Search Publications

X-Ray Variability in the Symbiotic Binary RT Cru: Principal Component Analysis
DOI: 10.3847/1538-4357/ad5cf6 Bibcode: 2024ApJ...972..109D

Luna, G. J. M.; Drake, J. J.; Danehkar, A.

Hard X-ray-emitting (δ-type) symbiotic binaries, which exhibit a strong hard X-ray excess, have posed a challenge to our understanding of accretion physics in degenerate dwarfs. RT Cru, which is a member of the δ-type symbiotics, shows stochastic X-ray variability. Timing analyses of X-ray observations from XMM-Newton and NuSTAR, which we consider…

2024 The Astrophysical Journal
XMM-Newton 3
Wide Area VISTA Extra-galactic Survey (WAVES): unsupervised star-galaxy separation on the WAVES-Wide photometric input catalogue using UMAP and HDBSCAN
DOI: 10.1093/mnras/stae2389 Bibcode: 2024MNRAS.535.2129C

Holwerda, Benne W.; Driver, Simon P.; Robotham, Aaron S. G. +13 more

Star-galaxy separation is a crucial step in creating target catalogues for extragalactic spectroscopic surveys. A classifier biased towards inclusivity risks including high numbers of stars, wasting fibre hours, while a more conservative classifier might overlook galaxies, compromising completeness and hence survey objectives. To avoid bias introd…

2024 Monthly Notices of the Royal Astronomical Society
Gaia 3
Gas-phase metallicity for the Seyfert galaxy NGC 7130
DOI: 10.1051/0004-6361/202451168 Bibcode: 2024A&A...689A.193A

Lehmer, B. D.; Marconi, A.; Knapen, J. H. +2 more

Metallicity measurements in galaxies can provide valuable clues about galaxy evolution. One of the mechanisms postulated for metallicity redistribution in galaxies is gas flows induced by active galactic nuclei (AGNs), but the details of this process remain elusive. We report the discovery of a positive radial gradient in the gas-phase metallicity…

2024 Astronomy and Astrophysics
eHST 3
An optically dark merging system at z ∼ 6 detected by JWST
DOI: 10.1051/0004-6361/202450541 Bibcode: 2024A&A...691A..69R

Rodighiero, G.; Vulcani, B.; Castellano, M. +16 more

Context. Near- to mid-infrared observations (from Spitzer and JWST) have revealed a hidden population of galaxies at redshift z = 3 ‑ 6 called optically dark objects, which are believed to be massive and dusty star-formers. They contribute substantially to the cosmic star-formation rate (SFR) density at z ∼ 4 ‑ 5 (up to 30 ‑ 40%). Aims. While opti…

2024 Astronomy and Astrophysics
JWST 3
Chemical abundances for a sample of FGK dwarfs in the Pleiades open cluster from APOGEE
DOI: 10.1093/mnras/stae2209 Bibcode: 2024MNRAS.534.3005G

Wanderley, Fábio; Cunha, Katia; Souto, Diogo +8 more

This paper presents chemical abundances of 12 elements (C, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, and Fe) for 80 FGK dwarfs in the Pleiades open cluster, which span a temperature range of $\sim$2000 K in T$_{\rm …

2024 Monthly Notices of the Royal Astronomical Society
Gaia 3
JWST-TST DREAMS: Nonuniform Dayside Emission for WASP-17b from MIRI/LRS
DOI: 10.3847/1538-3881/ad5c61 Bibcode: 2024AJ....168..123V

Stevenson, Kevin B.; MacDonald, Ryan J.; Valenti, Jeff A. +23 more

We present the first spectroscopic characterization of the dayside atmosphere of WASP-17b in the mid-infrared using a single JWST MIRI/LRS eclipse observation. From forward-model fits to the 5–12 µm emission spectrum, we tightly constrain the heat redistribution factor of WASP-17b to be 0.92 ± 0.02 at the pressures probed by this data, indic…

2024 The Astronomical Journal
JWST 3
A Study of Nine Extremely Low Mass Ratio-contact Binary Systems
DOI: 10.3847/1538-3881/ad4882 Bibcode: 2024AJ....168...50L

Ferreira Lopes, C. E.; Catelan, Márcio; Lalounta, Eleni +2 more

Low-mass ratio systems (LMR) are a very interesting class of contact eclipsing binaries challenging the theoretical models of stability. These systems are also considered possible progenitors of the rare low-mass optical transients called red novae. In this study, we present the identification of 7 new totally eclipsing LMR systems from Catalina S…

2024 The Astronomical Journal
Gaia 3
"Beads-on-a-string" Star Formation Tied to One of the Most Powerful Active Galactic Nucleus Outbursts Observed in a Cool-core Galaxy Cluster
DOI: 10.3847/1538-4357/ad1101 Bibcode: 2024ApJ...963....1O

Baum, Stefi A.; O'Dea, Christopher P.; Vaddi, Sravani +19 more

With two central galaxies engaged in a major merger and a remarkable chain of 19 young stellar superclusters wound around them in projection, the galaxy cluster SDSS J1531+3414 (z = 0.335) offers an excellent laboratory to study the interplay between mergers, active galactic nucleus (AGN) feedback, and star formation. New Chandra X-ray imaging rev…

2024 The Astrophysical Journal
eHST 3
Toward Unveiling Cosmic Reionization: The Ionizing Photon Production Efficiency (ξ ion) of Low-mass Hα Emitters at z ∼ 2.3
DOI: 10.3847/1538-4357/ad4033 Bibcode: 2024ApJ...968...32C

Nakajima, Kimihiko; Spitler, Lee; Motohara, Kentaro +2 more

We investigate the galaxy properties of ∼400 low-mass (<109 M ) Hα emitters (HAEs) at z ∼ 2.3 in the ZFOURGE survey. The selection of these HAEs is based on the excess in the observed K s broadband flux compared to the stellar continuum estimated from the best-fit spectral energy distribution. These low-mass …

2024 The Astrophysical Journal
eHST 3
JADES Ultrared Flattened Objects: Morphologies and Spatial Gradients in Color and Stellar Populations
DOI: 10.3847/1538-4357/ad64c2 Bibcode: 2024ApJ...974...48G

Bunker, Andrew J.; Maiolino, Roberto; Willott, Chris +20 more

One of the more surprising findings after the first year of JWST observations is the large number of spatially extended galaxies (ultrared flattened objects, or UFOs) among the optically faint galaxy (OFG) population otherwise thought to be compact. Leveraging the depth and survey area of the JWST Advanced Deep Extragalactic Survey, we extend obse…

2024 The Astrophysical Journal
Herschel JWST 3