Search Publications

Development and verification of signal processing system of avalanche photo diode for the active shields onboard ASTRO-H

Yamaoka, K.; Fukazawa, Y.; Kataoka, J. +45 more

The hard X-ray Imager and Soft Gamma-ray Detector onboard ASTRO-H demonstrate high sensitivity to hard X-ray (5-80 keV) and soft gamma-rays (60-600 keV), respectively. To reduce the background, both instruments are actively shielded by large, thick Bismuth Germanate scintillators. We have developed the signal processing system of the avalanche pho…

Special issue: The Vlasov equation, from space to laboratory plasmas

Califano, F.; Valentini, F.; Manfredi, G.

Spectral clustering for optical confirmation and redshift estimation of X-ray selected galaxy cluster candidates in the SDSS Stripe 82

Takey, A.; Mahmoud, E.; Shoukry, A.

We develop a galaxy cluster finding algorithm based on spectral clustering technique to identify optical counterparts and estimate optical redshifts for X-ray selected cluster candidates. As an application, we run our algorithm on a sample of X-ray cluster candidates selected from the third XMM-Newton serendipitous source catalog (3XMM-DR5) that a…

O⁺ and H⁺ above the polar cap: Observations and semikinetic simulations

Nilsson, H.; Slapak, R.; Barghouthi, I. A. +1 more

A one-dimensional direct simulation Monte Carlo model is used to study the outflow of O⁺ and H⁺ ions from 1.2 R_E to 15.2 R_E along two flight trajectories originating from the polar cap, namely, the central polar cap (CPC) and the cusp. To study the effect of varying geophysical conditions and to deduce t…

Searching for supergiant fast X-ray transients with Swift

D'Avanzo, P.; Campana, S.; Sbarufatti, B. +11 more

Supergiant fast X-ray transients (SFXTs) are high mass X-ray binaries (HMXBs) hosting a neutron star and an OB supergiant companion. We examine the available Swift data, as well as other new or archival/serendipitous data, on three sources: IGR J17407-2808, 2XMM J185114.3-000004, and IGR J18175-2419, whose X-ray characteristics qualify them as can…

Detecting Planet Pairs in Mean Motion Resonances via the Astrometry Method

Zhang, Hui; Zhou, Ji-Lin; Liu, Hui-Gen +2 more

Gaia is leading us into a new era with a high astrometry precision of ∼10 µas. Under such precision, astrometry can play an important role in detecting and characterizing exoplanets. In particular, we can identify planet pairs in mean motion resonances (MMRs), which constrain the formation and evolution of planetary systems. In accordance wi…

AKARI Near-infrared Spectroscopy of the Extended Green Object G318.05+0.09: Detection of CO Fundamental Ro-vibrational Emission

Onaka, Takashi; Sakon, Itsuki; Mori, Tamami +1 more

We present the results of near-infrared (2.5-5.4 µm) long-slit spectroscopy of the extended green object (EGO) G318.05+0.09 with AKARI. Two distinct sources are found in the slit. The brighter source has strong red continuum emission with H₂O ice, CO₂ ice, and CO gas and ice absorption features at 3.0, 4.25 µm, 4.…

Evaluation of standoff distance method to determine the coronal magnetic field using CME-driven shocks

Shanmugaraju, A.; Suresh, K.; Syed Ibrahim, M.

We have analyzed the propagation characteristics of four limb coronal mass ejections (CMEs) with their shocks. These CMEs were observed in 18 frames up to 18 solar radii using LASCO white light images. Gopalswamy and Yashiro (Astrophys. J. 736:L17, 2011) introduced the standoff distance method (SOD) to find the magnetic field in the corona using C…

Suzaku observation of a high-entropy cluster Abell 548W

Makishima, Kazuo; Nakazawa, Kazuhiro; Gu, Liyi +4 more

Abell 548W, one of the galaxy clusters located in the Abell 548 region, has about an order of magnitude lower X-ray luminosity compared to ordinal clusters in view of the well-known intracluster medium (ICM) temperature vs. X-ray luminosity (kT-L_X) relation. The cluster hosts a pair of diffuse radio sources to the northwest and north, b…

Corrigendum to "The SESAME/CASSE instrument listening to the MUPUS PEN insertion phase on comet 67P/Churyumov-Gerasimenko" [Acta Astronaut., DOI: 10.1016/j.actaastro.2016.02.018]

Schmidt, W.; Knollenberg, J.; Knapmeyer, M. +7 more

This contribution corrects a table given in a previous contribution.