Search Publications
Post-flare formation of the accretion stream and a dip in pulse profiles of LMC X-4
Paul, Biswajit; Beri, Aru
We report here a pulse profile evolution study of an accreting X-ray pulsar LMC X-4 during and after the large X-ray flares using data from the two observatories XMM-Newton and RXTE. During the flares, the pulse profiles were found to have a significant phase offset in the range of 0.2-0.5 compared to the pulse profiles immediately before or after…
Detection of Prominent Stellar Disks in the Progenitors of Present-day Massive Elliptical Galaxies
Ho, Luis C.; Mobasher, Bahram; Canalizo, Gabriela +1 more
Massive galaxies at high redshifts (z > 2) show different characteristics from their local counterparts: they are compact and most likely have a disk. In this study, we trace the evolution of local massive galaxies by performing a detailed morphological analysis, namely, fitting single Sérsic profiles and performing bulge+disk decompositions. W…
CTIO, ROSAT HRI, and Chandra ACIS Observations of the Archetypical Mixed-morphology Supernova Remnant W28 (G6.4-0.1)
Kargaltsev, Oleg; Rho, Jeonghee; Hare, Jeremy +6 more
We present a joint analysis of optical emission-line and X-ray observations of the archetypical Galactic mixed-morphology supernova remnant (MMSNR) W28 (G6.4-0.1). MMSNRs comprise a class of sources whose shell-like radio morphology contrasts with a filled center in X-rays; the origin of these contrasting morphologies remains uncertain. Our CTIO i…
The effect of unresolved contaminant stars on the cross-matching of photometric catalogues
Wilson, Tom J.; Naylor, Tim
A fundamental process in astrophysics is the matching of two photometric catalogues. It is crucial that the correct objects be paired, and that their photometry does not suffer from any spurious additional flux. We compare the positions of sources in Wide-field Infrared Survey Explorer (WISE), INT Photometric H α Survey, Two Micron All Sky Survey …
Multi-spacecraft Observations of the Coronal and Interplanetary Evolution of a Solar Eruption Associated with Two Active Regions
Wang, Rui; Yang, Zhongwei; Liu, Ying D. +3 more
We investigate the coronal and interplanetary evolution of a coronal mass ejection (CME) launched on 2010 September 4 from a source region linking two active regions (ARs), 11101 and 11103, using extreme ultraviolet imaging, magnetogram, white-light, and in situ observations from SDO, STEREO, SOHO, VEX, and Wind. A potential-field source-surface m…
Simulated Galactic methanol maser distribution to constrain Milky Way parameters
Reid, M. J.; Quiroga-Nuñez, L. H.; van Langevelde, H. J. +1 more
Context. Using trigonometric parallaxes and proper motions of masers associated with massive young stars, the Bar and Spiral Structure Legacy (BeSSeL) survey has reported the most accurate values of the Galactic parameters so far. The determination of these parameters with high accuracy has a widespread impact on Galactic and extragalactic measure…
The outflow of gas from the Centaurus A circumnuclear disk. Atomic spectral line maps from Herschel/PACS and APEX
Stutzki, J.; Güsten, R.; Requena-Torres, M. A. +2 more
The physical state of the gas in the central 500 pc of NGC 5128 (the radio galaxy Centaurus A), was investigated using the fine-structure lines of carbon [CI], [CII]; oxygen [OI], [OIII], and nitrogen [NII], [NIII] as well as the 12CO(4-3) molecular line. The circumnuclear disk (CND) is traced by emission from dust and the neutral gas (…
Statistical study of polar negative magnetic bays driven by interplanetary fast-mode shocks
Liou, Kan; Sotirelis, Thomas; Gjerloev, Jesper
The question of whether an interplanetary (IP) fast-mode shock can trigger the substorm expansion is still not resolved. Some scientists believe that the substorm expansion can be triggered by a sudden compression of the magnetosphere if a substorm growth phase is in progress (e.g., the magnetosphere precondition hypothesis). Such a hypothesis has…
Physical Properties of the Very Young PN Hen3-1357 (Stingray Nebula) Based on Multiwavelength Observations
Hubrig, S.; Otsuka, Masaaki; Parthasarathy, M. +1 more
We carried out a detailed analysis of the interesting and important very young planetary nebula (PN) Hen3-1357 (Stingray Nebula) based on a unique data set of optical to far-IR spectra and photometric images. We calculated the abundances of nine elements using collisionally excited lines (CELs) and recombination lines (RLs). The RL C/O ratio indic…
A catalogue of white dwarf candidates in VST ATLAS
Hermes, J. J.; Raddi, Roberto; Gänsicke, Boris T. +6 more
The Sloan Digital Sky Survey (SDSS) has created a knowledge gap between the Northern and the Southern hemispheres, which is very marked for white dwarfs: Only ≃15 per cent of the known white dwarfs are south of the equator. Here, we make use of the VLT Survey Telescope (VST) ATLAS survey, one of the first surveys obtaining deep, optical, multiband…