Day 1595

Monday.

1907.02693
Calibrating the standard candles with strong lensing
Wen, Liao

We propose a new model-independent strategy to calibrate the distance relation of Type Ia supernovae (SNe) and to probe the intrinsic properties of SNe Ia, especially the absolute magnitude $M_B$, based on strong lensing observations in the upcoming LSST era. The strongly lensed quasars can provide the Time Delay Distances (TDDs) and the Angular Diameter Distances (ADDs) to the lens galaxies, which can model-independently anchor the SNe Ia at cosmological distances and may in turn solve the Hubble constant issues locally related with Cepheids. We simulated 55 high-quality lens samples with $5\%$ uncertainties for the two kinds of lensing distances basing on future observation conditions. For the time delay distances and the angular diameter distances as the calibration standards, the calibrated $1\sigma$ uncertainties of $M_{B}$ are 0.1 and 0.03, respectively. Besides, we also consider an evolving distance relation, for example, caused by the cosmic opacity. In this case, the $1\sigma$ uncertainties of $M_B$ obtained by TDDs and ADDs are 0.12 and 0.08, respectively.

1907.02795

Life time evolution of coronal holes

Jercic, et al

We investigate the evolution of eight well-observed persistent coronal holes (CHs) with life spans of 5-12 solar rotations, that were observed between 2010 and 2015. The aim is to increase our understanding of the evolution of CHs, as well as to investigate the basic physical mechanisms that govern the CH behaviour over its lifetime. Using combined AIA/SDO and HMI/SDO data, we derive several CH parameters such as area, intensity, and magnetic field characteristics as function of time. Using in-situ data from the ACE satellite located at L1, we study the corresponding solar wind plasma measurements. We find that 6 out of 8 CHs in our data set reveal a steady increase in the area followed by a decrease. The average absolute change of area between two points in the growing phase of the regular CHs is (10.2 +/- 3.5) x 10^8 km^2 per day, while for the decaying phase is (8.6 +/- 3.7) x 10^8 km^2 per day. For those CHs we found that the CH magnetic field strength is strongly related to the amount of area strong flux tubes contribute to the CH area. However, there is no correlation between the magnetic field and the total CH area itself, hence, the magnetic field variation follows a different evolutionary pattern. With the in-situ proton bulk speed, we derive for the growing area phase a strong correlation (Pearson cc = 0.69) and for the decaying phase a moderate one (cc = 0.45).