J/ApJS/263/9 Multiple maser transitions from G358.93-0.03 burst (Miao+, 2022)
New methanol maser transitions and maser variability identified from an
accretion burst source G358.93-0.03.
Miao D., Chen Xi, Song S.-M., Sobolev A.M., Breen S.L., MacLeod G.C., Li B.,
Parfenov S., Bisyarina A., Shen Z.-Q.
<Astrophys. J. Suppl. Ser., 263, 9 (2022)>
=2022ApJS..263....9M 2022ApJS..263....9M
ADC_Keywords: Masers; YSOs; Radio sources
Keywords: Interstellar masers ; Star formation ; Massive stars ;
Accretion ; Young stellar objects
Abstract:
The high-mass young stellar object G358.93-0.03 underwent an accretion
burst during the period from 2019 January to June. Given its
extraordinary conditions, a number of new maser transitions may have
been naturally excited during the burst stage. Searching for new maser
lines and monitoring maser variability associated with the accretion
burst event are important for understanding the complex conditions of
the massive star formation toward G358.93-0.03. In this work, using
the Shanghai 65m Tianma Radio Telescope, we continuously monitored the
multiple maser (including methanol and water) transitions toward
G358.93-0.03 during the burst in the period from 2019 March 14 to
May 20. There were 23 CH3OH maser transitions and one H2O maser
transition detected from the monitoring. Nearly all the detected maser
transitions toward this source have dramatic variations in their
intensities within a short period of ∼2 months. Eight new methanol
transitions from G358.93-0.03 were identified to be masering in our
observations based on their spectral profile, line width, intensity,
and the rotation diagram. During the monitoring, the gas temperature
of the clouds in the case of saturated masers can show a significant
decline, indicating that the maser clouds were going through a cooling
process, possibly associated with the propagation of a heat wave
induced by the accretion burst. Some of the maser transitions were
even detected with the second flares in 2019 April, which may be
associated with the process of the heat-wave propagation induced by
the same accretion burst acting on different maser positions.
Description:
The the Shanghai 65m Tianma Radio Telescope (TMRT) was used to
conduct monitoring observations of a series of molecular lines,
including masers, toward the flaring 6.7GHz maser, G358.93-0.03. These
observations began on 2019 March 14, and concluded on 2019 May 20,
with a number of epochs in order to sample the different phases of the
bursting source. We used the cryogenically cooled C-, Ku-, K-, Ka- and
Q-band receivers covering a frequency range of 4-50GHz.
Objects:
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RA (ICRS) DE Designation(s)
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17 43 10.10 -29 51 45.6 G358.93-0.03 = [BHT2019] G358.93-00.03 MM1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 72 368 Gaussian fit parameters of all transitions
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See also:
J/A+A/428/1019 : Rest frequencies of methanol maser lines (Mueller+, 2004)
J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)
J/ApJS/206/22 : Newly EGOs from GLIMPSE II survey. II. MoC (Chen+, 2013)
J/MNRAS/439/2584 : Southern methanol masers at 36 and 44GHz (Voronkov+, 2014)
J/ApJ/866/87 : VLA 22GHz water masers obs. in NGC6334I-MM1 (Brogan+, 2018)
J/ApJ/854/170 : Methanol (CH3OH) & OH masers in NGC 6334I (Hunter+, 2018)
J/A+A/664/A44 : G358.93-0.03 22GHz H2O maser parameters (Bayandina+, 2022)
J/AJ/163/83 : G358.93-0.03 6.67-23.12GHz CH3OH masers (Bayandina+, 2022)
J/ApJS/258/19 : CH3OH maser survey toward 6.7GHz masers (Song+, 2022)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 5 F5.2 GHz Freq [6.18/48.71] Adopted rest frequency of
maser transitions
7- 10 I4 yr Obs.Y Observation epoch, year (always "2019")
12- 13 I2 "month" Obs.M Observation epoch, numeric month
15- 16 I2 d Obs.D Observation epoch, day
18- 22 A5 --- Comp Velocity component (1)
24- 29 F6.2 km/s xc [-21.12/-12.61] Center velocity (1)
31- 34 F4.2 km/s e_xc [0.01/0.3] Uncertainty in xc
36- 42 F7.2 Jy.km/s A [0.13/1188.2] Integrated flux density (1)
44- 48 F5.2 Jy.km/s e_A [0.01/12.6] Uncertainty in A
50- 53 F4.2 km/s w [0.13/1.7] Linewidth (1)
55- 58 F4.2 km/s e_w [0.01/0.41] Uncertainty in w
60- 66 F7.2 Jy yc [0.18/2900.7] Peak flux density (1)
68- 72 F5.2 Jy e_yc [0.05/40.4] Uncertainty in yc
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Note (1): All parameters of a Gaussian fit to each component.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Nov-2022