Search Publications

Radiation Belt Response to Fast Reverse Shock at Geosynchronous Orbit
DOI: 10.3847/1538-4357/abd702 Bibcode: 2021ApJ...910..154B

Kanekal, Shrikanth G.; Sibeck, David; Bhaskar, Ankush +5 more

Fast reverse shocks (FRSs) cause the magnetosphere to expand, by contrast to the well-known compressions caused by the impact of fast forward shocks (FFS). Usually, FFSs are more geoeffective than FRSs, and consequently the inner magnetosphere dynamic responses to both shock types can be quite different. In this study, we investigate for the first…

2021 The Astrophysical Journal
Cluster 6
Retrieving Exoplanet Atmospheres Using Planetary Infrared Excess: Prospects for the Night Side of WASP-43 b and Other Hot Jupiters
DOI: 10.3847/2041-8213/ac2cc2 Bibcode: 2021ApJ...921L...4L

Lustig-Yaeger, Jacob; Stevenson, Kevin B.; Mayorga, L. C. +4 more

To increase the sample size of future atmospheric characterization efforts, we build on the planetary infrared excess (PIE) technique that has been proposed as a means to detect and characterize the thermal spectra of transiting and non-transiting exoplanets using sufficiently broad wavelength coverage to uniquely constrain the stellar and planeta…

2021 The Astrophysical Journal
Gaia 6
Deciphering the 3D Orion Nebula. II. A Low Ionization Region of Multiple Velocity Components Southwest of θ1 Ori C Confounds Interpretation of Low Velocity Resolution Studies of Temperature, Density, and Abundance
DOI: 10.3847/1538-4357/abce57 Bibcode: 2021ApJ...907..119O

Abel, N. P.; O'Dell, C. R.; Ferland, G. J.

We establish that there are two velocity systems along lines of sight that contribute to the emission-line spectrum of the brightest parts of the Orion Nebula. These overlie the Orion-S embedded molecular cloud southwest of the dominant ionizing star (θ1 Ori C). Examination of 10 × 10″ samples of high spectral resolution emission-line s…

2021 The Astrophysical Journal
eHST 6
Herschel Photometric Observations of LITTLE THINGS Dwarf Galaxies
DOI: 10.3847/1538-3881/abfd2e Bibcode: 2021AJ....162...83C

Madden, Suzanne C.; Gomez, Haley L.; Brinks, Elias +6 more

We present here far-infrared photometry of galaxies in a sample that is relatively unexplored at these wavelengths: low-metallicity dwarf galaxies with moderate star formation rates. Four dwarf irregular galaxies from the LITTLE THINGS survey are considered, with deep Herschel PACS and SPIRE observations at 100, 160, 250, 350, and 500 µm. Re…

2021 The Astronomical Journal
Herschel 6
The host galaxy of the short GRB 050709
DOI: 10.1051/0004-6361/202039689 Bibcode: 2021A&A...650A.117N

Magnelli, B.; Palazzi, E.; Greiner, J. +10 more

The host of the short gamma-ray burst (GRB) 050709 is a morphologically disturbed low-luminous galaxy. At a redshift of z = 0.16, it belongs to one of the cosmologically nearest short-GRB hosts identified to date. Consequently, it represents a promising target for sensitive, spatially resolved observational studies. We have used the Multi Unit Spe…

2021 Astronomy and Astrophysics
eHST 6
Cross-match between the Latest Swift-BAT and Fermi-LAT Catalogs
DOI: 10.3847/1538-4357/ac0341 Bibcode: 2021ApJ...916...28T

Mukherjee, Reshmi; Yoneda, Hiroki; Inoue, Yoshiyuki +4 more

We report the results of a cross-match study between the hard X-ray and GeV gamma-ray catalogs, by making use of the latest 105 month Swift-Burst Alert Telescope (BAT) and 10 yr Fermi-Large Area Telescope (LAT) catalogs, respectively. The spatial cross-matching between the two catalogs results in the matching of 132 point-like sources, including ~…

2021 The Astrophysical Journal
INTEGRAL 6
New Subgrouping of Multiple Stellar Populations in NGC 2808 Based on Low-resolution Spectroscopy
DOI: 10.3847/1538-3881/ac0ce6 Bibcode: 2021AJ....162..130H

Kim, Jaeyeon; Han, Sang-Il; Chung, Chul +3 more

We performed low-resolution spectroscopy for the red giant branch stars in an intriguing globular cluster (GC) NGC 2808, which hosts subpopulations with extreme helium and light-element abundances. In order to trace N, C, and Ca abundance differences among subpopulations, we measured CN, CH, and Ca II H&K spectral indices, respectively. We ide…

2021 The Astronomical Journal
eHST 6
Probing the Nucleosynthetic Contribution of Low-metallicity, Low-mass Star Companions of CEMP Stars
DOI: 10.3847/1538-4357/ac1ac9 Bibcode: 2021ApJ...921...77S

Shejeelammal, J.; Goswami, Aruna

The observed abundance diversities among CEMP stars can shed light on the formation and evolution of elements in the early Galaxy. In this work, we present results obtained from a detailed abundance analysis of a sample of seven extrinsic carbon stars. The analysis is based on high-resolution spectra obtained with HCT/HESP (R~60,000) and SUBARU/HD…

2021 The Astrophysical Journal
Gaia 6
Signature of a Massive Rotating Metal-poor Star Imprinted in the Phoenix Stellar Stream
DOI: 10.3847/1538-4357/ac1346 Bibcode: 2021ApJ...921...67C

Lewis, Geraint F.; Casey, Andrew R.; Erkal, Denis +13 more

The Phoenix stellar stream has a low intrinsic dispersion in velocity and metallicity that implies the progenitor was probably a low-mass globular cluster. In this work we use Magellan/Magellan Inamori Kyocera Echelle (MIKE) high-dispersion spectroscopy of eight Phoenix stream red giants to confirm this scenario. In particular, we find negligible …

2021 The Astrophysical Journal
Gaia 6
The Gaia RVS benchmark stars. I. Chemical inventory of the first sample of evolved stars and its Rb NLTE investigation
DOI: 10.1051/0004-6361/202140808 Bibcode: 2021A&A...651A..20C

Steffen, M.; Ludwig, H. -G.; Bonifacio, P. +21 more

Context. The Radial Velocity Spectrometer (RVS) on board the Gaia satellite is not provided with a wavelength calibration lamp. It uses its observations of stars with known radial velocity to derive the dispersion relation. To derive an accurate radial velocity calibration, a precise knowledge of the line spread function (LSF) of the RVS is necess…

2021 Astronomy and Astrophysics
Gaia 6