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At least 1,603 records · Page 89

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DOE OSTI2017

Star Formation Under the Outflow: The Discovery of a Non-thermal Jet from OMC-2 FIR 3 and Its Relationship to the Deeply Embedded FIR 4 Protostar

We carried out multiwavelength (0.7–5 cm), multi-epoch (1994–2015) Very Large Array (VLA) observations toward the region enclosing the bright far-IR sources FIR 3 (HOPS 370) and FIR 4 (HOPS 108) in OMC-2. We report the detection of 10 radio sources, 7 of them identified as young stellar objects. We image a well-collimated radio jet with a thermal free–free core (VLA 11) associated with the Class I intermediate-mass protostar HOPS 370. The jet features several knots (VLA 12N, 12C, 12S) of non-thermal radio emission (likely synchrotron from shock-accelerated relativistic electrons) at distances of ∼7500–12,500 au from the protostar, in a region where other shock tracers have been previously identified. These knots are moving away from the HOPS 370 protostar at ∼100 km s{sup −1}. The Class 0 protostar HOPS 108, which itself is detected as an independent, kinematically decoupled radio source, falls in the path of these non-thermal radio knots. These results favor the previously proposed scenario in which the formation of HOPS 108 is triggered by the impact of the HOPS 370 outflow with a dense clump. However, HOPS 108 has a large proper motion velocity of ∼30 km s{sup −1}, similar to that of other runaway stars in Orion, whose origin would be puzzling within this scenario. Alternatively, an apparent proper motion could result because of changes in the position of the centroid of the source due to blending with nearby extended emission, variations in the source shape, and/or opacity effects.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2017

Embedded Filaments in IRAS 05463+2652: Early Stage of Fragmentation and Star Formation Activities

We present a multiwavelength data analysis of IRAS 05463+2652 (hereafter I05463+2652) to study star formation mechanisms. A shell-like structure around I05463+2652 is evident in the Herschel column density map, which is not associated with any ionized emission. Based on the Herschel submillimeter images, several parsec-scale filaments (including two elongated filaments, “s-fl” and “nw-fl” having lengths of ∼6.4 and ∼8.8 pc, respectively) are investigated in the I05463+2652 site. The Herschel temperature map depicts all these features in a temperature range of ∼11–13 K. 39 clumps are identified and have masses between ∼70--945 M{sub ⊙}. The majority of clumps (having M{sub clump}≳300 M{sub ⊙}) are distributed toward the shell-like structure. 175 young stellar objects (YSOs) are selected using the photometric 1–5 μm data and a majority of these YSOs are distributed toward the four areas of high column density (≳5×10{sup 21} cm{sup −2}; A {sub V} ∼ 5.3 mag) in the shell-like structure, where massive clumps and a spatial association with filament(s) are also observed. The knowledge of observed masses per unit length of elongated filaments and critical mass length reveals that they are supercritical. The filament “nw-fl” is fragmented into five clumps (having M{sub clump}∼100--545 M{sub ⊙}) and contains noticeable YSOs, while the other filament “s-fl” is fragmented into two clumps (having M{sub clump}∼170--215 M{sub ⊙}) without YSOs. Together, these observational results favor the role of filaments in the star formation process in I05480+2545. This study also reveals the filament “s-fl,” containing two starless clumps, at an early stage of fragmentation.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2024

Afterglows from Binary Neutron Star Postmerger Systems Embedded in Active Galactic Nuclei Disks

Abstract The observability of afterglows from binary neutron star mergers occurring within active galactic nuclei (AGN) disks is investigated. We perform 3D GRMHD simulations of a postmerger system and follow the jet launched from the compact object. We use semianalytic techniques to study the propagation of the blast wave powered by the jet through an AGN disk-like external environment, extending to distances beyond the disk scale height. The synchrotron emission produced by the jet-driven forward shock is calculated to obtain the afterglow emission. The observability of this emission at different frequencies is assessed by comparing it to the quiescent AGN emission. In the scenarios where the afterglow could temporarily outshine the AGN, we find that detection will be more feasible at higher frequencies (≳10 14 Hz) and the electromagnetic counterpart could manifest as a fast variability in the AGN emission, on timescales less than a day.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2017

First Detection of Prominence Material Embedded within a 2 × 10{sup 6} K CME Front Streaming away at 100–1500 km s{sup −1} in the Solar Corona

Coronal mass ejections (CMEs) are the largest and most dynamic explosions detected in the million degree solar corona, with speeds reaching up to 3000 km s{sup −1} at Earth’s orbit. Triggered by the eruption of prominences, in most cases, one of the outstanding questions pertaining to the dynamic CME-prominence system is the fate of the cool 10{sup 4}--10{sup 5} K ejected filaments. We present spectroscopic observations acquired during the 2015 March 20 total solar eclipse, which captured a plethora of redshifted plasmoids from Fe xiv emission at 2×10{sup 6} K. Approximately 10% of these plasmoids enshrouded the same neutral and singly ionized plasma below 2×10{sup 5} K, observed in prominences anchored at the Sun at that time. This discovery was enabled by the novel design of a dual-channel spectrometer and the exceptionally clear sky conditions on the island of Svalbard during totality. The Doppler redshifts corresponded to speeds ranging from under 100 to over 1500 km s{sup −1}. These are the first comprehensive spectroscopic observations to unambiguously detect a 2×10{sup 6} K filamentary CME front with inclusions of cool prominence material. The CME front covered a projected area of 2.5×1.5 R{sub s}{sup 2} starting from the solar surface. These observations imply that cool prominence inclusions within a CME front maintain their ionic composition during expansion away from the Sun.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2022

Embedding a Critical Point in a Hadron to Quark–Gluon Crossover Equation of State

It is shown how to embed a critical point in a smooth background equation of state so as to yield the critical exponents and critical amplitude ratios expected of a transition in the same universality class as the liquid–gas phase transition and the 3D Ising model. There are only two independent critical exponents; the relations α + 2β + $\gamma$ = 2 and β(δ - 1) = $\gamma$ arise automatically, as does a new relation between the two critical amplitudes. The resulting equation of state has parameters which may be inferred by hydrodynamic modeling of heavy-ion collisions in the Beam Energy Scan II at the Relativistic Heavy Ion Collider.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2013

Development of film-on-foil ceramic dielectrics for embedded capacitors for power inverters in electric drive vehicles

Abstract not provided

Balachandran, U.↗

DOE OSTI2021

Replication Data for: Dilute Pd/Au Alloy Nanoparticles Embedded in Colloid-Templated Porous SiO 2 : Stable Au-Based Oxidation Catalysts

The data underlying this published work have been made publicly available in this repository as part of the IMASC Data Management Plan. This work was supported as part of the Integrated Mesoscale Architectures for Sustainable Catalysis (IMASC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0012573.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRSDate not supplied