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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…
Underestimation of the dust mass in protoplanetary disks: Effects of disk structure and dust properties
Fang, Min; Flock, Mario; Henning, Thomas +6 more
The total number of dust grains in protoplanetary disks is one of the key properties that characterizes the potential for planet formation. With (sub-)millimeter flux measurements, literature studies usually derive the dust mass using an analytic formula under the assumption of optically thin emission, which may lead to a substantial underestimati…
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…
Changing-look Event in NGC 3516: Continuum or Obscuration Variability?
Brenneman, Laura W.; Kriss, Gerard A.; Mehdipour, Missagh +6 more
The Seyfert-1 galaxy NGC 3516 has undergone major spectral changes in recent years. In 2017 we obtained Chandra, NuSTAR, and Swift observations during its new low-flux state. Using these observations, we model the spectral energy distribution (SED) and the intrinsic X-ray absorption, and compare the results with those from historical observations …
The Physical Properties of the SVS 13 Protobinary System: Two Circumstellar Disks and a Spiraling Circumbinary Disk in the Making
Ho, Paul T. P.; Zapata, Luis A.; Carrasco-González, Carlos +13 more
We present Very Large Array (VLA) and Atacama Large Millimeter/submillimeter Array (ALMA) observations of the close (0.″3 = 90 au separation) protobinary system SVS 13. We detect two small circumstellar disks (radii ~12 and ~9 au in dust, and ~30 au in gas) with masses of ~0.004-0.009 M ⊙ for VLA 4A (the western component) and ~0.009-0.…
Disentangling the formation mechanisms of nuclear star clusters
Fahrion, Katja; Leaman, Ryan; van de Ven, Glenn +1 more
Nuclear star clusters (NSCs) are massive star clusters found ubiquitously in the centres of galaxies, from the dwarf regime to massive ellipticals and spirals. The fraction of nucleated galaxies is as high as > 90% at Mgal ∼ 109 M⊙. However, how NSC formation mechanisms work in different regimes and what determi…
Early Results from GLASS-JWST. VI. Extreme Rest-optical Equivalent Widths Detected in NIRISS Wide Field Slitless Spectroscopy
Vulcani, B.; Brammer, G.; Treu, T. +27 more
Wide Field Slitless Spectroscopy (WFSS) provides a powerful tool for detecting strong line emission in star-forming galaxies (SFGs) without the need for target preselection. As part of the GLASS-JWST Early Release Science (ERS) program, we leverage the near-infrared wavelength capabilities of NIRISS (1-2.2 µm) to observe rest-optical emissio…
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…
New Constraints on the Spin of the Black Hole Cygnus X-1 and the Physical Properties of its Accretion Disk Corona
Krawczynski, H.; Beheshtipour, B.
We present a new analysis of NuSTAR and Suzaku observations of the black hole Cygnus X-1 in the intermediate state. The analysis is performed using kerrC, a new model for analyzing spectral and spectropolarimetric X-ray observations of black holes. kerrC builds on a large library of simulated black holes in X-ray binaries. The model accounts for t…