Search Publications
Observations of the Ultraviolet-bright Star Y453 in the Globular Cluster M4 (NGC 6121)
Chayer, Pierre; Benjamin, Robert A.; Latour, Marilyn +2 more
We present a spectral analysis of the UV-bright star Y453 in M4. Model fits to the star’s optical spectrum yield {T}{eff} ∼ 56,000 K. Fits to the star’s FUV spectrum, obtained with the Cosmic Origins Spectrograph on board the Hubble Space Telescope, reveal it to be considerably hotter, with {T}{eff} ∼ 72,000 K. We adopt {T}
A CO survey on a sample of Herschel cold clumps
Juvela, M.; Ristorcelli, I.; Montillaud, J. +4 more
Context. The physical state of cold cloud clumps has a great impact on the process and efficiency of star formation and the masses of the forming stars inside these objects. The sub-millimetre survey of the Planck space observatory and the far-infrared follow-up mapping of the Herschel space telescope provide an unbiased, large sample of these col…
Identification of the Hard X-Ray Source Dominating the E > 25 keV Emission of the Nearby Galaxy M31
Lien, A.; Lehmer, B. D.; Hornschemeier, A. E. +15 more
We report the identification of a bright hard X-ray source dominating the M31 bulge above 25 keV from a simultaneous NuSTAR-Swift observation. We find that this source is the counterpart to Swift J0042.6+4112, which was previously detected in the Swift BAT All-sky Hard X-ray Survey. This Swift BAT source had been suggested to be the combined emiss…
Investigating the Evolution of the Dual AGN System ESO 509-IG066
Harrison, F. A.; Stern, D.; Treister, E. +13 more
We analyze the evolution of the dual active galactic nucleus (AGN) in ESO 509-IG066, a galaxy pair located at z = 0.034 whose nuclei are separated by 11 kpc. Previous observations with XMM-Newton on this dual AGN found evidence for two moderately obscured ({N}{{H}} ∼ 1022 cm-2) X-ray luminous ({L}{{X}} ∼…
Exploring the Helium Core of the δ Scuti Star CoRoT 102749568 with Asteroseismology
Li, Yan; Chen, Xinghao; Chen, Yanhui +2 more
Based on regularities in rotational splitting, we seek possible multiplets for the observed frequencies of CoRoT 102749568. There are 21 sets of multiplets identified, including four sets of multiplets with l = 1, nine sets of multiplets with l = 2, and eight sets of multiplets with l = 3. In particular, there are three complete triplets (f10…
Complex UV/X-ray variability of 1H 0707-495
Papadakis, I. E.; Dewangan, G. C.; Pal, Main +3 more
We study the relationship between the UV and X-ray variability of the narrow-line Seyfert 1 galaxy 1H 0707-495. Using a year-long Swift monitoring and four long XMM-Newton observations, we perform cross-correlation analyses of the UV and X-ray light curves, on both long and short time-scales. We also perform time-resolved X-ray spectroscopy on 1-2…
Thermophysics of fractures on comet 67P/Churyumov-Gerasimenko
Jorda, L.; Lamy, P. L.; Bertaux, J. -L. +55 more
Context. The camera OSIRIS on board Rosetta obtained high-resolution images of the nucleus of comet 67P/Churyumov-Gerasimenko (67P). Great parts of the nucleus surface are composed of fractured terrain.
Aims: Fracture formation, evolution, and their potential relationship to physical processes that drive activity are not yet fully understood.…
A Systematic Study of the Thermal and Nonthermal Emission in the Supernova Remnant RCW 86 with Suzaku
Katsuda, Satoru; Vink, Jacco; Bamba, Aya +2 more
Diffusive shock acceleration by the shockwaves in supernova remnants (SNRs) is widely accepted as the dominant source for Galactic cosmic rays. However, it is unknown what determines the maximum energy of accelerated particles. The surrounding environment could be one of the key parameters. The SNR RCW 86 shows both thermal and nonthermal X-ray em…
Geologic analysis of the Rosetta NavCam, Osiris and ROLIS images of the comet 67P/Churyumov-Gerasimenko nucleus
Keller, H. U.; Mottola, S.; Hviid, S. F. +5 more
This paper is based on geologic analysis of the surface morphology of nucleus of the Jupiter family comet 67P. This comet was visited by the ESA mission Rosetta, which escorted the comet since May 2014 till the end of September 2016 and studied it by 11 instruments of the mission orbiter and 10 instruments of the lander. The nucleus is 4 km in dia…
Optical and UV Spectra of the Remnant of SN 1885 (S And) in M31
Fesen, Robert A.; Hamilton, Andrew J. S.; Weil, Kathryn E. +1 more
We present multi-slit, 1D and 2D optical and UV spectra of the remnant of supernova 1885 (SN 1885; S And) taken using the Hubble Space Telescope’s Imaging Spectrograph (HST/STIS). These spectra of this probable subluminous Type Ia remnant, seen in silhouette against the central bulge of the Andromeda galaxy (M31), show strong and broad absorptions…