Search Publications

Gone in a Blaze of Glory: The Demise of Comet C/2015 D1 (SOHO)

Battams, Karl; Clark, David; Ye, Quan-Zhi +2 more

We present studies of C/2015 D1 (SOHO), the first sunskirting comet ever seen from ground stations over the past half century. The Solar and Heliospheric Observatory (SOHO) witnessed its peculiar light curve with a huge dip followed by a flare-up around perihelion: the dip was likely caused by sublimation of olivines, directly evidenced by a coinc…

Investigating the Consistency of Stellar Evolution Models with Globular Cluster Observations via the Red Giant Branch Bump

Chaboyer, B.; Joyce, M.

Synthetic Red Giant Branch Bump (RGBB) magnitudes are generated with the most recent theoretical stellar evolution models computed with the Dartmouth Stellar Evolution Program (DSEP) code. They are compared to the observational work of Nataf et al., who present RGBB magnitudes for 72 globular clusters. A DSEP model using a chemical composition wit…

Composition of inner-source heavy pickup ions at 1 AU: SOHO/CELIAS/CTOF observations. Implications for the production mechanisms

Wimmer-Schweingruber, R. F.; Berger, L.; Drews, C. +1 more

Context. Pickup ions in the inner heliosphere mainly originate in two sources, one interstellar and one in the inner solar system. In contrast to the interstellar source that is comparatively well understood, the nature of the inner source has not been clearly identified. Former results obtained with the Solar Wind Ion Composition Spectrometer on-…

The Panchromatic STARBurst IRregular Dwarf Survey (STARBIRDS): Observations and Data Archive

McQuinn, Kristen B. W.; Skillman, Evan D.; Mitchell, Noah P.

Understanding star formation in resolved low mass systems requires the integration of information obtained from observations at different wavelengths. We have combined new and archival multi-wavelength observations on a set of 20 nearby starburst and post-starburst dwarf galaxies to create a data archive of calibrated, homogeneously reduced images…

Spatial Structures in the Globular Cluster Distribution of the 10 Brightest Virgo Galaxies

Zezas, A.; Fabbiano, G.; D'Abrusco, R.

We report the discovery of significant localized structures in the projected two-dimensional spatial distributions of the Globular Cluster (GC) systems of the 10 brightest galaxies in the Virgo Cluster. We use catalogs of GCs extracted from the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) Virgo Cluster Survey (ACSVCS) imaging dat…

The companion candidate near Fomalhaut - a background neutron star?

Neuhäuser, R.; Schmidt, T. O. B.; Ginski, C. +3 more

The directly detected planetary mass companion candidate close to the young, nearby star Fomalhaut is a subject of intense discussion. While the detection of common proper motion led to the interpretation as Jovian-mass companion, later non-detections in the infrared raised doubts. Recent astrometric measurements indicate a belt crossing or highly…

Computational Modeling of the Class I Low-Mass Protostar Elias 29 Applying Optical Constants of Ices Processed By High Energy Cosmic Ray Analogs

Rocha, W. R. M.; Pilling, S.

We present a study of the effects of high energy cosmic rays (CRs) over the astrophysical ices, observed toward the embedded class I protostar Elias 29, by using computational modeling and laboratory data. Its spectrum was observed with the Infrared Space Observatory (ISO) covering 2.3-190 µm. The modeling employed the three-dimensional Mont…

Dust Impact Monitor (SESAME-DIM) measurements at comet 67P/Churyumov-Gerasimenko

Flandes, Alberto; Krüger, Harald; Loose, Alexander +9 more

Context. The Rosetta lander Philae successfully landed on the nucleus of comet 67P/Churyumov-Gerasimenko on 12 November 2014. Philae carries the Dust Impact Monitor (DIM) on board, which is part of the Surface Electric Sounding and Acoustic Monitoring Experiment (SESAME). DIM employs piezoelectric PZT sensors to detect impacts by submillimeter- an…

On the Black Hole Mass---X-Ray Excess Variance Scaling Relation for Active Galactic Nuclei in the Low-mass Regime

Yuan, Weimin; Pan, Hai-Wu; Liu, Bifang +2 more

Recent studies of active galactic nuclei (AGNs) found a statistically inverse linear scaling between the X-ray normalized excess variance {σ }_{rms}² (variability amplitude) and the black hole (BH) mass spanning over {M}_{BH}={10}⁶-{10}⁹ {M}_⊙ . Suggested as having a small scatter, thi…

Modeling of the energetic ion observations in the vicinity of Rhea and Dione

Dandouras, Iannis; Krupp, Norbert; Roussos, Elias +1 more

During several flybys of the Cassini spacecraft by the saturnian moons Rhea and Dione the energetic particle detector MIMI/LEMMS measured a significant reduction of energetic ion fluxes (20-300 keV) in their vicinity, which is caused by the absorption of those ions at the moon surfaces.

In order to simulate the observed depletion profiles we …