Search Publications
Missions
Journals
Publication Years
Joint fit of Warm Absorbers in COS and HETG spectra of NGC 3783
Sun, Wei; Ji, Li; Fu, Xiao-Dan +2 more
Warm Absorbers (WAs), as an important form of AGN outflows, show absorption in both the UV and X-ray bands. Using XSTAR generated photoionization models, for the first time we present a joint fit to the simultaneous observations of HST/COS and Chandra/HETG on NGC 3783. A total of five WAs explain well all absorption features from the AGN outflows,…
Sharp spectral features from light dark matter decay via gravity portals
Ibarra, Alejandro; Catà, Oscar; Ingenhütt, Sebastian
We investigate the phenomenology of dark matter decay assuming that it is induced by non-minimal coupling to gravity, when the dark matter mass is in the sub-GeV range, i.e. below the QCD confinement scale. We show that the decay of the singlet scalar dark matter candidate produces sharp features in the photon spectrum, in the form of lines, boxes…
A SOFIA FORCAST Grism Study of the Mineralogy of Dust in the Winds of Proto-planetary Nebulae: RV Tauri Stars and SRd Variables
Gehrz, R. D.; Lebzelter, T.; Hinkle, K. H. +10 more
We present a SOFIA FORCAST grism spectroscopic survey to examine the mineralogy of the circumstellar dust in a sample of post-asymptotic giant branch (post-AGB) yellow supergiants that are believed to be the precursors of planetary nebulae. Our mineralogical model of each star indicates the presence of both carbon-rich and oxygen-rich dust species…
Investigating the nature of the INTEGRAL gamma-ray bursts and sub-threshold triggers with Swift follow-up
Götz, D.; Mereghetti, S.; Gehrels, N. +9 more
We explore the potential of the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) to improve our understanding of the low-fluence regime for explosive transients, such as Gamma-ray Bursts (GRBs). We probe the nature of the so-called 'WEAK' INTEGRAL triggers, when the gamma-ray instruments record intensity spikes that are below the usual S…
Grid-mapping Hellas Planitia, Mars - Insights into distribution, evolution and geomorphology of (Peri)-glacial, fluvial and lacustrine landforms in Mars' deepest basin
Jaumann, R.; Hauber, E.; Voelker, M. +1 more
Traditional maps of Hellas Planitia, the most prominent impact basin on Mars, have focused on the delineation of continuous surface units. We applied the newly developed grid-mapping method in order to quantitatively analyze the distribution and geostatistics of selected (peri)-glacial, fluvial, and lacustrine landforms. The study area was subdivi…
Discussing the distance bias in the estimation of Hi-GAL compact source physical properties - II. Evolutionary status and star formation rate
Elia, D.; Pezzuto, S.; Schisano, E. +2 more
The derivation of the evolutionary stage and rate of star formation of star-forming sites from Galactic single-dish far-infrared and submillimetre surveys suffers from the relatively limited spatial resolution that prevents access to 'core' scales (r ≤ 0.1 pc) for heliocentric distances d ≳ 1 kpc. In a previous article, we studied the implications…
Community Tools for Cartographic and Photogrammetric Processing of Mars Express HRSC Images
Kirk, R. L.; Gwinner, K.; Hare, T. +4 more
The High Resolution Stereo Camera (HRSC) on the Mars Express orbiter (Neukum et al. 2004) is a multi-line pushbroom scanner that can obtain stereo and color coverage of targets in a single overpass, with pixel scales as small as 10 m at periapsis. Since commencing operations in 2004 it has imaged  77 % of Mars at 2…
Identifying four INTEGRAL sources in the Galactic plane via VLT/optical and XMM-Newton/X-ray spectroscopy
Rahoui, Farid; Krivonos, Roman; Tomsick, John. A.
We report on FORS2 (FOcal Reducer/low dispersion Spectrograph 2) spectroscopy aiming at the identification of four Galactic plane sources discovered by INTEGRAL, IGR J18088-2741, IGR J18381-0924, IGR J17164-3803, and IGR J19173+0747, complemented by XMM-Newton spectroscopy for IGR J18381-0924. The presence of broad H I and He I emission lines and …
Estimating Spectra from Photometry
Connolly, Andrew J.; Kalmbach, J. Bryce
Measuring the physical properties of galaxies such as redshift frequently requires the use of spectral energy distributions (SEDs). SED template sets are, however, often small in number and cover limited portions of photometric color space. Here we present a new method to estimate SEDs as a function of color from a small training set of template S…
Multiple Populations in NGC 1851: Abundance Variations and UV Photometric Synthesis in the Washington and HST/WFC3 Systems
Cummings, Jeffrey D.; Geisler, D.; Villanova, S.
The analysis of multiple populations (MPs) in globular clusters (GCs), both spectroscopically and photometrically, is key in understanding their formation and evolution. The relatively narrow Johnson U, F336W, and Stromgren and Sloan u filters have been crucial in exhibiting these MPs photometrically, but in Paper I we showed that the broader Wash…