Search Publications
Determination of Potassium Abundances for Giant and Dwarf Stars in the Galactic Disk
Takeda, Yoichi
An extensive study on the potassium abundances of late-type stars was carried out by applying the non-LTE spectrum-fitting analysis to the K I resonance line at 7698.96Å to a large sample of 160 FGK dwarfs and 328 late-G/early-K giants (including 89 giants in the Kepler field with seismologically known ages) belonging to the disk population (‑1≤[F…
The Re-Processing Results of Photographic Observations of Asteroids with GAIA Catalog at the Mao Nas of Ukraine
Andruk, V. M.; Shatokhina, S. V.; Kazantseva, L. V.
In total, about 4,500 asteroid po-sitions were determined from photographic observations conducted at the MAO NAS of Ukraine in 1952-1996. These are the early positions of the selected minor planets, mostly bright, the observations of which were initiated by the founders of the ORBITA observational program and were made in 1952-1986. The second la…
Clustering of extremely red objects in the AKARI NEP-deep field
Goto, Tomotsugu; Pearson, Chris; Jeong, Woong-Seob +6 more
We study the clustering property of extremely red objects (EROs) using Canada-France-Hawaii Telescope (CFHT) surveys with 0.55 deg2 in the AKARI north ecliptic pole (NEP) deep field. EROs are selected by the color criterion of r' - Ks > 3.66, which is equivalent to (R - Ks)Vega > 5. We conducted th…
The evolving X-ray spectrum of active galactic nuclei: Evidence for an increasing reflection fraction with redshift
Ballantyne, D. R.; Avirett-Mackenzie, M. S.
The cosmic X-ray background (XRB) spectrum and active galaxy number counts encode essential information about the spectral evolution of active galactic nuclei (AGNs) and have been successfully modelled by XRB synthesis models for many years. Recent measurements of the 8-24 keV AGN number counts by NuSTAR and Swift-BAT are unable to be simultaneous…
Peculiar Outbursts of an Ultra-luminous Source: Likely Signs of an Aperiodic Disk-wind
Stiele, H.; Kong, A. K. H.
The metal-rich globular cluster RZ 2109 in the massive Virgo elliptical galaxy NGC 4472 (M49) harbors the ultra-luminous X-ray source XMMU 122939.7+075333. Previous studies showed that this source varies between bright and faint phases on timescales of just a few hours. Here, we report the discovery of two peculiar X-ray bursting events that last …
Unusual infrared emission toward Sgr B2: possible planar C24
Li, Aigen; Xiang, Fu-Yuan; Yang, Xue-Juan +1 more
Interstellar graphene could be present in the interstellar medium (ISM), resulting from the photochemical processing of polycyclic aromatic hydrocarbon (PAH) molecules and/or collisional fragmentation of graphitic particles. Indeed, by comparing the observed ultraviolet (UV) extinction and infrared (IR) emission of the diffuse ISM with that predic…
A Six-year Image-subtraction Light Curve of SN2010jl
Sollerman, J.; Gal-Yam, A.; Kulkarni, S. R. +9 more
SN 2010jl was a luminous Type IIn supernova (SN), detected in radio, optical, X-ray and hard X-rays. Here we report on its six-year R- and g-band light curves obtained using the Palomar Transient Factory. The light curve was generated using a pipeline based on the proper image-subtraction method and we discuss the algorithm performances. As noted …
Conjunction Observations of Energetic Oxygen Ions O+ Accumulated in the Sequential Flux Ropes in the High-Altitude Cusp
Dandouras, I.; Reme, H.; Wang, Chi +5 more
Conjunction observations of the magnetic field and plasma by Cluster and TC-1 at the dayside magnetosphere are presented to investigate the sequential flux ropes transferred from the low latitude boundary layer to the high-altitude cusp on 10 March 2004.Three sequential flux ropes originating from the dayside low latitude magnetopause are first de…
Star formation and gas in the minor merger UGC 10214
Boquien, M.; Xu, C. K.; Verley, S. +6 more
Minor mergers play a crucial role in galaxy evolution. UGC 10214 (the Tadpole galaxy) is a prime example of this process in which a dwarf galaxy has interacted with a large spiral galaxy ∼250 Myr ago and produced a perturbed disc and a giant tidal tail. We used a multi-wavelength dataset that partly consists of new observations (Hα, HI, and CO) an…
Explaining the asymmetric line profile in Cepheus X-4 with spectral variation across pulse phase
Fürst, Felix; Pottschmidt, Katja; Ballhausen, Ralf +4 more
The high mass X-ray binary Cepheus X-4, during its 2014 outburst, showed evidence for an asymmetric cyclotron line in its hard X-ray spectrum. The 2014 spectrum provides one of the clearest cases of an asymmetric line profile among all studied sources with Cyclotron Resonance Scattering Features (CRSF). We present a phase-resolved analysis of NuST…