J/A+A/675/A112 ATLASGAL. 3mm class I masers (Yang+, 2023)
ATLASGAL: 3-mm class I methanol masers in high-mass star formation regions.
Yang W., Gong Y., Menten K.M., Urquhart J.S., Henkel C., Wyrowski F.,
Csengeri T., Ellingsen S.P., Bemis A.R., Jang J.
<Astron. Astrophys. 675, A112 (2023)>
=2023A&A...675A.112Y 2023A&A...675A.112Y (SIMBAD/NED BibCode)
ADC_Keywords: Masers ; Radio lines; Radio sources
Keywords: masers - star: formation - ISM: molecules - radio lines: ISM
Abstract:
Class I methanol masers are known to be associated with shocked
outflow regions around massive protostars, indicating a possible link
between the maser properties and those of their host clumps.
The main goals of this study are (1) to search for new class I
methanol masers, (2) to statistically study the relationship between
class I masers and shock tracers, (3) to compare the properties
between class I masers and their host clumps, also as a function of
their evolutionary stage, and (4) to constrain the physical conditions
that excite multiple class I masers simultaneously.
We analysed the 3mm wavelength spectral line survey of 408 clumps
identified by the APEX Telescope Large Area Survey of the Galaxy
(ATLASGAL), which were observed with the IRAM 30-meter telescope,
focusing on the class I methanol masers with frequencies near 84, 95,
and 104.3GHz.
We detect narrow maser-like features towards 54, 100, and 4 sources in
the maser lines near 84, 95, and 104.3GHz, respectively. Among them,
50 masers at 84GHz, 29 masers at 95GHz, and 4 rare masers at 104.3GHz
are new discoveries. The new detections increase the number of known
104.3GHz masers from five to nine. The 95 GHz class I methanol maser
is generally stronger than the 84 GHz maser counterpart. We find nine
sources showing class I methanol masers, but no SiO emission,
indicating that class I methanol masers might be the only signpost of
protostellar outflow activity in extremely embedded objects at the
earliest evolutionary stage. Class I methanol masers that are
associated with sources that show SiO line wings are more numerous and
stronger than those without such wings. The total integrated intensity
of class I methanol masers is well correlated with the integrated
intensity and velocity coverage of the SiO (2-1) emission. The
properties of class I methanol masers are positively correlated with
the bolometric luminosity, clump mass, and peak H_2 column density of
their associated clumps, but are uncorrelated with the
luminosity-to-mass ratio, dust temperature, and mean H2 volume
density.
We suggest that the properties of class I masers are related to shocks
traced by SiO. Based on our observations, we conclude that class I
methanol masers at 84 and 95GHz can trace a similar evolutionary
stage to the H_2O maser, and appear prior to 6.7 and 12.2GHz methanol
and OH masers. Despite their small number, the 104.3GHz class I
masers appear to trace a shorter and more evolved stage compared to
the other class I masers.
Description:
Source information and class I methanol maser detection results for
the 408 ATLASGAL clumps.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 133 408 Summary of observed ATLASGAL sources
table3.dat 18 408 Overview of the class I methanol maser detections
table4.dat 79 741 Observational results of class I methanol transitions
--------------------------------------------------------------------------------
See also:
J/A+A/586/A149 : ATLASGAL II. Evolutionary stages and SiO emission
(Csengeri+, 2016)
J/MNRAS/473/1059 : Complete sample of Galactic clumps (Urquhart+, 2018)
J/MNRAS/510/3389 : ATLASGAL - evolutionary trends (Urquhart+, 2022)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Source Source name
14 A1 --- f_Source [d] Flags the sources with a nearby
observed target within 30 arcsec
16- 17 I2 h RAh Right Ascension (J2000)
19- 20 I2 min RAm Right Ascension (J2000)
22- 26 F5.2 s RAs Right Ascension (J2000)
28 A1 --- DE- Declination sign (J2000)
29- 30 I2 deg DEd Declination (J2000)
32- 33 I2 arcmin DEm Declination (J2000)
35- 38 F4.1 arcsec DEs Declination (J2000)
40- 57 A18 --- AGAL ? ATLASGAL CSC name
59- 63 F5.1 km/s VLSR ?=- Radial velocity
65- 68 F4.1 kpc Dist ?=- Distance
70- 72 F3.1 kpc RGC ?=- Galactocentric distance
74- 89 A16 --- EvolType Star formation evolutionary stage
91- 94 F4.1 K Tdust ?=- Dust temperature
96-101 F6.3 [Lsun] logLbol ?=- Log of bolometric luminosity
103-108 F6.3 [Msun] logMFWHM ?=- Log of the FWHM mass
110-115 F6.3 [cm-2] logNH2 ?=- log of H2 column density
117-121 F5.3 [cm-3] lognH2 ?=- H2 volume density
123-129 F7.2 Lsun/Msun Lbol/MFWHM ?=- Bolometric luminosity to FWHM mass
ratio
131 A1 --- SiO(2-1) [Y-] SiO (2-1) detection?
133 A1 --- SiO(5-4) [Y-] SiO (5-4) detection?
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Source Source name
14 A1 --- Det84 [YyN-] 84 GHz maser detection? (1)
16 A1 --- Det95 [YyN] 95 GHz maser detection? (1)
18 A1 --- Det104.3 [YyN-] 104.3 GHz maser detection? (1)
--------------------------------------------------------------------------------
Note (1): Flag as follows:
Y = indicates a maser detection
y = indicates a maser candidate
N = indicates a non-detection
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Source Source name
14- 18 F5.1 GHz Line Frequecy of maser transition
20- 25 F6.2 km/s Vpk Peak velocity
27- 30 F4.2 km/s e_Vpk Uncertainty in peak velocity
32- 36 F5.2 km/s deltaV FWHM line width
38- 41 F4.2 km/s e_deltaV Uncertainty in FWHM line width
43- 47 F5.2 Jy Spk Peak flux density
49- 52 F4.2 Jy e_Spk Uncertainty in peak flux density
54- 59 F6.2 Jy.km/s S Integrated flux density
61- 64 F4.2 Jy.km/s e_S Uncertainty in integrated flux density
66- 71 F6.2 Jy.km/s Sint ? Total integrated flux density
73- 79 E7.1 Lsun LCH3OH ?=- Isotropic luminosity of methanol emission
--------------------------------------------------------------------------------
Acknowledgements:
Wenjin Yang, wjyang(at)mpifr-bonn.mpg.de
(End) Patricia Vannier [CDS] 10-Jun-2023