J/ApJ/884/140 VLA obs. of the H2O maser source G25.65+1.05 (Bayandina+, 2019)
VLA overview of the bursting H2O maser source G25.65+1.05.
Bayandina O.S., Burns R.A., Kurtz S.E., Shakhvorostova N.N., Val'tts I.E.
<Astrophys. J., 884, 140 (2019)>
=2019ApJ...884..140B 2019ApJ...884..140B
ADC_Keywords: Masers; Star Forming Region; Radio lines
Keywords: evolution ; masers
Abstract:
The source G25.65+1.05 (RAFGL7009S, IRAS 18316-0602) is the least
studied of the three regions of massive star formation known to show
exceptionally powerful H2O maser bursts. We report spectral line
observations of the H2O maser at 22GHz, the methanol maser
transitions at 6.7, 12.2, and 44GHz, and the continuum in these same
frequency bands with The Karl G. Jansky Very Large Array at the
post-burst epoch of 2017. For the first time, maps of 22GHz H2O and
44GHz CH3OH maser spots are obtained and the absolute position of
the 22GHz H2O bursting feature is determined with milliarcsecond
precision. We detected four continuum components, three of which are
closely spaced in a linear orientation, suggesting a physical link
between them.
Description:
Observations were carried out in two sessions on 2017 November 2 and
December 9 with the Jansky Very Large Array (VLA, NRAO) in the B
configuration as a Target of Opportunity program (project code 17B-408).
The total observing time was 2hr. Four frequency bands were used:
C (6GHz), Ku (15GHz), K (22GHz), and Q (45GHz).
These VLA observations of G25.65+1.05 were conducted during the
post-burst period: Q-band observations were performed on 2017 November 2.
C-, Ku-, and K-band observations were performed on 2017 December 9;
following the H2O maser burst of 2017 September.
The reference single-dish spectra for 6.7GHz methanol and 22GHz H2O
masers were obtained with the Torun 32m telescope (RT-32 of the Torun
Centre for Astronomy of Nicolaus Copernicus University), the HartRAO
26m telescope (RT-26 of Hartebeesthoek Radio Astronomy Observatory),
and the Simeiz 22m telescope (RT-22 of Crimean Astrophysical
Observatory) on the epoch of VLA observations on 2017 December 6-9.
For the 44GHz methanol maser, only archival data from the literature
are available (Fontani+ 2010A&A...517A..56F 2010A&A...517A..56F). See Section 3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 55 210 22GHz H2O maser parameters
table4.dat 54 78 6.7GHz CH3OH maser parameters
table5.dat 53 27 44GHz CH3OH maser parameters
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See also:
J/A+AS/103/541 : Arcetri Catalogue of H2O Maser Sources (Brand+ 1994)
J/ApJS/91/659 : Ultracompact HII regions radio images (Kurtz+ 1994)
J/A+AS/110/81 : Methanol masers towards IRAS sources (van der Walt+ 1995)
J/A+AS/115/81 : A CS(2-1) survey of UC HII regions (Bronfman+, 1996)
J/A+A/308/573 : Ammonia on YSOs IRAS sources (Molinari+ 1996)
J/MNRAS/291/261 : Methanol maser of IRAS-selected sources (Walsh+ 1997)
J/MNRAS/301/640 : Ultracompact H II regions studies. II. (Walsh+, 1998)
J/A+AS/134/115 : Medicina 6.7GHz methanol masers survey (Slysh+ 1999)
J/A+AS/143/269 : 6.7GHz methanol maser emission survey (Szymczak+, 2000)
J/A+A/394/225 : JHK photometry around RAFGL 7009S (Zavagno+, 2002)
J/A+A/453/1003 : SCUBA ultracompact HII regions (Thompson+, 2006)
J/PASJ/59/1185 : Water maser in galactic IRAS sources (Sunada+, 2007)
J/ApJ/717/L133 : Formaldehyde maser flares in IRAS 18566+0408 (Araya+, 2010)
J/MNRAS/404/661 : Young stellar outflows near-IR imaging (Varricatt+ 2010)
J/ApJS/194/29 : Observations of blazars at 15GHz (Richards+, 2011)
J/A+A/557/A94 : SiO & HCO+ massive molecular outflows (Sanchez-Monge+, 2013)
J/A+A/578/A102 : 6.7GHz methanol maser polarization in SFR (Surcis+, 2015)
J/ApJ/833/18 : Ultra-compact HII regions & methanol masers. I. (Hu+, 2016)
J/ApJ/866/87 : VLA 22GHz water masers obs. in NGC6334I-MM1 (Brogan+, 2018)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh [18] Hour of Right Ascension (J2000)
4- 5 I2 min RAm [34] Minute of Right Ascension (J2000)
7- 13 F7.4 s RAs [20.8/21] Second of Right Ascension (J2000)
15- 21 F7.5 s e_RAs [4e-05/0.0011] Uncertainty in RAs
23 A1 --- DE- [-] Sign of the Declination (J2000)
24 I1 deg DEd [5] Degree of Declination (J2000)
26- 27 I2 arcmin DEm [59] Arcminute of Declination (J2000)
29- 34 F6.3 arcsec DEs [41.5/42.6] Arcsecond of Declination (J2000)
36- 40 F5.3 arcsec e_DEs [0.001/0.017] Uncertainty in DEs
42- 46 F5.2 km/s Vel [36.29/55] Velocity
48- 52 F5.3 --- Amp [0.001/1] Normalized Flux Density (1)
54- 55 A2 --- Group Group name (2)
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Note (1): The flux densities are normalized to the strongest maser channel,
see Section 3. Single-dish flux density of 22GHz H2O maser in the
source was ∼9.8kJy on the dates close to VLA observation
(Maser Monitoring Organization (M2O) data:
Torun 32-m and Crimea 22-m telescopes).
Note (2): Conditional large-scale grouping of 22GHz H2O maser spots.
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh [18] Hour of Right Ascension (J2000)
4- 5 I2 min RAm [34] Minute of Right Ascension (J2000)
7- 13 F7.4 s RAs [20.9/21] Second of Right Ascension (J2000)
15- 20 F6.4 s e_RAs [0.0001/0.001] Uncertainty in RAs
22 A1 --- DE- [-] Sign of the Declination (J2000)
23 I1 deg DEd [5] Degree of Declination (J2000)
25- 26 I2 arcmin DEm [59] Arcminute of Declination (J2000)
28- 33 F6.3 arcsec DEs [42.1/42.6] Arcsecond of Declination (J2000)
35- 39 F5.3 arcsec e_DEs [0.002/0.03] Uncertainty in DEs
41- 45 F5.2 km/s Vel [38.4/43.1] Velocity
47- 51 F5.3 --- Amp [0.002/1] Normalized Flux Density (1)
53- 54 A2 --- Group Group name (2)
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Note (1): The flux densities are normalized to the strongest maser channel,
see Section 3. Single-dish flux density of 6.7GHz CH3OH maser in
the source was ∼170Jy on the dates close to VLA observation (M2O
data: Torun 32-m and HartRAO 26-m telescopes).
Note (2): Conditional large-scale grouping of 6.7GHz CH3OH maser spots
detected in the field.
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh [18] Hour of Right Ascension (J2000)
4- 5 I2 min RAm [34] Minute of Right Ascension (J2000)
7- 13 F7.4 s RAs [20.5/21.1] Second of Right Ascension (J2000)
15- 20 F6.4 s e_RAs [0.0002/0.0009] Uncertainty in RAs
22 A1 --- DE- [-] Sign of the Declination (J2000)
23 I1 deg DEd [5] Degree of Declination (J2000)
25- 26 I2 arcmin DEm [59] Arcminute of Declination (J2000)
28- 33 F6.3 arcsec DEs [39.9/43.4] Arcsecond of Declination (J2000)
35- 39 F5.3 arcsec e_DEs [0.004/0.02] Uncertainty in DEs
41- 45 F5.2 km/s Vel [41.2/44] Velocity
47- 50 F4.2 --- Amp [0.03/1] Normalized Flux Density (1)
52- 53 A2 --- Group Group name (2)
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Note (1): The flux densities are normalized to the strongest maser channel,
see Section 3. Single-dish flux density of 44GHz CH3OH maser in
the source is ∼10Jy according to data from literature
(Fontani+ 2010A&A...517...56F 2010A&A...517...56F).
Note (2): Conditional large-scale grouping of 44GHz CH3OH maser spots detected
in the field, spots are labeled according to their velocity: "B1"
and "B2" - blue spots, "G" - green, and "R" - red.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 25-Mar-2021