88 citations · 474 across the 18 of their papers we have counts for
18 papers
Chandra Observations of a Young Embedded Magnetic B Star in the rho Ophiuchus Cloud
Kenji Hamaguchi, Michael F. Corcoran, Kensuke Imanishi
This paper reports on an analysis of two Chandra X-ray observations of the young magnetic B star rho Ophiuchus S1. X-ray emission from the star was detected in both observations. T…
X-Ray Observation on the Monoceros R2 Star-Forming Region with the Chandra ACIS-I Array
Hiroshi Nakajima, Kensuke Imanishi, Shin-ichiro Takagi +2
We report on the results of the Chandra observation on the central region of the Monoceros R2 cloud (Mon R2), a high-mass star-forming region (SFR). With a deep exposure of 100 ks,…
A Systematic Study of X-Ray Flares from Low-Mass Young Stellar Objects in the Rho Ophiuchi Star-Forming Region with Chandra
K. Imanishi, H. Nakajima, M. Tsujimoto +2
We report on the results of a systematic study of X-ray flares from low-mass young stellar objects, using Chandra observations of the main region of the Rho Oph. From 195 X-ray sou…
Review of Discrete X-Ray Sources in the Small Magellanic Cloud: Summary of the ASCA Results and Implication on the Recent Star Forming Activity
Jun Yokogawa, Kensuke Imanishi, Masahiro Tsujimoto +2
We made 22 observations on the Small Magellanic Cloud (SMC) and covered full regions by the end of the ASCA mission. We detected 106 discrete sources with a criterion of S/N > 5 an…
Errata: The X-Ray Emission Measure (EM) of the Young Stellar Objects (YSOs) in the Rho Ophiuchi (Rho Oph) and Monoceros R2 Dark Clouds (Mon R2)
Kensuke Imanishi, Makoto Kohno, Katsuji Koyama
Errors were made in the calculations of EMs using the best fit normalizations in XSPEC. Lists of the errors and corrections are as follows. (1)Tables 1, 3, and 4 in ApJ, 557, 747 a…
Chandra and ASCA Observations of the X-ray-brightest T-Tauri Stars in the Rho Ophiuchi Cloud
Kensuke Imanishi, Masahiro Tsujimoto, Katsuji Koyama
We present the Chandra ACIS and ASCA GIS results for a series of four long-term observations on DoAr 21, ROXs 21 and ROXs 31; the X-ray brightest T-Tauri stars (TTSs) in the Rho Op…
Centrally Peaked X-Ray Supernova Remnants in the Small Magellanic Cloud Studied with ASCA and ROSAT
Jun Yokogawa, Kensuke Imanishi, Katsuji Koyama +2
This paper presents ASCA/SIS and ROSAT/HRI results of three supernova remnants (SNRs) in the Small Magellanic Cloud: 0103-726, 0045-734, and 0057-7226. The ROSAT/HRI images of thes…
X-ray Detection from Bona-fide and Candidate Brown Dwarfs in the Rho Ophiuchi Cloud with Chandra
Kensuke Imanishi, Masahiro Tsujimoto, Katsuji Koyama
We present results of an X-ray search from bona-fide and candidate brown dwarfs in the Rho Ophiuchi cloud cores with the Chandra X-ray Observatory. The selected areas are two field…
Chandra Observation of the Rho Oph Cloud
Kensuke Imanishi, Katsuji Koyama, Yohko Tsuboi
We observed a 17 region of the Oph molecular cloud, using the ACIS-I array onboard the {\it Chandra X-ray Observatory} (CXO). A 100-ks exposure observation revealed…
Discovery of a 9-s X-Ray Pulsar, AX J0049-732, in the Small Magellanic Cloud
Masaru Ueno, Jun Yokogawa, Kensuke Imanishi +1
We report the ASCA discovery of a new X-ray pulsar, AX J0049-732, in the Small Magellanic Cloud (SMC). The pulse shape is sinusoidal with a barycentric period of 9.1320 +/- 0.0004…
Discovery of the Slowest X-Ray Pulsar in the SMC, AX J0049.5-7323, with ASCA
Jun Yokogawa, Kensuke Imanishi, Masaru Ueno +1
The discovery of coherent pulsations with ASCA from an X-ray source, AX J0049.5-7323, is reported. The barycentric period was determined to be 755.5 +/- 0.6 s, which is the longest…
Discovery of 101-s Pulsations from AX J0057.4-7325 in the SMC with ASCA
Jun Yokogawa, Ken'ichi Torii, Takayoshi Kohmura +2
The results from two ASCA observations of AX J0057.4-7325 = RX J0057.3-7325 are presented. Coherent pulsations with a barycentric period of 101.45 +/- 0.07 s were discovered in the…
Discovery of 172-s Pulsations from a Be/X-ray Binary Candidate AX J0051.6-7311 in the SMC with ASCA
Jun Yokogawa, Ken'ichi Torii, Kensuke Imanishi +1
The results from three ASCA observations of AX J0051.6-7311 = RX J0051.9-7311 are reported. Coherent pulsations with a barycentric period of 172.40 +/- 0.03 s were discovered in th…
A Study of the Populations of X-ray Sources in the Small Magellanic Cloud with ASCA
Jun Yokogawa, Kensuke Imanishi, Masahiro Tsujimoto +4
The Advanced Satellite for Cosmology and Astrophysics (ASCA) has made multiple observations of the Small Magellanic Cloud (SMC). X-ray mosaic images in the soft (0.7--2.0 keV) and…
Quasi-periodic X-ray Flares from the Protostar YLW15
Yohko Tsuboi, Kensuke Imanishi, Katsuji Koyama +2
With ASCA, we have detected three X-ray flares from the Class I protostar YLW15. The flares occurred every ~20 hours and showed an exponential decay with time constant 30-60 ks. Th…
Discovery of an X-Ray Pulsar in the SMC: AX J0058-7203
Masahiro Tsujimoto, Kensuke Imanishi, Jun Yokogawa +1
We report on the discovery and analysis of an X-ray pulsar, AX J0058-7203, in the Small Magellanic Cloud. This pulsar exhibits coherent pulsations at P= 280.3 s with a double-peak…
ASCA Discovery of a Be X-Ray Pulsar in the SMC: AX J0051-733
Kensuke Imanishi, Jun Yokogawa, Masahiro Tsujimoto +1
ASCA observed the central region of the Small Magellanic Cloud, and found a hard X-ray source, AX J0051-733, at the position of the ROSAT source RX J0050.8-7316, which has an optic…
Further studies of 1E 1740.7-2942 with ASCA
Masaaki Sakano, Kensuke Imanishi, Masahiro Tsujimoto +2
We report the ASCA results of the Great Annihilator 1E 1740.7-2942 obtained with five pointing observations in a time span of 3.5 years. The X-ray spectrum for each period is well…