J/AJ/162/68 Water masers in Serpens South (Ortiz-Leon+, 2021) ================================================================================ Discovery of 22 GHz water masers in the Serpens South region. Ortiz-Leon G.N., Plunkett A.L., Loinard L., Dzib S.A., Rodriguez-Garza C.B., Pillai T., Gong Y., Brunthaler A. =2021AJ....162...68O (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Star Forming Region ; Radio sources Keywords: Water masers - Low mass stars - Star-forming regions - Interferometers - Protoclusters - Young stellar objects - Protostars Abstract: Using the Karl G. Jansky Very Large Array (VLA), we have conducted a survey for 22 GHz, 6_1,6_-5_2,3_ H_2_O masers toward the Serpens South region. The masers were also observed with the Very Long Baseline Array following the VLA detections. We detect for the first time H_2_O masers in the Serpens South region that are found to be associated to three Class 0-Class I objects, including the two brightest protostars in the Serpens South cluster, known as CARMA-6 and CARMA-7. We also detect H_2_O masers associated to a source with no outflow or jet features. We suggest that this source is most probably a background asymptotic giant branch star projected in the direction of Serpens South. The spatial distribution of the emission spots suggest that the masers in the three Class 0-Class I objects emerge very close to the protostars and are likely excited in shocks driven by the interaction between a protostellar jet and the circumstellar material. Based on the comparison of the distributions of bolometric luminosity of sources hosting 22GHz H_2_O masers and 162 young stellar objects covered by our observations, we identify a limit of L_Bol_~=10L_{sun}_ for a source to host water masers. However, the maser emission shows strong variability in both intensity and velocity spread, and therefore masers associated to lower-luminosity sources may have been missed by our observations. We also report 11 new sources with radio continuum emission at 22GHz. Description: We have conducted an interferometric survey of 22GHz H_2_O masers toward the low-mass star-forming region Serpens South. Our observations were first carried out with the VLA covering all known protostars (Class 0-Class I objects) across the region. Table 5 lists the 17 sources detected with radio continuum, as well as their positions and fluxes as obtained by fitting the brightness distribution with a Gaussian model using the task imfit in CASA. The fluxes are listed for each epoch and for the combined image. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table5.dat 122 78 Properties of the VLA Detected Radio Continuum Sources -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- ID [1/17] Source ID 4- 6 A3 --- Epoch Epoch ID (all, 1, 2, 3, 4) 8- 9 I2 h RAh ? Right ascension (J2000) 11- 12 I2 min RAm ? Right ascension (J2000) 14- 18 F5.2 s RAs ? Right ascension (J2000) 21 A1 --- DE- Declination sign (J2000) 22 I1 deg DEd ? Declination (J2000) 24- 25 I2 arcmin DEm ? Declination (J2000) 27- 30 F4.1 arcsec DEs ? Declination (J2000) 32 A1 --- l_Peak Limit flag on Peak 33- 36 F4.2 mJy/beam Peak Peak flux density at 22GHz 38- 41 F4.2 mJy/beam e_Peak ? Peak flux density error at 22GHz 43- 46 F4.2 mJy Int ? Integrated flux density at 22GHz 48- 51 F4.2 mJy e_Int ? Integrated flux density error at 22GHz 53-105 A53 --- Name Known name(s) 107-114 A8 --- Type Object Type 116 I1 --- Refs [1/6]? References 118-122 A5 --- New [Y;H2O ] New radio detection? Y (yes) H2O (new maser) -------------------------------------------------------------------------------- Acknowledgements: Gisela Ortiz-Leon, gortiz(at)astro.unam.mx ================================================================================ (End) Patricia Vannier [CDS] 22-Jan-2023