Search Publications
Results from the worldwide coma morphology campaign for comet ISON (C/2012 S1)
Samarasinha, Nalin H.; Mueller, Beatrice E. A.; Schleicher, David G. +46 more
We present the results of a global coma morphology campaign for comet C/2012 S1 (ISON), which was organized to involve both professional and amateur observers. In response to the campaign, many hundreds of images, from nearly two dozen groups were collected. Images were taken primarily in the continuum, which help to characterize the behavior of d…
A Chandra Observation of the Eclipsing Wolf-Rayet Binary CQ Cep
Skinner, Stephen L.; Zhekov, Svetozar A.; Güdel, Manuel +1 more
The short-period (1.64 d) near-contact eclipsing WN6+O9 binary system CQ Cep provides an ideal laboratory for testing the predictions of X-ray colliding wind shock theory at close separation where the winds may not have reached terminal speeds before colliding. We present results of a Chandra X-ray observation of CQ Cep spanning ~1 day during whic…
LBT/LUCI Spectroscopic Observations of z≃7 Galaxies
Fan, Xiaohui; Jiang, Linhua; McGreer, Ian D. +7 more
We present deep near-infrared spectroscopic observations of 13 luminous z≃ 7 Lyman break galaxies (LBGs) ({{M}UV}≃ -21) and a z≃ 9.6 lensed LBG candidate, MACS1149-JD1, using the LBT/LUCI spectrograph in the multi-object mode and long-slit mode, respectively. The z∼ 7 galaxies are selected in one of the Cosmic Assembly Near-infrared Dee…
Lower mass normalization of the stellar initial mass function for dense massive early-type galaxies at z ~ 1.4
Longhetti, M.; Gargiulo, A.; Saracco, P. +3 more
Aims: This paper aims at understanding whether the normalization of the stellar initial mass function (IMF) of massive galaxies varies with cosmic time and/or with mean stellar mass density Σ = M⋆/(2πRe2).
Methods: We have tackled this question by taking advantage of a spectroscopic sample of 18 dense (Σ …
Probing the Solar Wind Acceleration Region with the Sun-grazing Comet C/2002 S2
Lamy, P.; Raymond, J. C.; Dobrzycka, D. +2 more
Comet C/2002 S2, a member of the Kreutz family of sungrazing comets, was discovered in white-light images of the Large Angle and Spectromeric Coronagraph Experiment coronagraph on the Solar and Heliospheric Observatory (SOHO) on 2002 September 18 and observed in H I Lyα emission by the SOHO Ultraviolet Coronagraph Spectrometer (UVCS) instrument at…
A Detection of Gas Associated with the M31 Stellar Stream
Danforth, Charles W.; Rich, R. Michael; Keeney, Brian A. +2 more
Detailed studies of stellar populations in the halos of the Milky Way and the Andromeda (M31) galaxies have shown increasing numbers of tidal streams and dwarf galaxies, attesting to a complicated and on-going process of hierarchical structure formation. The most prominent feature in the halo of M31 is the Giant Stellar Stream, a structure ∼4.°5 i…
A Luminous X-Ray Flare from the Nucleus of the Dormant Bulgeless Spiral Galaxy NGC 247
Tao, Lian; Feng, Hua; Grisé, Fabien +4 more
NGC 247 is a nearby late-type bulgeless spiral galaxy that contains an inactive nucleus. We report a serendipitous discovery of an X-ray flare from the galaxy center with a luminosity of up to 2× {10}39 erg s-1 in the 0.3-10 keV band with XMM-Newton. A Chandra observation confirms that the new X-ray source is spatially coinci…
Tracking Cluster Debris (TraCD) - I. Dissolution of clusters and searching for the solar cradle
Gibson, Brad K.; Flynn, Chris; Hurley, Jarrod R. +1 more
The capability to reconstruct dissolved stellar systems in dynamical and chemical space is a key factor in improving our understanding of the evolution of the Milky Way. Here we concentrate on the dynamical aspect and given that a significant portion of the stars in the Milky Way have been born in stellar associations or clusters that have lived a…
When did Round Disk Galaxies Form?
Ohta, K.; Yabe, K.; Takeuchi, T. M. +1 more
When and how galaxy morphology, such as the disk and bulge seen in the present-day universe, emerged is still not clear. In the universe at z >~ 2, galaxies with various morphologies are seen, and star-forming galaxies at z ~ 2 show the intrinsic shape of bar-like structures. Then, when did the round disk structure form? Here we take a simple a…
Tracing the general structure of Galactic molecular clouds using Planck data - I. The Perseus region as a test case
Klessen, Ralf S.; Kauffmann, Jens; Veltchev, Todor V. +4 more
We present an analysis of probability distribution functions (pdfs) of column density in different zones of the star-forming region Perseus and its diffuse environment based on the map of dust opacity at 353 GHz available from the Planck archive. The pdf shape can be fitted by a combination of a lognormal function and an extended power-law tail at…