Search Publications
Mapping the Galactic Disk with the LAMOST and Gaia Red Clump Sample. VIII. Mapping the Kinematics of the Galactic Disk Using Mono-age and Mono-abundance Stellar Populations
Huang, Yang; Jiang, Biwei; Zhang, Huawei +5 more
We present a comprehensive study of the kinematic properties of the different Galactic disk populations, as defined by the chemical abundance ratios and stellar ages, across a large disk volume (4.5 ≤ R ≤ 15.0 kpc and ∣Z∣ ≤ 3.0 kpc), by using the LAMOST-Gaia red clump sample stars. We determine the median velocities for various spatial and populat…
J-PLUS: Beyond Spectroscopy. III. Stellar Parameters and Elemental-abundance Ratios for Five Million Stars from DR3
Fan, Zhou; Huang, Yang; Liu, Jifeng +24 more
We present a catalog of stellar parameters (effective temperature T eff, surface gravity
Reading between the (Spectral) Lines: Magellan/IMACS Spectroscopy of the Ultrafaint Dwarf Galaxies Eridanus IV and Centaurus I
James, D. J.; Li, T. S.; Carlin, J. L. +18 more
We present a spectroscopic analysis of Eridanus IV (Eri IV) and Centaurus I (Cen I), two ultrafaint dwarf galaxies of the Milky Way. Using IMACS/Magellan spectroscopy, we identify 28 member stars of Eri IV and 34 member stars of Cen I. For Eri IV, we measure a systemic velocity of ${v}_{\mathrm{sys}}=-{31.5}_{-1.2}^{+1.3}\ \mathrm{km}\,{{\rm{s}}}^…
What is the Reynolds Number of the Solar Wind?
Wrench, Daniel; Parashar, Tulasi N.; Oughton, Sean +2 more
The Reynolds number, Re, is an important quantity for describing a turbulent flow. It tells us about the bandwidth over which energy can cascade from large scales to smaller ones, prior to the onset of dissipation. However, calculating it for nearly collisionless plasmas like the solar wind is challenging. Previous studies have used formulations o…
A Dynamical Model for IRAS 00500+6713: The Remnant of a Type Iax Supernova SN 1181 Hosting a Double Degenerate Merger Product WD J005311
Uchida, Hiroyuki; Bamba, Aya; Tanaka, Takaaki +6 more
IRAS 00500+6713 is a hypothesized remnant of a Type Iax supernova SN 1181. Multiwavelength observations have revealed its complicated morphology; a dusty infrared ring is sandwiched by the inner and outer X-ray nebulae. We analyze the archival X-ray data taken by XMM-Newton and Chandra X-ray Observatory to constrain the angular radius, mass, and m…
The high energy X-ray probe (HEX-P): probing the physics of the X-ray corona in active galactic nuclei
Nardini, Emanuele; Ricci, Claudio; Walton, Dominic J. +27 more
The hard X-ray emission in active galactic nuclei (AGN) and black hole X-ray binaries is thought to be produced by a hot cloud of electrons referred to as the corona. This emission, commonly described by a power law with a high-energy cutoff, is suggestive of Comptonization by thermal electrons. While several hypotheses have been proposed to expla…
A hot-Jupiter progenitor on a super-eccentric retrograde orbit
Schneider, Donald P.; Cochran, William D.; Mahadevan, Suvrath +57 more
Giant exoplanets orbiting close to their host stars are unlikely to have formed in their present configurations1. These `hot Jupiter' planets are instead thought to have migrated inward from beyond the ice line and several viable migration channels have been proposed, including eccentricity excitation through angular-momentum exchange w…
OCCASO. V. Chemical-abundance trends with Galactocentric distance and age
Jordi, C.; Casamiquela, L.; Anders, F. +12 more
Context. Open clusters provide valuable information on stellar nucleosynthesis and the chemical evolution of the Galactic disk, as their age and distances can be measured more precisely with photometry than in the case of field stars.
Aims: Our aim is to study the chemical distribution of the Galactic disk using open clusters by analyzing the…
VIRA: an exoplanet atmospheric retrieval framework for JWST transmission spectroscopy
Madhusudhan, Nikku; Constantinou, Savvas
JWST observations are leading to important new insights into exoplanetary atmospheres through transmission spectroscopy. In order to harness the full potential of the broad spectral range and high sensitivity of JWST, atmospheric retrievals of exoplanets require a high level of robustness and accuracy in the underlying models. We present the VIRA …
Survival in the Neptune desert: LTT 9779 b kept its atmosphere thanks to an unusually X-ray faint host star
Fernández Fernández, Jorge; Wheatley, Peter J.; Jenkins, James S. +1 more
The Neptunian desert is a region in period-radius parameter space with very few Neptune-sized planets at short orbital periods. Amongst these, LTT 9779 b is the only known Neptune with a period shorter than 1 d to retain a significant H-He atmosphere. If the Neptune desert is the result of X-ray/EUV-driven photoevaporation, it is surprising that t…