J/ApJ/928/129 4.7GHz OH masers in northern star formation regions (Qiao+, 2022)
6cm OH masers in northern star formation regions.
Qiao H.-H., Shen Z.-Q., Breen S.L., Yang K., Chen Xi, Li J.
<Astrophys. J., 928, 129 (2022)>
=2022ApJ...928..129Q 2022ApJ...928..129Q
ADC_Keywords: Masers; Interstellar medium; Radio lines; Star Forming Region
Keywords: Interstellar medium
Abstract:
We have used the Shanghai Tianma Radio Telescope to search for three
OH transitions at 4.7GHz toward 155 northern star formation regions.
We detect 4.7GHz OH masers in 18 star formation regions, 8 of which
are reported here for the first time. From these 18 sources, we detect
6 4660MHz masers, 13 4765MHz masers, and no 4750MHz masers. A further
1 source (Sgr B2N) has been re-detected with broad quasi-thermal
emission in all three OH lines. W49SW was re-detected with broad
quasi-thermal emission at both 4660 and 4750MHz. One source (W31,
G010.626-0.387) was re-detected with quasi-thermal emission at both
4750 and 4765MHz. One source (G005.885-0.392) was first detected with
quasi-thermal emission at 4660MHz. We have investigated the
associations between the detected 4.7GHz OH masers with ground-state
OH masers near 1.7GHz, 6.7GHz methanol masers and 22GHz water masers
reported in the literature. We find that the presence of 1665MHz OH
masers is a better indicator of the presence of 4.7GHz OH masers than
1720MHz OH masers. The majority of the 4.7GHz OH masers are associated
with 6.7GHz methanol and/or 22GHz water masers. We have compared the
characteristics of our detections with those reported previously in
the literature and found that only five sources are fairly stable.
Description:
The observations were carried out in 2018 Jul 7-15, 2018 Sep 3-4 and
6-8, and 2019 April 3, 5, 9-10, and 16, with the 65m Shanghai Tianma
Radio Telescope (TMRT). The observations used a cryogenically cooled
receiver (frequency range of 4-8GHz).
We selected targets from sources showing 1665 and/or 1720MHz from the
ground-state OH maser catalog of Qiao+ (2014MNRAS.441.3137Q 2014MNRAS.441.3137Q).
We detected the 4.7GHz OH emission toward 20 sources: 7 sources show
the 4660 MHz emission (6 of them are masers), 3 sources show the
4750MHz emission (none are masers), and 15 sources show the 4765MHz
emission (13 of them are masers). The details of each source are
summarized in Table 2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 89 155 Sources searched for 4.7GHz OH masers
table2.dat 81 25 Star formation regions showing 4.7GHz OH emission
table3.dat 67 45 Fitted line parameters of the 4.7GHz OH emission
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See also:
VIII/96 : 6-GHz methanol multibeam maser catalogue (Caswell+, 2010-12)
J/A+AS/101/153 : Galactic H2O masers (Palagi+ 1993)
J/A+AS/120/283 : Water maser features in ultracompact HII reg. (Hofner+ 1996)
J/A+AS/137/43 : OH/H2O masers database (Forster+, 1999)
J/A+AS/143/269 : 6.7GHz methanol maser emission survey (Szymczak+, 2000)
J/A+A/414/235 : OH maser emission from star forming reg. (Szymczak+, 2004)
J/A+A/432/737 : General Cat. of 6.7GHz Methanol Masers (Pestalozzi+, 2005)
J/A+A/465/865 : OH masers towards protostellar objects (Edris+, 2007)
J/MNRAS/442/2240 : Accurate water maser positions from HOPS (Walsh+, 2014)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Name Target name (GLLL.lll+BB.bbb)
17- 18 I2 h RAh Hour of right ascension (J2000)
20- 21 I2 min RAm Minute of right ascension (J2000)
23- 26 F4.1 s RAs Second of right ascension (J2000)
28 A1 --- DE- Sign of declination (J2000)
29- 30 I2 deg DEd Degree of declination (J2000)
32- 33 I2 arcmin DEm Arcminute of declination (J2000)
35- 36 I2 arcsec DEs Arcsecond of declination (J2000)
38- 40 A3 --- Epoch Epoch(s) of observation (1)
42 A1 --- f_Epoch Flag on Epoch (2)
44- 67 A24 MHz PrevDet Transition(s) previously detected
69- 76 A8 --- OName Other name
78- 89 A12 --- Ref Reference (3)
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Note (1): Epoch of observation as follows:
a = 2018 July 7-15,
b = 2018 September 3-4 and 6-8,
c = 2019 April 3, 5, 9-10 and 16
Note (2): Flag as follows:
b = The 4.7GHz OH transitions of G024.505-0.046 were observed in epoch b
and the 6.0GHz OH transitions of G024.505-0.046 were observed in epoch c.
Note (3): Reference as follows:
A2000 = Argon et al. 2000ApJS..129..159A 2000ApJS..129..159A
C98 = Caswell 1998MNRAS.297..215C 1998MNRAS.297..215C
C99 = Caswell 1999MNRAS.308..683C 1999MNRAS.308..683C
C2004 = Caswell 2004MNRAS.349...99C 2004MNRAS.349...99C
CBJ88 = Cohen et al. 1988MNRAS.231..205C 1988MNRAS.231..205C
EF2007 = Edris et al. 2007A&A...465..865E 2007A&A...465..865E
FC99 = Forster & Caswell 1999, J/A+AS/137/43
SG2004 = Szymczak & Gerard 2004, J/A+A/414/235
B74 = Baudry 1974A&A....33..381B 1974A&A....33..381B
CM91 = Cohen et al. 1991MNRAS.250..611C 1991MNRAS.250..611C
DE2002 = Dodson & Ellingsen 2002MNRAS.333..307D 2002MNRAS.333..307D
GM1983 = Gardner & Martin-Pintado 1983A&A...121..265G 1983A&A...121..265G
PG2004 = Palmer et al. 2004MNRAS.347.1164P 2004MNRAS.347.1164P
SC2005 = Harvey-Smith & Cohen 2005MNRAS.356..637H 2005MNRAS.356..637H
SK2000 = Szymczak et al. 2000MNRAS.312..211S 2000MNRAS.312..211S
S2003 = Smits 2003MNRAS.339....1S 2003MNRAS.339....1S
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Name Target name (GLLL.lll+BB.bbb)
17- 20 I4 MHz Freq [4660/4765] Frequency of the detection
22 A1 --- f_Freq Flag on Freq (1)
24- 32 A9 "Y/M/D" Date Date of observation (UT)
34- 38 F5.1 km/s DelV1 [-62.4/110.7] Lower velocity range of
OH emission
40- 44 F5.1 km/s DelV2 [-61.9/111.5] Upper velocity range of
OH emission
46- 50 F5.1 km/s Vpk [-62.1/111.1] Peak velocity of the maser
emission (2)
52- 55 F4.1 Jy Spk [0.2/44.5] Peak flux density (3)
57- 64 A8 --- OName Other name
66- 71 A6 --- Ref OH maser emission reference (4)
73 A1 --- f_Ref Flag on Ref (1)
75- 81 A7 --- Other Maser species
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Note (1): Flag as follows:
a = Quasi-thermal emission superimposed with maser emission.
b = Quasi-thermal emission only.
c = The quasi-thermal emission of G043.148+0.013 at 4660MHz was detected by
Gardner & Martin-Pintado (1983), and the maser
emission at 4660MHz is a new detection.
Note (2): The peak velocity of the maser emission or of the OH quasi-thermal
emission at the brightest channel.
Note (3): The peak flux density, which is the flux density of the brightest
channel.
Note (4): Reference as follows:
GM83 = Gardner & Martin-Pintado 1983A&A...121..265G 1983A&A...121..265G
CM91 = Cohen et al. 1991MNRAS.250..611C 1991MNRAS.250..611C
DE2002 = Dodson & Ellingsen 2002MNRAS.333..307D 2002MNRAS.333..307D
SC2005 = Harvey-Smith & Cohen 2005MNRAS.356..637H 2005MNRAS.356..637H
PG2004 = Palmer et al. 2004MNRAS.347.1164P 2004MNRAS.347.1164P
N = New
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Name Target name (GLLL.lll+BB.bbb)
17- 20 I4 MHz Freq [4660/4765] Frequency of the OH transition
22 A1 --- f_Freq Flag on Freq (1)
24- 29 F6.2 km/s Vlsr [-62.2/111.2] Peak velocity of the fitted
spectral component
31- 34 F4.2 km/s e_Vlsr [0/0.7] Vlsr uncertainty
36- 40 F5.2 km/s delV [0.19/21.5] FWHM line width
42- 45 F4.2 km/s e_delV [0/2] delV uncertainty
47- 51 F5.2 Jy.km/s S [0.09/14.3] Integrated flux density
53- 56 F4.2 Jy.km/s e_S [0.01/0.4] S uncertainty
58- 62 F5.2 Jy Spk [0.15/48.2] Peak flux density of the fitted
spectral feature
64- 67 F4.2 Jy sigma [0.04/0.15]? 1σ level of each spectrum
before smoothing
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Note (1): Flag as follows:
a = Quasi-thermal emission with fitted peak flux density larger than 3σ
calculated with the original velocity resolution.
b = Quasi-thermal emission with fitted peak flux density larger than 3σ
calculated with the velocity resolution after smoothing (the argument of
smoothing is hanning, i.e., the new spectrum has twice less channels and
twice less resolution after smoothing once) the spectrum once.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 23-Feb-2024