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Interplanetary Coronal Mass Ejections as the Driver of Non-recurrent Forbush Decreases
Papaioannou, Athanasios; Belov, Anatoly; Abunina, Maria +5 more
Interplanetary coronal mass ejections (ICMEs) are the counterparts of coronal mass ejections (CMEs) that extend in the interplanetary (IP) space and interact with the underlying solar wind (SW). ICMEs and their corresponding shocks can sweep out galactic cosmic rays (GCRs) and thus modulate their intensity, resulting in non-recurrent Forbush decre…
Resolving 3D Disk Orientation Using High-resolution Images: New Constraints on Circumgalactic Gas Inflows
Martin, Crystal L.; Ho, Stephanie H.
We constrain gas inflow speeds in star-forming galaxies with color gradients consistent with inside-out disk growth. Our method combines new measurements of disk orientation with previously described circumgalactic absorption in background quasar spectra. Two quantities, a position angle and an axis ratio, describe the projected shape of each gala…
Forward Modeling of Double Neutron Stars: Insights from Highly Offset Short Gamma-Ray Bursts
Fong, Wen-fai; Zevin, Michael; Kalogera, Vicky +3 more
We present a detailed analysis of two well-localized, highly offset short gamma-ray bursts—GRB 070809 and GRB 090515—investigating the kinematic evolution of their progenitors from compact object formation until merger. Calibrating to observations of their most probable host galaxies, we construct semi-analytic galactic models that account for sta…
Application of an X-Ray Clumpy Torus Model (XCLUMPY) to 10 Obscured Active Galactic Nuclei Observed with Suzaku and NuSTAR
Tanimoto, Atsushi; Ueda, Yoshihiro; Odaka, Hirokazu +4 more
We apply XCLUMPY, an X-ray spectral model from a clumpy torus in an active galactic nucleus (AGN), to the broadband X-ray spectra of 10 obscured AGNs observed with both Suzaku and NuSTAR. The infrared spectra of these AGNs were analyzed by Ichikawa et al. with the CLUMPY code. Because XCLUMPY adopts the same clump distribution as that in the CLUMP…
The Effect of Solar Wind Expansion and Nonequilibrium Ionization on the Broadening of Coronal Emission Lines
Cranmer, Steven R.; Gilly, Chris R.
When observing spectral lines in the optically thin corona, line-of-sight (LOS) effects can strongly affect the interpretation of the data, especially in regions just above the limb. We present a semiempirical forward model, called the Global Heliospheric Optically thin Spectral Transport Simulation (GHOSTS), to characterize these effects. GHOSTS …
Identification of a Group III CEMP-no Star in the Dwarf Spheroidal Galaxy Canes Venatici I
Yoon, Jinmi; Whitten, Devin D.; Beers, Timothy C. +3 more
CEMP-no stars, a subclass of carbon-enhanced metal-poor (CEMP) stars, are one of the most significant stellar populations in galactic archeology, because they dominate the low end of the metallicity distribution function, providing information on the early star formation and chemical-evolution history of the Milky Way and its satellite galaxies. H…
Modeling the Accretion Disk around the High-mass Protostar GGD 27-MM1
Galván-Madrid, R.; Osorio, M.; Fernández-López, M. +9 more
Recent high angular resolution (≃40 mas) ALMA observations at 1.14 mm resolve a compact (R ≃ 200 au), flattened dust structure perpendicular to the HH 80-81 jet emanating from the GGD 27-MM1 high-mass protostar, making it a robust candidate for a true accretion disk. The jet-disk system (HH 80-81/GGD 27-MM1) resembles those found in association wi…
Effects of Radial Distances on Small-scale Magnetic Flux Ropes in the Solar Wind
Hu, Qiang; Chen, Yu
Small-scale magnetic flux ropes (SFRs) in the solar wind have been studied for decades. Statistical analysis utilizing various in situ spacecraft measurements is the main observational approach to investigating the generation and evolution of these small-scale structures. Based on the Grad-Shafranov reconstruction technique, we use the automated d…
Phase-dependent Study of Near-infrared Disk Emission Lines in LB-1
Soria, Roberto; Liu, Jifeng; Wang, Shu +18 more
The mass, origin, and evolutionary stage of the binary system LB-1 have been intensely debated, following the claim that it hosts an ∼70M⊙ black hole, in stark contrast with the expectations for Galactic remnants. We conducted a high-resolution, phase-resolved spectroscopic study of its Paschen lines, using the Calar Alto 3.5 m telescop…
The Gaia-ESO Survey: Carbon Abundance in the Galactic Thin and Thick Disks
Kordopatis, Georges; Calura, Francesco; Bragaglia, Angela +24 more
This paper focuses on carbon, which is one of the most abundant elements in the universe and is of high importance in the field of nucleosynthesis and galactic and stellar evolution. The origin of carbon and the relative importance of massive and low- to intermediate-mass stars in producing it is still a matter of debate. We aim at better understa…