J/PASJ/72/55 L1482 filament cores (Omodaka+, 2020) ================================================================================ Star formation rates in the L 1482 filament of the California molecular cloud. Omodaka T., Nagayama T., Dobashi K., Chibueze J.O., Yamabi A., Shimajiri Y., Inoue S., Hamada S., Sunada K., Ueno Y. =2020PASJ...72...55O (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Molecular clouds ; Masers ; Radio sources Keywords: masers - astrometry stars: formation - stars: individual Abstract: We measured the trigonometric parallax of the H_2_O maser source associated with the L1482 molecular filament hosting the most massive young star, LkH{alpha} 101, in the California molecular cloud. The measured parallax is 1.879+/-0.096mas, corresponding to the distance of 532+/-28pc. This parallax is consistent with that of the nearby star cluster LkH{alpha} 101, which was recently measured with Gaia DR2. We found that the L1482 molecular filament and the LkH{alpha} 101 cluster are located at the same distance within 3+/-30pc. We observed the southern parts of L1482 molecular clouds including the H_2_O maser source, which is adjacent to LkH{alpha} 101, using the Nobeyama 45m telescope in the J=1-0 transitions of both ^12^CO and ^13^CO. The peak intensity of the ^12^CO line revealed the high excitation temperature region (60-70K) due to heating by UV radiation from LkH{alpha} 101. We derived the column density of these molecular clouds assuming local thermodynamic equilibrium (LTE) from the ^13^CO emission. Using Dendrogam, we searched for small-scale, dense structures (cores) and identified 337 cores in the ^13^CO data. Gravitationally bound cores with a virial mass to LTE mass ratio <=1.5 and young stars are concentrated in the high excitation temperature region. The column density in the warm region is five to six times larger than that of the surrounding colder molecular region. This suggests that the warm region has been compressed by a high-pressure wave and successive radiation-driven star formation is in progress in this warm region. In the cold molecular cloud to the north of the warm region, the cores are likely gravitationally unbound, which may be the reason why star formation is not active there. Description: The VLBI observations of the 22.235080GHz H_2_O maser in L1482 were carried out on 2010/333, 2011/016, 2011/113, 2011/228, 2011/297, and 2011/353 (year/day of the year) with VERA. The observing time was approximately eight hours at each epoch. In order to study the star formation activity in the L1482 filament, we identified cores using the fiducial core-finding algorithm Dendrogram (Rosolowsky et al. 2008ApJ...679.1338R). File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table2.dat 81 337 Properties of identified cores using dendrogram -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- ID Sequential number 6 I1 h RAh Right ascension (J2000) 8- 9 I2 min RAm Right ascension (J2000) 11- 15 F5.2 s RAs Right ascension (J2000) 17 A1 --- DE- Declination sign (J2000) 18- 19 I2 deg DEd Declination (J2000) 21- 22 I2 arcmin DEm Declination (J2000) 24- 27 F4.1 arcsec DEs Declination (J2000) 29- 33 F5.3 pc Rcore Core radius 35- 40 F6.3 K Tpeak Peak temperature 42- 45 F4.1 K backg Background level 47- 51 F5.3 km/s DV Line width 53- 57 F5.2 Msun Mvir Virial mass 59- 63 F5.2 10+23cm-2 SNH2 Total molecular column density 65- 69 F5.2 Msun MLTE LTE mass 71- 75 F5.2 10+3cm-3 n Mean molecular number density 77- 81 F5.2 --- Mvir/MLTE Virial to core mass ratio (={alpha}_vir_) -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Patricia Vannier [CDS] 10-Nov-2023