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The number of globular clusters around the iconic UDG DF44 is as expected for dwarf galaxies
Beasley, Michael A.; Trujillo, Ignacio; Peletier, Reynier F. +2 more
There is a growing consensus that the vast majority of ultradiffuse galaxies (UDGs) are dwarf galaxies. However, there remain a few UDGs that seem to be special in terms of their globular cluster (GC) systems. In particular, according to some authors, certain UDGs exhibit large GC populations when compared to expectations from their stellar (or to…
The parallax zero-point offset from Gaia EDR3 data
Groenewegen, M. A. T.
The second data release of Gaia revealed a parallax zero-point offset of −0.029 mas based on quasars. The value depended on the position on the sky, and also likely on magnitude and colour. The offset and its dependence on other parameters inhibited improvement in the local distance scale using for example the Cepheid and RR Lyrae period-luminosit…
Medium-resolution spectrum of the exoplanet HIP 65426 b
D'Orazi, V.; Boccaletti, A.; Lagrange, A. -M. +18 more
Medium-resolution integral-field spectrographs (IFS) coupled with adaptive-optics such as Keck/OSIRIS, VLT/MUSE, or SINFONI are appearing as a new avenue for enhancing the detection and characterization capabilities of young, gas giant exoplanets at large heliocentric distances (>5 au). We analyzed K-band VLT/SINFONI medium-resolution (Rλ<…
Aurora: A Generalized Retrieval Framework for Exoplanetary Transmission Spectra
Madhusudhan, Nikku; Welbanks, Luis
Atmospheric retrievals of exoplanetary transmission spectra provide important constraints on various properties, such as chemical abundances, cloud/haze properties, and characteristic temperatures, at the day-night atmospheric terminator. To date, most spectra have been observed for giant exoplanets due to which retrievals typically assume hydroge…
A constraint on light primordial black holes from the interstellar medium temperature
Kim, Hyungjin
Primordial black holes are a viable dark matter candidate. They decay via Hawking evaporation. Energetic particles from the Hawking radiation interact with interstellar gas, depositing their energy as heat and ionization. For a sufficiently high Hawking temperature, fast electrons produced by black holes deposit a substantial fraction of energy as…
Ultra diffuse galaxies in the MATLAS low-to-moderate density fields
Müller, Oliver; Duc, Pierre-Alain; Lim, Sungsoon +10 more
Recent advances in deep dedicated imaging surveys over the past decade have uncovered a surprisingly large number of extremely faint low surface brightness galaxies with large physical sizes called ultra diffuse galaxies (UDGs) in clusters and, more recently, in lower density environments. As part of the Mass Assembly of early-Type GaLAxies with t…
Structure and morphology of the MATLAS dwarf galaxies and their central nuclei
Müller, Oliver; Duc, Pierre-Alain; Lim, Sungsoon +10 more
We present a photometric study of the dwarf galaxy population in the low to moderate density environments of the MATLAS (Mass Assembly of early-Type gaLAxies with their fine Structures) deep imaging survey. The sample consists of 2210 dwarfs, including 508 nucleated. We define a nucleus as a compact source that is close to the galaxy photocentre (…
Superflares, Chromospheric Activities, and Photometric Variabilities of Solar-type Stars from the Second-year Observation of TESS and Spectra of LAMOST
Wang, H. -F.; Yang, Ming; Tu, Zuo-Lin +1 more
In this work, 1272 superflares on 311 stars are collected from 22,539 solar-type stars from the second-year observation of the Transiting Exoplanet Survey Satellite (TESS), which almost covered the northern hemisphere of the sky. Three superflare stars contain hot Jupiter candidates or ultrashort-period planet candidates. We obtain γ = -1.76 ± 0.1…
Mapping solar magnetic fields from the photosphere to the base of the corona
Hara, Hirohisa; De Pontieu, Bart; Carlsson, Mats +25 more
Routine ultraviolet imaging of the Sun's upper atmosphere shows the spectacular manifestation of solar activity; yet we remain blind to its main driver, the magnetic field. Here we report unprecedented spectropolarimetric observations of an active region plage and its surrounding enhanced network, showing circular polarization in ultraviolet (Mg I…
The Sizes of Quasar Host Galaxies in the Hyper Suprime-Cam Subaru Strategic Program
Schramm, Malte; Strauss, Michael A.; Xue, Yongquan +11 more
The relationship between quasars and their host galaxies provides clues on how supermassive black holes (SMBHs) and massive galaxies are jointly assembled. To elucidate this connection, we measure the structural and photometric properties of the host galaxies of ~5000 Sloan Digital Sky Survey quasars at 0.2 < z < 1 using five-band (grizy) op…