Search
Now showing items 81-89 of 89
Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way
(2015-11-26)
The first stars are predicted to have formed within 200 million years after the Big Bang, initiating the cosmic dawn. A true first star has not yet been discovered, although stars with tiny amounts of elements heavier than ...
Radio monitoring of the periodically variable IR source LRLL 54361: No direct correlation between the radio and IR emissions
(2015-11-12)
LRLL 54361 is an infrared source located in the star forming region IC 348 SW. Remarkably, its infrared luminosity increases by a factor of 10 during roughly one week every 25.34 days. To understand the origin of these ...
Smoke in the Pipe Nebula: dust emission and grain growth in the starless core FeSt 1-457
(2015-08-13)
(abridged) Methods: We derive maps of submillimeter dust optical depth and effective dust temperature from Herschel data that were calibrated against Planck. After calibration, we then fit a modified blackbody to the ...
Subclasses of Type Ia Supernovae as the origin of [α/Fe] ratios in dwarf spheroidal galaxies
(2015-04-23)
Recent extensive observations of Type Ia Supernovae (SNe Ia) have revealed the existence of a diversity of SNe Ia, including SNe Iax. We introduce two possible channels in the single degenerate scenario: 1) double detonations ...
Tomography of Galactic star-forming regions and spiral arms with the Square Kilometer Array
(Proceedings of Science (PoS), 2014-12-19)
Very Long Baseline Interferometry (VLBI) at radio wavelengths can provide astrometry accurate to 10 micro-arcseconds or better (i.e. better than the target GAIA accuracy) without being limited by dust obscuration. This ...
Constraints on photoevaporation models from (lack of) radio emission in the Corona Australis protoplanetary disks
(2014-10-21)
Photoevaporation due to high-energy stellar photons is thought to be one of the main drivers of protoplanetary disk dispersal. The fully or partially ionized disk surface is expected to produce free-free continuum emission ...
Light, Alpha, and Fe-Peak Element Abundances in the Galactic Bulge
(2014-09-09)
We present radial velocities and chemical abundances of O, Na, Mg, Al, Si, Ca, Cr, Fe, Co, Ni, and Cu for a sample of 156 red giant branch stars in two Galactic bulge fields centered near (l,b)=(+5.25,-3.02) and (0,-12). ...
Some like it cold: molecular emission and effective dust temperatures of dense cores in the Pipe Nebula
(2014-08-08)
Aims. The Pipe Nebula is characterized by a low star-formation rate and is therefore an ideal environment to explore how initial conditions, including core characteristics, affect star-formation efficiencies. Methods. In ...
Elemental and isotopic abundances and chemical evolution of galaxies
(Astronomical Society of the Pacific, 2012-02-15)
Elemental and isotopic abundances are the fossils of galactic archaeology. The observed [X/Fe]-[Fe/H] relations in the Galactic bulge and disk and the mass-metallicity relation of galaxies are roughly reproduced with ...