J/ApJS/256/7 18cm OH masers VLA obs. toward 80 SFRs (Bayandina+, 2021)
Search for collisionally pumped 1720MHz OH masers in star-forming regions:
a VLA survey of 18cm OH masers toward 80 class I methanol masers.
Bayandina O.S., Val'tts I.E., Kurtz S.E., Shakhvorostova N.N.
<Astrophys. J. Suppl. Ser., 256, 7-7 (2021)>
=2021ApJS..256....7B 2021ApJS..256....7B (SIMBAD/NED BibCode)
ADC_Keywords: Star Forming Region; Masers; Radio continuum
Keywords: Star-forming regions; Hydroxyl masers; Astrophysical masers
Very Large Array; Shocks; Surveys
Abstract:
Class I methanol masers (cIMMs) and 1720MHz OH masers are believed to
arise from a common collisional pumping mechanism, and both trace
shocked gas regions in supernova remnants (SNRs). However, their
coexistence in star formation regions (SFRs) and their association
with a front of bipolar outflow (a source of shock-stimulated
collisional pumping) remain unclear. To search for collisionally
pumped OH(1720) masers, we conducted a Very Large Array survey of the
18cm OH masers and continuum emission toward a sample of 80 SFRs
associated with 44GHz cIMMs. Main-line OH maser emission was detected
in 50% of the sample, and OH(1720) maser emission was detected in 20%.
Continuum emission was detected in 28% of sources. A catalog of the
detected OH masers is presented. Individual OH masers are found in
close proximity, and the regions of masers of different transitions
are often overlapping. A typical linear projected offset between the
OH(1720) and OH(1665) masers is ∼0.04pc. A remarkable number of ∼81%
of the OH(1720) masers are associated with the continuum emission. The
median separation between the targeted 44GHz cIMMs and OH(1720) masers
is ∼0.2pc, which is similar to reported distances between cIMMs and
HII regions. The observed properties of the detected OH(1720) masers
are different from those in SNRs and indicate that a nonlocal line
overlap mechanism is responsible for their excitation. Thus, while
both 44GHz cIMMs and OH(1720) masers trace shocked gas in SNRs,
physical conditions favorable for excitation of cIMMs, but not
OH(1720) masers, are present in SFRs.
Description:
The catalog of Class I methanol masers (cIMMs;
Bayandina+ 2012, J/AZh/89/611) was used as the basis of our sample.
The catalog contains 206 cIMMs detected toward known star formation
regions (SFRs). Most of the sources were detected at 44GHz in
single-dish observations with a beam of ∼2'.
The observations were conducted with the VLA of the National Radio
Astronomy Observatory. The array was in its C-configuration, and the
observations were performed during 2013 July-August under project
code 13A-406.
Using L band, we simultaneously observed the continuum at 1000-2000MHz
and OH maser emission from the four ground-state transitions at
1612.231, 1665.402, 1667.359, and 1720.53MHz.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 116 80 Observed source list
table2.dat 90 807 OH maser parameters
table3.dat 100 22 Parameters of 20cm continuum emission associated
with OH masers
table4.dat 239 16 Separation between a 20cm continuum source and
other objects
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See also:
J/A+AS/98/589 : IRAS Sources behind the Solar circle (Wouterloot+ 1993)
J/A+A/336/339 : VLA observations of ultracompact HII regions (Molinari+ 1998)
J/A+AS/137/43 : OH/H2O masers database (Forster+, 1999)
J/A+A/414/235 : OH maser emission from star forming regions (Szymczak+, 2004)
J/A+A/426/503 : High velocity molecular outflows (Update) (Wu+ 2004)
J/ApJS/155/149 : CH3OH 70-61 A+ maser sources (Kurtz+, 2004)
J/ApJS/160/220 : Full-polarization observations of OH masers (Fish+, 2005)
J/A+A/430/941 : Star formation region NGC 6530 (Prisinzano+, 2005)
J/A+A/465/865 : OH masers towards high mass protostellar object (Edris+, 2007)
J/AJ/136/2391 : GLIMPSE Extended Green Objects catalog (Cyganowski+, 2008)
J/ApJ/702/1615 : CH3OH maser survey of EGOs (Cyganowski+, 2009)
J/ApJ/720/1055 : VBLA observations of W51 Main/South (Sato+, 2010)
J/AZh/89/611 : Class I methanol maser catalog (Bayandina+, 2012)
J/A+A/628/A90 : OH maser emission in THOR survey (Beuther+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Name Source name
17- 37 A21 --- OName Alias(es)
39- 40 I2 h RAh Hour of Right Ascension (J2000)
42- 43 I2 min RAm Minute of Right Ascension (J2000)
45- 48 F4.1 s RAs Second of Right Ascension (J2000)
50- 50 A1 --- DE- Sign of the Declination (J2000)
51- 52 I2 deg DEd Degree of Declination (J2000)
54- 55 I2 arcmin DEm Arcminute of Declination (J2000)
57- 60 F4.1 arcsec DEs Arcsecond of Declination (J2000)
62- 67 F6.1 km/s Vlsr [-58/115] Median velocity, local standard
of rest
69- 69 A1 --- d1612 [±] Detection at 1612 MHz?
71- 71 A1 --- d1665 [±] Detection at 1665 MHz?
73- 73 A1 --- d1667 [±] Detection at 1667 MHz?
75- 75 A1 --- d1720 [±] Detection at 1720 MHz?
77- 81 F5.2 arcsec amajOH [11.2/46] OH synthetic beam, major axis
83- 87 F5.2 arcsec bminOH [10.2/17.6] OH synthetic beam, minor axis
89- 94 F6.2 deg PAOH [-90/88] OH beam, position angle
96- 96 A1 --- d1.5GHz [±] Detection at 1.5 GHz?
98-102 F5.2 arcsec amajCont [10.4/48.1] Continuum synthetic beam,
major axis
104-108 F5.2 arcsec bminCont [8/16.8] Continuum synthetic beam, minor axis
110-116 F7.2 deg PACont [-179/91] Continuum beam, position angle
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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 Source name
17- 20 I4 MHz Freq [1612/1720] Frequency
22- 22 A1 --- Pol [LR] Polarisation
24- 25 I2 h RAh Hour of Right Ascension (J2000)
27- 28 I2 min RAm Minute of Right Ascension (J2000)
30- 35 F6.3 s RAs Second of Right Ascension (J2000)
37- 41 F5.3 s e_RAs Uncertainty in RAs
43- 43 A1 --- DE- Sign of the Declination (J2000)
44- 45 I2 deg DEd Degree of Declination (J2000)
47- 48 I2 arcmin DEm Arcminute of Declination (J2000)
50- 54 F5.2 arcsec DEs Arcsecond of Declination (J2000)
56- 59 F4.2 arcsec e_DEs Uncertainty in DEs
61- 66 F6.2 Jy Int [0.09/389] Integrated Flux
68- 71 F4.2 Jy e_Int [0.01/7] Uncertainty in Int
73- 78 F6.2 Jy/beam Flux [0.1/387] Peak Flux
80- 83 F4.2 Jy/beam e_Flux [0.01/4] Uncertainty in Flux
85- 90 F6.2 km/s Vel [-60.3/114.3] Velocity
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Name Source name
17- 18 I2 h RAh Hour of Right Ascension (J2000)
20- 21 I2 min RAm Minute of Right Ascension (J2000)
23- 28 F6.3 s RAs Second of Right Ascension (J2000)
30- 34 F5.3 s e_RAs ? Uncertainty in RAs
36- 36 A1 --- DE- Sign of the Declination (J2000)
37- 38 I2 deg DEd Degree of Declination (J2000)
40- 41 I2 arcmin DEm Arcminute of Declination (J2000)
43- 47 F5.2 arcsec DEs Arcsecond of Declination (J2000)
49- 52 F4.2 arcsec e_DEs ? Uncertainty in DEs
54- 57 F4.1 arcsec amaj [15.6/85]? Size, semi-major axis
59- 62 F4.1 arcsec e_amaj [0.4/11.1]? Uncertainty in amaj
64- 67 F4.1 arcsec bmin [10.6/65]? Size, semi-minor axis
69- 71 F3.1 arcsec e_bmin [0.4/7]? Uncertainty in bmin
73- 75 I3 deg PA [55/167]? Position angle
77- 78 I2 deg e_PA [2/45]? Uncertainty in PA
80- 83 F4.2 Jy Int [0.01/5.1] Integrated Flux
85- 89 F5.3 Jy e_Int [0.001/0.09]? Uncertainty in Int
91- 94 F4.2 Jy/beam Flux [0.01/1.3] Peak Flux in units of Jy/beam
96-100 F5.3 Jy/beam e_Flux [0.001/0.01]? Uncertainty in Flux
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Name Source name
17- 18 I2 h RA20h ? Hour of Right Ascension,
20cm cont. (J2000) (1)
20- 21 I2 min RA20m ? Minute of Right Ascension,
20cm cont. (J2000) (1)
23- 28 F6.3 s RA20s ? Second of Right Ascension,
20cm cont. (J2000) (1)
30- 30 A1 --- DE20- Sign of the Declination,
20cm cont. (J2000)(1)
31- 32 I2 deg DE20d ? Degree of Declination,
20cm cont. (J2000) (1)
34- 35 I2 arcmin DE20m ? Arcminute of Declination,
20cm cont. (J2000) (1)
37- 41 F5.2 arcsec DE20s ? Arcsecond of Declination,
20cm cont. (J2000) (1)
43- 44 I2 h RA12h ? Hour of Right Ascension,
OH(1612) (J2000) (1)
46- 47 I2 min RA12m ? Minute of Right Ascension,
OH(1612) (J2000) (1)
49- 54 F6.3 s RA12s ? Second of Right Ascension,
OH(1612) (J2000) (1)
56- 56 A1 --- DE12- Sign of the Declination, OH(1612) (J2000)(1)
57- 58 I2 deg DE12d ? Degree of Declination,
OH(1612) (J2000) (1)
60- 61 I2 arcmin DE12m ? Arcminute of Declination,
OH(1612) (J2000) (1)
63- 67 F5.2 arcsec DE12s ? Arcsecond of Declination,
OH(1612) (J2000) (1)
69- 70 I2 h RA65h ? Hour of Right Ascension,
OH(1665) (J2000) (1)
72- 73 I2 min RA65m ? Minute of Right Ascension,
OH(1665) (J2000) (1)
75- 80 F6.3 s RA65s ? Second of Right Ascension,
OH(1665) (J2000) (1)
82- 82 A1 --- DE65- Sign of the Declination, OH(1665) (J2000)(1)
83- 84 I2 deg DE65d ? Degree of Declination,
OH(1665) (J2000) (1)
86- 87 I2 arcmin DE65m ? Arcminute of Declination,
OH(1665) (J2000) (1)
89- 93 F5.2 arcsec DE65s ? Arcsecond of Declination,
OH(1665) (J2000) (1)
95- 96 I2 h RA67h ? Hour of Right Ascension,
OH(1667) (J2000) (1)
98- 99 I2 min RA67m ? Minute of Right Ascension,
OH(1667) (J2000) (1)
101-106 F6.3 s RA67s ? Second of Right Ascension,
OH(1667) (J2000) (1)
108-108 A1 --- DE67- Sign of the Declination,
OH(1667) (J2000)(1)
109-110 I2 deg DE67d ? Degree of Declination,
OH(1667) (J2000) (1)
112-113 I2 arcmin DE67m ? Arcminute of Declination,
OH(1667) (J2000) (1)
115-119 F5.2 arcsec DE67s ? Arcsecond of Declination,
OH(1667) (J2000) (1)
121-122 I2 h RAh Hour of Right Ascension,
OH(1720) (J2000) (1)
124-125 I2 min RAm Minute of Right Ascension,
OH(1720) (J2000) (1)
127-132 F6.3 s RAs Second of Right Ascension,
OH(1720) (J2000) (1)
134-134 A1 --- DE- Sign of the Declination,
OH(1720) (J2000) (1)
135-136 I2 deg DEd Degree of Declination, OH(1720) (J2000) (1)
138-139 I2 arcmin DEm Arcminute of Declination,
OH(1720) (J2000) (1)
141-145 F5.2 arcsec DEs Arcsecond of Declination,
OH(1720) (J2000) (1)
147-148 I2 h RAcIMMh Hour of Right Ascension, cIMM (J2000) (2)
150-151 I2 min RAcIMMm Minute of Right Ascension, cIMM (J2000) (2)
153-157 F5.2 s RAcIMMs Second of Right Ascension, cIMM (J2000) (2)
159-159 A1 --- DEcIMM- Sign of the Declination, cIMM (J2000)(2)
160-161 I2 deg DEcIMMd Degree of Declination, cIMM (J2000) (2)
163-164 I2 arcmin DEcIMMm Arcminute of Declination, cIMM (J2000) (2)
166-169 F4.1 arcsec DEcIMMs Arcsecond of Declination, cIMM (J2000) (2)
171-173 A3 --- Ref-cIMM Reference for Position 6, cIMM (2)
175-179 F5.2 arcsec Sep12 ? Separation, OH1612, arcseconds
181-185 F5.3 pc Sep12pc ? Separation, OH1612, parsecs
187-191 F5.2 arcsec Sep65 ? Separation, OH1665, arcseconds
193-196 F4.2 pc Sep65pc ? Separation, OH1665, parsecs
198-202 F5.2 arcsec Sep67 ? Separation, OH1667, arcseconds
204-208 F5.3 pc Sep67pc ? Separation, OH1667, parsecs
210-214 F5.2 arcsec Sep ? Separation, OH1720, arcseconds
216-219 F4.2 pc Seppc ? Separation, OH1720, parsecs
221-225 F5.2 arcsec SepcIMM ? Separation, cIMM, arcseconds
227-230 F4.2 pc SepcIMMpc ? Separation, cIMM, parsecs
232-236 F5.2 kpc Dist Distance
238-239 I2 --- r_Dist Reference for Dist (3)
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Note (1): Position of the brightest maser spot detected in this survey.
Note (2): Positions of the brightest cIMM spot as follows:
1 = Slysh et al. (1994MNRAS.268..464S 1994MNRAS.268..464S);
2 = Kurtz et al. (2004, J/ApJS/155/149);
3 = Gomez-Ruiz et al. (2016ApJS..222...18G 2016ApJS..222...18G);
4 = Gomez et al. (2010ApJS..191..207G 2010ApJS..191..207G);
5 = Haschick et al. (1990ApJ...354..556H 1990ApJ...354..556H);
* = Single-dish data;
** = No 44GHz masers were detected in this field in
Kurtz+ 2004, J/ApJS/155/149
Note (3): Information on distances as follows:
1 = Reid et al. (2016ApJ...823...77R 2016ApJ...823...77R), values calculated
with "Bayesian Distance Calculator";
2 = Motogi et al. (2011PASJ...63...31M 2011PASJ...63...31M);
3 = Prisinzano et al. (2005, J/A+A/430/941);
4 = Green & McClure-Griffiths (2011MNRAS.417.2500G 2011MNRAS.417.2500G);
5 = Zhang et al. (2013ApJ...775...79Z 2013ApJ...775...79Z);
6 = Sato et al. (2010, J/ApJ/720/1055);
7 = Xu et al. (2013ApJ...769...15X 2013ApJ...769...15X);
8 = Rygl et al. (2012A&A...539A..79R 2012A&A...539A..79R);
9 = Hirota et al. (2008PASJ...60..961H 2008PASJ...60..961H);
10 = Moscadelli et al. (2009ApJ...693..406M 2009ApJ...693..406M);
11 = Xu et al. (2006Sci...311...54X 2006Sci...311...54X);
12 = Fish et al. (2003ApJ...587..701F 2003ApJ...587..701F).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 28-Dec-2021