Search Publications
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…
The Carnegie-Chicago Hubble Program. IX. Calibration of the Tip of the Red Giant Branch Method in the Megamaser Host Galaxy, NGC 4258 (M106)
Madore, Barry F.; Freedman, Wendy L.; Beaton, Rachael L. +7 more
In the nearby galaxy NGC 4258, the well-modeled orbital motion of H2O masers about its supermassive black hole provides the means to measure a precise geometric distance. As a result, NGC 4258 is one of a few "geometric anchors" available to calibrate the true luminosities of stellar distance indicators such as the Tip of the Red Giant …
The growth of intracluster light in XCS-HSC galaxy clusters from 0.1 < z < 0.5
Baldry, Ivan K.; Kelvin, Lee S.; Stott, John P. +14 more
We estimate the intracluster light (ICL) component within a sample of 18 clusters detected in the XMM Cluster Survey (XCS) data using the deep (~26.8 mag) Hyper Suprime-Cam Subaru Strategic Programme data release 1 i-band data. We apply a rest-frame µB = 25 mag arcsec-2 isophotal threshold to our clusters, below which w…
Evaluating Rotation Periods of M Dwarfs across the Ages
Angus, Ruth; Kiman, Rocio; Faherty, Jacqueline K. +5 more
In this work we examine M dwarf rotation rates at a range of ages to establish benchmarks for M dwarf gyrochronology. This work includes a sample of 713 spectroscopically classified M0-M8 dwarfs with new rotation rates measured from K2 light curves. We analyze data and recover rotation rates for 179 of these objects. We add these to rotation rates…
Resolving local and global kinematic signatures of satellite mergers with billion particle simulations
Laporte, Chervin F. P.; Johnston, Kathryn V.; Hunt, Jason A. S. +3 more
In this work, we present two new ~109 particle self-consistent simulations of the merger of a Sagittarius-like dwarf galaxy with a Milky Way (MW)-like disc galaxy. One model is a violent merger creating a thick disc, and a Gaia-Enceladus/Sausage-like remnant. The other is a highly stable disc which we use to illustrate how the improved …