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.
<Astron. J., 162, 68-68 (2021)>
=2021AJ....162...68O 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, 61,6-52,3 H2O 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 H2O
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 H2O 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 H2O masers and 162 young stellar objects
covered by our observations, we identify a limit of LBol~=10L☉
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 H2O 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:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 122 78 Properties of the VLA Detected Radio Continuum
Sources
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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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)
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Acknowledgements:
Gisela Ortiz-Leon, gortiz(at)astro.unam.mx
(End) Patricia Vannier [CDS] 22-Jan-2023