Browsing by Author "Yao, Yuhan"

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    Prospects for Time-Domain and Multi-Messenger Science with AXIS
    (2024) Arcodia, Riccardo; Bauer, Franz E.; Cenko, S. Bradley; Dage, Kristen C.; Haggard, Daryl; Ho, Wynn C. G.; Kara, Erin; Koss, Michael; Liu, Tingting; Mallick, Labani; Negro, Michela; Pradhan, Pragati; Quirola-Vasquez, J.; Reynolds, Mark T.; Ricci, Claudio; Rothschild, Richard E.; Sridhar, Navin; Troja, Eleonora; Yao, Yuhan
    The Advanced X-ray Imaging Satellite (AXIS) promises revolutionary science in the X-ray and multi-messenger time domain. AXIS will leverage excellent spatial resolution (<1.5 arcsec), sensitivity (80x that of Swift), and a large collecting area (5-10x that of Chandra) across a 24-arcmin diameter field of view at soft X-ray energies (0.3-10.0 keV) to discover and characterize a wide range of X-ray transients from supernova-shock breakouts to tidal disruption events to highly variable supermassive black holes. The observatory's ability to localize and monitor faint X-ray sources opens up new opportunities to hunt for counterparts to distant binary neutron star mergers, fast radio bursts, and exotic phenomena like fast X-ray transients. AXIS will offer a response time of <2 h to community alerts, enabling studies of gravitational wave sources, high-energy neutrino emitters, X-ray binaries, magnetars, and other targets of opportunity. This white paper highlights some of the discovery science that will be driven by AXIS in this burgeoning field of time domain and multi-messenger astrophysics. This White Paper is part of a series commissioned for the AXIS Probe Concept Mission; additional AXIS White Papers can be found at the AXIS website.
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    ZTF Early Observations of Type Ia Supernovae. III. Early-time Colors As a Test for Explosion Models and Multiple Populations
    (2020) Bulla, Mattia; Miller, Adam A.; Yao, Yuhan; Dessart, Luc; Dhawan, Suhail; Papadogiannakis, Semeli; Biswas, Rahul; Goobar, Ariel; Kulkarni, S. R.; Nordin, Jakob; Nugent, Peter; Polin, Abigail; Sollerman, Jesper; Bellm, Eric C.; Coughlin, Michael W.; Dekany, Richard; Golkhou, V. Zach; Graham, Matthew J.; Kasliwal, Mansi M.; Kupfer, Thomas; Laher, Russ R.; Masci, Frank J.; Porter, Michael; Rusholme, Ben; Shupe, David L.
    Colors of Type Ia supernovae (SNe Ia) in the first few days after explosion provide a potential discriminant between different models. In this paper, we present g - r colors of 65 SNe Ia discovered within 5 days from first light by the Zwicky Transient Facility in 2018, a sample that is about three times larger than that in the literature. We find that g - r colors are intrinsically rather homogeneous at early phases, with about half of the dispersion attributable to photometric uncertainties (0.18 mag). Colors are nearly constant starting from 6 days after first light (g-r similar to -0.15 mag), while the time evolution at earlier epochs is characterized by a continuous range of slopes, from events rapidly transitioning from redder to bluer colors (slope of similar to-0.25 mag day(-1)) to events with a flatter evolution. The continuum in the slope distribution is in good agreement both with models requiring some amount of Ni-56 mixed in the outermost regions of the ejecta and with "double-detonation" models having thin helium layers (M-He = 0.01 M-circle dot) and varying carbon-oxygen core masses. At the same time, six events show evidence for a distinctive "red bump" signature predicted by double-detonation models with larger helium masses. We finally identify a significant correlation between the early-timeg - rslopes and supernova brightness, with brighter events associated to flatter color evolution (p-value = 0.006). The distribution of slopes, however, is consistent with being drawn from a single population, with no evidence for two components as claimed in the literature based on B - V colors.