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Radio interferometric imaging of RS Oph bipolar ejecta for the 2021 nova outburst
Munari, U.; Giroletti, M.; Williams, D. R. A. +5 more
The recurrent nova and symbiotic binary RS Oph erupted again in August 2021 for its eighth known outburst. We observed RS Oph 34 days after the outburst at 5 GHz with the European VLBI Network (EVN). The radio image is elongated over the east-west direction for a total extension of about 90 mas (or about 240 AU at the Gaia DR3 distance d = 2.68
Early-time Ultraviolet Spectroscopy and Optical Follow-up Observations of the Type IIP Supernova 2021yja
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Modjaz, Maryam +19 more
We present three epochs of early-time ultraviolet (UV) and optical HST/STIS spectroscopy of the young, nearby Type IIP supernova (SN) 2021yja. We complement the HST data with two earlier epochs of Swift UVOT spectroscopy. The HST and Swift UVOT spectra are consistent with those of other well-studied Type IIP SNe. The UV spectra exhibit rapid cooli…
First Observation of the MeV Gamma-Ray Universe with Bijective Imaging Spectroscopy Using the Electron-tracking Compton Telescope on Board SMILE-2+
Hamaguchi, Kenji; Takada, Atsushi; Kubo, Hidetoshi +12 more
MeV gamma-rays provide a unique window for the direct measurement of line emissions from radioisotopes, but observations have made little significant progress since COMPTEL on board the Compton Gamma-ray Observatory (CGRO). To observe celestial objects in this band, we are developing an electron-tracking Compton camera (ETCC) that realizes both bi…
A 2D Model for Coronal Bright Points: Association with Spicules, UV Bursts, Surges, and EUV Coronal Jets
Moreno-Insertis, F.; Nóbrega-Siverio, D.
Coronal bright points (CBPs) are ubiquitous structures in the solar atmosphere composed of hot small-scale loops observed in extreme-ultraviolet (EUV) or X-rays in the quiet Sun and coronal holes. They are key elements to understanding the heating of the corona; nonetheless, basic questions regarding their heating mechanisms, the chromosphere unde…
Turning points in the age-metallicity relations - created by late satellite infall and enhanced by radial migration
Ness, Melissa K.; Buck, Tobias; Lu, Yuxi Lucy +1 more
The present-day age-metallicity relation (AMR) is a record of the star formation history of galaxies, as this traces the chemical enrichment of the gas over time. We use a zoomed-in cosmological simulation that reproduces key signatures of the Milky Way (MW), g2.79e12 from the NIHAO-UHD project, to examine how stellar migration and satellite infal…
Stellar populations and star formation histories of the most extreme [O III] emitters at z = 1.3 - 3.7
Tang, Mengtao; Stark, Daniel P.; Ellis, Richard S.
As the James Webb Space Telescope approaches scientific operation, there is much interest in exploring the redshift range beyond that accessible with Hubble Space Telescope imaging. Currently, the only means to gauge the presence of such early galaxies is to age-date the stellar population of systems in the reionisation era. As a significant fract…
The Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER). III. The Mass Function of Young Stellar Clusters in M33
Williams, Benjamin F.; Johnson, L. Clifton; Dolphin, Andrew +7 more
We measure the star cluster mass function (CMF) for the Local Group galaxy M33. We use the catalog of stellar clusters selected from the Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region survey. We analyze 711 clusters in M33 with $7.0\lt \mathrm{log}(\mathrm{Age}/\mathrm{yr})\lt 8.5$ , and log(M/M ⊙) > 3.0 as determ…
Simultaneous X-ray and optical spectroscopy of V404 Cygni supports the multi-phase nature of X-ray binary accretion disc winds
Ponti, Gabriele; Muñoz-Darias, Teo
Observational signatures of accretion disc winds have been found in a significant number of low-mass X-ray binaries at either X-ray or optical wavelengths. The 2015 outburst of the black hole transient V404 Cygni provided a unique opportunity for studying both types of outflows in the same system. We used contemporaneous X-ray (Chandra Observatory…
Evaluating Lyα Emission as a Tracer of the Largest Cosmic Structure at z 2.47
Pentericci, Laura; Hathi, Nimish; Sawicki, Marcin +13 more
The discovery and spectroscopic confirmation of Hyperion, a protosupercluster at z ~ 2.47, provides an unprecedented opportunity to study distant galaxies in the context of their large-scale environment. We carry out deep narrowband imaging of a ≈1° × 1° region around Hyperion and select 157 Lyα emitters (LAEs). The inferred LAE overdensity is δ <…
Quiet Sun Center to Limb Variation of the Linear Polarization Observed by CLASP2 Across the Mg II h and k Lines
Auchère, F.; Kubo, M.; De Pontieu, B. +25 more
The CLASP2 (Chromospheric LAyer Spectro-Polarimeter 2) sounding rocket mission was launched on 2019 April 11. CLASP2 measured the four Stokes parameters of the Mg II h and k spectral region around 2800 Å along a 200″ slit at three locations on the solar disk, achieving the first spatially and spectrally resolved observations of the solar polarizat…