourchelle, A. +3 more
The supernova remnant SN 1006 is a powerful source of high-energy particles and evolves in a relatively tenuous and uniform environment despite interacting with an atomic cloud in its northwestern limb. The X-ray image of SN 1006 reveals an indentation in the southwestern part of the shock front and the H I maps show an isolated (southwestern) clo…
Salpeter Normalization of the Stellar Initial Mass Function for Massive Galaxies at z ~ 1
Cappellari, Michele; Shetty, Shravan
The stellar initial mass function (IMF) is a key parameter for studying galaxy evolution. Here we measure the IMF mass normalization for a sample of 68 field galaxies in the redshift range 0.7-0.9 within the Extended Groth Strip. To do this we derive the total (stellar + dark matter) mass-to-light [(M/L)] ratio using axisymmetric dynamical models.…