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The Blue Supergiant Progenitor of the Supernova Imposter AT 2019krl
DOI: 10.3847/1538-4357/ac09e1 Bibcode: 2021ApJ...917...63A

Van Dyk, Schuyler D.; Filippenko, Alexei V.; Kochanek, C. S. +20 more

Extensive archival Hubble Space Telescope, Spitzer Space Telescope, and Large Binocular Telescope imaging of the recent intermediate-luminosity transient, AT 2019krl in M74, reveal a bright optical and mid-infrared progenitor star. While the optical peak of the event was missed, a peak was detected in the infrared with an absolute magnitude of M

2021 The Astrophysical Journal
Gaia eHST 19
Far-ultraviolet Spectra of Main-sequence O Stars at Extremely Low Metallicity
DOI: 10.3847/1538-4357/ac1ce2 Bibcode: 2021ApJ...922..191T

McQuinn, Kristen B. W.; Chisholm, John; Berg, Danielle A. +1 more

Metal-poor massive stars dominate the light we observe from star-forming dwarf galaxies and may have produced the bulk of energetic photons that reionized the universe at high redshift. Yet, the rarity of observations of individual O stars below the 20% solar metallicity (Z ) of the Small Magellanic Cloud (SMC) hampers our ability to m…

2021 The Astrophysical Journal
eHST 19
The Global Magneto-ionic Medium Survey: A Faraday Depth Survey of the Northern Sky Covering 1280-1750 MHz
DOI: 10.3847/1538-3881/abf7c1 Bibcode: 2021AJ....162...35W

Leahy, J. P.; Kothes, R.; Gaensler, B. M. +17 more

The Galactic interstellar medium hosts a significant magnetic field, which can be probed through the synchrotron emission produced from its interaction with relativistic electrons. Linearly polarized synchrotron emission is generated throughout the Galaxy and, at longer wavelengths, modified along nearly every path by Faraday rotation in the inter…

2021 The Astronomical Journal
Gaia 19
Asteroseismology of evolved stars to constrain the internal transport of angular momentum. IV. Internal rotation of Kepler-56 from an MCMC analysis of the rotational splittings
DOI: 10.1051/0004-6361/202140518 Bibcode: 2021A&A...654A.133F

Buldgen, G.; Khan, S.; Eggenberger, P. +4 more

Context. The observations of global stellar oscillations of post-main-sequence stars by space-based photometry missions have allowed us to directly determine their internal rotation. These constraints have pointed towards the existence of angular momentum transport processes not accounted for in theoretical models. Constraining the properties of t…

2021 Astronomy and Astrophysics
Gaia 19
Identification of AKARI infrared sources by the Deep HSC Optical Survey: construction of a new band-merged catalogue in the North Ecliptic Pole Wide field
DOI: 10.1093/mnras/staa3359 Bibcode: 2021MNRAS.500.4078K

Momose, Rieko; Hashimoto, Tetsuya; Goto, Tomotsugu +21 more

The North Ecliptic Pole field is a natural deep-field location for many satellite observations. It has been targeted many times since it was surveyed by the AKARI space telescope with its unique wavelength coverage from the near- to mid-infrared (mid-IR). Many follow-up observations have been carried out, making this field one of the most frequent…

2021 Monthly Notices of the Royal Astronomical Society
AKARI Herschel 19
Semi-regular red giants as distance indicators. I. The period-luminosity relations of semi-regular variables revisited
DOI: 10.1051/0004-6361/202142022 Bibcode: 2021A&A...656A..66T

Mowlavi, N.; Lebzelter, T.; Trabucchi, M.

Context. Semi-regular variables (SRVs) are similar to Miras in brightness, and they also follow one or more period-luminosity relations (PLRs), though not necessarily the same one as Miras. As potential standard candles they are more challenging than Miras because of their smaller variability amplitudes and less regular light curves, but they are …

2021 Astronomy and Astrophysics
Gaia 19
Milky Way archaeology using RR Lyrae and type II Cepheids. I. The Orphan stream in 7D using RR Lyrae stars
DOI: 10.1051/0004-6361/202140422 Bibcode: 2021A&A...648A..78P

Lemasle, B.; Thévenin, F.; Altavilla, G. +19 more

We present a chemo-dynamical study of the Orphan stellar stream using a catalog of RR Lyrae pulsating variable stars for which photometric, astrometric, and spectroscopic data are available. Employing low-resolution spectra from the Sloan Digital Sky Survey (SDSS), we determined line-of-sight velocities for individual exposures and derived the sys…

2021 Astronomy and Astrophysics
Gaia 19
Acoustic-gravity wave propagation characteristics in three-dimensional radiation hydrodynamic simulations of the solar atmosphere
DOI: 10.1098/rsta.2020.0170 Bibcode: 2021RSPTA.37900170F

Carlsson, M.; Rempel, M.; Fleck, B. +3 more

There has been tremendous progress in the degree of realism of three-dimensional radiation magneto-hydrodynamic simulations of the solar atmosphere in the past decades. Four of the most frequently used numerical codes are Bifrost, CO5BOLD, MANCHA3D and MURaM. Here we test and compare the wave propagation characteristics in model runs from these fo…

2021 Philosophical Transactions of the Royal Society of London Series A
Hinode SOHO 19
Spectroscopy of the first resolved strongly lensed Type Ia supernova iPTF16geu
DOI: 10.1093/mnras/staa3829 Bibcode: 2021MNRAS.502..510J

Cenko, S. B.; Kulkarni, S. R.; Nugent, P. E. +14 more

We report the results from spectroscopic observations of the multiple images of the strongly lensed Type Ia supernova (SN Ia), iPTF16geu, obtained with ground-based telescopes and the Hubble Space Telescope (HST). From a single epoch of slitless spectroscopy with HST, we resolve spectra of individual lensed supernova images for the first time. Thi…

2021 Monthly Notices of the Royal Astronomical Society
eHST 19
"Worst-case" Microlensing in the Identification and Modeling of Lensed Quasars
DOI: 10.3847/1538-4357/ac2228 Bibcode: 2021ApJ...922...70W

Schechter, Paul L.; Weisenbach, Luke; Pontula, Sahil

Although microlensing of macrolensed quasars and supernovae provides unique opportunities for several kinds of investigations, it can add unwanted and sometimes substantial noise. While microlensing flux anomalies may be safely ignored for some observations, they severely limit others. "Worst-case" estimates can inform the decision whether or not …

2021 The Astrophysical Journal
Gaia 19