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A 1.46-2.48 µm spectroscopic atlas of a T6 dwarf (1060 K) atmosphere with IGRINS: first detections of H2S and H2, and verification of H2O, CH4, and NH3 line lists
Fortney, Jonathan J.; Metchev, Stanimir; Morley, Caroline V. +5 more
We present Gemini South/IGRINS observations of the 1060 K T6 dwarf 2MASS J08173001-6155158 with unprecedented resolution ($R\equiv \lambda /\Delta \lambda =45\, 000$) and signal-to-noise ratio (S/N > 200) for a late-type T dwarf. We use this benchmark observation to test the reliability of molecular line lists used up-to-date atmospheric models…
Clusters of galaxies up to z = 1.5 identified from photometric data of the Dark Energy Survey and unWISE
Han, J. L.; Wen, Z. L.
Using photometric data from the Dark Energy Survey and the Wide-field Infrared Survey Explorer, we estimate photometric redshifts for 105 million galaxies using the nearest-neighbour algorithm. From such a large data base, 151 244 clusters of galaxies are identified in the redshift range of 0.1 < z ≲ 1.5 based on the overdensity of the total st…
Origin of highly r-process-enhanced stars in a cosmological zoom-in simulation of a Milky Way-like galaxy
Beers, Timothy C.; Hirai, Yutaka; Saitoh, Takayuki R. +5 more
The r-process-enhanced (RPE) stars provide fossil records of the assembly history of the Milky Way (MW) and the nucleosynthesis of the heaviest elements. Observations by the R-Process Alliance (RPA) and others have confirmed that many RPE stars are associated with chemo-dynamically tagged groups, which likely came from accreted dwarf galaxies of t…
SORA: Stellar occultation reduction and analysis
Sicardy, B.; Gomes-Júnior, A. R.; Braga-Ribas, F. +6 more
The stellar occultation technique provides competitive accuracy in determining the sizes, shapes, astrometry, etc., of the occulting body, comparable to in-situ observations by spacecraft. With the increase in the number of known Solar system objects expected from the LSST, the highly precise astrometric catalogs, such as Gaia, and the improvement…
Nothing to see here: failed supernovae are faint or rare
Fraser, M.; Byrne, R. A.
The absence of Type IIP core-collapse supernovae arising from progenitors above 17 solar masses suggests the existence of another evolutionary path by which massive stars end their lives. The direct collapse of a stellar core to a black hole without the production of a bright, explosive transient is expected to produce a long-lived, dim, red trans…
Gaia DR3 in 6D: the search for fast hypervelocity stars and constraints on the galactic centre environment
Marchetti, Tommaso; Evans, Fraser A.; Rossi, Elena Maria
The third data release (DR3) of the European Space Agency satellite Gaia provides coordinates, parallaxes, proper motions, and radial velocities for a sample of ~34 million stars. We use the combined 6D phase space information to search for hypervelocity stars (HVSs), unbound stars accelerated by dynamical processes happening in the Galactic Centr…
Angular clustering properties of the DESI QSO target selection using DR9 Legacy Imaging Surveys
Myers, Adam D.; Palanque-Delabrouille, Nathalie; Yèche, Christophe +12 more
The quasar target selection for the upcoming survey of the Dark Energy Spectroscopic Instrument (DESI) will be fixed for the next 5 yr. The aim of this work is to validate the quasar selection by studying the impact of imaging systematics as well as stellar and galactic contaminants, and to develop a procedure to mitigate them. Density fluctuation…
Can tides explain the low dark matter density in Fornax?
Fattahi, Azadeh; Read, Justin I.; Frenk, Carlos S. +1 more
The low dark matter density in the Fornax dwarf galaxy is often interpreted as being due to the presence of a constant density 'core', but it could also be explained by the effects of Galactic tides. The latter interpretation has been disfavoured because it is apparently inconsistent with the orbital parameters and star formation history of Fornax…
Evolution of the Sun's activity and the poleward transport of remnant magnetic flux in Cycles 21-24
Banerjee, Dipankar; Karak, Bidya Binay; Kumar, Pawan +4 more
Detailed study of the solar magnetic field is crucial to understand its generation, transport, and reversals. The timing of the reversals may have implications on space weather and thus identification of the temporal behaviour of the critical surges that lead to the polar field reversals is important. We analyse the evolution of solar activity and…
The COMBS Survey - III. The chemodynamical origins of metal-poor bulge stars
Kobayashi, Chiaki; Hawkins, Keith; Lucey, Madeline +6 more
The characteristics of the stellar populations in the Galactic bulge inform and constrain the Milky Way's formation and evolution. The metal-poor population is particularly important in light of cosmological simulations, which predict that some of the oldest stars in the Galaxy now reside in its centre. The metal-poor bulge appears to consist of m…