J/A+A/661/A114 Periodic flares in two 6.7GHz methanol masers (Olech+, 2022)
Detection of periodic flares in 6.7 GHz methanol masers G45.804-0.356 and
G49.043-1.079.
Olech M., Durjasz M., Szymczak M., Bartkiewicz A.
<Astron. Astrophys. 661, A114 (2022)>
=2022A&A...661A.114O 2022A&A...661A.114O (SIMBAD/NED BibCode)
ADC_Keywords: Masers ; Radio lines
Keywords: masers - stars: formation - ISM: clouds - radio lines: ISM
Abstract:
Periodicity in the 6.7GHz methanol maser sources is a rare phenomenon
discovered during long-term monitoring programs. Understanding
underlying processes leading to periodic variability might give
insight of the physical processes in high-mass starforming regions.
We aim to identify and describe new periodic methanol masers.
The observations were obtained with the Torun 32m antenna. Analysis of
time series was conducted using well-proven statistical methods.
Additionally, NEOWISE data were used to search for infra-red and maser
fluxes correlation.
We found two new periodic sources: G45.804-0.356 and G49.043-1.079
with periods of 416.9 and 469.3 days, respectively. For
G49.043-1.079, infra-red variability is simultaneous with methanol
flares.
A most likely cause of periodicity in G49.043-1.079 is modulated
accretion, while for G45.804-0.356 cannot be explained with the
available data and further research is needed.
Description:
Both targets were observed with the Torun 32 m antenna as part of an
ongoing long-term monitoring programme of methanol maser sources
(Szymczak et al., 2018MNRAS.474..219S 2018MNRAS.474..219S, Cat. J/MNRAS/474/219).
G45.804-0.356 (RA = 19 16 31.08, Dec = 11 16 12.0 (J2000))
was observed from June 2009 to October 2021, with a cadence of 1.8
observations per month.
monthFor G49.043-1.079 (RA = 19 25 22.20, Dec = 13 47 19.5 (J2000)),
monitoring started in April 2016 and ended in November 2021, with a
cadence of 2.4 observations per month. Coordinates used for the
observations were taken from Breen et al. (2015MNRAS.450.4109B 2015MNRAS.450.4109B).
Integrated flux timeseries of 7 spectral features are presented. Two
features from source G45.804-0.356 and five from G49.043-1.079.
For each time of observation in MJD, integrated flux measurement and
RMS error is presented.
Objects:
-----------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------
19 16 31 +11 16 11 G45.804-0.356
19 25 22 +13 47 19 G49.043-1.079
-----------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig3a.dat 45 285 Timeseries for source G45.804-0.356
fig3b.dat 93 177 Timeseries for source G49.043-1.079
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Byte-by-byte Description of file: fig3a.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 d MJD Time of observation
17- 21 F5.3 Jy.km/s F59.94 Integrated flux of feature 59.94km/s
25- 29 F5.3 Jy.km/s e_F59.94 RMS error of integrated flux measurement
of feature 59.94km/s
33- 37 F5.3 Jy.km/s F69.29 Integrated flux of feature 69.29km/s
41- 45 F5.3 Jy.km/s e_F69.29 RMS error of integrated flux measurement
of feature 59.94km/s
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Byte-by-byte Description of file: fig3b.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 d MJD Time of observation
16- 21 F6.3 Jy.km/s F35.60 Integrated flux of feature 35.60km/s
25- 29 F5.3 Jy.km/s e_F35.60 RMS error of integrated flux measurement
of feature 35.60km/s
33- 38 F6.3 Jy.km/s F37.01 Integrated flux of feature 37.01km/s
41- 45 F5.3 Jy.km/s e_F37.01 RMS error of integrated flux measurement
of feature 37.01km/s
49- 53 F5.3 Jy.km/s F38.41 Integrated flux of feature 38.41km/s
57- 61 F5.3 Jy.km/s e_F38.41 RMS error of integrated flux measurement
of feature 38.41km/s
64- 69 F6.3 Jy.km/s F39.25 Integrated flux of feature 39.25km/s
73- 77 F5.3 Jy.km/s e_F39.25 RMS error of integrated flux measurement
of feature 39.25km/s
81- 85 F5.3 Jy.km/s F40.83 Integrated flux of feature 40.83km/s
89- 93 F5.3 Jy.km/s e_F40.83 RMS error of integrated flux measurement
of feature 40.83km/s
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Acknowledgements:
Mateusz Olech, mateusz.olech(at)uwm.edu.pl
(End) Patricia Vannier [CDS] 16-Mar-2022