Search Publications
In Situ Data and Effect Correlation During September 2017 Solar Particle Event
Müller, D.; Vainio, R.; Sánchez-Cano, B. +28 more
Solar energetic particles are one of the main sources of particle radiation seen in space. In the first part of September 2017 the most active solar period of cycle 24 produced four large X-class flares and a series of (interplanetary) coronal mass ejections, which gave rise to radiation storms seen over all energies and at the ground by neutron m…
Titan as Revealed by the Cassini Radar
Rodriguez, S.; Barnes, J. W.; Soderblom, J. M. +45 more
Titan was a mostly unknown world prior to the Cassini spacecraft's arrival in July 2004. We review the major scientific advances made by Cassini's Titan Radar Mapper (RADAR) during 13 years of Cassini's exploration of Saturn and its moons. RADAR measurements revealed Titan's surface geology, observed lakes and seas of mostly liquid methane in the …
Subpercent Photometry: Faint DA White Dwarf Spectrophotometric Standards for Astrophysical Observatories
Rest, Armin; Matheson, Thomas; Points, Sean +18 more
We have established a network of 19 faint (16.5 mag < V < 19 mag) northern and equatorial DA white dwarfs (WDs) as spectrophotometric standards for present and future wide-field observatories. Our analysis infers spectral energy distribution (SED) models for the stars that are tied to the three CALSPEC primary standards. Our SED models are c…
A deep view of a fossil relic in the Galactic bulge: the Globular Cluster HP 1
Bica, E.; Nardiello, D.; Barbuy, B. +7 more
HP 1 is an α-enhanced and moderately metal-poor bulge globular cluster with a blue horizontal branch. These combined characteristics make it a probable relic of the early star formation in the innermost Galactic regions. Here, we present a detailed analysis of a deep near-infrared (NIR) photometry of HP 1 obtained with the NIR GSAOI + GeMS camera …
What the Sudden Death of Solar Cycles Can Tell Us About the Nature of the Solar Interior
Rempel, Matthias; McIntosh, Scott W.; Leamon, Robert J. +3 more
We observe the abrupt end of solar-activity cycles at the Sun's Equator by combining almost 140 years of observations from ground and space. These "terminator" events appear to be very closely related to the onset of magnetic activity belonging to the next solar cycle at mid-latitudes and the polar-reversal process at high latitudes. Using multi-s…
Carbon and oxygen in metal-poor halo stars
Asplund, M.; Amarsi, A. M.; Nissen, P. E. +2 more
Carbon and oxygen are key tracers of the Galactic chemical evolution; in particular, a reported upturn in [C/O] towards decreasing [O/H] in metal-poor halo stars could be a signature of nucleosynthesis by massive Population III stars. We reanalyse carbon, oxygen, and iron abundances in 39 metal-poor turn-off stars. For the first time, we take into…
Evidence for ram-pressure stripping in a cluster of galaxies at z = 0.7
Pointecouteau, E.; Boselli, A.; Brinchmann, J. +10 more
Multi-Unit Spectroscopic Explorer (MUSE) observations of the cluster of galaxies CGr32 (M200 ≃ 2 × 1014 M⊙) at z = 0.73 reveal the presence of two massive star-forming galaxies with extended tails of diffuse gas detected in the [O II]λλ3727-3729 Å emission-line doublet. The tails, which have a cometary shape with a…
Planck's Dusty GEMS. VII. Atomic carbon and molecular gas in dusty starburst galaxies at z = 2 to 4
Kneissl, R.; Le Floc'h, E.; Omont, A. +5 more
The bright 3P1-3P0 ([CI] 1-0) and 3P2-3P1 ([CI] 2-1) lines of atomic carbon are becoming more and more widely employed as tracers of the cold neutral gas in high-redshift galaxies. Here we present observations of these lines in the 11 galaxies of the set of Pla…
Extremely Low Molecular Gas Content in a Compact, Quiescent Galaxy at z = 1.522
Franx, Marijn; Bezanson, Rachel; Weiner, Benjamin +4 more
One of the greatest challenges to theoretical models of massive galaxy formation is the regulation of star formation at early times. The relative roles of molecular gas expulsion, depletion, and stabilization are uncertain as direct observational constraints of the gas reservoirs in quenched or quenching galaxies at high redshift are scant. We pre…
Unbiased Distribution of Binary Parameters from LAMOST and Kepler Observations
Qian, Sheng-Bang; Zhang, Jia; Wu, Yue +1 more
The parameter distribution of binaries is a fundamental knowledge of the stellar systems. A statistical study on the binary stars is carried out based on the LAMOST spectral and Kepler photometric database. We presented a catalog of 1320 binary stars with plentiful parameters, including period, binary subtype, atmosphere parameters (T eff