Search Publications
X-ray lags in PDS 456 revealed by Suzaku observations
Fabian, A. C.; Reynolds, C. S.; Cackett, E. M. +5 more
X-ray reverberation lags from the vicinity of supermassive black holes have been detected in almost 30 active galactic nuclei (AGNs). The soft lag, which is the time delay between the hard and soft X-ray light curves, is usually interpreted as the time difference between the direct and reflected emission, but is alternatively suggested to arise fr…
Outgas analysis of mechanical cryocoolers for long lifetime
Nakagawa, Takao; Mitsuda, Kazuhisa; Kanao, Kenichi +9 more
Mechanical cryocoolers for space applications are required to have high reliability to achieve long-term operation in orbit. ASTRO-H (Hitomi), the 6th Japanese X-ray astronomy mission, has a major scientific instrument onboard-the Soft X-ray Spectrometer (SXS) with several 20K-class two-stage Stirling (2ST) coolers and a 4K-class Joule Thomson (JT…
Coronal X-ray emission and planetary irradiation in HD 209458
Schmitt, J. H. M. M.; Czesla, S.; Salz, M. +2 more
HD 209458 is one of the benchmark objects in the study of hot Jupiter atmospheres and their evaporation through planetary winds. The expansion of the planetary atmosphere is thought to be driven by high-energy extreme ultraviolet (EUV) and X-ray irradiation. We obtained new Chandra High Resolution Camera (HRC-I) data, which unequivocally show that…
Tethered Prominence-CME Systems Captured during the 2012 November 13 and 2013 November 3 Total Solar Eclipses
Habbal, Shadia R.; Druckmüller, Miloslav; Alzate, Nathalia +1 more
We report on white light observations of high latitude tethered prominences acquired during the total solar eclipses of 2012 November 13 and 2013 November 3, at solar maximum, with a field of view spanning several solar radii. Distinguished by their pinkish hue, characteristic of emission from neutral hydrogen and helium, the four tethered promine…
An Improved Method for Determining the Integrated Properties of Nuclear Rings: NGC 1512
Ho, Luis C.; de Grijs, Richard; Ma, Chao
The integrated properties of nuclear rings are correlated with the secular evolution and dynamics of the host galaxies of the rings, as well as with the formation and evolution of the rings’ star cluster population(s). Here we present a new method to accurately measure the spectral energy distribution and current star formation rate (SFR) of the n…
An Evolving GeV Spectrum from Prompt to Afterglow: The Case of GRB 160509A
Tang, Qing-Wen; Wang, Xiang-Yu; Tam, Pak-Hin Thomas +1 more
We present the high-energy emission properties of GRB 160509A, from its prompt mission to late afterglow phase. GRB 160509A contains two emission episodes: 0-40 s and 280-420 s after the burst onset ({t}0). The relatively high fluence of GRB 160509A allows us to establish an evolving spectrum above 100 MeV. During the first emission epi…
Long-term Spectral Variability of the Ultraluminous X-Ray Source Holmberg IX X-1
Jithesh, V.; Wang, Zhongxiang; Misra, Ranjeev
We investigate the long-term spectral variability in the ultraluminous X-ray source Holmberg IX X-1. By analyzing the data from 8 Suzaku and 13 XMM-Newton observations conducted between 2001 and 2015, we perform a detailed spectral modeling for all spectra with simple models and complex physical models. We find that the spectra can be well explain…
Excess entropy and energy feedback from within cluster cores up to r200
Ettori, Stefano; Eckert, Dominique; Majumdar, Subhabrata +3 more
We estimate the 'non-gravitational' entropy-injection profiles, ΔK, and the resultant energy feedback profiles, ΔE, of the intracluster medium for 17 clusters using their Planck Sunyaev-Zel'dovich and ROSAT X-ray observations, spanning a large radial range from 0.2r500 up to r200. The feedback profiles are estimated by compar…
Observational study on the fine structure and dynamics of a solar jet. I. Energy build-up process around a satellite spot
Shibata, Kazunari; Ichimoto, Kiyoshi; Ueno, Satoru +3 more
We report on a solar jet phenomenon associated with successive flares on 2014 November 10. These explosive events were involved with the satellite spots' emergence around a δ-type sunspot in the decaying active region NOAA 12205. The data for this jet were provided by the Solar Dynamics Observatory, the X-Ray Telescope aboard Hinode, and the Inter…
The most massive galaxies in clusters are already fully grown at z ∼ 0.5
Davies, Roger L.; Houghton, R. C. W.; Oldham, L. J.
By constructing scaling relations for galaxies in the massive cluster MACSJ0717.5 at z = 0.545 and comparing with those of Coma, we model the luminosity evolution of the stellar populations and the structural evolution of the galaxies. We calculate magnitudes, surface brightnesses and effective radii using Hubble Space Telescope (HST)/ACS images a…