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Quiescent Low-mass Galaxies Observed by JWST in the Epoch of Reionization
Carniani, Stefano; Ferrara, Andrea; Pallottini, Andrea +2 more
The surprising JWST discovery of a quiescent, low-mass (M ⋆ = 108.7 M ⊙) galaxy at redshift z = 7.3 (JADES-GS-z7-01-QU) represents a unique opportunity to study the imprint of feedback processes on early galaxy evolution. We build a sample of 130 low-mass (M ⋆ ≲ 109.5 M ⊙) galaxies …
Gaia Data Release 3. Microlensing events from all over the sky
Audard, M.; Rimoldini, L.; Holl, B. +12 more
Context. One of the rarest types of variability is the phenomenon of gravitational microlensing, a transient brightening of a background star due to an intervening lensing object. Microlensing is a powerful tool for studying the invisible or otherwise undetectable populations in the Milky Way, including planets and black holes.
Aims: We descr…
IXPE and Multiwavelength Observations of Blazar PG 1553+113 Reveal an Orphan Optical Polarization Swing
Kaaret, Philip; Wu, Kinwah; Enoto, Teruaki +119 more
The lower-energy peak of the spectral energy distribution of blazars has commonly been ascribed to synchrotron radiation from relativistic particles in the jets. Despite the consensus regarding jet emission processes, the particle acceleration mechanism is still debated. Here, we present the first X-ray polarization observations of PG 1553+113, a …
Patchy Forsterite Clouds in the Atmospheres of Two Highly Variable Exoplanet Analogs
Marley, Mark; Faherty, Jacqueline K.; Morley, Caroline V. +12 more
We present an atmospheric retrieval analysis of a pair of highly variable, ~200 Myr old, early T type planetary-mass exoplanet analogs SIMP J01365662+0933473 and 2MASS J21392676+0220226 using the Brewster retrieval framework. Our analysis, which makes use of archival 1-15 µm spectra, finds almost identical atmospheres for both objects. For b…
The Time-averaged Mass-loss Rates of Red Supergiants as Revealed by Their Luminosity Functions in M31 and M33
Massey, Philip; Meynet, Georges; Neugent, Kathryn F. +2 more
Mass loss in red supergiants (RSGs) is generally recognized to be episodic, but mass-loss prescriptions fail to reflect this. Evolutionary models show that the total amount of mass lost in this phase determines if these stars evolve to warmer temperatures before undergoing core collapse. The current Geneva evolutionary models mimic episodic mass l…
Properties of flare events based on light curves from the TESS survey
Zhang, Liyun; Han, Xianming L.; Misra, Prabhakar +4 more
Aims: A stellar flare is a strong energy burst event. Understanding stellar flares is important for determining the properties of stellar magnetic activities. We aim to perform detailed statistical analyses on stellar flare characteristics in terms of the different stellar parameters using the light curves of the Transiting Exoplanet Survey S…
The extended 'stellar halo' of the Ursa Minor dwarf galaxy
Sestito, Federico; Jensen, Jaclyn; McConnachie, Alan W. +9 more
Stellar candidates in the Ursa Minor (UMi) dwarf galaxy have been found using a new Bayesian algorithm applied to Gaia EDR3 data. Five of these targets are located in the extreme outskirts of UMi, from ~5 to 12 elliptical half-light radii (rh), where rh(UMi) = 17.32 ± 0.11 arcmin, and have been observed with the high-resoluti…
Galaxy interactions are the dominant trigger for local type 2 quasars
Ramos Almeida, C.; Tadhunter, C.; Pierce, J. C. S. +8 more
The triggering mechanism for the most luminous, quasar-like active galactic nuclei (AGN) remains a source of debate, with some studies favouring triggering via galaxy mergers, but others finding little evidence to support this mechanism. Here, we present deep Isaac Newton Telescope/Wide Field Camera imaging observations of a complete sample of 48 …
Metal Mixing in the r-process Enhanced Ultrafaint Dwarf Galaxy Reticulum II
Klessen, Ralf S.; Johnson, Christian I.; Mateo, Mario +9 more
The ultrafaint dwarf galaxy Reticulum II was enriched by a single rare and prolific r-process event. The r-process content of Reticulum II thus provides a unique opportunity to study metal mixing in a relic first galaxy. Using multi-object high-resolution spectroscopy with VLT/GIRAFFE and Magellan/M2FS, we identify 32 clear spectroscopic member st…
Small Region, Big Impact: Highly Anisotropic Lyman-continuum Escape from a Compact Starburst Region with Extreme Physical Properties
Mahler, Guillaume; Chisholm, John; Rigby, Jane R. +13 more
Extreme, young stellar populations are considered to be the primary contributor to cosmic reionization. How the Lyman continuum (LyC) escapes these galaxies remains highly elusive, and it is challenging to observe this process in actual LyC emitters without resolving the relevant physical scales. We investigate the Sunburst Arc, a strongly lensed …