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X-ray and optical observations of the black hole candidate MAXI J1828-249
Makishima, Kazuo; Ueda, Yoshihiro; Itoh, Ryosuke +8 more
We report results from X-ray and optical observations of the Galactic black hole candidate MAXI J1828-249 performed with Suzaku and the Kanata telescope around the X-ray flux peak in the 2013 outburst. The time-averaged X-ray spectrum covering 0.6-168 keV was approximately characterized by a strong multi-color disk blackbody component with an inne…
Annual parallax measurements of a semi-regular variable star SV Pegasus with VERA
Honma, Mareki; Nakagawa, Akiharu; Nagayama, Takahiro +6 more
Many studies have shown that there are clear sequences in the period-luminosity relationship (PLR) for Mira variables and semi-regular variables (SRVs) in the Large Magellanic Cloud (LMC). To investigate the PLR for SRVs in our galaxy, we examined the annual parallax measurement and conducted K'-band photometric monitoring of an SRV star SV Pegasu…
A systematic study of ULIRGs using near-infrared absorption bands reveals a strong UV environment in their star-forming regions
Nakagawa, Takao; Baba, Shunsuke; Isobe, Naoki +3 more
We present a systematic study of the 3.0 µm H2O ice and the 3.4 µm aliphatic carbon absorption features toward 48 local ultraluminous infrared galaxies (ULIRGs) using spectra obtained by the AKARI Infrared Camera to investigate the UV environment in their star-forming regions. All the ULIRGs in our sample exhibit a ratio of …
Poisson vs. Gaussian statistics for sparse X-ray data: Application to the soft X-ray spectrometer
Eckart, Megan E.; Kelley, Richard L.; Kilbourne, Caroline A. +8 more
Reliable results when fitting X-ray data require proper consideration of the statistics involved. We probe the impact of Gaussian versus Poisson statistics at low count levels using both the standard χ2 method and maximum likelihood based on Poisson (C) statistics. The difference is studied and quantified through simulated spectra with …
Third-nearest WZ Sge-Type dwarf nova candidate ASASSN-14dx classified on the basis of Gaia Data Release 2
Nogami, Daisaku; Monard, Berto; Ohshima, Tomohito +8 more
ASASSN-14dx showed an extraordinary outburst whose features are a small outburst amplitude (∼2.3 mag) and long duration (>4 yr). Because we found a long observational gap of 123 d before the outburst detection, we propose that the main outburst plateau was missed and that this outburst is just a "fading tail" often seen after the WZ Sge-type su…
Revised wavelength and spectral response calibrations for AKARI near-infrared grism spectroscopy: Post-cryogenic phase
Nakagawa, Takao; Baba, Shunsuke; Onaka, Takashi +2 more
We present a new calibration for the second-order light contamination in the near-infrared grism spectroscopy with the Infrared Camera aboard AKARI, specifically for the post-cryogenic phase of the satellite (Phase 3). Following our previous work on the cryogenic phase (Phases 1 and 2), the wavelength and spectral response calibrations were revise…
Active galactic nucleus selection in the AKARI NEP-Deep field with the fuzzy support vector machine algorithm
Goto, Tomotsugu; Matsuhara, Hideo; Poliszczuk, Artem +15 more
The aim of this work is to create a new catalog of reliable active galactic nucleus (AGN) candidates selected from the AKARI NEP-Deep field. Selection of the AGN candidates was done by applying a fuzzy support vector machine algorithm, which allows the incorporation of measurement uncertainties into the classification process. The training dataset…
Spectral properties of gamma-ray bursts observed by the Suzaku wide-band all-sky monitor
Yamaoka, Kazutaka; Fukazawa, Yasushi; Kokubun, Motohide +17 more
We have systematically studied the spectral properties of 302 localized gamma-ray bursts (GRBs) observed by the Suzaku wide-band all-sky monitor (WAM) from 2005 August to 2010 December. The energy spectra in the 100-5000 keV range integrated over the entire emission and the 1 s peak were fitted by three models: a single power law, a power law with…
AKARI mid-infrared slit-less spectroscopic catalogue
Baba, Shunsuke; Onaka, Takashi; Yamamura, Issei +4 more
AKARI/IRC is capable of conducting slit-less spectroscopy in the mid-infrared (5-13 µm) over a 10' × 10' area with a spectral resolution of 50, which is suitable for serendipitous surveys. The data reduction is, however, rather complicated by the confusion of nearby sources after dispersing the spectra. To achieve efficient and reliable data…
On surface brightness and flux calibration for point and compact extended sources in the AKARI Far-IR All-Sky Survey (AFASS) maps
Takita, Satoshi; Ueta, Toshiya; Szczerba, Ryszard +1 more
The AKARI infrared astronomical satellite produced all-sky survey (AFASS) maps in the far-infrared at roughly arcminute spatial resolution, enabling us to investigate the whole sky in the far-infrared for objects having surface brightnesses greater than a few to a couple of dozen MJy sr-1. While the AFASS maps are absolutely calibrated …