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A study of the accretion mechanisms of the high-mass X-ray binary IGR J00370+6122
Fukazawa, Yasushi; Makishima, Kazuo; Takahashi, Hiromitsu +1 more
IGR J00370+6122 is a high-mass X-ray binary with a B1 Ib primary star and a companion suggested to be a neutron star because of the detection of a 346 s pulsation in a one-off 4 ks observation. To better understand the nature of the compact companion, the present work performs timing and spectral studies of the X-ray data of this object, taken wit…
Combined Analysis of X-Ray Spectra of NGC 3227
Newman, J.; Liebmann, A. C.; Haba, Y. +2 more
The 1.5 Seyfert galaxy NGC 3227 has been observed by several X-ray missions. We carried out a combined analysis of the data obtained by more recent major observations of this source—two observations performed by XMM-Newton in 2000 and 2006 and six observations performed by Suzaku in 2008. A unified model, which is consistent with all eight of the …
Low-radio frequency observations of seven nearby galaxies with GMRT
Roy, Subhashis; Manna, Souvik
We have observed seven nearby large-angular-sized galaxies at 0.33 GHz using Giant Metrewave Radio Telescope with an angular resolution of ~10 arcsec and sub-mJy sensitivity. Using archival higher frequency data at 1.4 or ~6 GHz, we have then determined their spatially resolved non-thermal spectrum. As a general trend, we find that the spectral in…
Volatile Composition and Outgassing in C/2018 Y1 (Iwamoto): Extending Limits for High-resolution Infrared Cometary Spectroscopy between 2.8 and 5.0 µm
Vervack, Ronald J., Jr.; Kawakita, Hideyo; DiSanti, Michael A. +7 more
We used the powerful high spectral resolution cross-dispersed facility spectrograph, iSHELL, at the NASA Infrared Telescope Facility (IRTF) to observe C/2018 Y1 (Iwamoto), a long-period comet from the Oort cloud. We report production rates for water and eight other parent molecules (native ices), C2H6, CO, CH4, H
Identification of emission-line stars in transition phase from pre-main sequence to main sequence
Mathew, Blesson; Kartha, Sreeja S.; Paul, K. T. +3 more
Pre-main-sequence (PMS) stars evolve into main-sequence (MS) phase over a period of time. Interestingly, we found a scarcity of studies in existing literature that examine and attempt to better understand the stars in PMS to MS transition phase. The purpose of this study is to detect such rare stars, which we named as 'transition phase' (TP) candi…
Chemodynamically Characterizing the Jhelum Stellar Stream with APOGEE-2
Cunha, Katia; Smith, Verne V.; Majewski, Steven R. +15 more
We present the kinematic and chemical profiles of red giant stars observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE)-2 survey in the direction of the Jhelum stellar stream, a Milky Way substructure located in the inner halo of the Milky Way at a distance from the Sun of ≈13 kpc. From the six APOGEE-2 Jhelum pointings, …
Double Peak Structures of Martian Nightside Total Electron Content in Strong Crustal Magnetic Cusp Regions
Futaana, Yoshifumi; Nielsen, Erling; Qin, JunFeng +4 more
With the help of the high spatial resolution total electron content (TEC) data obtained by Mars Advanced Radar for Subsurface and Ionospheric Sounding on board the Mars Express (MEx) during June 2005 to September 2007, the detailed configurations of the Martian nightside ionosphere in crustal magnetic field cusp regions are researched in this pape…
Brightness Fluctuation Spectra of Sun-like Stars. I. The Mid-frequency Continuum
Metcalfe, Travis S.; García, Rafael A.; Mathur, Savita +2 more
We analyze space-based time-series photometry of Sun-like stars, mostly in the Pleiades, but also field stars and the Sun itself. We focus on timescales between roughly 1 hr and 1 day. In the corresponding frequency band these stars display brightness fluctuations with a decreasing power-law continuous spectrum. K2 and Kepler observations show tha…
The GRAVITY young stellar object survey. V. The orbit of the T Tauri binary star WW Cha
Genzel, R.; Sturm, E.; Duchêne, G. +60 more
Context. Close young binary stars are unique laboratories for the direct measurement of pre-main-sequence (PMS) stellar masses and their comparison to evolutionary theoretical models. At the same time, a precise knowledge of their orbital parameters when still in the PMS phase offers an excellent opportunity for understanding the influence of dyna…
Radio-loud and radio-quiet CMEs: solar cycle dependency, influence on cosmic ray intensity, and geo-effectiveness
Joshi, Bhuwan; Chandra, Ramesh; Kharayat, Hema
Coronal mass ejections (CMEs) largely influence the space weather and cause geomagnetic perturbations. Hence, the statistical studies pertaining to the occurrence of CMEs over the solar cycles and their consequence at the near-Earth region are extremely important. For an in-depth understanding, such studies need to be carried out considering vario…