Search Publications
Single metal-poor ultra compact dwarf galaxy at one kiloparsec distance from the low-mass elliptical galaxy FCC 47
Fahrion, Katja; Alfaro-Cuello, Mayte; van de Ven, Glenn +7 more
Context. Photometric surveys of galaxy clusters have revealed a large number of ultra compact dwarfs (UCDs) around predominantly massive elliptical galaxies. Their origin is still debated as some UCDs are considered to be the remnant nuclei of stripped dwarf galaxies while others seem to mark the high-mass end of the star cluster population.
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A Code for Robust Astrometric Solution of Astronomical Images
Ofek, E. O.
I present a software tool for solving the astrometry of astronomical images. The code puts emphasis on robustness against failures for correctly matching the sources in the image to a reference catalog, and on the stability of the solutions over the field of view (e.g., using orthogonal polynomials for the fitted transformation). The code was test…
Modelling of Mg II lines in solar prominences
Labrosse, N.; Levens, P. J.
Context. Observations of the Mg II h and k lines in solar prominences with IRIS reveal a wide range of line shapes from simple non-reversed profiles to typical double-peaked reversed profiles, and with many other possible complex line shapes. The physical conditions responsible for this variety are not well understood.
Aims: Our aim is to und…
Raised Rims Around Titan's Sharp-Edged Depressions
Lunine, J. I.; Hayes, A. G.; Lopes, R. M. C. +6 more
We perform a systematic survey of Titan's sharp-edged depressions (SEDs) using a combination of Cassini synthetic aperture radar images and delay-Doppler processed altimetry. We identify a characteristic bright-dark pattern around 172 SEDs that correlates with elevated features only resolved with the highest resolution topographic data. We find th…
Formation of a New Great Dark Spot on Neptune in 2018
Simon, A. A.; Wong, M. H.; Hsu, A. I.
For the first time, Hubble Space Telescope visible-wavelength imaging shows the formation history of a dark vortex on Neptune. A new northern Great Dark Spot (NDS-2018) was discovered in September and November 2018 images, spanning roughly 12° of latitude and 27° in longitude (11,000 × 5,000 km) at 23°N planetographic latitude. NDS-2018 is similar…
Hot exozodiacal dust: an exocometary origin?
Augereau, J. -C.; Sezestre, É.; Thébault, P.
Context. Near- and mid-infrared interferometric observations have revealed populations of hot and warm dust grains populating the inner regions of extrasolar planetary systems. These are known as exozodiacal dust clouds, or exozodis, reflecting the similarity with the solar system's zodiacal cloud. Radiative transfer models have constrained the du…
Neutral carbon and highly excited CO in a massive star-forming main sequence galaxy at z = 2.2
Daddi, Emanuele; Aravena, Manuel; Decarli, Roberto +5 more
We used the Plateau De Bure Interferometer to observe multiple CO and neutral carbon transitions in a z = 2.2 main sequence disk galaxy, BX610. Our observation of CO(7-6), CO(4-3), and both far-infrared (FIR) [CI] lines complements previous observations of Hα and low-J CO, and reveals a galaxy that is vigorously forming stars with UV fields (Log(G…
A Closer Look at Some Gas-phase Depletions in the ISM: Trends for O, Ge, and Kr versus {F}_{* }, f(H2), and Starlight Intensity
Jenkins, Edward B.
In a survey of archived ultraviolet spectra of 100 stars recorded by the echelle spectrograph of the Space Telescope Imaging Spectrograph on the Hubble Space Telescope, we measure the strengths of the weak absorption features of O I, Ge II, and Kr I in the interstellar medium. Our objective is to undertake an investigation that goes beyond earlier…
Compositional variations of Titan's impact craters indicates active surface erosion
Janssen, M. A.; Cassini Radar Team; Werynski, A. +2 more
Titan, the only moon in the solar system with a considerable atmosphere, is host to a variety of exogenic processes that shape its surface. These processes form features that are quite similar to features on Earth, including sand dunes, rivers, and lakes. The combination of a thick atmosphere and active surface processes also leads to a scarcity o…
The water line emission and ortho-to-para ratio in the Orion Bar photon-dominated region
Le Petit, F.; Roueff, E.; Lis, D. C. +2 more
Context. The ortho-to-para ratio (OPR) of water in the interstellar medium (ISM) is often assumed to be related to the formation temperature of water molecules, making it a potentially interesting tracer of the thermal history of interstellar gas.
Aims: A very low OPR of 0.1-0.5 was previously reported in the Orion Bar photon-dominated region…