7 research outputs found
An Optical and Infrared Photometric Study of the Young Open Cluster IC 1805 in the Giant H II Region W4
We present deep wide-field optical CCD photometry and mid-infrared
Spitzer/IRAC and MIPS 24micron data for about 100,000 stars in the young open
cluster IC 1805. The members of IC 1805 were selected from their location in
the various color-color and color-magnitude diagrams, and the presence of
Halpha emission, mid-infrared excess emission, and X-ray emission. The
reddening law toward IC 1805 is nearly normal (R_V = 3.05+/-0.06). However, the
distance modulus of the cluster is estimated to be 11.9+/-0.2 mag (d =
2.4+/-0.2 kpc) from the reddening-free color-magnitude diagrams, which is
larger than the distance to the nearby massive star-forming region W3(OH)
measured from the radio VLBA astrometry. We also determined the age of IC 1805
(tau_MSTO = 3.5 Myr). In addition, we critically compared the age and mass
scale from two pre-main-sequence evolution models. The initial mass function
with a Salpeter-type slope of Gamma = -1.3+/-0.2 was obtained and the total
mass of IC 1805 was estimated to be about 2700+/-200 M_sun. Finally, we found
our distance determination to be statistically consistent with the Tycho-Gaia
Astrometric Solution Data Release 1, within the errors. The proper motion of
the B-type stars shows an elongated distribution along the Galactic plane,
which could be explained by some of the B-type stars being formed in small
clouds dispersed by previous episodes of star formation or supernova
explosions.Comment: 45 pages, 32 figures, 9 tables, accepted for publication in ApJ
Determination of the Parameter Sets for the Best Performance of IPS-driven ENLIL Model
Interplanetary scintillation-driven (IPS-driven) ENLIL model was jointly developed by University of California, San Diego
(UCSD) and National Aeronaucics and Space Administration/Goddard Space Flight Center (NASA/GSFC). The model has
been in operation by Korean Space Weather Cetner (KSWC) since 2014. IPS-driven ENLIL model has a variety of ambient
solar wind parameters and the results of the model depend on the combination of these parameters. We have conducted
researches to determine the best combination of parameters to improve the performance of the IPS-driven ENLIL model.
The model results with input of 1,440 combinations of parameters are compared with the Advanced Composition Explorer
(ACE) observation data. In this way, the top 10 parameter sets showing best performance were determined. Finally, the
characteristics of the parameter sets were analyzed and application of the results to IPS-driven ENLIL model was discussed